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Role of hedgerow systems for biodiversity and ecosystem services in agricultural landscapes
Abstract and Figures
Climate change and loss of biodiversity are causing important economic and societal problems that are among the greatest global challenges of our time. Despite being a significant contributor to climate change and biodiversity loss, agriculture also has the capacity to provide solutions in this challenge. Agricultural lands can be designed and managed to be multifunctional, i.e. providing not only food, but also supporting biodiversity and delivering a broad set of ecosystem services. Hedgerow systems can play an important role in the realisation of such multifunctional landscapes. In this study, we address some of the pressing knowledge gaps on the plant biodiversity supported by hedgerow systems, the level of wood production they provide, and the degree to which they contribute to carbon sequestration.
The high proportion of plant species present in the hedgerow systems clearly emphasises their role as (surrogate) habitat in the open landscape. The observed increase in plant species richness over a period of 40 years in hedgerow systems – opposite to the trend in nearby forests – indicates their importance as refugia and source habitats for plant species of both the open and closed habitats. Hedgerow trees are exposed to substantial solar radiation and consequently develop heavy crowns, resulting in higher proportions of branch wood (logs with diameter < 7 cm) compared to forest trees. Tree densities in hedgerow systems are high and hedgerow trees show a continuous diameter growth with aging, resulting in high yearly wood increments and carbon sequestration rates in their above-ground biomass. In addition, also in the hedgerow soil, carbon is sequestered through decomposition processes resulting in significantly higher soil carbon stocks compared to grass margins.
Our findings help to underpin the multifunctional value of hedgerow systems in agricultural lands. We argue that hedgerow conservation will benefit biodiversity at the landscape level. Also, it could be very interesting to include hedgerow systems in landscape biomass budgets, using hedgerow-specific allometries (wood increments, proportion branch wood). Moreover, hedgerow systems represent non-negligible carbon stocks in biomass and soil and should be included in national carbon budgets.
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... In addition, up to now our study only includes two ES, even though previous analyses have shown that considering multiple ES increases the cost/benefit ratio of conservation Polasky et al., 2012). Here, other ES provided by LLEs, such as natural pest control, water and air filtration, habitat connectivity and cultural services (de Groot, 2006;Hölting et al., 2020;López-Felices et al., 2022;Van Den Berge, 2021) were not taken into consideration because these are public services lacking explicit payments, because of unavailability of such data, or because the link with LLEs was not feasible to include. Moreover, in line with other studies, our sensitivity analysis showed that costs and benefits associated with the conservation plan are sensitive, among other things, to the number and type of layers used (Allan et al., 2022;Kujala et al., 2018). ...
... Furthermore, trees on farms improve microclimate in adjacent elds (Sanchez & McCollin, 2015), enrich the soil with organic material (Van Den Berge, 2021;Cardinael et al., 2017;Follain et al., 2007;Paul, 2018) and potentially contribute to crop yields and more resilient production systems Trees on farms provide multiple bene ts. For instance, a study by Yadessa et al. (2009) showed that native trees retained in agricultural landscapes promote multiple ecosystem services as patches or islands of high pH and nutrient accumulation. ...
In tropical Africa, a wide range of agroforestry practices exist, resulting in various configurations of trees in the landscape, with an unknown impact on ecosystem services. We evaluated tree occurrence, structure, and composition in agroforestry systems within four contrasting landscapes representing different levels of tree cover in peri-urban Kigali and in the eastern province of Rwanda. We used a stratified random sampling procedure, based on soil depth and slope, to allocate 60 plots of 0.26 ha in each of the four landscapes. We conducted an extensive field inventory to provide deeper insight into the dendrometric characteristics of woody vegetation and compare landscapes. We counted all woody plants with ≥ 4 cm diameter at breast height (DBH). Over 70% of the individual trees were exotic tree species across the four agricultural landscapes. The three most common and dominant tree species across the landscapes were Grevillea robusta , a tree used mainly for timber which represents 42.7% of all individuals encountered, followed by Mangifera indica ( 12.34%) mainly used for fruit production, and Euphorbia turcalii (11.04%) mainly used for hedgerows. Most of the agroforestry trees encountered were small, scattered individuals, with almost 80% < 15 cm DBH bordering the farmlands and cut before reaching bigger sizes. The occurrence of trees varied considerably within and between landscapes, suggesting the effect of agroecological systems. Here, future studies may potentially address this link more explicitly. We showed that it is important to consider native tree species in landscape restoration initiatives given a high adoption rate of exotics.
