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Comparing organic farming and land sparing: Optimizing yield and butterfly populations at a landscape scale
Ecology Letters
Abstract
Ecology Letters (2010) 13: 1358–1367
Organic farming aims to be wildlife-friendly, but it may not benefit wildlife overall if much greater areas are needed to produce a given quantity of food. We measured the density and species richness of butterflies on organic farms, conventional farms and grassland nature reserves in 16 landscapes. Organic farms supported a higher density of butterflies than conventional farms, but a lower density than reserves. Using our data, we predict the optimal land-use strategy to maintain yield whilst maximizing butterfly abundance under different scenarios. Farming conventionally and sparing land as nature reserves is better for butterflies when the organic yield per hectare falls below 87% of conventional yield. However, if the spared land is simply extra field margins, organic farming is optimal whenever organic yields are over 35% of conventional yields. The optimal balance of land sparing and wildlife-friendly farming to maintain production and biodiversity will differ between landscapes.
... Therefore, due to its lower yield, organic farming could reduce and even cancel out the positive effect on biodiversity gain when transferring from conventional farming by reducing natural land. Whether it is worthwhile to switch from conventional to organic farming in terms of the biodiversity gain and yield loss is under debate (Balmford et al., 2018;Hodgson et al., 2010;Phalan, Onial, et al., 2011;Tscharntke et al., 2012). ...
... The mean S c-o value is about 2.0 for the cereals, which indicates that organic farming is better if non-crop land has a biodiversity <2.0 times that of conventional farms. However, though there are rather few studies that have made this biodiversity comparison, semi-natural areas often exceed this biodiversity threshold, and even uncropped field margins may do so (Hodgson et al., 2010;Phalan, Onial, et al., 2011). Looking at the taxonomic breakdown for cereal crops, birds, microbes and invertebrates showed a low substitution index, indicating that it is easier for non-crop areas to exceed the threshold, whereas plants show a high substitution index. ...
... Beckmann et al., 2019), that is, to help the decision makers to address whether a less intensive farming system is more beneficial than an intensive one in terms of yield production and biodiversity conservation (Seppelt et al., 2020). The Biodiversity conservation and land-use intensification trade-off is also related to the 'land sparing' vs. 'land sharing' debate (Balmford et al., 2018;Godfray & Garnett, 2014;Hodgson et al., 2010;Phalan et al., 2016). In the 'land sparing' strategy, the agricultural land is intensively used for high yielding agriculture to leave as much land as possible for conserving high biodiversity in natural lands (Green et al., 2005;Ramankutty et al., 2018). ...
Organic farming supports higher biodiversity than conventional farming, but at the cost of lower yields. We conducted a meta‐analysis quantifying the trade‐off between biodiversity and yield, comparing conventional and organic farming. We developed a compatibility index to assess whether biodiversity gains from organic farming exceed yield losses, and a substitution index to assess whether organic farming would increase biodiversity in an area if maintaining total production under organic farming would require cultivating more land at the expense of nature. Overall, organic farming had 23% gain in biodiversity with a similar cost of yield decline. Biodiversity gain is negatively correlated to yield loss for microbes and plants, but no correlation was found for other taxa. The biodiversity and yield trade‐off varies under different contexts of organic farming. The overall compatibility index value was close to zero, with negative values for cereal crops, positive for non‐cereal crops, and varies across taxa. Our results indicate that, on average, the proportion of biodiversity gain is similar to the proportion of yield loss for paired field studies. For some taxa in non‐cereal crops, switching to organic farming can lead to a biodiversity gain without yield loss. We calculated the overall value of substitution index and further discussed the application of this index to evaluate when the biodiversity of less intensified farming system is advantageous.
... El modelo convergente o land-sharing, argumenta que la agricultura alternativa, diversa y agroecológica, también denominada orgánica o amigable con el ambiente (Hodgson, Kunin, Thomas, Benton, & Gabriel, 2010) puede mantener la biodiversidad a nivel local y a escala de paisaje (Green et al., 2005;Perfecto & Vandermeer, 2012). Esta práctica ha sido considerada como una alternativa que ha favorecido a la producción a pequeña escala, e incorpora nociones de seguridad y soberanía alimentaria, priorizando las economías campesinas (Perfecto & Vandermeer, 2012). ...
... Una consideración clave según varios autores es el efecto neto de cada modelo en la biodiversidad, tomando en cuenta la productividad de los sistemas (e.g. Chandler et al., 2013;Hodgson et al., 2010). El cultivo de café ha sido uno de los sistemas de producción centrales en la investigación sobre esta temática (Chandler et al., 2013). ...
... En este sentido, la escala es una consideración importante en los sistemas de producción, por lo que en muchos casos no es posible comparar y generalizar resultados de unos cuantos estudios. El modelo divergente frecuentemente asume extensiones geográficas amplias y de grano grueso, mientras que el modelo convergente se enfoca típicamente a integrar la producción y la conservación en una escala menor (Egan & Mortensen, 2012;Hodgson et al., 2010). ...
La pérdida de biodiversidad en paisajes agrícolas es un asunto preocupante a nivel mundial y tema central de mucha de la investigación contemporánea. Este fenómeno puede ser abordado desde dos perspectivas principales: la de la biología de la conservación y la agroecología. La primera enfatiza la importancia de la preservación de los ecosistemas naturales, ya que otros usos del suelo son considerados de legitimidad menor. Para la segunda, el interés se dirige a los agroecosistemas y la biodiversidad es relevante solamente si tiene una conexión con la sostenibilidad de los mismos. La realidad, es que hay agroecosistemas que albergan riqueza en el mismo orden de magnitud que en áreas conservadas y que la pérdida de algunas especies, aparentemente sin valor en la producción del sistema, puede desencadenar efectos cascada si estas son clave en las redes tróficas. Los modelos conceptuales de conservación biológica divergente/convergente, brindan argumentos sobre lo que debería ser la relación entre la agricultura y la biodiversidad; sin embargo, debido a su carga ideológica usualmente derivan en problemas de contextualización. Aquí se refuerzan elementos que parten de la ecología del paisaje y la teoría de metapoblaciones, cuyo soporte proviene de datos empíricos, para repensar este debate con implicaciones para las estrategias de conservación en la región.
... 30% higher compared to conventional farming (Tuck et al., 2014). Organic farming (which is part of AES in Europe) is generally considered as land sharing (Hodgson et al., 2010) (but see Gabriel et al., 2009). In a comparative study of English farms, the number of wild herbs in organically farmed winter cereals was almost four times higher than on conventionally farmed areas, and plant cover with wild herbs was up to nine times higher (Gabriel et al., 2013). ...
... Trade-offs require localized solutions, such as when biodiversity conservation is at odds with economic profits from land-use . In investigating the optimization of yields and biodiversity outcomes, Hodgson et al. (2010) demonstrated that organic agriculture promotes higher butterfly densities than conventional agricultural, but at lower densities than spared natural habitats. Whether land-sharing with organic farming or land-sparing with conventional farming leads to better conservation outcomes depends on the relationship of organic to conventional yields; Hodgson et al. (2010) propose land-sparing as the better solution when organic yields fall below 87% of conventional yields. ...
... In investigating the optimization of yields and biodiversity outcomes, Hodgson et al. (2010) demonstrated that organic agriculture promotes higher butterfly densities than conventional agricultural, but at lower densities than spared natural habitats. Whether land-sharing with organic farming or land-sparing with conventional farming leads to better conservation outcomes depends on the relationship of organic to conventional yields; Hodgson et al. (2010) propose land-sparing as the better solution when organic yields fall below 87% of conventional yields. Where land-sparing is solely achieved by adding field margins (instead of nature reserves) to agricultural landscapes, land-sharing with organic farming results in better conservation outcomes as long as organic yields surpass 35% of conventional yields (Hodgson et al., 2010). ...
Reconciling biodiversity conservation with increasing demand for agricultural production is a major challenge. A long-running discourse that addresses this challenge is the land-sparing vs land-sharing debate. However, the land-sparing vs land-sharing framework has also been criticized for favouring a dichotomous worldview, which contradicts the real-world complexity of agricultural landscapes. Here, we review land-sparing and land-sharing measures with a focus on European landscapes. Land-sparing is needed to preserve the last of Europe's wilderness (2.2% of the land) but will fail to conserve traditional agroecosystems and a wealth of synanthropic species with a long-history of human land-use influence. This is why land sparing should be combined with wildlife-friendly land-sharing practices needed for the preservation of these low-intensity agroecosystems, including European High Nature Value Farmland (15–25% of the land), which is of outstanding conservation value. By promoting generalist species associated with wildlife-friendly farming, land-sharing also enhances ecosystem services provision to agriculture, including pollination and biological pest control. Current land-sharing practices cover multiple spatial scales from local (e.g. wildflower strips) to field (e.g. organic farming) to landscape scale (e.g. diversified farming systems). In addition, productivity outcomes of land-sharing vary greatly, from comparatively high productivity (e.g. pastures for organic production) to agroecosystems that no longer provide any economic returns and are managed mostly for conservation purposes (e.g. dry grasslands). From an economic point of view, the latter may even be defined as land-sparing, highlighting that land-sparing and land-sharing sensu stricto are merely the endpoints of a spare-share continuum of the many agricultural practices in European landscapes. The best biodiversity outcomes and potentially smallest ecological-economic trade-offs result from landscape management that combines measures like agri-environment schemes and organic farming with small field sizes and high crop diversity to enhance spatial and temporal resource complementarity for associated species. Despite increasing progress towards win-win solutions, biodiversity-productivity trade-offs remain widespread, nonetheless. Multifunctional landscapes should therefore include elements from both land-sparing (e.g. natural ecosystems, intensively managed arable fields) and land-sharing (e.g. organic agriculture, agri-environment schemes) to halt declines of farmland biodiversity under increasing agricultural demand. Landscape heterogeneity is key to facilitate landscape connectivity, to avoid species extinctions in spared natural habitats and to promote spillover of organisms and ecosystem services from shared landscape elements to agricultural land. To halt ongoing losses of farmland biodiversity and to promote sustainable multifunctional landscapes, the post-2020 Common Agricultural Policy of the European Union should better reflect the need for agricultural diversification, sustainable agricultural practices and greater landscape heterogeneity.
... The effect of organic farming on butterflies has mainly been studied in herbaceous crops. Hodgson et al. (2010) compared organic, conventional, and pasture systems, finding the greatest diversity in the latter, followed by organic and then conventional. On a local scale, landscape plays an important role. ...
... Yet, they observed that this effect was only clearly visible in continuous landscapes of intensive farmland, while in more heterogeneous farming systems, the influence of landscape was stronger than that of the farming system (Rundlöf et al., 2006). Various authors point out that organic agriculture may not be so beneficial when carried out on large, continuous extensions of land with the same crop (Weibull et al., 2000;Rundlöf et al., 2006;Hodgson et al., 2010). ...
... Under the conditions applied in this study, crop abandonment does not therefore appear to result in any loss of biodiversity, just as other studies have suggested (Kosmas et al., 2015), and in fact has the opposite effect. Moreover, we can confirm that organic farming (with cover crops) increases biodiversity, as previous studies indicate for other agro-ecosystems (Rundlöf et al., 2006;Hodgson et al., 2010;Pe'er et al., 2011). In contrast, the least favourable results in terms of biodiversity were obtained in olive groves in which tillage and conventional non-tillage systems were applied. ...
• Olive groves on steep slopes with a low yield account for 29.6% of the total olive growing area in Andalusia, Spain. This type of olive grove is at high risk of abandonment. Thus, apart from their productive function, we should also take into consideration the ecosystem services that they provide.
• The diversity of Lepidoptera Rhopalocera was studied in sloping olive groves under conventional, organic, and abandoned farming systems. Line‐transect methods were used to survey butterflies in different olive grove treatments, which were defined by a combination of farming systems and soil management systems.
• The greatest diversity of Lepidoptera Rhopalocera was observed in organic and abandoned olive groves with cover crops. Mechanical soil tillage was found to have a negative effect in conventional and organic tillage treatments. From this viewpoint, although abandonment has economic repercussions, it does not lead to a loss of biodiversity. The environmental variables with the greatest influence are landscape complexity and the presence of areas of shrubland. The species Pyronia bathseba appears to be strongly associated with long‐abandoned olive groves.
• The results of this study confirm that the presence of sloping olive groves with cover crops and long‐abandoned groves set in heterogeneous landscapes and with areas of shrubland nearby, help to explain the distribution of Lepidoptera Rhopalocera communities, as well as fostering their richness and abundance.
... This means a major reduction in land use efficiency for food production on the agricultural area currently used (EP et al., 2019). It will lead to additional land use elsewhere, which conflicts with the aim of conserving nonagricultural habitats (Bystricky et al., 2020;Gabriel et al., 2013;Hodgson et al., 2010;Noleppa, 2016;Smith et al., 2019 ). To cover the shortfall in food production in EU, even more food would have to be imported (Zabel et al., 2019). ...
... The impact of plant protection measures on biodiversity has to be considered within the agricultural context and not in isolation. Risks and benefits of different approaches to achieving the same goal must be gauged in a similar way, as proposed by Hodgson et al. (2010) and Balmford (2021). Reducing noncrop plants with a broad-spectrum herbicide will have indirect effects on other organisms dependent on these noncrop plants, either as habitats or food. ...
Current publications that are shaping public perception repeatedly claim that residues of plant protection products (PPP) in the environment demonstrate gaps in assessing the exposure and effects of PPP, allegedly revealing the inability of the European regulatory system to prevent environmental contamination and damage such as biodiversity decline. The hypothesis is that environmental risk assessments rely on inappropriate predictive models that underestimate exposure and do not explicitly account for the impact of combinations of environmental stressors and physiological differences in stress responses. This article puts this criticism into context to allow for a more balanced evaluation of the European regulatory system for PPP. There is broad consensus that the decline in biodiversity is real. This article analyzed current literature for causes of this decline and of chemical contamination. The main drivers identified were land use changes and structural uniformity of agricultural landscapes or multiple contaminants emitted by various sources such as wastewater discharge systems. Comparing measured environmental concentrations from published monitoring studies with exposure predictions from the regulatory risk assessment reveals only slight occasional exceedances for a few environmental scenarios and compounds. Therefore, the call for greater conservatism in the European authorization process for PPPs will not lead to an improvement in the environmental situation. We suggest enhancing landscape diversity through the European Union Common Agricultural Policy and reducing contamination from wastewater and farmyard effluents. The current regulatory risk management toolbox should be expanded to include flexible localized mitigation measures and treatment options to reduce applied amounts and off-target exposure.
... By contrast, the effects of environmental conditions on butterfly assemblages in the wider countryside have been studied less intensively (Brereton et al., 2011b). As butterflies are particularly affected by current environmental changes, there is an urgent need to increase integrative environmental schemes aimed at maintaining biodiversity and ecosystem functioning in these non-protected landscapes (Hodgson et al., 2010;Samways et al., 2020). ...
... The lacking effect of protected areas on butterfly assemblages in the intensively used lowlands, highlights the need for novel environmental schemes in the wider countryside that go beyond the management of protected areas (cf. Hodgson et al., 2010;Samways et al., 2020). ...
