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... This study system is located along a very sharp climatic gradient and comprises a highly fragmented landscape in which habitat patches of different sizes are isolated, partly or entirely, by agricultural fields. Based on our previous studies (Yaacobi et al. 2007a, b;Giladi et al. 2011Giladi et al. , 2014May et al. 2012May et al. , 2013Rotem et al. 2013Rotem et al. , 2015Rotem and Ziv 2016), four explicit scales-landscape (the entire extent with its climatic variation that composes a mixture of reptile communities at different land units), land unit (a cluster of patches that provide opportunities for dispersal and species turnovers for diverse reptile species), patch (an isolated natural habitat that comprises several habitats and heterogenous local-scale conditions for reptile species) and plot (a sampling area within a given patch which may include few home ranges of particular reptiles)-can be identified in this system given its heterogeneity and complexity, making it an ideal study area for exploring the community structure of organisms in a patchy agroecosystem. Specifically, we asked: (1) Are reptile communities within our agroecosystem affected by a certain dominant variable that belongs to a particular scale, or, alternatively, by a combination of variables that operate at different scales? ...
... At the land unit-scale, the variable describing patch isolation (namely, the PI) had no significant effect on reptile abundance, but it negatively affected reptile species richness and diversity. Patch isolation may reduce the ability of reptile species to move between different patches through the agricultural matrix (e.g., Rotem and Ziv 2016). Since abundance may reflect the biomass and food availability for all individuals, regardless of their species identity (Shine and Madsen 1997;Smart et al. 2000), it might not be affected by patch isolation. ...
... Modern agriculture reduces habitat heterogeneity (Robinson and Sutherland 2002) and, therefore, negatively affects the ability of reptiles to find suitable habitats. We have already showed that reptiles can move between patches, however the effective permeability of the matrix to reptile movement depends on the crop type and the mosaic of natural habitat patches (Rotem et al. 2014;Rotem and Ziv 2016). Hence, one possibility for reducing this negative effect is to protect natural patches within the agricultural fields that retain, as much as possible, the local and spatial heterogeneity (Maisonneuve and Rioux 2001). ...
ContextStudying biodiversity in light of increased fragmentation in agroecosystems requires the understanding of scale-dependent and multi-scale determinants of various community measures.Objectives
In a heterogeneous agro-landscape, we aimed to understand whether: (1) Reptile communities are affected by a certain variable that belongs to a particular scale, or, by a combination of variables at different scales, and (2) Reptile community measures are affected differentially by variables related to different scales.Methods
We sampled reptiles in three 12.6 km2 land units by using 100 × 50 m plots within 27 natural habitat patches. We collected spatial information of different scale-oriented physical and biotic variables and analyzed changes in community measures at four scales—landscape, land unit, patch and plot—by using the model selection approach based on the AICc.ResultsMultiple-scale, rather than single-scale models, best explained all three community measures, indicating that the reptile community structure is highly affected by ecological processes operating at different scales, from the local up to the entire landscape scale. However, abundance, species richness and diversity were affected dissimilarly by different combined determinants and at different scales.Conclusions
Reptile biodiversity at our heterogenous agro-landscape is highly influenced by determinants of multiple scales, where each scale has its contribution to the overall obtained pattern. Number of individuals and species richness respond differently to various processes, depending on the scale at which these processes operate. Agro-landscapes retain the complexity of ecological systems and can serve to maintain natural communities through land sharing practices.
... G. hybridus reaches its southern geographical range edge within the study region (http://www.biogis.huji.ac.il). This area is characterized by a fragmented agroecosystem commenced about 70 years ago (Giladi et al., 2014), where patches of natural grassland and shrubland are scattered in the farmland of wheatfields, vineyards and orchards (Giladi et al., 2011;Rotem and Ziv, 2016). We conducted the study in three landscapes along the precipitation gradient: arid land unit (near Dvir village), intermediate land unit (near Lachish village), and mesic land unit (near Galon village). ...
... Variance partitioning of seed dispersal-related traits across nested ecological levels. (Murphy and Lovett-Doust, 2004;Rotem and Ziv, 2016), and thus dispersal costs and selections for reduced dispersal are moderate. The processes that fragmented our study system mainly disconnected already occupied remnant patches characterized as "island communities" with low overall colonization rates (May et al., 2013). ...