... This mental disconnection between agriculture and woody biomass production is interesting as formerly this was a normal part of the farming activities. Hedgerows and coppice cultures have historically been part of the Flemish agricultural landscape as a source of timber, firewood, food, land demarcation and protection against drought, wind, floods and erosion (Van Den Berge, 2021). Practices such as basket weaving are also directly connected with SRC, specifically from willow (Fehér et al., 2020). ...
The report gives an introduction to short rotation coppice in Belgium (chapter 1), with possible applications and an estimation of the current amount and availability of land. The complexity and challenges concerning policy and legislation on short rotation coppice is discussed in chapter 2. A summary of policy recommendations to adjust existing legislation can be found after the extended abstract. Insight into the interactions between stakeholders is given in the stakeholder analysis (chapter 3). Direct effects of short rotation coppice can be consulted under chapter 4. Here the ecosystem services, economics and social dimensions of short rotation coppice are discussed. The report ends with a discussion on the indirect and spillover effects of large scale short rotation coppice (chapter 5).
This study delves into the diversity and composition of agroforestry species in Rwanda's Eastern Plateau and Eastern Savannah agro-ecological zones. Examining these systems across diverse landscapes is crucial for selecting species adapted to local conditions. We surveyed four landscapes with varying tree cover levels, using stratified random sampling to allocate 240 plots for detailed field inventory. We analyzed dendrometric characteristics of woody vegetation, focusing on plants with ≥ 4 cm diameter at breast height (DBH). Exotic tree species comprised over 75% of trees across all landscapes. Diversity indices indicated significant differences in plant communities between the Eastern Savannah and Eastern Plateau, with higher diversity in the former. Sørensen's similarity coefficient for woody species between the two regions showed a moderate level of similarity (approximately 53%). However, there was a significant difference in the equitability of on-farm tree species between the zones, suggesting non-identical distribution patterns. The most common and dominant tree species were Grevillea robusta, Mangifera indica, and Persea americana, primarily used for timber and fruit production. Most encountered trees were small and scattered, with nearly 80% having a DBH below 20 cm, highlighting the prevalence of young trees. The dominance of exotic species emphasizes the need for further research on their impact on agricultural biodiversity, informing sustainable land management practices in Rwanda and similar contexts.
Natural, semi-natural, and extensively managed oak woodlands and forests are prevalent across the world. These lands fulfil a range of ecosystem services, goods, and functions. Increasing natural and anthropogenic pressures impose threats to these lands. This paper first describes the Quercus genus and discusses management and mismanagement practices of oak systems. Then, the provisioning ecosystem services related with oak systems are reviewed, including: (1) oak’s agroforestry and silvopasture systems for the production of food, pasture, and additional products; (2) browsing of oak leaves and acorns by livestock; (3) harvesting of oak wood for timber; (4) cork oak stripping, and the uses of cork; (5) acorn-based foods and beverages; and (6) others uses, such as the production of medicines and extraction of tannins for the leather industry. We discuss the multi-purpose and multi-functional nature of oak systems, and demonstrate how they diversify sources of income for local communities, resulting in improved economic and food security. Further, we show the important role of woodlands certification, aimed at protecting oak systems while ensuring environmental equity. Also, we demonstrate how providing of financial support for reforestation and afforestation schemes of degraded oak woodlands, could restore ecosystem functioning and reverse land degradation. Then, we stress the need to involve traditional knowledge in restoration schemes of degraded oak systems. Lastly, we demonstrate how policymaking and legislation regarding the oak’s commercial plantations and farming systems could alleviate stresses imposed on the world’s oak woodlands and forests by producing alternative sources of wood for the timber industry.
Natural, semi-natural, and extensively managed oak woodlands and forests are prevalent across the world. These lands fulfil a range of ecosystem services, goods, and functions. Increasing natural and anthropogenic pressures impose threats to these lands. This paper first describes the Quercus genus and discusses management and mismanagement practices of oak systems. Then, the provisioning ecosystem services related with oak systems are reviewed, including: (1) oak's agroforestry and sil-vopasture systems for the production of food, pasture, and additional products; (2) browsing of oak leaves and acorns by livestock; (3) harvesting of oak wood for timber; (4) cork oak stripping, and the uses of cork; (5) acorn-based foods and beverages; and (6) others uses, such as the production of medicines and extraction of tannins for the leather industry. We discuss the multipurpose and multi-functional nature of oak systems, and demonstrate how they diversify sources of income for local communities, resulting in improved economic and food security. Further, we show the important role of woodlands certification, aimed at protecting oak systems while ensuring environmental equity. Also, we demonstrate how providing of financial support for reforestation and afforestation schemes of degraded oak woodlands, could restore ecosystem functioning and reverse land degradation. Then, we stress the need to involve traditional knowledge in restoration schemes of degraded oak systems. Lastly, we demonstrate how policymaking and legislation regarding the oak's commercial plantations and farming systems could alleviate stresses imposed on the world's oak woodlands and forests by producing alternative sources of wood for the timber industry.