Studies from all over the world have recently reported severe declines in insect diversity and abundance. Due to their high sensitivity to environmental changes, butterflies are well-suited indicators for assessing the overall state of the terrestrial insect fauna. Though they rank among the best-studied insect groups, Europe's butterfly populations are still declining in many places, especially in landscapes under intensive land use. In this study, we investigated the response of butterfly assemblages to environmental conditions in 169 plots in the wider countryside of North Rhine-Westphalia (NW Germany, Central Europe). Our study revealed a strong relationship between butterfly species richness and density and the environmental conditions in the study area. Due to the maintenance of low-intensity land use, the uplands were characterised by more favourable conditions for butterflies and consistently had a higher species richness and density of species overall and of threatened species than the intensively used lowlands. In addition to elevation, landscape diversity in particular fostered butterfly diversity. By contrast, butterfly assemblages exhibited a negative response to urban areas and arable land, which were among the most dominant habitat types in the lowlands. Moreover, our study highlighted the importance of nutrient-poor grasslands for butterflies, which is mainly a result of their high habitat quality. According to the findings of our study, it is especially important to promote heterogeneous landscapes with a large extent of semi-natural, nutrient-poor habitats. Therefore, the key issue for butterfly conservation is to change the current farming policies to increase the amount of low-intensity farmland.
... Further they highlighted the context-dependency of the average lower yields in organic systems. Gabriel et al. (2013): Because of variances in yield gap, "it is difficult to predict how much more land is needed to produce the same amount of food with organic agriculture, but it seems clear that it requires substantially more land (Goklany 2002;Trewavas 2004) […] (locally or elsewhere), at a biodiversity cost much greater than the on-farm benefit of organic practice (Goklany 2002;Hodgson et al. 2010)" (p. 362). ...
... For the sources Goklany (2002) and Trewavas (2004), see above. Hodgson et al. (2010) adopted the land sparing/land sharing framework and measured density and species richness of butterflies on various sites. They predicted the optimal LU strategy to maintain yield whilst maximizing butterfly abundance: When yield gap is higher than 13 %, farming conventionally and using spared land as nature reserves is optimal. ...
Die Umweltwirkungen des ökologischen Landbaus (ÖL) werden seit vielen Jahren kontrovers in der Wissenschaft diskutiert. Weiterhin gibt es gegensätzliche Ansichten, ob der ökologische Landbau einen Beitrag zur Bewältigung der umwelt- und ressourcenpolitischen Herausforderungen leisten kann und seine Förderung ein geeignetes Instrument zur Lösung der Probleme darstellt. Bisher hat sich hierzu noch keine eindeutige Sichtweise durchgesetzt. Wie ist dieser Umstand zu erklären? Und liegt gegebenenfalls ein Lock-in des wissenschaftlichen Diskurses vor? Ziel der Arbeit ist es, den relevanten wissenschaftlichen Diskurs nachzuzeichnen und mögliche Erklärungen abzuleiten, warum die Umweltwirkungen weiterhin unterschiedlich bewertet werden. Dazu wurde eine qualitative Inhaltsanalyse mit einer Stichprobe von n=93 wissenschaftlichen Publikationen durchgeführt. Es konnten zwei Hauptdiskussionslinien herausgearbeitet werden: Zum einen geht es um die Frage, ob bei der Bewertung der Umweltwirkungen zwangsläufig auch Aspekte der Ernährungssicherung einzubeziehen sind (thematischer Betrachtungsrahmen); zum anderen, inwiefern die Netto-Umweltwirkungen bzw. mögliche Verlagerungseffekte in Folge eines niedrigeren Ertragsniveaus zu berücksichtigen sind (räumlicher Betrachtungsrahmen). In diesem Kontext wird auch die Frage nach der angemessenen Anwendung verschiedener Bezugseinheiten (Fläche, Ertrag) in Nachhaltigkeitsbewertungen eingehend analysiert. Zudem wird die Rolle des oftmals unzureichend reflektierten Nachhaltigkeitsbegriffs verschiedener landwirtschaftlicher Paradigmen durchleuchtet. Es wird geschlussfolgert, dass die polarisierende Debatte unter anderem durch die binäre Ausgangsfrage (Ist der ÖL besser als die konventionelle Landwirtschaft?) begründet ist und bisher unzureichend beleuchtete Aspekte, wie die Wahl der Bezugseinheiten oder normative Grundannahmen in der wissenschaftlichen Nachhaltigkeitsbewertung, in den Diskursen verstärkt berücksichtigt werden sollten.
... On each farm, we sampled two replicates of three habitat types, consisting of cereal fields, ley fields (rotational, sown, and improved temporary grassland, usually mown but sometimes grazed) and seminatural grasslands (cf. Hodgson et al., 2010). These three habitat types represent the major land use in farms in the region (Persson et al., 2010). ...
... This is however contrasting with a previous study that found the local beneficial effect of organic fields did not propagate at the landscape scale, due to compensation by plant diversity hosted by nonfarmed habitats in conventional farms (Schneider et al., 2014). In our study, we sampled mainly grazed seminatural habitats that are typically the most species-rich farmland habitats (Hodgson et al., 2010;Lindborg et al., 2014) and probably richer than the sampled set asides in Schneider et al. (2014), most of which were temporary grassy habitats (grass and herbaceous strip). Most likely, we were able to detect a significant farm-scale organic farming effect due to the systematic selection of similar habitat types along the landscape gradient, and to the matching of farming intensity with landscape complexity, that allowed us to explore interactive effects. ...
Biodiversity‐benefits of organic farming have mostly been documented at the field scale. However, these benefits from organic farming to species diversity may not propagate to larger scales because variation in the management of different crop types and seminatural habitats in conventional farms might allow species to cope with intensive crop management. We studied flowering plant communities using a spatially replicated design in different habitats (cereal, ley and seminatural grasslands) in organic and conventional farms, distributed along a gradient in proportion of seminatural grasslands. We developed a novel method to compare the rates of species turnover within and between habitats, and between the total species pools in the two farming systems. We found that the intrahabitat species turnover did not differ between organic and conventional farms, but that organic farms had a significantly higher interhabitat turnover of flowering plant species compared with conventional ones. This was mainly driven by herbicide‐sensitive species in cereal fields in organic farms, as these contained 2.5 times more species exclusive to cereal fields compared with conventional farms. The farm‐scale species richness of flowering plants was higher in organic compared with conventional farms, but only in simple landscapes. At the interfarm level, we found that 36% of species were shared between the two farming systems, 37% were specific to organic farms whereas 27% were specific to conventional ones. Therefore, our results suggest that that both community nestedness and species turnover drive changes in species composition between the two farming systems. These large‐scale shifts in species composition were driven by both species‐specific herbicide and nitrogen sensitivity of plants. Our study demonstrates that organic farming should foster a diversity of flowering plant species from local to landscape scales, by promoting unique sets of arable‐adapted species that are scarce in conventional systems. In terms of biodiversity conservation, our results call for promoting organic farming over large spatial extents, especially in simple landscapes, where such transitions would benefit plant diversity most.
... Furthermore, densities are more susceptible to fluctuations over time (particularly herbaceous plants and arthropods which constitute four of our groups), while overall richness is relatively stable. Our results were consistent with previous assessments in regards to the preferences of the species groups towards sparing and sharing (Hodgson et al., 2010;Phalan et al., 2011). Despite the ecological differences between taxonomic groups, both biodiversity metric and taxonomic group had smaller effect on the choice between sparing and sharing compared to the economic variables. ...
... Numerous studies of this trade-off examined the impact of various production methods and land management practices on ecological benefits, particularly biodiversity (e.g.Egan & Mortensen, 2012;Hodgson et al., 2010). Our study assessed varying parameters at both ends of the trade-off simultaneously and affirmed that economic considerations, rather than ecological considerations, dominated the production-biodiversity trade-off. ...
The framework of land sparing versus land sharing provides a useful analytical tool to address the crop‐production/biodiversity trade‐off. Despite multiple case studies testing the sparing–sharing trade‐off, this framework still lacks the ability to identify the conditions in which sparing, or sharing, would be the preferred strategy for pareto‐optimizing both food production and biodiversity. Under some conditions, ecosystem services may create a positive feedback between biodiversity and crop production, affecting the optimization.
This study aims to identify the conditions and the relevant variables that determine the preferred land use strategy in terms of maximizing both biodiversity and food production, while accounting for positive feedback of ecosystem services in this analysis. We used a simulation model with data from a mixed cropping landscape (100 km²) covering seven crop types, five taxonomic groups, three biodiversity metrics and 23 bioindicators to explore the variables shaping the biodiversity–production trade‐off and ecosystem services underlying it. We explored a continuum of sparing large semi‐natural patches to sharing by maintaining uncultivated field margins of varying size.
Land sparing outperformed land sharing in 62% of the scenarios and it was economically more predictable. The optimization was shaped by costs, associated with crop type, rather than by landscape composition and configuration, biodiversity metric, taxonomic group or bioindicator.
Landscape configuration and taxonomic group results corroborate the notion that land sharing benefits mainly small organisms, and that the common width of field margins in many agri‐environmental policies (10 m) is not cost‐effective compared to land sparing.
Land sharing was the optimal strategy whenever it resulted in minimal costs, despite contributing little to biodiversity. Yet, when field margins were >20 m wide (small‐scale sparing), land sharing maintained higher biodiversity and was at least as cost‐effective as sparing.
Synthesis and applications. Our model highlights the importance of socio‐economic variables compared to ecological variables in selecting land‐management strategy to pareto‐optimize both food production and biodiversity. Considering opportunity costs alongside economic benefits from ecosystem services in various cropping systems may therefore improve the cost‐effectiveness of biodiversity conservation policies in agricultural landscapes.
... An optimal land management strategy strives to (1) maximize the ecological ''productivity'' (measured in terms of some ecological metric of interest, such as biodiversity) of non-agricultural land; (2) maximize the contribution of agricultural land to ecological productivity; (3) maximize the agricultural value added and productivity of farmland; and (4) maximize the contribution of non-agricultural land to agricultural productivity (Harvest et al. 2012). In many cases, the goals of agricultural and ecological productivity are in conflict. ...
... For example, the ''Borlaug hypothesis'' proposes that increased crop yields lead to decreased demand for new agricultural land, an effect critical to the long-term efficacy of land sparing (Angelsen and Kaimowitz 2001). Others have questioned this assumption, pointing to an inverse relationship between farm size and agricultural productivity observed in many developing countries (Lipton 2010; Harvest et al. 2012). Additionally, over longer time scales, enforcement of a particular land management regime may influence the crops that farmers plant, limiting or even completely reversing conservation gains (Jackson 2002). ...
The global trend toward increased agricultural production puts pressure on undeveloped areas, raising the question of how to optimally allocate land. Land-use change has recently been linked to a number of human health outcomes, but these are not routinely considered in land-use decision making. We review examples of planners’ currently used strategies to evaluate land use and present a conceptual model of optimal land use that incorporates health outcomes. We then present a framework for evaluating the health outcomes of land-use scenarios that can be used by decision makers in an integrated approach to land-use planning.
... Consequently, organic farms typically exhibit higher levels of biodiversity compared to traditional farms [59][60][61][62]. However, focusing solely on organic agricultural systems overlooks important elements and underutilizes the potential for biodiversity in agroecosystems [63]. Furthermore, environmental intensification can lead to increased agricultural yields. ...
Agriculture is facing a severe threat to its sustainability due to the growing demands for food, feed, and other renewable nonfood raw materials in the face of global warming. Regenerative agriculture is increasingly recognized as a vital solution to a range of ecological and social issues. It actively revitalizes ecosystems, focusing on soil health, biodiversity, and mitigating climate change, going beyond sustainable practices. Governments and other organizations at all levels, from global to regional, are exploring how regenerative agriculture can be integrated into climate change initiatives to sustain ecosystem. This powerful benefit can be achieved without reducing yields or farmer profits. Soil, as a living and dynamic environment, is home to a diverse range of micro- and macro biota that contribute to its characteristics. Healthy soil is characterized by favorable physical properties (texture, water-holding capacity), chemical properties (pH, soil organic matter; SOM), and biological properties (microbial diversity, and soil respiration), which are essential for nurturing nutritious and profitable crops and improve human health. Regenerative farming is attracting interest from the public, private, and nonprofit sectors to improve soil health and sustain ecology. Several academics and non-governmental organizations have attempted to explain the scope and significance of regenerative agriculture. This review outlines how regenerative agriculture practices can mitigate global warming, improve soil health, boost biodiversity, and its socioecological impacts. For future prospects, further scientific research required to examine the effects of regenerative agriculture on both livestock and human health, in order to promote a healthier community.
... Indeed, the high abundance of a particular taxon on a farm does not necessarily result from the farm manager's efforts to provide more biodiversity. This may simply be due to the fact that the farm is located in a more biodiverse landscape and therefore fulfils the agri-environmental payment scheme requirements without making any additional efforts, such as changing farming practices (Matzdorf and Lorenz, 2010;Hodgson et al., 2010;Fleury et al., 2015). ...
... At the fundamental level both the land sparing and land sharing approaches of SI of agriculture are 'landscape approaches' (Englund et al., 2017;Hodgson et al., 2010). Therefore, successful implementation at significant scale requires a landscape management approach which may be part of national, regional or catchment scale land use planning. ...
Mitigation pathways that stabilise global warming to 1.5 • C describe rapidly increasing deployment of land-based solutions, including increased carbon sequestration in soils and biomass. This places additional demands on land, which is also required to provide food security and other ecosystem services. Sustainable Intensification (SI) of agriculture has the potential to facilitate meeting demands for food and fibre, while simultaneously meeting environmental and ecological goals. The scientific literature has most often addressed the challenge of SI separately to climate change mitigation objectives in agricultural systems. Using a systematic review approach, we explored the compatibility of SI and carbon sequestration research through two contrasting case studies: Case Study I on Grassland Agriculture in Europe, and Case Study II on Smallholder Agriculture in Africa. We find contrasting levels of research theme similarity for SI and carbon sequestration, with European grassland agriculture research having lower similarity compared with African smallholder agriculture research. There was a focus on minimising biodiversity loss and environmental impacts in Europe, in contrast to a food security emphasis in Africa, reflecting regional and development differences. While there are clear context and agricultural-system specific differences between both case studies, both suggest that sustainable land use policies can be used to achieve SI integrated with climate mitigation in agriculture.
... Some conservation planning exercises include production in a cost-benefit analysis, asking if the cost of a conservation action (in terms of lost production) is justified in terms of the benefit (in terms of nature saved) (e.g. Hodgson et al. 2010). This approach leads into the land sparing/land sharing spectrum of choices, discussed in Chapter 9. ...
... From the ecological point of view, there are many studies that point out the fact that intermediate systems may support significant levels of biodiversity contradicting LSP assumptions (Perfecto et al. 1996;Faria et al. 2006Faria et al. , 2007Clough et al. 2011). Despite its prominence, most of the papers supporting or criticizing land sparing come from analyzing the response of biodiversity to agriculture intensification or agricultural yield (Hodgson et al. 2010;Clough et al. 2011;Hulme et al. 2013;Phalan et al. 2011;Macchi et al. 2016). Others assume that agriculture intensification reduces habitat loss without directly testing it (Silva 2016;Phalan et al. 2016) or by testing such association at regional levels (Bergtold et al. 2017). ...