Deficient dispersal ability due to habitat fragmentation adversely impact demographic connectivity and gene flow among population in a metapopulation, and therefore potentially leads to local extinction. A rich body of theoretical work provides distinct predictions regarding the distribution of dispersal abilities in relation to fragmentation gradient. Yet, empirical data remains elusive in general, and it is lacking for anthropogenic-induced landscapes in particular. We collected 9884 seeds of a wind-dispersed annual species Geropogon hybridus (Asteraceae) from 807 individual plants of 55 populations spanning three landscapes in a fragmented agroecosystem and measured four major dispersal-related traits at the landscape, population, plant and seed levels. Contrary to previous studies that were based on island or urban landscapes and where fragmentation was associated with reduced dispersal, we revealed increased seed dispersal ability in the more fragmented patches. However, the specific relationships between dispersal-related traits and fragmentation characteristics varied with ecological scale. The discrepancy between our results and those from previous studies may be explained by the milder contrast between the fragmented patches and the surrounding matrix in our system, which is a common feature in many agroecosystems. The findings add to the accumulating evidence that different selection pressures and constraints act on seed dispersal evolution under the global land use change.
... According to the experimental landscape system composed of multiple crops, our previous results indicated high crop species richness could suppress the pest population, indicating that crop species richness could enhance biological control services (Sheng et al., 2017). As crop rotation between wheat and legume fields is common worldwide, the findings emphasized the importance of creating an agricultural mosaic to enhance biodiversity permeability within the agricultural matrix (Rotem and Ziv, 2016). However, few study focus on the explicit process of natural enemies, dynamics of pest population, ecological control service and its maintaining mechanism in multi-crop farmland landscape system for the whole crops growing cycle. ...
... Landscape structure, crop diversity or crop planting patterns in the agricultural ecosystem can influence the structure of ecological communities, population dynamics, ecosystem functioning and services (Batary et al., 2011;Rotem and Ziv, 2016). In this study, our result found that the rotation-intercropping ecosystem via wheat-maizecotton help to increase the abundances of the predatory natural enemy, P. japonica adults and then promoted aphid reduction in center cotton plots. ...
... By the same token, lower movement within grasslands and avoidance of farms relative to availability could be related to increased predation risk in these open habitats (Rotem & Ziv, 2016;Pulsford et al., 2017). The majority of farmland was composed of crop stubble or tilled soil at the time of our study and lizards spent most of their time in shrubs and dividing structures (e.g. ...
Agriculture is one of the greatest threats to biodiversity worldwide, but knowledge of how agriculture modifies animal movement, which is crucial for survival, is limited. Here, we examined the effect of landscape composition on the movements of the oriental garden lizard Calotes versicolor in agricultural landscapes of north-central Pakistan. We radio-tracked 32 individuals over 5 months to determine whether land cover type (farmland, tree patches, grassland) influences hourly movement rate, inter-day distance moved, and activity area size. We found that hourly movement rates were higher in tree patches compared to grasslands, and higher when animals moved between land cover types rather than within individual land cover types. Activity area size and movement rates became smaller as the season progressed, but they did not differ according to animal sex or body size. Habitat selection analysis showed that lizards preferred tree patches, avoided farms, roads, water bodies and human dwellings, and used grasslands in proportion to availability. When lizards used farmlands, they were found in field margins 85% of the time. Our results emphasize the importance of treed areas as reptile habitat in these highly modified agricultural lands. Agricultural intensification that reduces the availability of tree patches and field margins will likely reduce the extent to which lizards can use the landscape by removing preferred habitat. Maintaining tree cover and small fields with field margins should promote the coexistence of wildlife conservation and food production in agricultural landscapes. © 2022 The Authors. Animal Conservation published by John Wiley & Sons Ltd on behalf of Zoological Society of London.
... Loss of habitat heterogeneity may severely impact herpetofauna also, but not many studies have looked into this. Importance of assessing biodiversity at multiple spatial scales has been amply recognized in ecological literature over the past two decades as interacting species experience various environmental factors differentially at different spatial scales (Michael, Ikin, Crane, Okada, & Lindenmayer, 2017;Muñoz, Santos, & Felicísimo, 2016;Rotem & Ziv, 2016;Tylianakis, Tscharntke, & Klein, 2006;Willis & Whittaker, 2002). Different drivers across the agricultural landscape might also influence amphibians and reptiles differentially at different spatial scales, and hence demands detailed studies on whole herpetofauna. ...