Land Sparing predicts that agricultural intensification is the best way to meet productive, humanitarian and conservation goals, and the recent prominence of this strategy on conservation and agricultural agendas is notable. The basic idea is that, by producing more, agriculture intensification can spare natural habitats from further agriculture expansion. Nevertheless, some authors have suggested that intensifying and increasing productivity may actually lead to increasing expansion of agricultural lands (Jevons Paradox). We test the association between agricultural yield on farmland expansion and on deforestation between 2000 and 2015 in 122 nations along the tropics, and in the main tropical regions. To this end we used Generalized Linear Models, as well as Panel Data to verify the effects of agricultural yield and socioeconomic variables on farmland expansion and deforestation. Greater yield increases lead to higher deforestation rates in Sub-Saharan Africa and Latin America and Caribbean and increasing yield average induces agriculture expansion in East Asia and Pacific, giving support to the Jevons Paradox hypothesis. On the other hand, we found a positive association between yield average and forest area change in the tropics, nevertheless, regression coefficients were very small, compared to other significant models. Therefore, Jevons Paradox seems to be more common than Land Sparing and increasing yields inducing deforestation rather than curbing it.
... However, this this was not the case for specialist species, which were influenced by the number of plant species found within a 100m 2 in the field. Gabriel et al. (2010) showed that farms in organic hotspots (landscapes with a greater abundance of organic farms) had a higher abundance of butterflies, and Hodgson et al. (2010) similarly showed that the amount of organic farming in a landscape had a positive effect on butterfly abundance, but the magnitude of this effect was much smaller than for local (farm-scale) organic farming. However, Aviron et al. (2009) found the proportion of the surrounding landscape (in a 200m radius) either covered under ECA or under crop did not affect butterfly species richness on meadows or arable fields. ...
Scoping study to design a landscape-scale monitoring project of AES impacts on mobile species.
Published online by Defra: https://sciencesearch.defra.gov.uk/ProjectDetails?ProjectId=19727
... The structure of the forest stand varied with the land utilization regimes, with the low utilization regime showing a typical reverse J-shaped curve [74], which contained the highest number of stems in the first class. However, the highest number of stems in the first class of the high and moderate utilization regimes were induced by the high regeneration of trees of a similar age (5-10 years) induced by increased availability of light after opening of the forest canopy. ...
The Mayombe tropical forest has experienced dramatic changes over several decades due to human activities. However, the impact of these changes on tree biodiversity and ecosystem services has not been studied yet. Such a study could advance the current knowledge on tree biodiversity and carbon storage within the Mayombe forest, which is presently under high anthropogenic pressures. This information could benefit decision-makers to design and implement strategies for biodiversity conservation and sustainable natural resource utilization. As such, biodiversity surveys were conducted within the forest under different land utilization regimes. To evaluate the effect of human utilization on tree biodiversity and ecosystem services (carbon storage), land was classified into three categories based on the intensity of human utilization: low utilization, moderate utilization, and high utilization. Additionally, the study evaluated the recovery potential of the disturbed forest under both moderate and high utilization, after abandonment for 10 and 20 years. Tree diameter and height were measured for all trees whose diameter at breast height was greater than or equal to 10 cm. Our findings revealed that forest land with both high and moderate utilization regimes, and having no regulation, resulted in the decline of tree species richness, tree species diversity, and carbon storage. The magnitude of decrease was greater in high utilization compared to moderate utilization regimes. On the other hand, high values of biodiversity indices and carbon storage were observed in the low utilization regime. This study also demonstrated that fallow land that had been left undisturbed for more than 10 years, but had experienced both high and moderate utilization regimes, could reasonably recover carbon storage, and an acceptable level of tree species biodiversity can be achieved. However, there remains a significant difference when compared with the original level in the low utilization regime, suggesting that the Mayombe forest takes longer to recover. Based on the findings on tree biodiversity and carbon storage over the recovery trajectory, this study improves the understanding of the degraded forest restoration process within the Mayombe forest. It is therefore necessary to formulate new strategies to regulate forest land utilization within the Mayombe forest. This will ensure sustainability and availability of all ecosystem services this forest provides to a human population that strongly depends on it for their survival.
... In a large scale UK study, Gabriel et al. (2013) showed that arthropod diversity did not differ between organic and conventional cereal fields after correcting for the more than 50% yield loss in organic farming. In a follow-up study comparing the same dataset to grassland nature reserves (land sparing), Hodgson et al. (2010) found that to support butterfly population via organic farming (land sharing) instead of land sparing with reserves, the organic yield has to achieve 87% of conventional one. Here, we focus on different spatial scales of two popular AESs in Germany (Lakner et al., 2019), namely organic farming as an on-field measure and planted flower strips as an off-field measure, leading to contrasting assessments of their biodiversity value. ...
The effectiveness of agri-environment schemes depends on scheme type, taxon and landscape. Here, we show how spatial scale, i.e. studied transect, field or farm level, and controlling for yield loss, can drastically change the evaluation of biodiversity benefits of on-field (organic farming) vs. off-field (flower strips) schemes. We selected ten agricultural landscapes in Central Germany, each with a triplet of winter wheat fields: one organic, one conventional with flower strip, and one conventional without flower strip as a control. We surveyed the abundance of wild bees at field edges for two years. We found that comparing data at the transect level may lead to misleading conclusions, because flower strips, covering only 5% of conventional fields, support fewer bees than large organic fields. However, a 50% cereal yield loss of organic farming can be considered as equivalent to yield levels of 50 ha conventional plus 50 ha flower strip. This would promote 3.5-times more bees than 100 ha organic farming. In conclusion, considering various scales in the evaluation of agri-environment scheme measures is necessary to reach a balanced understanding of their ecological and economic effects and their effectiveness.
... Yet, as with any set of ecosystem services in a system or land use under consideration, ES provision may come with trade-offs between service types [14]. In the agriculture literature, food production is often placed at odds with other ecosystem services such as soil carbon sequestration or habitat provision due to the intensification of management at the farm or landscape scale that is assumed as required for food production [15][16][17]. This trade-off is not necessarily unique to rural landscapes, but also in UA, particularly at the scale of decision making by individuals. ...
Urban agricultural systems are a prominent social-ecological system in cities and towns across the world. The multifunctional nature of urban agriculture engenders many benefits to urban residents, from food provision to social cohesion. In addition, many environmental services such as climate regulation and habitat for urban wildlife are supported by these agroecosystems. Both local to landscape management factors including plant diversity and ground cover management influence the provision of ecosystem services. Yet, the management decisions may create trade-offs between and among ecosystem services with the increase in one service potentially reducing the ability of the system to provide another service at a desired level. While there are some services that practitioners may not care to lose as much, for other services, the maintenance of a service will be important, based on the goals of the system. Thus, balancing and sustaining ecosystem services must be carefully considered in ecosystem management decisions. Here, we review ecosystem services (ES) within urban agriculture (UA) with a focus on residential, community, and market garden systems, and how local to landscape management influence ES provision. In addition, we evaluate trade-offs between and across services, for example, between provisioning services (food production) versus other environmental services (regulating, supporting). Finally, we highlight future research directions on ecosystem services and the trade-offs for sustainable urban food production, biodiversity, and natural resource conservation.
... The results here support land sparing, especially if the goal is to protect high value areas like mangroves and coastal land, which will be important in both stymieing the impacts of climate change Donato et al., 2011;Macreadie et al., 2017) and protecting coastal communities from its impacts, such as severe storms (Danielsen et al., 2005). While several other studies have reached similar conclusions Hodgson et al., 2010;Hulme et al., 2013), it should be noted that land sparing is only effective when policies are in place to ensure the land is converted back to natural space (Fischer et al., 2011). In aquaculture, systems exist that operate under a principle of land-sharing, and these are referred to as "silvofisheries" or "integrated mangrove aquaculture". ...
Shrimp are one of the fastest growing commodities in aquaculture and have a considerable land footprint. Here, we explored the impact of utilizing different production methods (extensive vs intensive) for expanding shrimp production on the cumulative land footprint of shrimp aquaculture. A meta-analytic approach was utilized to simultaneously estimate model coefficients to explore three relationships: production intensity and total land burden, production intensity and the proportion of land at the farm, and production intensity and the farmland burden. A literature review was conducted and a total of 7 datasets, 22 subsets, and 973 individual farms were included in this study. The global models were as follows: model 1 → ln (total land burden) = 0.1165–0.3863 * ln (production intensity), model 2 → proportion of direct (farm) land use:total land use = 0.7592–0.1737 * ln (production intensity), model 3 → ln (direct land use) = 0.1991–0.9674 * ln (production intensity). Production expansion was modeled under different scenarios. The most land intensive projections involved using only extensive systems to increase production when compared to a business-as-usual scenario. The least land intensive scenario involved utilizing intensive systems. A scenario where farmland was not expanded used 17% less land and 28% less land to produce 7.5 and 10 million tons of shrimp, respectively, when compared to business-as-usual scenarios. These estimates are limited by uncertainty in shrimp feed composition but demonstrate the effect of production intensity on the overall land footprint of shrimp production.
... 219 For example, in the UK a study comparing 'land-sharing landscapes' (rich in organic farming) and 'land-sparing landscapes' (intensive farms plus land set aside into wildlife areas) found that, most of the time, the land-sparing landscapes should provide higher agricultural yields and more biodiversity across a larger area. 220 More recently, 221 a broadening of the conceptual approach has indicated that land-sparing is also potentially better for other aspects of sustainability: per unit of production, land-efficient systems generate lower negative externalities (such as GHG emissions). ...
... Therefore, the marginal (less productive) land is going to be spared for ecological restoration therein, production systems existing on such landscapes, would be encouraged financially to take up ecosystem services options such as compensation for land left out of production and for planting woodland clusters (Rey Benayas and Bullock, 2012;Zahawi et al., 2013). Land governance, is a rather complicated process where multiple dynamics compete with each other to produce food, conserve natural values or achieve both at an optimally minimal trade-off between the two (Hodgson et al., 2010;Garnett and Godfray, 2012). Thus, to bridge the global targets it is imperative that strategies will lead to effective environmental conservation without delivering unequal socioeconomic burdens (Ellis, 2019) and this probably emerges as one of the most significant challenges for the land sparing strategies implementation (Phalan et al., 2016;Folberth et al., 2020). ...
Growing competition for land, water and energy call for global strategies ensuring affordable food production at minimum environmental impacts. Economic modelling studies suggest trade-off relationships between environmental sustainability and food prices. However, evidence based on empirical cost-functions supporting such trade-offs remains scarce at the global level. Here, based on cost engineering modelling, we show that optimised spatial allocation of 10 major crops, would reduce current costs of agricultural production by approximately 40% while improving environmental performance. Although production inputs per unit of output increase at local scales, a reduction of cultivated land of 50% overcompensates the slightly higher field-scale costs enabling improved overall cost-effectiveness. Our results suggest that long-run food prices are bound to continue to decrease under strong environmental policies. Policies supporting sustainability transitions in the land sector should focus on managing local barriers to the implementation of high-yield regenerative agricultural practices delivering multiple regional and global public goods.
... In the context of the sparing-sharing model, organic farming can play a role according to the land sharing mechanism, since it makes the cultivated area more favorable to wildlife due to the lower use of pesticides and fertilizers [4]. On the other hand, precision agriculture involves means to obtain very high efficiency from technical inputs and high yield increase, thus requiring theoretically less soil to produce food. ...
Soilless cultivation systems were primarily developed in response to the excessive spread of soil pathogens; however, they also allow an optimal control of plant grow, high productivity and product quality as well as very high efficiency of water and fertilizer use. At the same time, consumers remain critical towards soilless-cultivated vegetables, mainly due to the perception of these techniques as unnatural, resulting from artificial growth and consequently characterized by low quality. This mini review analyzes the evolutionary process of soilless cultivation within a vision of agriculture that supports environmental sustainability as the central theme of the discussion. Current knowledge suggests that, although apparently opposite, organic and high-tech soilless cultivation have several common or converging points in view of a sustainable use of resources on the planet. As a consequence, new policies should be oriented toward a reduction of environmental “pressure” by introducing a process certification of low environmental impact, which, together with an adequate product certification, related not only to the environmental aspect but also to product quality, can reduce the opposition of the two cultivation systems.
... In particular, we aim to evaluate changes in soil properties represented in soil functions under the land use strategies LSH, LSP, a combination thereof (LBA), and under climate change. As such, dynamic SFAs complement land use assessments on biodiversity and ecosystem services under climate change (Hodgson et al., 2010;Martinez-Harms et al., 2017). They may inform private (e.g. ...
Soils as key component of terrestrial ecosystems are under increasing pressures. As an advance to current static assessments, we present a dynamic soil functions assessment (SFA) to evaluate the current and future state of soils regarding their nutrient storage, water regulation, productivity, habitat and carbon sequestration functions for the case-study region in the Lower Austrian Mostviertel. Carbon response functions simulating the development of regional soil organic carbon (SOC) stocks until 2100 are used to couple established indicator-based SFA methodology with two climate and three land use scenarios, i.e. land sparing (LSP), land sharing (LSH), and balanced land use (LBA). Results reveal a dominant impact of land use scenarios on soil functions compared to the impact from climate scenarios and highlight the close link between SOC development and the quality of investigated soil functions, i.e. soil functionality. The soil habitat and soil carbon sequestration functions on investigated agricultural land are positively affected by maintenance of grassland under LSH (20% of the case-study region), where SOC stocks show a steady and continuous increase. By 2100 however, total regional SOC stocks are higher under LSP compared to LSH or LBA, due to extensive afforestation. The presented approach may improve integrative decision-making in land use planning processes. It bridges superordinate goals of sustainable development, such as climate change mitigation, with land use actions taken at local or regional scales. The dynamic SFA broadens the debate on LSH and LSP and can reduce trade-offs between soil functions through land use planning processes.
... This model has been applied to several situations to examine the role of intensifying agriculture. While many studies often reach nuanced conclusions (e.g., Balmford et al., 2005;Hodgson et al., 2010;Hulme et al., 2013), generally many of the authors do recognize that land sparing is an effective conservation measure. However, this is only true when measures are in place to ensure the land is actually spared (Fischer et al., 2011). ...
Aquaculture production is an important part of the global food supply and has equaled or surpassed fisheries production as the main source of aquatic foods. Aquaculture is a resource intensive practice that can use large amounts of land, water, energy, and cause pollution and degradation to the local environment. Intensive production practices have been criticized in the past for causing environmental harm; however recent studies have suggested that resource use may decrease with increasing production intensities at the farm level. Here we used a conceptual farm to access the impact of a few key production parameters on land, water, and energy use. A series of calculations were conducted at various production intensities with modifications made to the type of feed used and water exchange rate. The resulting relationships were then modeled with production intensity. Additionally, the effect of various feedstuffs on embodied resource coefficients was examined through varying protein and carbohydrate feedstuffs. Land and water use were found to have an asymptotic relationship with production intensity, with the most important factor in land use being production intensity and the most important factor in water use being the water exchange rate. Energy use was found to be higher with a diet that has fish meal as a protein source and at higher water exchange rates. The most land intensive diets used for shrimp contained high fish meal with rice as carbohydrate feedstuffs (0.550 ha/tonne). The most water intensive diet was no fish meal with corn as a carbohydrate (1863 m 3 /tonne), and the most energy intensive diet was high fish meal with corn as a carbohydrate (11.73 GJ/tonne). The results herein suggest that intensifying shrimp aquaculture could save resources based on per tonne of production basis.
... 219 For example, in the UK a study comparing 'land-sharing landscapes' (rich in organic farming) and 'land-sparing landscapes' (intensive farms plus land set aside into wildlife areas) found that, most of the time, the land-sparing landscapes should provide higher agricultural yields and more biodiversity across a larger area. 220 More recently, 221 a broadening of the conceptual approach has indicated that land-sparing is also potentially better for other aspects of sustainability: per unit of production, land-efficient systems generate lower negative externalities (such as GHG emissions). ...
The report describes the food system impacts on biodiversity loss at the global level and recommends three levers for food system transformation in support of nature.
... Due to the significance of habitat transformation for biodiversity loss, an evaluation of the influence of farming methods on biodiversity has to control yields, which a small number of studies have carried out to date [86,87]. The studies of both Gabriel et al. [86] and Schneider et al. [85] proposed that there are trade-offs between the biodiversity advantages of organic handling yields. ...
The argument on whether organic agriculture can produce enough food to cater for the world’s growing population has been debated severally by various scholars. While organic farming is rapidly increasing, the paramount question is to know how organic farming can yield to viable systems of producing food. This paper aims to identify the benefits and context reliant performance of organic farming as a development trail to sustainable farming. Gathering of articles from different peer review journals was used to develop this paper. The findings of this paper show that organic farming has many potential benefits including higher biodiversity, improved soil, and enhanced profitability as well as supporting local production, with locally produced source inputs. The findings also show that organic farming is environmentally friendly, promotes distribution of resources, and is economically and socially acceptable to mankind. In order to have a clear view of the contribution that organic farming plays on sustainability, further research is necessary.
... In line with the magnitude of change, a lot of research has gone into documenting the effects of agricultural expansion and intensification on native biodiversity. Studies dealing with this subject have focused on a variety of taxa including birds (Kamp et al., 2015;Mendenhall, Sekercioglu, Brenes, Ehrlich, & Daily, 2011;Phalan et al., 2011), plants (Egan & Mortensen, 2012;Kleijn et al., 2012;Phalan et al., 2011), mammals (Decarre, 2015;MacDonald, Tattersall, Service, Firbank, & Feber, 2007) and insects (Hodgson, Kunin, Thomas, Benton, & Gabriel, 2010). In this spectrum, effects of land-use on birds have been assessed in most detail and these studies have been synthesized in numerous reviews and meta-analyses at both regional (Chamberlain, Fuller, Bunce, Duckworth, & Shrubb, 2000;Donald, Green, & Heath, 2001) and global scales (Gaston et al., 2003;Newbold et al., 2012). ...
1. The Indian Thar desert has seen a massive loss of grassland habitat in the last few decades. The main driver of this habitat loss has been the large-scale change in land-use from pastoralism to agriculture, leading to expansion of cultivated land over grasslands. This expansion, further compounded by a simultaneous rise in livestock population has drastically increased grazing pressure on the remaining rangelands. To complicate things further, irrigation schemes (notably the Indira Gandhi Canal) have led to intensification of agriculture in many areas. Protected area network in this landscape is minimal and ineffective, making the multiple-use agro-pastoral landscapes very important for conservation of wildlife. The largest protected area in the landscape – the “DNP WLS” – is also a multiple-use landscape and home to more than 50k people whose livelihood is tied to the federal mandate of conservation in the sanctuary. Understanding the impact of land use change on native biodiversity is thus very important for conservation of biodiversity in this critical habitat. In this context, my study tries to find effects of land-use change on community structure of birds in the arid grassland of Jaisalmer district in the Thar Desert.
2. Understanding ecology or distribution and abundance of species is incomplete without holistically understanding the patterns and processes occurring at the community level. To this end, I explored the patterns of bird community structure in the Thar Desert and tried to understand how these properties change with land-use driven habitat change, by comparing fundamental properties of biological communities like species richness, abundance and composition. Additionally, I tried to find out potential habitat correlates of these properties, so as to shed some light on the processes that might be driving community assembly in response to land-use change.
3. Bird community structure: My results indicate that local-scale species richness, abundance and composition did not differ significantly between protected grasslands, rangelands and rain-fed croplands, during either of the seasons. However, intensive irrigated croplands had a notably different community structure with higher species richness and abundance, during both winter and summer. The change is community structure of irrigated croplands was influenced by the change in native species along with ingression of newly colonised species. Most of the newly colonised species were restricted to areas with intensive agriculture where their survival was potentially facilitated by the new microhabitats created by irrigation and associated changes (Rahmani & Soni, 1997).
4. Regional species pool: Intensive agriculture increased the overall species of birds in the region by sustaining newly colonised bird species; while the number of native species in this pool was only marginally lower than protected grasslands and comparable to all the other land-uses in both the seasons. Considering both the seasons together, protected grasslands had the highest naïve and estimated number of native species while the naïve and estimated number of native species in other three land-uses – Rangelands, rainfed croplands and irrigated croplands – was only marginally lower. This signifies that most species found in the region can use the entire gradient of land-use types at their current levels of intensification. Although this result by itself does not indicate that, all land-use types can sustain all the native species.
5. Seasonality of patterns: In winter, protected grasslands, rangelands and rainfed croplands had similar bird communities, which together were significantly different from the communities in irrigated croplands. The same pattern repeated in summer, but the magnitude of difference between bird communities in intensive agriculture and other land-uses was much lower. This pattern was correlated to the pattern shown by vegetation structure of intensive agriculture, which also became more similar to other land-uses after harvesting of crops in the summer. This potentially suggests that bird communities are influenced by vegetation structure and areas with similar vegetation structure would have similar bird communities.
6. Habitat correlates of species richness and bird community composition: In both the seasons, species richness was positively associated with the foliar volume of woody vegetation and negatively associated with forb volume (which in turn was negatively correlated with grass volume). During winter, species richness was positively related to crop volume and during summer, with compositional diversity of vegetation. Community composition like richness was influenced significantly by woody plant foliar biomass in both the seasons. Crop volume also had a significant influence on bird communities during both winter and summer, whereas grass volume was significantly influential only in winters.
7. Conservation implications: This study corroborates many others in indicating that low-impact land-uses are important secondary habitats for conservation of grassland species (Dutta & Jhala, 2014; Wright, Lake, & Dolman, 2012). The inferences further support the commonly advocated approach of conserving grasslands at a landscape scale by strategically placing them as mosaics of low-impact agro pastoral land-use with small protected areas embedded within them (Dutta & Jhala, 2014; Dutta, Rahmani, & Jhala, 2011; Singh et al., 2006)
... The pros and cons of land sparing versus land sharing have been discussed in detail from many different viewpoints: economic, ecological, agricultural, political, etc. Green et al., 2005;Hodgson et al., 2010;Tscharntke et al., 2005). Here, we ask whether one of these two solutions is overall likely to perform better than the other, considering eco-evolutionary dynamics. ...
... Separating the territory between areas to be protected and others to be left to intensive agriculture is at odds with the European approach of rural development (Cochrane and Wojan, 2008). However, zoning relates to the debate on land sparing vs land sharing which has resurfaced in the EU, given the recent findings on the relative environmental benefits of both policies (Hodgson et al., 2010, Gabriel et al., 2013, Phalan et al., 2011. The need to conciliate the protection of biodiversity and higher production makes it worth to investigate more thoroughly the pros and cons of zoning. ...
This thesis analyses both theoretically and empirically some of the issues that emerge when applying environmental policies to the agricultural sector in a trade context. In a first part, Chapter II illustrates the possible leakage effects of environmental policies implemented unilaterally. A computable general equilibrium model is used to quantify the indirect global impacts of a greening of European agriculture through a large shift to organic farming. Organic farming is known for its local environmental benefits, especially on water and soil quality, biodiversity and greenhouse gas emissions. However, organic yields are on average 25% lower than those of conventional farming. We calibrate organic production technologies using micro-level data and find that using organic production techniques on 20% of the European area cultivated with maize, rapeseed, sunflower and wheat results in a large negative productivity shock. This shock affects global markets and induces production and demand displacements, unless the yield gap is reduced. The resulting land use changes are assessed, as well as the corresponding changes in greenhouse gas emissions, chemical inputs use and biodiversity. The negative indirect effects on the environment appear limited compared to the local benefits of adopting greener forms of agriculture in the EU. However, in the case of greenhouse gases, the indirect emissions more than offset the local benefits of organic agriculture. In the case of chemical pollution and biodiversity, results show that indirect effects deserve to be accounted for in life cycle analyses. These findings should not be used to point a finger on organic farming, a large variety of policies and consumption patterns have greater land use change impacts. Nevertheless, they rise some issues, especially on the need for more systematic sustainability assessments, even for environmental polices, the importance of research and development in organic farming to reduce yield gaps and of public policies to help to remove economic factors that could limit the increase of organic yields, such as the relative cost of production factors. In a second part, focus is on crop biodiversity, which is known to maintain agricultural productivity under a large range of environmental conditions. Interactions between crop biodiversity effects, environmental policies and trade are complex. Specialisation induced by trade, following comparative advantages, tends to reduce the number of crops cultivated in a given country and then reduces crop biodiversity. A decrease in crop biodiversity results in lower resilience to pest attacks. To face higher pest attacks, farmers use pesticides. But since pesticides harm environment and human health, governments regulate their use. In a free trade context, an environmental policy on pesticides can thus have a strategic aspect: allowing the use of more pesticides can lead to gain larger agricultural market shares. Chapter III represents these interactions in a Ricardian trade model. It shows that, because not in my backyard effects are larger than strategic impacts, the optimal environmental policy is more stringent under trade than under autarky. Furthermore, because of this stringency, production volatility is generally higher under trade. This could explain part of the background volatility observed on agricultural markets, which have been historically more volatile than those of manufactured products. Chapter IV empirically confirms the positive impact of crop biodiversity on agricultural production using a large dataset on South African agriculture. Developing a structural approach, it also analyses the role played by biodiversity on the exposure of farmers to production risks and downside risks.
... Organic farming is seen as a land use system that strives to minimize negative environmental impacts such as the loss of biodiversity, nutrient leakage, and soil degradation (e.g., Lori et al. 2017). Although there is strong evidence that organic farming can reduce the negative impacts of land use, the positive effects on biodiversity are viewed controversially (Seufert and Ramankutty 2017;Hodgson et al. 2010). A relatively small proportion of land up to now has been certified organic in the European Union. ...
The loss of biodiversity in agricultural landscapes has been dramatic over the past few decades with negative trends persisting. Organic farming has received widespread recognition in the scientific and politic fields for its environmental benefits, although the proportion of land cultivated organically is still small and the extent to which organic farming contributes to the promotion of biodiversity is viewed controversially. We present a critical, quantitative review of 98 mainly peer-reviewed papers selected from 801 studies in temperate climate zones published over the period 1990–2017. We quantified differences in the species richness and abundance of selected flora and fauna groups. In total, 474 pairwise comparisons that compared organic and conventional farming systems were considered. Overall, organic farming showed higher species richness or abundance in 58% of the pairs. No differences were found for 38%, 4% indicated negative effects from organic farming. The average (median) species numbers of flora on arable land were 95% higher under organic management as well as 61% higher for seedbank and 21% higher for field margin vegetation. For field birds, the species richness was 35%, and the abundance was 24% higher in organic farming; for insects, the corresponding values are 22% and 36% and for spiders 15% and 55%. Our study underlines that organic farming can play an effective role in acting against the loss of biodiversity. Future research should focus on the combined effects of landscape structures and organic farming, the effect of large-scale organic farming, as well as on the correlation of species diversity and production parameters. To meet the systems’ representativeness, even more strict selection criteria need to be applied in further analysis.
... Por tanto, parece imposible encontrar una estrategia universalmente efectiva, y más bien, debemos evaluar la efectividad de cada una dependiendo del contexto socio-ecológico del lugar. Hodgson et al. (2010) sugieren que la estrategia de aislamiento es más adecuada en paisajes altamente productivos mientras que, en paisajes de baja productividad (e.g., ecosistemas de montaña), la estrategia de integración es más favorable. En la medida que logremos entender mejor las necesidades ecológicas de las poblaciones y comunidades biológicas, lograremos formular estrategias de conservación más efectivas para cada caso. ...
Actividades productivas como la ganadería y la agricultura están promoviendo la expansión acelerada de paisajes antrópicos (PAs). Estos paisajes están compuestos por diferentes tipos de coberturas (e.g. vegetación nativa, cultivos, pastizales, asentamientos humanos), cada una de ellas con diferente geometría y arreglo espacial (e.g. número, tamaño, forma y aislamiento de parches). Entender la respuesta de la biodiversidad a estos cambios espaciales en el hábitat tiene implicaciones teóricas y aplicadas muy importantes. Aunque este tema ha recibido un interés creciente en las ciencias biológicas, la vasta disponibilidad de modelos teóricos y su dispersión en la literatura científica puede dificultar la selección del abordaje teórico más adecuado y su aplicación en ecología y biología de la conservación. Este trabajo sintetiza los principales modelos teóricos y debates sobre los factores determinantes de la biodiversidad en PAs. Encontramos que es un tema en expansión desde los años 60, con modelos y debates cada vez más complejos. Por ejemplo, observamos un incremento en la escala de análisis, desde los primeros modelos basados en factores locales (e.g. tamaño, aislamiento y calidad de parches de hábitat) a modelos basados en atributos del paisaje (e.g. cantidad de hábitat). Dicha complejidad también está asociada a la incorporación de variables de respuesta a nivel de comunidad, pues se inició estudiando patrones de ocupación de especies, pero los modelos más recientes incorporan medidas de diversidad alfa, beta y gamma. También son cada vez más realistas, pues se ha pasado de modelos basados en paisajes binarios (parche-matriz), a modelos basados en paisajes heterogéneos (mosaicos). Aunque faltan evidencias empíricas para sustentar muchos de los modelos propuestos, el desarrollo de herramientas de análisis cada vez más robustas y accesibles está contribuyendo a construir una ciencia con mayor capacidad predictiva sobre los principales determinantes de la biodiversidad en PAs-información clave para informar planes de manejo y conservación.
... A useful indicator of habitat quality can be established if it lies within or partly within a designated or proposed Wildlife Site. Such sites are often maintained through sensitive habitat management practices (Selman 2009), and must reach a certain quality standard before being designated, for example Sites of Special Scientific Interest (Spash and Simpson 1992) and subsequently managed for biodiversity (Hodgson et al. 2010). Vector dataset layers for proposed and designated Wildlife Sites for the study area were acquired directly from the SWT and were used in combination with habitat area to indicate quality. ...
Context
Habitat loss and fragmentation contribute significantly to pollinator decline and biodiversity loss globally. Conserving high quality habitats whilst restoring and connecting remnant habitat is critical to halt such declines.
Objectives
We quantified the connectivity of pollinator habitats for a generic focal species (GFS) which represented three groups of pollinators in an existing coastal nectar habitat network. Subsequently, in partnership with a conservation agency, we modelled an improved landscape that identified priority habitat patches to increase connectivity for pollinators.
Methods
We selected 4260 pollinator habitats along an 80 km section of coastland in Scotland using Phase 1 habitat data. A GFS represented three vulnerable European pollinator groups while graph theory and spatial metrics were used to identify optimal sites that could enhance habitat connectivity.
Results
Higher dispersing species experienced greater habitat connectivity in the improved landscape and habitat availability increased substantially in response to small increases in habitat. The improved landscape revealed important habitat patches in the existing landscape that should be protected and developed.
Conclusions
Our findings highlight that optimal landscapes can be designed through the integration of habitat data with spatial metrics for a GFS. By adopting this novel approach, conservation strategies can be targeted in an efficient manner to conserve at-risk species and their associated habitats. Integrating these design principles with policy and practice could enhance biodiversity across Europe.