Agricultural intensification and the associated factors, including land transformation, are among the major global threats affecting biodiversity especially herpetofauna. However, little information is available about how different factors shape herpeto-fauna species assemblages in agricultural landscape at different spatial scales from patch (125-250m) to the landscape (500-1000m). We assessed the diversity of amphibians and reptiles in areas under low and high degrees of agricultural intensi-fication and explored different factors regulating diversity at different spatial scales using four sampling methods. Diversity and abundance of amphibians varied significantly between the two zones, but not for reptiles. Agricultural intensification index (AII), calculated based on agrochemical use and area under agriculture at 250m scale, seemed to affect amphibians both at patch as well as at 500m and 1000m landscape scales. The AII influenced reptilian diversity only at patch and 500m scales. Vicinity of natural forest had a stronger influence on reptilian abundance. Seminatural vegetation impacted herpetofauna diversities at larger spatial scales. The extent of water bodies influenced the reptilian abundance at 250m patch scale and amphibian abundance both at 250m and 1000m scale. Fallow lands affected only reptilian diversity at all spatial scales. Plantation affected amphibian at all scales but reptiles only at the landscape scale. Habitat heterogeneity regulated only amphibian diversity. These results highlight the fact that different patch and landscape-scale factors regulate the diversity of reptiles and amphibians differentially. Such scale-specific information will crucially inform future conservation action for the herpetofauna in the agricultural landscape. K E Y W O R D S agricultural intensification, amphibian, habitat heterogeneity, land-use elements, multiple spatial scale, reptiles
... Benefits Fig. 2 The disproportionate benefits hypothesis (from Asbjornsen et al. 2013) suggests that strategic integration of perennial cover provides more societal benefits than nonstrategic approaches, especially for landscapes of intermediate complexity (at intermediate proportions) If rotations between perennial plants and annual crops can be strategically timed, they can extend predator habitat for crop pests like aphids (Rotem and Ziv 2016), reduce drainage discharge volumes-and stream erosion-during peak flow periods, and slow nitrate nitrogen loss (Randall et al. 1997). Strategic timing can also increase the amount of organic nitrogen fixation by legumes such as clovers and alfalfa and strategic durations can contribute to weed control (Davis et al. 2012). ...
Context
Natural habitat patches can mitigate the negative effects of agriculture on biodiversity. Local communities within natural patches are connected by dispersal and affected by multi-scale processes. Network theory enables to analyze metacommunity structures of different groups of species, such as common and rare species, and provides tools to prioritize the habitat patches.
Objectives
We ask what are the local and landscape determinants of common and rare species diversities and whether the relative importance of the patches within the networks is similar for common and rare species.
Methods
We sampled arthropod communities within natural patches in a fragmented agroecosystem of the Southern Judea Lowlands, Israel. We classified Coleoptera, Araneae, and Hemiptera taxa into common and rare species and constructed a metacommunity network for each group of species.
Results
For Coleoptera and Hemiptera the association of patch connectivity is stronger with rare species than with common species diversities, suggesting that landscape determinants are more dominant in shaping rare than common species assemblages. Moreover, the spatial scale at which patch connectivity affects common and rare species differs between taxa. By comparing the relative importance of patches within the networks, we found a high correlation between common and rare species in each taxon. However, several patches diverge from this trend of similarity.
Conclusions
This study emphasizes the importance of multi-scale determinants in shaping ecological communities at agroecosystems and stresses that common and rare species are distinctive groups of species that should receive explicit consideration in conservation management and planning.
Crop rotation has been used as an effective tool of pest, disease, and weed management since distant past which dates back to the Roman and Greek times. The magnitude of yield improvement and other associated benefits of crop rotation may vary with crops because some crops are quite responsive, while others showed a bit yield improvement. However, the management of these issues from crop rotation disappeared during the twentieth century due to easy access to synthetic inputs. No doubt it is also equally effective in the current scenario to solve problems like stagnant yield, resource depletion, and reduced reliance on synthetic inputs. The write-up of the chapter was based on assessing the benefits of crop rotation and highlighting its significance for successful management of issues related to continuous cropping. The cropping practices remain uniform and invariable if the same crop is grown on a long-term basis. It promotes the pest pressure buildup and reduces the resource-use efficiency. Crop rotation improves farm productivity, but adaptation by growers is limited because small piece of land required independent management which is quite difficult and hinders mechanization. Certain principles have been laid to improve the effectiveness of crop rotation to meet specific objective. The importance of crop rotation was realized again, and now it has become an important agenda among agriculture experts for the management of issues related to present agriculture.