Enhancing crop diversification in intensive fields has the potential to increase crop yield and reduce environmental footprint. However, these relationships at the landscape scale remained unclear in intensive farming. Addressing this gap, this paper aims to elucidate how crop yield, resources use efficiency (RUE), and environmental footprint (EF) vary with crop diversification levels in the North China Plain. Management practices, including crop pattern, field size, and agronomic inputs, were collected for 421 landscapes of 1 × 1 km subplots using Sentinel-2 and Landsat-8 images and survey. The results showed that, at the landscape scale, energy and fertilizer contributed over 53 %, and 37 % of the carbon footprint, respectively. N fertilizer constituted >98 % of the nitrogen footprint. P fertilizer accounted for over 80 %, while electricity comprised >13 % of the phosphorus footprint. Compared with simplified landscapes, diversified landscapes exhibited several significant features: 1) 56 % reduction of the area ratio of winter wheat-summer maize double crop pattern (WM), 2) a significant decrease in field size, 3) the decreased use of total NPK fertilizers at 32 %, 30 %, and 30 %, respectively, 4) the increased inputs of irrigation water, diesel, electricity, pesticide and labour at 21 %, 19 %, 21 %, 77 %, and 92 %, respectively. Although yield could be reduced at 33 % when transforming simplified landscapes into moderately diversified ones, they increased with the further promotion of crop diversification. Thus, the diversified landscapes could achieve a balance in yield, RUE, and EF to enhance sustainability, whereas simplified landscapes can similarly achieve a balance to benefit productivity. We emphasize the viable potential of diversified landscapes to enhance sustainable agricultural development by optimizing crop composition. This analysis offers pioneering evidence of landscape-scale agronomic and environmental performances of crop diversification.
Agriculture is the main driver of the rapid collapse of biodiversity, upon which all life on Earth, including agricultural production, depends. As we face the challenge of feeding a growing human population under a changing climate regime, the pressure on biodiversity is expected to further intensify. While the potential to expand and improve natural habitats for biodiversity conservation has been widely explored in large-scale scenarios of agricultural systems, the critical role of agricultural landscapes’ management on halting the loss of biodiversity remains unexplored at this scale. We argue that, to achieve an effective conservation of biodiversity (both natural and agricultural), the combined multivariate effects of agriculture on biodiversity must be accounted for, including its surface area as well as its management. Based on a literature review, we identified the main biodiversity pressures stemming from agriculture: land-use change, contribution to climate change, water withdrawal, pesticide pollution, nutrient (nitrogen and phosphorus) pollution, and landscape and farm-scale simplification (of croplands and pastures). For each one, we proposed a critical boundary, based on reviews of studies covering a range of taxa, biodiversity metrics, and biomes, below or above which negative impacts on biodiversity are minimized or positive effects arise. Implemented simultaneously, the identified boundaries would integrate biodiversity conservation within and across farmlands and minimize agriculture’s far-reaching impacts on biodiversity. We present a framework called “agricultural boundaries for biodiversity” that will allow to explore the potential of developing agricultural systems that effectively reconcile food production and biodiversity conservation at large scales.
Since the introduction of the terms in the early 2000s, the land sharing versus land sparing dichotomy has sparked considerable discussion stemming from the relationship between food production and ecological function. The theory underpinning these approaches straddles disciplinary and ideological boundaries and is frequently outlined within a general economy versus ecology background. Both strategies have come up with competing models on the relationship linking agricultural production and ecological function.
The present work introduces a conceptual synthesis to unify alternative models under a single coherent framework. A generalized model linking agricultural production with ecological function that can harmonize these conflicting views is presented. In addition, a conceptual shift of paradigm is suggested to approach the issue, moving from yield targets to preservation thresholds.
This article provides the theoretical means to identify the environmental and policy conditions under which land sharing strategies, based on low inputs and low impact per unit of cultivated land, can compete with land sparing approaches for the combined goals of biodiversity preservation and food safety.
European ecosystems and species remain under pressure from intensive agriculture and forestry, fishing, pollution, urban sprawl, invasive species and climate change. This book provides a detailed description and critical analysis of nature conservation responses, achievements and failures, motivated by the concerning state of nature and missed biodiversity targets. It summarises Europe's nature and the impact of human activities, and then gives an overview of relevant international biodiversity treaties and the EU nature conservation policy and legislative framework. The core of the book comprises chapters written by national experts, which cover the UK and twenty-five EU Member States, providing comparative case studies from which valuable lessons are drawn. Covering wide-ranging topics such as biodiversity pressures, legislation and governance, biodiversity strategies, species protection, protected areas, habitat management, and funding, this book is of interest to a wide audience, including academics and professionals involved in nature conservation and related environmental fields.
To assess the biodiversity consequences of contemporary land-use trends in Northern Europe, where agriculture is being replaced by forestry, we need a better knowledge of the contributions of constituting habitats to biodiversity. Here, we use purposefully collected data from 87 sites to model how agricultural habitats, including semi-natural pastures, sown temporary grassland (leys), cereal crops, and forest habitats comprising both mature production forests and clear-cuts, contribute to landscape-scale diversity of plants, bumblebees and butterflies in boreonemoral Sweden. At the local scale, species richness was highest in semi-natural pastures, intermediate in cereal crops and leys and lowest in forest. In clear-cuts, species richness was similarly high to that in semi-natural pastures. Countryside species-area models show that at a landscape scale, the high local richness in clear-cuts was more than offset by the low species richness encountered in forest. At landscape scale, semi-natural pastures, and in the case of plants also cereal crops, were major contributors of unique species. Leys and semi-natural pastures were both important contributors to bumblebee diversity. The effect of the surrounding landscape composition on local diversity was weak, suggesting that area-based approximations of landscape-scale species richness were reasonable. We conclude that clear-cuts constitute habitats for open-land species but cannot maintain landscape-scale diversity in the face of agricultural abandonment when open land is replaced by even-aged production forests. Maintaining farmland, in particular semi-natural pastures but also cereals and leys, is therefore critical to maintaining the landscape-scale species richness of plants and insects in forestry-dominated areas.
The socio-economic implications of the novel agricultural practices have been studied by many of the social scientists. Such studies contrast from micro to meso and national levels. The degree of overall transformation in the combinations of crops in space and time has, however, not been studied at national level. Apart from the physical environment, changes in the socio-economic conditions and land tenure have brought change in cropping patterns and thus made the structure of the Indian agriculture non-rigid. The present effort is a modest challenge to make appraisal of crop-based farming system for sustainable agricultural development. The study was carried out for characterization of land resources of overriding farming systems of Katihar district in Bihar. The evaluation of land resources for Land Utilization Index (LUI) was done by Sentinel-2 along with farmers’ surveyed data in GIS domain. Spatial distribution of NPK (nitrogen, potassium, and phosphorus), organic carbon, electrical conductivity, and pH were analyzed for assessing soil health and physiognomies. These indices were also used to devise agricultural land utilization index for suggesting cropping patterns. Agricultural land resources and their characterizations were categorized on the basis of seasonal cropping practices in the study area as single, double, and triple cropping pattern along with productivity. The study revealed nutrient availability, number of irrigation intensity, slope, and seasonal variation of crop vegetation (Kharif and Rabi) index and validated productivity available in the study area based on the combination of different agricultural practices.KeywordsLand resourceLand utilization indexSoil micronutrientsCharacterization
Grassland insects face some of the most severe declines in species diversity and total abundance, in part due to agriculture. Livestock grazing is the largest agricultural land use and can have both positive and negative effects on insect communities and populations. A global synthesis is needed to guide butterfly conservation and provide recommendations for scientists, managers, and other stakeholders seeking to use grazing as a tool for butterfly conservation. Here I review 115 studies that evaluate how cattle grazing affects butterfly communities and species. I discuss how various aspects of cattle grazing affect butterfly community and species responses. Thirty-five studies concluded cattle grazing has positive effects on butterflies, while 20 concluded cattle grazing has negative effects. Thirty-six were inconclusive or found no effect of grazing. Conclusions depended heavily on the management chosen as well as environmental and evolutionary factors. Eighty-five studies (74%) were located in Europe, providing a useful framework for the rest of the world, but also creating opportunities for further research.
Implications for practice
Low to moderate grazing intensity is the most beneficial grazing management strategy for butterflies. There is also potential for rotational grazing to provide benefits, but more research is needed. It is important to have variation in grazing management and other disturbance types in the landscape (mowing, prescribed fire, etc.) to accommodate differing habitat needs of butterfly species. Cattle grazing has potential as a land-sharing opportunity to promote grassland butterfly diversity in agroecosystems.
The diversity and abundance of wild pollinators, has undergone tremendous decline. The exact cause of such reduction is obscure and not localized. However, the significant drivers of pollinator decline are habitat loss, exposure to parasites, indiscriminate use of pesticides, and flowers' absence. The present study investigates the impact of conservation practices over the native pollinators' population and the yield of Brassica napus (Canola) using a case study. Three locations were selected as conservation and sampling sites to collect the pollinator's population data and impact the quality and yield of canola from 2014 to 2019. Results revealed that the pollinators' activity in canola surrounding fields was enriched in the conservation sites. Plants have the highest pollinator activity and pollen deposition within 1000 m of the conservation sites than plants at a more considerable distance from the conservation sites. Beyond the 1000 m range, fewer pollinators were observed, including the A. mellifera, A. dorsata, and A. cerana. This study deduces that the decline in the diversity and abundance of pollinator could threaten the crop pollination and ultimately causes yield loss. Based on our study, we recommend maintaining the on farm conservation of pollinators and the employment of effective crop management methods that enhance the pollinators' foraging activity should be adopted.
Land use change has detrimental impacts on the planet. It is not only a major cause of biodiversity loss, through habitat destruction and fragmentation, but also an important driver for climate change, through deforestation and peat oxidation. Land use change is mainly driven by food production, of which meat production comprises the major share. Ecomodernists therefore feel reduction of the impact of meat production is paramount for a sustainable future. To achieve this, ecomodernists focus on intensification of the production process to produce more on less land, both through the closing of global yield gaps and through the development of integrated indoor systems like agroparks. On the demand side, ecomodernists feel a diverse strategy is needed, from the development of meat substitutes and lab meat, to the persuasion of consumers to move from beef to monogastrics like pork or chicken.
The current model of agricultural intensification has increased crop yields and profits for farmers. However, this increase takes place by significant loss of biodiversity as well as ecosystem services, which has become a global concern. In agricultural landscapes, biodiversity loss impairs the functionality of ecosystem in the form of pollination, natural pest control, habitat provision and water purification. In order to restore biodiversity along with maintaining agricultural production, there is need for farmers to switch to a novel farming approach that can optimize ecosystem functions and enhance crop yields. Reports reveal that ecological intensification has potential to ameliorate environmental externalities while preserving crop yields and profitability. To intensify ecological processes in agricultural landscapes, a potential strategy is to employ management practices that reduce or substitute synthetic agrochemical use, maintain or enhance landscape heterogeneity and connectivity. Intensification of eco-friendly nature may be achieved by wildlife-friendly approaches in the form of organic farming, conservation farming, agroforestry, integrated pest management and intercropping. However, lack of comprehensive information on the net benefits of ecological intensification farming practices is currently preventing widespread adoption by farmers. To increase uptake, it is critical that scientists address not only the ecological facets of biodiversity-friendly farming practices but also the economic and social facets.
Current food production systems are major contributors to the environmental degradation that leads to climate change and biodiversity loss. Levels of production required for future food security cannot be met by further increases in inputs of non-renewable resources. The world's food crops must therefore be managed in a sustainable way that maintains long-term ecological functioning, including nutrient, carbon and water cycles, soil quality, primary productivity, microbe-plant associations, pest and pathogen regulation, pollination and arable food web resilience. All of these are determined by agronomic practices at local and regional scales, and all are sustained by the abundance, diversity and functional composition of plants, microbes and invertebrates in the farmed ecosystem. Presence of viable populations and communities of these organisms is therefore essential for system resilience. Long-term sustainability must rely more heavily on the internal generation of products and regulatory ecosystem services than on external inputs. Fully closed systems are impossible to achieve in agriculture as the product is removed for human consumption. There is ample evidence, however, that semi-closed, regenerative, systems can harness the ecosystem services provided by functional biodiversity to enhance crop production whilst simultaneously improving environmental quality. Here, agroecological alternatives to intensive farming practices are reviewed, focusing on key functional indicators and whole-system integration of practical management options designed to achieve multiple beneficial outcomes at field and farm scales.
Context Better balancing agricultural production and biodiversity conservation is a central goal for many landscapes. Yet, empirical work on how to best achieve such a balance has focused mainly on the local scale, thereby disregarding that landscape context might mediate biodiversity-agriculture trade-offs. Objectives Focusing on vertebrates in the Argentine Chaco, we evaluate how trade-offs between agriculture and biodiversity vary with landscape context, from landscapes where agricultural and natural areas are separated to landscapes where both are interspersed. Methods We modelled the distributions of 226 vertebrates and use the resulting maps to describe the species richness of ecosystem-service providing guilds. We calculated three agricultural intensity metrics, and evaluated how both species richness and agricultural intensity vary along a gradient of landscape configuration, while controlling for landscape composition. Results Species richness and agricultural yields both
varied with landscape configuration. Biodiversity was highest in mixed landscapes where agricultural and natural area are interspersed, whereas agricultural yields showed a more heterogeneous response, with some yield metrics highest in mixed and others in separated landscapes. As a result, agriculture/biodiversity trade-offs depended strongly on landscape configuration, irrespective of landscape composition. We also identified large areas with low vertebrate
richness and agricultural yields, suggesting considerable potential for improving in at least one dimension. Conclusions Agriculture/biodiversity trade-offs varied with landscape configuration, suggesting that landscape design can balance these trade-offs. Our
simple and broadly applicable approach can provide baseline information for landscape planning aimed at realizing co-benefits between agriculture and biodiversity—in the Gran Chaco and elsewhere.
The organisation of human-populated landscapes results from many interacting processes tied to the historical development of societies and human activities. Agriculture, in particular, has dramatically altered much of the Earth's surface over many millennia. Landscape mosaics can be used to understand these impacts, which are increasing at an accelerating rate on a global scale. On a local-to-regional scale, mosaic concepts are also of practical interest for designing natural enemy-based pest control strategies as an alternative to intensive pesticide use. Considerable empirical and theoretical work has been conducted into these approaches recent years, although it has largely dealt with issues of landscape biodiversity at the species population level, rather than considering the role of species interactions. When viewed as interaction networks, agricultural landscapes can be used to address a more diverse suite of topics, such as those related to network complexity, community demographics, or ecosystem functioning, and how these properties vary with the complexity of the landscape mosaic over time and space. Ultimately, the functioning of an agricultural landscape determines the production of ecosystem services, such as crop production and pest control, yet ecological theory-based management options are still scarce. Consequently, there is a significant gap to be bridged between the current state-of-the-art in theoretical ecology and practical strategies for the management of agricultural landscapes. One way to bridge this gap involves developing metaecosystem models that can account for the movement and internal dynamics of both biotic and abiotic components of ecosystems. By recognising the specifics of agricultural landscapes, that is, their heterogeneity over time and space, the occurrence of frequent perturbations and the importance of nutrient additions at the landscape scale, metaecosystem models can be proposed to answer some current challenges in agroecology.