Grazing plays an important role in shaping ecological communities in human-related ecosystems. Although myriad studies have explored the joint effect of grazing and climate on plant communities, this interactive effect has rarely been studied in animals. We hypothesized that the effect of grazing on the reptile community varies along a climatic gradient in relation to the effect of grazing on habitat characteristics, and that grazing differentially affects reptiles of different biogeographic regions. We tested our hypotheses by collecting data on environmental characteristics and by trapping reptiles in four heterogeneous landscapes experiencing differing grazing intensities and distributed along a sharp climatic gradient. We found that while reptile diversity increased with grazing intensity at the mesic end of the gradient, it decreased with grazing intensity at the arid end. Moreover, the proportion of reptile species of differing biogeographic origins varied with the interactive effect of climate and grazing. The representation of species originating in arid biogeographic zones was highest at the arid end of the climatic gradient, and representation increased with grazing intensity within this area. Regardless of the climatic context, increased grazing pressure results in a reduction in vegetation cover and thus in changes in habitat characteristics. By reducing vegetation cover, grazing increased habitat heterogeneity in the dense mesic sites and decreased habitat heterogeneity in the arid sites. Thus, our results suggest that the same direction of habitat alteration caused by grazing may have opposite effects on biodiversity and community composition in different climatic contexts.
Farmland Conservation is the third volume in the Synopses of Conservation Evidence series, linked to the online resource www.conservationevidence.com.
Achieving sustainable global food security is one of humanity’s contemporary challenges. Here we present an analysis identifying
key “global leverage points” that offer the best opportunities to improve both global food security and environmental sustainability.
We find that a relatively small set of places and actions could provide enough new calories to meet the basic needs for more
than 3 billion people, address many environmental impacts with global consequences, and focus food waste reduction on the
commodities with the greatest impact on food security. These leverage points in the global food system can help guide how
nongovernmental organizations, foundations, governments, citizens’ groups, and businesses prioritize actions.
The equilibrium theory of island biogeography is the basis for estimating extinction rates and a pillar of conservation science. The default strategy for conserving biodiversity is the designation of nature reserves, treated as islands in an inhospitable sea of human activity. Despite the profound influence of islands on conservation theory and practice, their mainland analogues, forest fragments in human-dominated landscapes, consistently defy expected biodiversity patterns based on island biogeography theory. Countryside biogeography is an alternative framework, which recognizes that the fate of the world's wildlife will be decided largely by the hospitality of agricultural or countryside ecosystems. Here we directly test these biogeographic theories by comparing a Neotropical countryside ecosystem with a nearby island ecosystem, and show that each supports similar bat biodiversity in fundamentally different ways. The island ecosystem conforms to island biogeographic predictions of bat species loss, in which the water matrix is not habitat. In contrast, the countryside ecosystem has high species richness and evenness across forest reserves and smaller forest fragments. Relative to forest reserves and fragments, deforested countryside habitat supports a less species-rich, yet equally even, bat assemblage. Moreover, the bat assemblage associated with deforested habitat is compositionally novel because of predictable changes in abundances by many species using human-made habitat. Finally, we perform a global meta-analysis of bat biogeographic studies, spanning more than 700 species. It generalizes our findings, showing that separate biogeographic theories for countryside and island ecosystems are necessary. A theory of countryside biogeography is essential to conservation strategy in the agricultural ecosystems that comprise roughly half of the global land surface and are likely to increase even further.
REPTILE SPECIES ARE DECLINING ON A GLOBAL SCALE. SIX SIGNIFICANT THREATS TO REPTILE POPULATIONS ARE HABITAT
LOSS AND DEGRADATION, INTRODUCED INVASIVE SPECIES, ENVIRONMENTAL POLLUTION, DISEASE, UNSUSTAINABLE
USE, AND GLOBAL CLIMATE CHANGE.
Understanding species-diversity patterns in heterogeneous landscapes invites comprehensive research on how scale-dependent
processes interact across scales. We used two common beetle families (Tenebrionidae, detrivores; Carabidae, predators) to
conduct such a study in the heterogeneous semi-arid landscape of the Southern Judean Lowland (SJL) of Israel, currently undergoing
intensive fragmentation. Beetles were censused in 25 different-sized patches (500–40,000m2). We used Fisher’s α and non-parametric extrapolators to estimate species diversity from 11,125 individuals belonging to
56 species. Patch characteristics (plant species diversity and cover, soil cover and degree of stoniness) were measured by
field transects. Spatial variables (patch size, shape, physiognomy and connectivity) and landscape characteristics were analyzed
by GIS and remote-sensing applications. Both patch-scale and landscape-scale variables affected beetle species diversity.
Path-analysis models showed that landscape-scale variables had the strongest effect on carabid diversity in all patches. The
tenebrionids responded differently: both patch-scale and landscape-scale variables affected species diversity in small patches,
while mainly patch-scale variables affected species diversity in large patches. Most of the paths affected species diversity
both directly and indirectly, combining the effects of both patch-scale and landscape-scale variables. These results match
the biology of the two beetle families: Tenebrionidae, the less mobile and more site-attached family, responded to the environment
in a fine-grained manner, while the highly dispersed Carabidae responded to the environment in a coarse-grained manner. We
suggest that understanding abiotic and biotic variable interactions across scales has important consequences for our knowledge
of community structure and species diversity patterns at large spatial scales.
An important goal of ecological compensation measures in agricultural areas is the conservation and enhancement of regional species diversity. However, some current European agri-environment schemes seem to be rather ineffective. A likely explanation is the lack of source populations in intensely cultivated landscapes. Remnants of natural and seminatural habitats can contribute to regional biodiversity in various ways: as essential habitats for specialised species, as stepping stones, and as temporary habitats for hibernation, larval development, or preovipository feeding. The overall percentage of arthropod species, for which seminatural habitats are an essential prerequisite for living in an agricultural landscape, was assessed with a 5 km long transect of 18 standardised trapping stations. The transect extended from an isolated area of wetland through intensely managed crop fields and grassland to an isolated semiarid meadow bordered by mixed forest. For more than 1000 arthropod species the spatial and temporal distribution of a one year's catch along the transect was interpreted with regard to their affinity to seminatural habitats. Experts were asked to judge questionable cases of apparent ubiquist species. All in all, more than 63% of all animal species (except for soil and water fauna) living in the agriculturally managed areas of the Limpach valley seem to depend on the presence of seminatural habitats. We conclude that remnant islands of natural or seminatural habitats provide the most important source populations for agri-environment schemes in order to enhance biodiversity in an otherwise depleted agricultural landscape.
![Figure][1]
Land sharing.
A wildlife-friendly landscape in Romania.
CREDIT: KIMBERLIE RAWLINGS
According to B. Phalan et al. (“Reconciling food production and biodiversity conservation: Land sharing and land sparing compared,” Reports, 2 September, p. [1289][2]), land sparing—
The question of how to meet rising food demand at the least cost to biodiversity requires the evaluation of two contrasting
alternatives: land sharing, which integrates both objectives on the same land; and land sparing, in which high-yield farming
is combined with protecting natural habitats from conversion to agriculture. To test these alternatives, we compared crop
yields and densities of bird and tree species across gradients of agricultural intensity in southwest Ghana and northern India.
More species were negatively affected by agriculture than benefited from it, particularly among species with small global
ranges. For both taxa in both countries, land sparing is a more promising strategy for minimizing negative impacts of food
production, at both current and anticipated future levels of production.
Ecology Letters (2011) 14: 101–112
Biodiversity in agricultural landscapes can be increased with conversion of some production lands into ‘more-natural’– unmanaged or extensively managed – lands. However, it remains unknown to what extent biodiversity can be enhanced by altering landscape pattern without reducing agricultural production. We propose a framework for this problem, considering separately compositional heterogeneity (the number and proportions of different cover types) and configurational heterogeneity (the spatial arrangement of cover types). Cover type classification and mapping is based on species requirements, such as feeding and nesting, resulting in measures of ‘functional landscape heterogeneity’. We then identify three important questions: does biodiversity increase with (1) increasing heterogeneity of the more-natural areas, (2) increasing compositional heterogeneity of production cover types and (3) increasing configurational heterogeneity of production cover types? We discuss approaches for addressing these questions. Such studies should have high priority because biodiversity protection globally depends increasingly on maintaining biodiversity in human-dominated landscapes.