En réponse aux pertes de biodiversité et à une insécurité alimentaire croissante, l’agriculture moderne doit se tourner vers une gestion plus durable des paysages agricoles. L’Agriculture Biologique (AB) est considérée comme une solution prometteuse à ces enjeux. En effet, ses pratiques agricoles étant globalement plus favorables aux ennemis naturels de ravageurs que celles de l’Agriculture Conventionnelle (AC), elle pourrait permettre de remplacer l'utilisation des pesticides par celle du contrôle biologique. Cependant, les études évaluant ces effets restent contradictoires, probablement car elles ne tiennent pas compte de la diversité des pratiques réalisées en AB et en AC. A plus large échelle, les pratiques ont par ailleurs rarement été considérées dans la description de l’hétérogénéité paysagère, bien que la nature et l’organisation spatiale de la matrice agricole soit susceptible d’affecter les espèces qui y vivent. L’objectif de ce travail de thèse est d’évaluer les effets de la diversité et de l’organisation spatiale des pratiques en AB et en AC sur les insectes auxiliaires, à l’échelle de la parcelle et du paysage. Un travail de terrain a été réalisé en 2012 et 2013 en Ille et Vilaine. Quarante paires de parcelles de blé d’hiver en AB et en AC ont été sélectionnées, réparties le long d’un gradient paysager de surfaces en AB. Dans chaque parcelle, les communautés d'ennemis naturels de pucerons (coccinelles, carabes, parasitoïdes) ont été échantillonnées. Des enquêtes ont permis de caractériser les pratiques agricoles réalisées par les agriculteurs dans les parcelles suivies et dans leur environnement paysager. Nous avons mis en évidence l’existence d’une large diversité de pratiques agricoles dans les systèmes en AB et en AC. A l’échelle parcellaire, les effets des pratiques sur la diversité des insectes auxiliaires sont forts, les systèmes en AB leur étant globalement plus favorables. Considérer un niveau plus fin de description des pratiques nous a permis d’identifier celles qui affectent réellement les insectes et de montrer qu’il est possible de favoriser leur présence, quel que soit le mode de production. A l’échelle du paysage, nous n’avons mis en évidence aucun effet de l’étendue et de l’organisation de l’AB sur les ennemis naturels. Une description plus fine des pratiques nous a malgré tout permis de souligner l’importance de certaines stratégies de pratiques, à certaines échelles. A partir de ces résultats, nous proposons des pistes pour l’aménagement des paysages agricoles. Les problèmes méthodologiques liés à la description des pratiques agricoles à l’échelle du paysage sont également discutés.
The principal objections to the proposition that organic agriculture can contribute significantly to the global food supply are low yields and insufficient quantities of organically acceptable fertilizers. We evaluated the universality of both claims. For the first claim, we compared yields of organic versus conventional or low-intensive food production for a global dataset of 293 examples and estimated the average yield ratio (organic:non-organic) of different food categories for the developed and the developing world. For most food categories, the average yield ratio was slightly <1.0 for studies in the developed world and >1.0 for studies in the developing world. With the average yield ratios, we modeled the global food supply that could be grown organically on the current agricultural land base. Model estimates indicate that organic methods could produce enough food on a global per capita basis to sustain the current human population, and potentially an even larger population, without increasing the agricultural land base. We also evaluated the amount of nitrogen potentially available from fixation by leguminous cover crops used as fertilizer. Data from temperate and tropical agroecosystems suggest that leguminous cover crops could fix enough nitrogen to replace the amount of synthetic fertilizer currently in use. These results indicate that organic agriculture has the potential to contribute quite substantially to the global food supply, while reducing the detrimental environmental impacts of conventional agriculture. Evaluation and review of this paper have raised important issues about crop rotations under organic versus conventional agriculture and the reliability of grey-literature sources. An ongoing dialogue on these subjects can be found in the Forum editorial of this issue.
Butterfly transects were conducted on eight pairs of organic and conventional farms in the UK in 1994, and ten pairs of farms in 1995. Each transect included areas of conventional and organic farmland. All species seen, and the abundance of each species, were recorded separately for the uncropped field boundary and the crop edge. In both years, significantly more non-pest butterflies were recorded on organic than on conventional farmland, and more non-pest butterflies were recorded over the uncropped boundary habitat than over the crop edge habitat in both systems. By contrast, there was no significant difference in either year in the abundance of two pest species, Pieris brassicae (the large white) and Pieris rapae (the small white) between the two systems. Implications of the results for the conservation of butterflies within agricultural systems are discussed • © 1997 Elsevier Science B.V.
The efficiency of agricultural subsidy programmes for preserving biodiversity and improving the environment has been questioned in recent years. Organic farming operates without pesticides, herbicides and inorganic fertilizers, and usually with a more diverse crop rotation. It has been suggested that this system enhances biodiversity in agricultural landscapes. We analysed the effects of organic farming on species richness and abundance using meta‐analysis of literature published before December 2002.
Organic farming usually increases species richness, having on average 30% higher species richness than conventional farming systems. However, the results were variable among studies, and 16% of them actually showed a negative effect of organic farming on species richness. We therefore divided the data into different organism groups and according to the spatial scale of the study.
Birds, insects and plants usually showed an increased species richness in organic farming systems. However, the number of studies was low in most organism groups (range 2–19) and there was significant heterogeneity between studies. The effect of organic farming was largest in studies performed at the plot scale. In studies at the farm scale, when organic and conventional farms were matched according to landscape structure, the effect was significant but highly heterogeneous.
On average, organisms were 50% more abundant in organic farming systems, but the results were highly variable between studies and organism groups. Birds, predatory insects, soil organisms and plants responded positively to organic farming, while non‐predatory insects and pests did not. The positive effects of organic farming on abundance were prominent at the plot and field scales, but not for farms in matched landscapes.
Synthesis and applications. Our results show that organic farming often has positive effects on species richness and abundance, but that its effects are likely to differ between organism groups and landscapes. We suggest that positive effects of organic farming on species richness can be expected in intensively managed agricultural landscapes, but not in small‐scale landscapes comprising many other biotopes as well as agricultural fields. Measures to preserve and enhance biodiversity should be more landscape‐ and farm‐specific than is presently the case.
One of the main aims of agri‐environment schemes (AES) is to increase biodiversity on farmland. Common conservation practice is to identify areas containing valuable resources (e.g. habitats, ecosystems and species) and then to protect them: ‘protected area’ schemes. AES differ from typical protected area schemes because they are often applied to small patches of land, such as field boundaries, and are sometimes located in areas where the target species does not occur.
AES require an enormous amount of funding and they have been applied across a large geographical area, i.e. the European Union. However, recent evidence suggests mixed results regarding the effects of AES on biodiversity.
It is hard to predict the consequences of AES on biodiversity because a number of factors are seldom accounted for explicitly. For example: (i) the occurrence of target species will vary between patches; (ii) there will be variation in habitat preference by species in different geographical areas; (iii) both optimal foraging theory and metapopulation theory predict that the distance from breeding individuals is likely to determine patch use; (iv) if resources are widely spread then the home ranges of some species may need to increase to encompass the multiple resources needed for breeding. The potential for these factors to affect the outcome of AES on biodiversity is discussed.
Synthesis and applications . AES are likely to increase biodiversity if a lower number of larger resource patches are provided, in contrast to current practice that promotes many small fragmented areas of environmental resource. One way of achieving this may be to run these schemes more like traditional protected area schemes, with farms or groups of farms managed using extensive farming methods. Such an approach negates some of the problems of current AES and may help to address a wider range of concerns held by different countryside stakeholders.
Agricultural intensification is a major cause for biodiversity loss. It occurs at field scales through increased inputs and outputs, and at landscape scales through landscape simplification. Agri-environment schemes (AES) of the European Common Agricultural Policy (CAP) aim at reducing biodiversity loss by promoting extensification of agricultural practises mostly at field scales. We present a conceptual model for the relationship between landscape complexity and ecological effectiveness of AES based on (a) non-linear relationships between landscape complexity and abundance and diversity at field scales and (b) four possible interactive scenarios between landscape- and field scale effects on abundance and diversity. We then evaluated whether and how effectiveness of AES interacted with landscape-scale effects of intensification along a landscape complexity gradient established in central Spain. Pairs of cereal fields with and without AES but with the same landscape context were selected in three regions differing in landscape complexity. Effectiveness of AES was measured as differences between paired fields in species richness and abundance of five target groups (birds, grasshoppers and crickets, spiders, bees and plants). Landscape metrics were measured in 500–m radius circular plots around field centres. Positive, negative and no effects of landscape complexity on effectiveness of AES were found, suggesting that effects of complexity on effectiveness of AES changes from positive to negative along gradients of landscape complexity. Effectiveness of AES for improving biodiversity was then constrained by landscape. Compulsory measures aimed at enhancing or maintaining landscape complexity would enhance the effectiveness of AES for preserving biodiversity in farmed landscapes.
This paper provides a detailed description and analysis of habitat and management differences between 89 pairs of organic and non-organic fields on 161 farms containing arable crops distributed throughout England. Data were derived at different scales ranging from field to landscape scale using a range of methods including: land manager questionnaires, habitat surveys and the use of large-scale landscape datasets. Organic farms were situated in inherently more diverse landscape types, had smaller field sizes, higher, wider and less gappy hedgerows subject to less frequent management, used rotational practices including grass, were more likely to be mixed farms and did not use artificial fertilisers and pesticides.Organic farms were associated with heterogeneous landscape types. However, even in such landscape types the organic farming system produced greater field and farm complexity than farms employing a non-organic system. The findings of the study point to the importance of organic farming systems for maintaining landscape and local complexity with consequent benefits for biodiversity in arable farming landscapes.
Does the intensification of agriculture reduce cultivated areas and, in so doing, spare some lands by concentrating production on other lands? Such sparing is important for many reasons, among them the enhanced abilities of released lands to sequester carbon and provide other environmental services. Difficulties measuring the extent of spared land make it impossible to investigate fully the hypothesized causal chain from agricultural intensification to declines in cultivated areas and then to increases in spared land. We analyze the historical circumstances in which rising yields have been accompanied by declines in cultivated areas, thereby leading to land-sparing. We use national-level United Nations Food and Agricultural Organization data on trends in cropland from 1970-2005, with particular emphasis on the 1990-2005 period, for 10 major crop types. Cropland has increased more slowly than population during this period, but paired increases in yields and declines in cropland occurred infrequently, both globally and nationally. Agricultural intensification was not generally accompanied by decline or stasis in cropland area at a national scale during this time period, except in countries with grain imports and conservation set-aside programs. Future projections of cropland abandonment and ensuing environmental services cannot be assumed without explicit policy intervention.
During the next 50 years, which is likely to be the final period of rapid agricultural expansion, demand for food by a wealthier and 50% larger global population will be a major driver of global environmental change. Should past dependences of the global environmental impacts of agriculture on human population and consumption continue, 10(9) hectares of natural ecosystems would be converted to agriculture by 2050. This would be accompanied by 2.4- to 2.7-fold increases in nitrogen- and phosphorus-driven eutrophication of terrestrial, freshwater, and near-shore marine ecosystems, and comparable increases in pesticide use. This eutrophication and habitat destruction would cause unprecedented ecosystem simplification, loss of ecosystem services, and species extinctions. Significant scientific advances and regulatory, technological, and policy changes are needed to control the environmental impacts of agricultural expansion.
Climate change over the past approximately 30 years has produced numerous shifts in the distributions and abundances of species and has been implicated in one species-level extinction. Using projections of species' distributions for future climate scenarios, we assess extinction risks for sample regions that cover some 20% of the Earth's terrestrial surface. Exploring three approaches in which the estimated probability of extinction shows a power-law relationship with geographical range size, we predict, on the basis of mid-range climate-warming scenarios for 2050, that 15-37% of species in our sample of regions and taxa will be 'committed to extinction'. When the average of the three methods and two dispersal scenarios is taken, minimal climate-warming scenarios produce lower projections of species committed to extinction ( approximately 18%) than mid-range ( approximately 24%) and maximum-change ( approximately 35%) scenarios. These estimates show the importance of rapid implementation of technologies to decrease greenhouse gas emissions and strategies for carbon sequestration.
There is growing concern about increased population, regional, and global extinctions of species. A key question is whether extinction rates for one group of organisms are representative of other taxa. We present a comparison at the national scale of population and regional extinctions of birds, butterflies, and vascular plants from Britain in recent decades. Butterflies experienced the greatest net losses, disappearing on average from 13% of their previously occupied 10-kilometer squares. If insects elsewhere in the world are similarly sensitive, the known global extinction rates of vertebrate and plant species have an unrecorded parallel among the invertebrates, strengthening the hypothesis that the natural world is experiencing the sixth major extinction event in its history.
World food demand is expected to more than double by 2050. Decisions about how to meet this challenge will have profound effects on wild species and habitats. We show that farming is already the greatest extinction threat to birds (the best known taxon), and its adverse impacts look set to increase, especially in developing countries. Two competing solutions have been proposed: wildlife-friendly farming (which boosts densities of wild populations on farmland but may decrease agricultural yields) and land sparing (which minimizes demand for farmland by increasing yield). We present a model that identifies how to resolve the trade-off between these approaches. This shows that the best type of farming for species persistence depends on the demand for agricultural products and on how the population densities of different species on farmland change with agricultural yield. Empirical data on such density-yield functions are sparse, but evidence from a range of taxa in developing countries suggests that high-yield farming may allow more species to persist.
Habitat and biodiversity differences between matched pairs of organic and non-organic farms containing cereal crops in lowland England were assessed by a large-scale study of plants, invertebrates, birds and bats. Habitat extent, composition and management on organic farms was likely to favour higher levels of biodiversity and indeed organic farms tended to support higher numbers of species and overall abundance across most taxa. However, the magnitude of the response varied; plants showed larger and more consistent responses than other taxa. Variation in response across taxa may be partly a consequence of the small size and isolated context of many organic farms. Extension of organic farming could contribute to the restoration of biodiversity in agricultural landscapes.
The present path of agricultural development will not achieve development goals according to a recent assessment, but a solid foundation for improvements exists.
"Measuring Biological Diversity assumes no specialist mathematical knowledge and includes worked examples and links to web-based software. It will be essential reading for all students, researchers, and managers who need to measure biological diversity."--BOOK JACKET.
As the demands on agricultural lands to produce food, fuel, and fiber continue to expand, effective strategies are urgently needed to balance biodiversity conservation and agricultural production. "Land sparing" and "wildlife-friendly farming" have been proposed as seemingly opposing strategies to achieve this balance. In land sparing, homogeneous areas of farmland are managed to maximize yields, while separate reserves target biodiversity conservation. Wildlife-friendly farming, in contrast, integrates conservation and production within more heterogeneous landscapes. Different scientific traditions underpin the two approaches. Land sparing is associated with an island model of modified landscapes, where islands of nature are seen as separate from human activities. This simple dichotomy makes land sparing easily compatible with optimization methods that attempt to allocate land uses in the most efficient way. In contrast, wildlife-friendly farming emphasizes heterogeneity, resilience, and ecological interactions between farmed and unfarmed areas. Both social and biophysical factors influence which approach is feasible or appropriate in a given landscape. Drawing upon the strengths of each approach, we outline broad policy guidelines for conservation in agricultural landscapes.
To examine the importance of management practices and landscape structure on diversity of butterflies 16 farms with organic or conventional management were censused during 1997 and 1998. On each farm a transect route was walked during July and the beginning of August, six times in 1997 and five times in 1998. The farms were located in the central part of Sweden in two adjacent regions with the same pool of species. The organic and conventional farms were paired with help of the Bray-Curtis dissimilarity index according to land use to control for landscape structure on the farm level.
On each farm calculations were made of large- and small-scale landscape heterogeneity with the help of GIS. A grid with a mesh size of 400 m was placed over each farm and the small-scale heterogeneity was calculated as the mean habitat diversity of four squares. The large-scale landscape heterogeneity described the landscape in which the farms were imbedded, and covered an area of 5x5 km.
No differences in butterfly diversity, number of species or number of observations were noted between organic and conventional farms. Butterfly diversity was positively correlated with small-scale landscape heterogeneity while butterfly abundance was positively correlated with large-scale heterogeneity. Both large-scale and small-scale heterogeneity were important for the composition of species. The landscape structure seemed to be more important for butterfly diversity and species composition than the farming system in itself.
A method based on transect count has been developed to assess changes in abundance of butterflies from year to year. The method involves weekly walks around atransect route making counts of butterflies seen within defined limits. The transects are divided into sections related to habitat or management units. Walks are made only when weather conditions satisfy specified minimum requirements. The method has been tested for three years at Monks Wood and for two years at a number of other sites.The basis for annual comparisons is an index of abundance which is produced for each brood of each species, except when separation of broods is not possible. This index is correlated with abundance, although the precise nature of the relationship will vary from species to species. Evidence on this presented for two species.The method makes it possible to monitor the abundance of butterflies at selected sites, using recorders, such as nature reserve wardens, who can fit in one or two hours recording each week when the weather is suitable. Such a scheme, based on the methods described in this paper, began in 1976. In addition to the monitoring of fluctuations of abundance, the method provides considerable information on the phenology and ecology of butterflies. The division of the transects into sections makes some assessment of the effects of habitat change, due to management or other factors, possible.
This study examined how field boundary habitat quality and farming system (organic or conventional) affect species richness and abundance of diurnal lepidopterans and bumblebees in boreal agricultural landscapes. The results showed positive effects of field boundary area on lepidopteran diversity, as well as positive effects of nectar flower abundance on lepidopterans and bumblebee abundance. Organic farming did not show any significant effects on lepidopteran diversity. The results suggested that a successful conservation strategy for lepidopterans occurring in boreal agroecosystems depend on proper management of field boundaries, irrespective of farming regime. As bumblebee diversity tended to be higher at organic plots it is concluded that these important pollinators might be able to react on even small changes in habitat quality of cultivated lands. The results concord with a general hypothesis that effects of organic farming might be overpowered by effects of landscape structure in heterogeneous landscapes.
The recent dramatic decline in farmland biodiversity is often attributed to agricultural intensification and structural changes in the agricultural landscape. One suggested farm practice seen to benefit biodiversity and reverse declines is organic farming. Because organic farming is viewed as a more sustainable form of agriculture it is currently subsidized by European agri‐environment schemes. However, the efficiency of agri‐environment schemes to preserve biodiversity has recently been questioned, partly because their uptake has been highest in extensively farmed more heterogeneous landscapes.
We investigated the effect of farming practice on butterfly species richness and abundance along cereal field headlands and margins on 12 matched pairs of organic and conventional farms in contrasting landscapes (homogeneous and heterogeneous landscape diversity).
Both organic farming and landscape heterogeneity significantly increased butterfly species richness and abundance. There was also a significant interaction between farming practice and landscape heterogeneity, because organic farming only significantly increased butterfly species richness and abundance in homogeneous rather than heterogeneous landscapes.
An analysis of the distribution of organic farming in Sweden in relation to productivity of the arable land (yield of spring barley, kg ha ⁻¹ ) indicated that the distribution of organic farms was skewed towards extensively farmed agricultural areas.
Synthesis and applications. The species richness and abundance of butterflies can be enhanced by actions aimed at both promoting organic farming and increasing landscape heterogeneity. However, the beneficial effect of organic farming was only evident in intensively farmed homogeneous landscapes. Currently, the majority of organic arable land in Sweden is located in heterogeneous landscapes where changing the type of farming practice adds little to the existing biodiversity. We therefore propose that the interaction between landscape heterogeneity and farming practice must be considered when promoting farmland biodiversity, for example in Europe by developing context‐based agri‐environment schemes to increase the amount of organic farming in intensively farmed landscapes. We also propose that in homogeneous agricultural landscapes, organic farming could be used as a more efficient tool to restore landscape heterogeneity if the creation of semi‐natural landscape elements was mandatory in the regulations associated with organic agri‐environment schemes.
Habitat loss and reduction in quality, together with increasing homogeneity of the farmed landscape and more intensive field management, are believed to be major drivers of biodiversity loss on farmland. Organic farms demonstrate features that are now rare elsewhere in UK farming systems, such as crop rotations incorporating grass leys, exclusion of synthetic pesticides and fertilizers, and reliance on animal and green manures. They may also contain greater densities of uncropped habitats such as hedgerows. In this study, we examined whether organic farming affected populations of one group of insects of conservation interest, butterflies, on farmland. The abundance of butterflies on pairs of organically and conventionally managed farms was recorded over 3 years and a number of habitat and crop variables, likely to be related to butterfly abundance, were also measured. Organic farms attracted significantly more butterflies overall than conventional farms. Significantly more butterflies in both farming systems were recorded over the uncropped field margin than the crop edge. The difference in butterfly abundance between crop edge and field margin was relatively greater in conventional than organic systems. Species richness of butterflies tended to be greater on organic farms. Five species of butterfly were significantly more abundant on organic farms in at least 1 year, while no species was significantly more abundant on conventional farms. Organic and conventional cropping patterns differed, the former having proportionally more grass leys, and hedgerows were larger on organic farms. Although no significant effects of farming system on the numbers of grass or forb species present in the field margin or crop edge were detected, some individual plant species showed differences in frequency between organic and conventional field boundaries. Increasing the extent of organic farming, or practices associated with it, could help to restore biodiversity in agricultural landscapes.
Agri‐environmental schemes (AES) are commonly adopted in Europe to reduce the loss of farmland biodiversity. These schemes have, however, been criticized as not fulfilling this goal, partly because their effectiveness is thought to differ depending on external factors such as landscape heterogeneity, the focal organism and scale of application.
We used one AES, organic farming, as a landscape‐scale experiment to test whether its effect on butterflies depends on the spatial scale at which it is applied. Our study system consisted of organically and conventionally managed fields within eight pairs of matched landscapes, differing in the proportion of land under organic management at the landscape scale. Butterflies and their nectar and host‐plant resources were surveyed along the fields and adjacent field borders.
Butterfly species richness and abundance were significantly increased by organic farming at the local scale. However, local butterfly species richness was also positively affected by a large proportion of organic farming in the surrounding landscape, independent of the local farming practice. Local and landscape farming practices interacted such that the farming practice within fields had a larger effect on butterfly abundance if surrounded by conventionally rather than organically managed fields. These results could only partly be explained by variation in local availability of nectar and host‐plant resources.
The total observed species richness (γ‐diversity) was higher in organically managed landscapes, mainly because of higher within‐field diversity (α‐diversity), whereas the between‐field diversity (β‐diversity) tended to be similar in both landscape types.
Synthesis and applications . Butterflies were positively affected by organic farming at a local scale, but the amount of organic farming in the surrounding landscape had either an additive (species richness) or interactive (abundance) effect. Therefore, the spatial distribution of AES must be taken into account to maximize their potential to increase farmland biodiversity. We have shown that organic farming affected butterfly species richness on nearby conventionally managed land. This suggests a landscape effect of organic farming that may indicate a wider benefit of AES for biodiversity conservation.
Increasing concern over the environmental impact of agriculture in Europe has led to the introduction of agri‐environment schemes. These schemes compensate farmers financially for any loss of income associated with measures that aim to benefit the environment or biodiversity. There are currently agri‐environment schemes in 26 out of 44 European countries.
Agri‐environment schemes vary markedly between countries even within the European Union. The main objectives include reducing nutrient and pesticide emissions, protecting biodiversity, restoring landscapes and preventing rural depopulation. In virtually all countries the uptake of schemes is highest in areas of extensive agriculture where biodiversity is still relatively high and lowest in intensively farmed areas where biodiversity is low.
Approximately €24·3 billion has been spent on agri‐environment schemes in the European Union (EU) since 1994, an unknown proportion of it on schemes with biodiversity conservation aims. We carried out a comprehensive search for studies that test the effectiveness of agri‐environment schemes in published papers or reports. Only 62 evaluation studies were found originating from just five EU countries and Switzerland (5). Indeed 76% of the studies were from the Netherlands and the United Kingdom, where until now only c . 6% of the EU agri‐environmental budget has been spent. Other studies were from Germany (6), Ireland (3) and Portugal (1).
In the majority of studies, the research design was inadequate to assess reliably the effectiveness of the schemes. Thirty‐one percent did not contain a statistical analysis. Where an experimental approach was used, designs were usually weak and biased towards giving a favourable result. The commonest experimental design (37% of the studies) was a comparison of biodiversity in agri‐environment schemes and control areas. However, there is a risk of bias if either farmers or scheme co‐ordinators select the sites for agri‐environment schemes. In such cases the sites are likely to have a higher biodiversity at the outset compared to the controls. This problem may be addressed by collecting baseline data (34% of studies), comparing trends (32%) or changes (26%) in biodiversity between areas with and without schemes or by pairing scheme and control sites that experience similar environmental conditions (16%).
Overall, 54% of the examined species (groups) demonstrated increases and 6% decreases in species richness or abundance compared with controls. Seventeen percent showed increases for some species and decreases for other species, while 23% showed no change at all in response to agri‐environment schemes. The response varied between taxa. Of 19 studies examining the response of birds that included a statistical analysis, four showed significant increases in species richness or abundance, two showed decreases and nine showed both increases and decreases. Comparative figures for 20 arthropod studies yielded 11 studies that showed an increase in species richness or abundance, no study showed a decrease and three showed both increases and decreases. Fourteen plant studies yielded six studies that showed increases in species richness or abundance, two showed decreases and no study showed both increases and decreases.
Synthesis and applications . The lack of robust evaluation studies does not allow a general judgement of the effectiveness of European agri‐environment schemes. We suggest that in the future, ecological evaluations must become an integral part of any scheme, including the collection of baseline data, the random placement of scheme and control sites in areas with similar initial conditions, and sufficient replication. Results of these studies should be collected and disseminated more widely, in order to identify the approaches and prescriptions that best deliver biodiversity enhancement and value for money from community support.
Summary • Given the current debate on the global food crisis, conservation in Europe is expected to shift from maximizing biodiversity at the expense of yield to conserving biodiversity under food production constraints. Organic farming is potentially of great importance for environmentally sustainable farming. Understanding the distribution of organic farms and the environmental, social and cultural correlates is necessary to predict the way in which this may change over time. • We collated data from 30 variables describing the topography, climate, soils, farm size/type, human population characteristics and farm business in the English agricultural landscape. Factor analysis reduced these variables to six orthogonal axes, which describe the suitability of land for arable farming, the degree of ruralization (distance to urban centres and population density), the farm size and type, the soil hydrology and texture, and the amount of woodland (forestry). • An analysis of the distribution of organic farms showed that they are spatially aggregated at the regional and neighbourhood scales and that their presence in a 10 × 10-km grid square can be predicted from the farm size/type. • Analysis of the concentration of organic farms showed that about a third of the variance in their occurrence across the country can be predicted by a statistical model including the six landscape axes and a term to account for spatial aggregation. • Synthesis and applications. Our results show that a combination of environmental variables associated with a lower agricultural potential predisposes farmers to convert to organic farming, which further promotes conversion of farmers in the neighbourhood. Organic farming as a ‘wildlife friendly’ method is more likely to occur in agriculturally less-favoured areas where economic incentives for conversion to organic farming do not need to be high and the loss of production due to conversion will be comparatively small. This suggests that an efficient conservation strategy, which takes the global demand for food into account, would be to promote organic farming as an agri-environment scheme in landscapes that are already rich in organic farms at the expense of those existing high-production landscapes that are not.
Pollinators are traditionally thought to perceive non-flowering crop fields as hostile landscape matrix. In this study, we show that landscapes composed of higher proportions of organic crop fields support more bee species at greater abundances in fallow strips. An increase in organic cropping in the surrounding landscape from 5% to 20% enhanced bee species richness in fallow strips by 50%, density of solitary bees by 60% and bumble bee density by 150%. Bee species richness and bumble bee density responded strongest to organic cropping in landscape sectors with 500 m radius, solitary bee density in landscape sectors with 250 m radius. The most likely source of these results is that crop and noncrop habitats are strongly connected via bee foraging at the landscape scale. It seems likely that bees depending on nesting sites in fallow strips benefited from the more abundant flower resources provided by broadleaved weeds in organic crop fields. We conclude that the incorporation of organic crop fields into conventionally managed agricultural landscapes can provide food resources needed to sustain greater pollinator species richness in noncrop habitats.
1. The challenge of climate change forces us to re-examine the assumptions underlying conservation planning.
2. Increasing ‘connectivity’ has emerged as the most favoured option for conservation in the face of climate change.
3. We argue that the importance of connectivity is being overemphasized: quantifying the benefits of connectivity per se is plagued with uncertainty, and connectivity can be co-incidentally improved by targeting more concrete metrics: habitat area and habitat quality.
4. Synthesis and applications. Before investing in connectivity projects, conservation practitioners should analyse the benefits expected to arise from increasing connectivity and compare them with alternative investments, to ensure as much biodiversity conservation and resilience to climate change as possible within their budget. Strategies that we expect to remain robust in the face of climate change include maintaining and increasing the area of high quality habitats, prioritizing areas that have high environmental heterogeneity and controlling other anthropogenic threatening processes.
Feeding a rapidly expanding human population will require a large increase in the supply of agricultural products during the coming decades. This may lead to the transformation of many landscapes from natural vegetation cover to agricultural land use, unless increases in crop yields reduce the need for new farmland. Here, we assess the evidence that past increases in agricultural yield have spared land for wild nature. We investigated the relationship between the change in the combined energy yield of the 23 most energetically important food crops over the period 1979–1999 and the change in per capita cropland area for 124 countries over the same period. Per capita area of the 23 staple crops tended to decrease in developing countries where large yield increases occurred. However, this was counteracted by a tendency for the area used to grow crops other than staples to increase in the countries where staple crop yields increased. There remained a weak tendency in developing countries for the per capita area of all cropland to decline as staple crop yield increased, a pattern that was most evident in developing countries with the highest per capita food supplies. In developed countries, there was no evidence that higher staple crop yields were associated with decreases in per capita cropland area. This may be because high agricultural subsidies in developed countries override any land-sparing pattern that might otherwise occur. Declines in the area of natural forest were smaller in countries where the yield of staple crops increased most, when the negative effects of human population increases on forest area were controlled for. Our results show that land-sparing is a weak process that occurs under a limited set of circumstances, but that it can have positive outcomes for the conservation of wild nature.