Expansion and intensification of cultivation are among the predominant global changes of this century. Intensification of
agriculture by use of high-yielding crop varieties, fertilization, irrigation, and pesticides has contributed substantially
to the tremendous increases in food production over the past 50 years. Land conversion and intensification, however, also
alter the biotic interactions and patterns of resource availability in ecosystems and can have serious local, regional, and
global environmental consequences. The use of ecologically based management strategies can increase the sustainability of
agricultural production while reducing off-site consequences.
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.
Conservation biologists worry that fragmenting a bloc of natural habitat might reduce its species diversity. However, they also recognize the difficulty and importance of isolating the effect of fragmentation from that of simple loss of area. Using two different methods (species-area curve and Fisher's alpha index of diversity) to analyse the species diversities of plants, tenebrionid beetles and carabid beetles in a highly fragmented Mediterranean scrub landscape, we decoupled the effect of degree of fragmentation from that of area loss. In this system, fragmentation by itself seems not to have influenced the number of species. Our results, obtained at the scale of hectares, agree with similar results at island and continent scales.
Understanding the regional dynamics of plant communities is crucial for predicting the response of plant diversity to habitat fragmentation. However, for fragmented landscapes the importance of regional processes, such as seed dispersal among isolated habitat patches, has been controversially debated. Due to the stochasticity and rarity of among-patch dispersal and colonization events, we still lack a quantitative understanding of the consequences of these processes at the landscape-scale. In this study, we used extensive field data from a fragmented, semi-arid landscape in Israel to parameterize a multi-species incidence-function model. This model simulates species occupancy pattern based on patch areas and habitat configuration and explicitly considers the locations and the shapes of habitat patches for the derivation of patch connectivity. We implemented an approximate Bayesian computation approach for parameter inference and uncertainty assessment. We tested which of the three types of regional dynamics – the metacommunity, the mainland-island, or the island communities type – best represents the community dynamics in the study area and applied the simulation model to estimate the extinction debt in the investigated landscape. We found that the regional dynamics in the patch-matrix study landscape is best represented as a system of highly isolated ‘island’ communities with low rates of propagule exchange among habitat patches and consequently low colonization rates in local communities. Accordingly, the extinction rates in the local communities are the main drivers of community dynamics. Our findings indicate that the landscape carries a significant extinction debt and in model projections 33–60% of all species went extinct within 1000 yr. Our study demonstrates that the combination of dynamic simulation models with field data provides a promising approach for understanding regional community dynamics and for projecting community responses to habitat fragmentation. The approach bears the potential for efficient tests of conservation activities aimed at mitigating future losses of biodiversity.
Patterns that relate species richness with fragment area (the species–area relationship, SAR) and with isolation (the species–isolation relationship, SIR) are well documented. However, those that relate species density – the number of species within a standardized area – with fragment area (D-SAR) or isolation (D-SIR) have not been sufficiently explored, despite the potential for such an analysis to disentangle the underlying mechanisms of SARs and SIRs. Previous spatial theory predicts that a significant D-SAR or D-SIR is unlikely to emerge in taxa with high dispersal limitation, such as plants. Furthermore, a recent model predicts that the detection and the significance of D-SARs or D-SIRs may decrease with grain size. We combined a literature review with grain size-dependent sampling in a fragmented landscape to evaluate the prevalence and grain size-dependent nature of D-SARs and D-SIRs in plants.
Under the current scenario of rapid human population increase, achieving efficient and productive agricultural land use while conserving biodiversity is a global challenge. There is an ongoing debate whether land for nature and for production should be segregated (land sparing) or integrated on the same land (land sharing, wildlife-friendly farming). While recent studies argue for agricultural intensification in a land sparing approach, we suggest here that it fails to account for real-world complexity. We argue that agriculture practiced under smallholder farmer-dominated landscapes and not large-scale farming, is currently the backbone of global food security in the developing world. Furthermore, contemporary food usage is inefficient with one third wasted and a further third used inefficiently to feed livestock and that conventional intensification causes often overlooked environmental costs. A major argument for wildlife friendly farming and agroecological intensification is that crucial ecosystem services are provided by “planned” and “associated” biodiversity, whereas the land sparing concept implies that biodiversity in agroecosystems is functionally negligible. However, loss of biological control can result in dramatic increases of pest densities, pollinator services affect a third of global human food supply, and inappropriate agricultural management can lead to environmental degradation. Hence, the true value of functional biodiversity on the farm is often inadequately acknowledged or understood, while conventional intensification tends to disrupt beneficial functions of biodiversity. In conclusion, linking agricultural intensification with biodiversity conservation and hunger reduction requires well-informed regional and targeted solutions, something which the land sparing vs sharing debate has failed to achieve so far.
Land-use intensification has led to a landscape mosaic that juxtaposes human-managed and natural areas. In such human-dominated and heterogeneous landscapes, spillover across habitat types, especially in systems that differ in resource availability, may be an important ecological process structuring communities. While there is much evidence for spillover from natural habitats to managed areas, little attention has been given to flow in the opposite direction. This paper synthesizes studies published to date from five functionally important trophic groups, herbivores, pathogens, pollinators, predators, and seed dispersers, and discusses evidence for spillover from managed to natural systems in all five groups. For each of the five focal groups, studies in the natural to managed direction are common, often with multiple review articles on each subject which document dozens of examples. In contrast, the number of studies which examine movement in the managed to natural direction is generally less than five studies per trophic group. These findings suggest that spillover in the managed to natural direction has been largely underestimated. As habitat modification continues, resulting in increasingly fragmented landscapes, the likelihood and size of any spillover effect will only increase.
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.
Rising demands for agricultural products will increase pressure to further intensify crop production, while negative environmental impacts have to be minimized. Ecological intensification entails the environmentally friendly replacement of anthropogenic inputs and/or enhancement of crop productivity, by including regulating and supporting ecosystem services management in agricultural practices. Effective ecological intensification requires an understanding of the relations between land use at different scales and the community composition of ecosystem service-providing organisms above and below ground, and the flow, stability, contribution to yield, and management costs of the multiple services delivered by these organisms. Research efforts and investments are particularly needed to reduce existing yield gaps by integrating context-appropriate bundles of ecosystem services into crop production systems.
Aims: (1) Understanding how the relationship between species richness and its determinants depends on the interaction between scales at which the response and explanatory variables are measured. (2) Quantifying the relative contributions of local, intermediate and large-scale determinants of species richness in a fragmented agro-ecosystem. (3) Testing the hypothesis that the relative contribution of these determinants varies with the grain size at which species richness is measured.
Location: A fragmented agro-ecosystem in the Southern Judea Lowland, Israel, within a desert–Mediterranean transition zone.
Methods: Plant species richness was estimated using hierarchical nested sampling in 81 plots, positioned in 38 natural vegetation patches within an agricultural matrix (mainly wheat fields) among three land units along a sharp precipitation gradient. Explanatory variables included position along that gradient, patch area, patch isolation, habitat heterogeneity and overall plant density. We used general linear models and hierarchical partitioning of variance to test and quantify the effect of each explanatory variable on species richness at four grain sizes (0.0625, 1, 25 and 225 m2).
Results: Species richness was mainly affected by position along a precipitation gradient and overall plant density, and to a lesser extent by habitat heterogeneity. It was also significantly affected by patch area and patch isolation, but only for small grain sizes. The contribution of each explanatory variable to explained variance in species richness varied with grain size, i.e. scale-dependent. The influence of geographic position and habitat heterogeneity on species richness increased with grain size, while the influence of plant density decreased with grain size.
Main conclusions: Species richness is determined by the combined effect of several scale-dependent determinants. Ability to detect an effect and effect size of each determinant varies with the scale (grain size) at which it is measured. The combination of a multi-factorial approach and multi-scale sampling reveals that conclusions drawn from studies that ignore these dimensions are restricted and potentially misleading.