The provision of food causes environmental impacts that range from local through to global in scale. Organic farming, used in general here to mean farming practices with a greater emphasis on long-term sustainability, is one general approach to reduce these impacts. Whilst organic farming may be argued to be superior to conventional farming on the basis of local impacts, it is not often clear how organic farming performs relative to conventional farming in terms of wider, global impacts. In this paper we present a comparative assessment of on-farm and indirect energy consumption, land disturbance, water use, employment, and emissions of greenhouse gases, NOx, and SO2 of organic and conventional farming in Australia. A hybrid input-output-based life-cycle technique is employed in order to ensure a complete coverage of indirect requirements originating from all upstream production stages. Using data from a detailed survey of organic farms, the results show that direct energy use, energy related emissions, and greenhouse gas emissions are higher for the organic farming sample than for a comparable conventional farm sample. Direct water use and employment are significantly lower for the organic farms than for the conventional farms. However, the indirect contributions for all factors are much higher for the conventional farms, leading to their total impacts being substantially higher. This shows that indirect effects must be taken into account in the consideration of the environmental consequences of farming, in particular for energy use and greenhouse gas emissions, where the majority of impacts usually occur off-farm. Subject to yield uncertainties for organic versus conventional farming, from the sample here we can conclude that in addition to their local benefits, organic farming approaches can reduce the total water, energy and greenhouse gases involved in food production.
How best to optimize the biodiversity gain from agri-environment schemes (AES) has recently been identified as a key policy-relevant question. Here, the effects of two features of lowland agricultural landscapes on the abundance and diversity of larger moths are contrasted. Although both features bring about positive effects, hedgerow trees have a larger impact than 6 m wide grassy field margins. Whilst AES payments are given to create and maintain grass margins, no financial reward is currently offered for the retention of hedgerow trees. Furthermore, it was only in areas where the amount of land under AES was experimentally increased, by targeting farmers, that the presence of hedgerow trees resulted in a substantially higher abundance (+60%) and diversity (+38%) of moths. Thus, by using larger moths as bio-indicators of landscape-scale quality, it is demonstrated that improvements to the cost-effectiveness of AES could be achieved, firstly, by providing more appropriate financial rewards to farmers for different landscape features, and secondly, through landscape-scale targeting of farmers to encourage participation in AES.
Climate change creates new challenges for biodiversity conservation. Species ranges and ecological dynamics are already responding to recent climate shifts, and current reserves will not continue to support all species they were designed to protect. These problems are exacerbated by other global changes. Scholarly articles recommending measures to adapt conservation to climate change have proliferated over the last 22 years. We systematically reviewed this literature to explore what potential solutions it has identified and what consensus and direction it provides to cope with climate change. Several consistent recommendations emerge for action at diverse spatial scales, requiring leadership by diverse actors. Broadly, adaptation requires improved regional institutional coordination, expanded spatial and temporal perspective, incorporation of climate change scenarios into all planning and action, and greater effort to address multiple threats and global change drivers simultaneously in ways that are responsive to and inclusive of human communities. However, in the case of many recommendations the how, by whom, and under what conditions they can be implemented is not specified. We synthesize recommendations with respect to three likely conservation pathways: regional planning; site-scale management; and modification of existing conservation plans. We identify major gaps, including the need for (1) more specific, operational examples of adaptation principles that are consistent with unavoidable uncertainty about the future; (2) a practical adaptation planning process to guide selection and integration of recommendations into existing policies and programs; and (3) greater integration of social science into an endeavor that, although dominated by ecology, increasingly recommends extension beyond reserves and into human-occupied landscapes.
The intensification and expansion of modern agriculture is amongst the greatest current threats to worldwide biodiversity. Over the last quarter of the 20th century, dramatic declines in both range and abundance of many species associated with farmland have been reported in Europe, leading to growing concern over the sustainability of current intensive farming practices. Purportedly ‘sustainable’ farming systems such as organic farming are now seen by many as a potential solution to this continued loss of biodiversity and receive substantial support in the form of subsidy payments through EU and national government legislation.
Most arable field margins are sown grass strips which are limited in the avian food resources they offer but potentially supply grass seeds and, depending on the complexity of the sward structure, a range of arthropods. Adding perennial forbs to a grass mixture provides more diverse plant and invertebrate food resources for birds. The availability of seeds and invertebrates on uncropped margins is strongly influenced by management, particularly cutting, cultivation and herbicide use. Cropped margins with reduced chemical inputs and wild bird cover crops can provide relatively high food resources compared with a conventionally managed crop. However, resources are only present until harvest, their plant communities are relatively poor and arthropod abundance is usually lower than in uncropped margins.The best winter food supplies for birds will be provided by options that create seed-rich habitats in winter. The best summer food supplies will be provided by options that create a structurally and floristically diverse sward. The least valuable margin in terms of food resources is a grass-only strip. On an area-for-area basis, field margins will potentially produce food resources for birds more cost-effectively than whole farm practices such as organic farming, though the value of margins will depend on their management and the diversity of margin types at a farm scale. Because no single margin type can provide the optimum year-round food supply, different types of margins should be incorporated at the farm level, but appropriate management (and further innovation in margin design) is needed to deliver their benefits. Field margins should be managed in conjunction with adjacent boundary features, especially hedgerows, to create complex structures that maximise nesting opportunities for birds and create habitats for a range of invertebrates.
In this revisional article, we criticize (strongly) the use made by Medar et al., and those whose work they base themselves
on, of the name ‘convexity’ in definitions which intend to relate to convex functions, or cones, or sets, but actually seem
to be incompatible with the most basic consequences of having the name ‘convexity’ associated to them. We then believe to
have fixed the ‘denominations’ associated with Medar’s (et al.) work, up to a point of having it all matching the existing
literature in the field [which precedes their work (by long)]. We also expand his work scope by introducing s
1-convexity concepts to his group of definitions, which encompasses only convex and its proper extension, s
2-convex, so far. This article is a long version of our previous review of Medar’s work, published by FJMS (Pinheiro, M.R.:
S-convexity revisited. FJMS, 26/3, 2007).
Projected responses of species' to climate change have so far included few of the factors that are important determinants of species' distributions within its range. In this paper we utilise a spatially explicit cellular lattice, colonisation–extinction model to investigate the effect of habitat loss, fragmentation and species characteristics on range shifting in response to climate change. Contrary to the predictions of patch occupancy in static climate models we show that fragmentation can have a positive effect on species survival when species have high colonisation rates. For species with low colonisation rates aggregative behaviours prevent success on fragmented landscapes at high levels of habitat loss, and range shifting is more successfully achieved where habitat is correlated. At levels of habitat loss near the extinction threshold, less fragmented landscapes can facilitate range shifting even for the best colonisers. We discuss how imposing a climate window may reduce percolation routes and have implications for the area of usable habitat at any given level of habitat availability. We demonstrate the importance of landscape structure for range shifting dynamics and argue that management of reserve networks needs to consider the requirements of species with different life history characteristics.
Abstract Understanding the negative and positive effects of agricultural land use for the conservation of biodiversity, and its relation to ecosystem services, needs a landscape perspective. Agriculture can contribute to the conservation of high-diversity systems, which may provide important ecosystem services such as pollination and biological control via complementarity and sampling effects. Land-use management is often focused on few species and local processes, but in dynamic, agricultural landscapes, only a diversity of insurance species may guarantee resilience (the capacity to reorganize after disturbance). Interacting species experience their surrounding landscape at different spatial scales, which influences trophic interactions. Structurally complex landscapes enhance local diversity in agroecosystems, which may compensate for local high-intensity management. Organisms with high-dispersal abilities appear to drive these biodiversity patterns and ecosystem services, because of their recolonization ability and larger resources experienced. Agri-environment schemes (incentives for farmers to benefit the environment) need to broaden their perspective and to take the different responses to schemes in simple (high impact) and complex (low impact) agricultural landscapes into account. In simple landscapes, local allocation of habitat is more important than in complex landscapes, which are in total at risk. However, little knowledge of the relative importance of local and landscape management for biodiversity and its relation to ecosystem services make reliable recommendations difficult.
Linear Mixed-Effects * Theory and Computational Methods for LME Models * Structure of Grouped Data * Fitting LME Models * Extending the Basic LME Model * Nonlinear Mixed-Effects * Theory and Computational Methods for NLME Models * Fitting NLME Models
Ecology Letters (2010) 13: 858–869
There is increasing recognition that ecosystems and their services need to be managed in the face of environmental change. However, there is little consensus as to the optimum scale for management. This is particularly acute in the agricultural environment given the level of public investment in agri-environment schemes (AES). Using a novel multiscale hierarchical sampling design, we assess the effect of land use at multiple spatial scales (from location-within-field to regions) on farmland biodiversity. We show that on-farm biodiversity components depend on farming practices (organic vs. conventional) at farm and landscape scales, but this strongly interacts with fine- and coarse-scale variables. Different taxa respond to agricultural practice at different spatial scales and often at multiple spatial scales. Hence, AES need to target multiple spatial scales to maximize effectiveness. Novel policy levers may be needed to encourage multiple land managers within a landscape to adopt schemes that create landscape-level benefits.
The prospect of biofuel production on a large scale has focused attention on energy efficiencies associated with different agricultural systems and production goals. We used 17 years of detailed data on agricultural practices and yields to calculate an energy balance for different cropping systems under both food and fuel scenarios. We compared four grain and one forage systems in the U.S. Midwest: corn (Zea mays) - soybean (Glycine max) - wheat (Triticum aestivum) rotations managed with (1) conventional tillage, (2) no till, (3) low chemical input, and (4) biologically based (organic) practices, and (5) continuous alfalfa (Medicago sativa). We compared energy balances under two scenarios: all harvestable biomass used for food versus all harvestable biomass used for biofuel production. Among the annual grain crops, average energy costs of farming for the different systems ranged from 4.8 GJ ha(-1) y(-1) for the organic system to 7.1 GJ ha(-1) y(-1) for the conventional; the no-till system was also low at 4.9 GJ ha(-1) y(-1) and the low-chemical input system intermediate (5.2 GJ ha(-1) y(-1)). For each system, the average energy output for food was always greater than that for fuel. Overall energy efficiencies ranged from output:input ratios of 10 to 16 for conventional and no-till food production and from 7 to 11 for conventional and no-till fuel production, respectively. Alfalfa for fuel production had an efficiency similar to that of no-till grain production for fuel. Our analysis points to a more energetically efficient use of cropland for food than for fuel production and large differences in efficiencies attributable to management, which suggests multiple opportunities for improvement.
Environmental synergisms may pose the greatest threat to tropical biodiversity. Using recently updated data sets from the International Union for Conservation of Nature (IUCN) Red List, we evaluated the incidence of perceived threats to all known mammal, bird, and amphibian species in tropical forests. Vulnerable, endangered, and extinct species were collectively far more likely to be imperiled by combinations of threats than expected by chance. Among 45 possible pairwise combinations of 10 different threats, 69%, 93%, and 71% were significantly more frequent than expected for threatened mammals, birds, and amphibians, respectively, even with a stringent Bonferroni-corrected probability value (p= 0.003). Based on this analysis, we identified five key environmental synergisms in the tropics and speculate on the existence of others. The most important involve interactions between habitat loss or alteration (from agriculture, urban sprawl, infrastructure, or logging) and other anthropogenic disturbances such as hunting, fire, exotic-species invasions, or pollution. Climatic change and emerging pathogens also can interact with other threats. We assert that environmental synergisms are more likely the norm than the exception for threatened species and ecosystems, can vary markedly in nature among geographic regions and taxa, and may be exceedingly difficult to predict in terms of their ultimate impacts. The perils posed by environmental synergisms highlight the need for a precautionary approach to tropical biodiversity conservation.
A generalization of the coefficient of determination R2 to general regression models is discussed. A modification of an earlier definition to allow for discrete models is proposed.
globally. If there is some decrement in per-hectare agri- cultural yield from wildlife-friendly compared with inten- sive agriculture and if the relationship between land-use intensity and measures of diversity is concave (upward) for a substantial number of species (both reasonable as- sumptions), then more bird diversity (in their analyses) could be sustained by partitioning land between inten- sive agriculture and reserves than by practicing wildlife- friendly farming. They demonstrate that with sustained rapid growth in per-hectare yields (something that is not assured), most of the increased food demand in de- veloping regions can be met from the current area of agricultural land, although some new land will be re- quired. (Given similar assumptions—and reasonable lev- els of trade—developed countries may require a little less agricultural land than at present.) They conclude that con- servationists should pay as much attention to increasing per-hectare yields of food crops as we do to human pop- ulation growth and rates of consumption.
Agri-environment schemes are an increasingly important tool for the maintenance and restoration of farmland biodiversity in Europe but their ecological effects are poorly known. Scheme design is partly based on non-ecological considerations and poses important restrictions on evaluation studies. We describe a robust approach to evaluate agri-environment schemes and use it to evaluate the biodiversity effects of agri-environment schemes in five European countries. We compared species density of vascular plants, birds, bees, grasshoppers and crickets, and spiders on 202 paired fields, one with an agri-environment scheme, the other conventionally managed. In all countries, agri-environment schemes had marginal to moderately positive effects on biodiversity. However, uncommon species benefited in only two of five countries and species listed in Red Data Books rarely benefited from agri-environment schemes. Scheme objectives may need to differentiate between biodiversity of common species that can be enhanced with relatively simple modifications in farming practices and diversity or abundance of endangered species which require more elaborate conservation measures.
Securing Food Supplies up to 2050: The Challenges Faced by the UK, Fourth Report of 2008-09 Session of the Environment, Food and Rural Affairs Committee (HC 213-I) The Stationery Office Limited
- Commons House
House of Commons (2009). Securing Food Supplies up to 2050: The Challenges Faced by the UK, Fourth Report of 2008-09 Session of the Environment, Food and Rural Affairs Committee (HC 213-I). The Stationery Office Limited, London. Available at: http://www. publications.parliament.uk/pa/cm200809/cmselect/cmenvfru/ 213/213i.pdf Kiers, E.T., Leakey, R.R.B., Izac, A.M., Heinemann, J.A., Rosen-thal, E., Nathan, D. et al. (2008). Ecology – agriculture at a crossroads. Science, 320, 320–321.
The Millenium Atlas of Butterflies in Britain and Ireland Organic agriculture and the global food supply
- R E F E R E N C E S Asher
- J Warren
- M Fox
- R Harding
- P Jeffcoate
- G Jef-Fcoate
- S Oxford
- C Badgley
- J Moghtader
- E Quintero
- E Zakem
- M J Chappell
- K Aviles-Vazquez
R E F E R E N C E S Asher, J., Warren, M., Fox, R., Harding, P., Jeffcoate, G. & Jef-fcoate, S. (2001). The Millenium Atlas of Butterflies in Britain and Ireland. Oxford University Press, Oxford. Badgley, C., Moghtader, J., Quintero, E., Zakem, E., Chappell, M.J., Aviles-Vazquez, K. et al. (2007). Organic agriculture and the global food supply. Renew. Agric. Food Syst., 22, 86–108.
Interim Report – Prospects for Food, Nutrition, Agriculture and Major Commodity Groups Available at: http://www.fao.org/fileadmin The effects of organic farming on pest and non-pest butterfly abundance
- R E Firbank
- L G Johnson
- P J Macdonald
FAO (2006). World Agriculture: Towards 2030 ⁄ 2050 – Interim Report
– Prospects for Food, Nutrition, Agriculture and Major Commodity Groups. Food and Agriculture Organization of the
United Nations, Rome. Available at: http://www.fao.org/fileadmin/user upload/esag/docs/Interim report AT2050web.pdf
Feber, R.E., Firbank, L.G., Johnson, P.J. & Macdonald, D.W.
(1997). The effects of organic farming on pest and non-pest
butterfly abundance. Agric. Ecosyst. Environ., 64, 133–139.