The fact that the expansion and intensification of agriculture has been the major driver of past biodiversity loss and ecosystem degradation globally is beyond dispute. It is highly likely that these trends will continue through the 21st century, unless action is taken to design effective management strategies for biodiversity in agricultural landscapes. To do this, we first need to recognize that some biodiversity is retained in farmland, and that it is the degree of biodiversity retention that we need to understand and effectively manage. We need to understand which biodiversity components are retained as a natural ecosystem is converted to agriculture and why; how community dynamics affect biodiversity retention; and how we can effectively manage biodiversity retention. These questions are being addressed, but much remains to be done; and we have to accept that progress will be contentious. Challenging as these questions are, conservationists cannot address them in isolation. Multifunctional ecosystem science and policy linked to human well-being is the ultimate goal. While the goal seems distant and daunting, integration between relevant research disciplines is happening, research funding is beginning to recognize the need for better integration and policy has to respond. Conservation science has a key role to play and must be ready to meet this challenge.
Agricultural intensification has led to a widespread decline in farmland biodiversity measured across many different taxa. The changes in agricultural practices affect many different aspects of the farmland habitat, but agricultural industry, policy and much previous research has tended to be concerned with specific sectors or practices (e.g. pesticide use or cereal husbandry). Here, we review the empirical literature to synthesize the research effort that has been directed to investigate specific practices or goals to make general statements regarding the causes and consequences of farmland biodiversity decline. We argue that the loss of ecological heterogeneity at multiple spatial and temporal scales is a universal consequence of multivariate agricultural intensification and, therefore, that future research should develop cross-cutting policy frameworks and management solutions that recreate that heterogeneity as the key to restoring and sustaining biodiversity in temperate agricultural systems.
Understanding how landscape characteristics affect biodiversity patterns and ecological processes at local and landscape scales is critical for mitigating effects of global environmental change. In this review, we use knowledge gained from human-modified landscapes to suggest eight hypotheses, which we hope will encourage more systematic research on the role of landscape composition and configuration in determining the structure of ecological communities, ecosystem functioning and services. We organize the eight hypotheses under four overarching themes. Section A: 'landscape moderation of biodiversity patterns' includes (1) the landscape species pool hypothesis-the size of the landscape-wide species pool moderates local (alpha) biodiversity, and (2) the dominance of beta diversity hypothesis-landscape-moderated dissimilarity of local communities determines landscape-wide biodiversity and overrides negative local effects of habitat fragmentation on biodiversity. Section B: 'landscape moderation of population dynamics' includes (3) the cross-habitat spillover hypothesis-landscape-moderated spillover of energy, resources and organisms across habitats, including between managed and natural ecosystems, influences landscape-wide community structure and associated processes and (4) the landscape-moderated concentration and dilution hypothesis-spatial and temporal changes in landscape composition can cause transient concentration or dilution of populations with functional consequences. Section C: 'landscape moderation of functional trait selection' includes (5) the landscape-moderated functional trait selection hypothesis-landscape moderation of species trait selection shapes the functional role and trajectory of community assembly, and (6) the landscape-moderated insurance hypothesis-landscape complexity provides spatial and temporal insurance, i.e. high resilience and stability of ecological processes in changing environments. Section D: 'landscape constraints on conservation management' includes (7) the intermediate landscape-complexity hypothesis-landscape-moderated effectiveness of local conservation management is highest in structurally simple, rather than in cleared (i.e. extremely simplified) or in complex landscapes, and (8) the landscape-moderated biodiversity versus ecosystem service management hypothesis-landscape-moderated biodiversity conservation to optimize functional diversity and related ecosystem services will not protect endangered species. Shifting our research focus from local to landscape-moderated effects on biodiversity will be critical to developing solutions for future biodiversity and ecosystem service management.
The global decline of reptiles
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- T Leiden
- Y Poppy
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The Red Book: Vertebrates in Israel. Israel Nature and Parks Authority and The Society for the Protection of
- A Bouskila
Bouskila, A., 2002. Reptiles. In: Dolev, A., Perevolotsky, A. (Eds.), The Red Book:
Vertebrates in Israel. Israel Nature and Parks Authority and The Society for the
Protection of Nature in Israel pp 71-121.
Handbook of Amphibians and Reptiles of Israel
- A Bouskila
- P Amitai
Bouskila, A., Amitai, P., 2001. Handbook of Amphibians and Reptiles of Israel. Keter
Publishing House, Jerusalem.