The global role of tree-based climate change mitigation is widely recognized; trees sequester large amounts of atmospheric carbon, and woody biomass has an important role in the future biobased economy. In national carbon and biomass budgets, trees growing in hedgerows and tree rows are often allocated the same biomass increment data as forest-grown trees. However, the growing conditions in these linear habitats are different from forests given that the trees receive more solar radiation, potentially benefit from fertilization residuals from adjacent fields and have more physical growing space. Tree biomass increment and carbon storage in linear woody elements should therefore be quantified and correctly accounted for. We examined four different hedgerow systems with combinations of pedunculate oak, black alder and silver birch in northern Belgium. We used X-ray CT scans of pith-to-bark cores of 73 trees to model long-term (tree life span) and short-term (last five years) trends in basal area increment and increment in aboveground stem biomass. The studied hedgerows and tree rows showed high densities (168-985 trees km⁻¹) and basal areas (22.1-44.9 m² km⁻¹). In all four hedgerow systems, we found a strong and persistent increase in stem biomass and thus carbon accumulation with diameter (long-term trend). The current growth performance (short-term trend) also increased with tree diameter and was not related to hedgerow tree density or basal area, which indicates that competition for light does not (yet) limit tree growth in these ecosystems. The total stem volume was 82.0-339.7 m³ km⁻¹ (corresponding to 18.8-100.7 Mg aboveground carbon km⁻¹) and the stem volume increment was 3.1-14.5 m³ km⁻¹ year⁻¹ (aboveground carbon sequestration 0.7-4.3 Mg km⁻¹ year⁻¹). The high tree densities and the persistent increase in growth of trees growing in hedgerow systems resulted in substantial wood production and carbon sequestration rates at the landscape scale. Our findings show that trees growing in hedgerow systems should be included when biomass and carbon budgets are drafted. The biomass production rates of hedgerow trees we provide can help refine the IPCC Guidelines for National Greenhouse Gas Inventories.
Agroforestry can contribute significantly to carbon sequestration in agricultural lands, as carbon accumulates both in tree biomass and the soil. One of the oldest, yet declining, forms of agroforestry in Europe are hedgerow-bordered fields. An analysis of historical maps of our study area in Belgium shows that 70% of the hedgerow network was cleared since 1960, creating a large number of ‘ghost’ hedgerows. We selected arable fields next to hedgerows, 'ghost' hedgerows and grass strips to study how hedgerow trees influence SOC stocks and how much of these are still present after hedgerow clearing. SOC stocks to a depth of 23 cm reached up to 81.7 ± 28.8 Mg C ha⁻¹ in hedgerows, storing a considerably larger amount of soil carbon compared to grass strips (56.6 ± 14.5 Mg C ha⁻¹). These built-up stocks were completely gone in 'ghost' hedgerows (57.9 ± 14.1 Mg C ha⁻¹). In the fields adjacent to hedgerows, SOC stocks were only slightly (and insignificantly) increased compared to stocks in fields with grass strips (56.4 ± 6.3 vs 55.6 ± 5.0 Mg C ha⁻¹) with an exponential decay up to 30 m from the margin. This trend was still limitedly detectable in 'ghost' hedgerowbordered fields, however stocks were not elevated anymore (53.9 ± 6.1 Mg C ha⁻¹). Since 1960, 4 957 ± 1 664 Mg C from the soil alone were released back into the atmosphere due to hedgerow removal in the study area. The implementation of a strict hedgerow conservation policy would thus be a highly effective climate change mitigation measure in agricultural landscapes.
Agroforestry can contribute significantly to carbon sequestration in agricultural lands, as carbon accumulates both in tree biomass and the soil. One of the oldest, yet declining, forms of agroforestry in Europe are hedgerow-bordered fields. An analysis of historical maps of our study area in Belgium shows that 70% of the hedgerow network was cleared since 1960, creating a large number of ‘ghost’ hedgerows. We selected arable fields next to hedgerows, 'ghost' hedgerows and grass strips to study how hedgerow trees influence SOC stocks and how much of these are still present after hedgerow clearing. SOC stocks to a depth of 23 cm reached up to 81.7 ± 28.8 Mg C ha⁻¹ in hedgerows, storing a considerably larger amount of soil carbon compared to grass strips (56.6 ± 14.5 Mg C ha⁻¹). These built-up stocks were completely gone in 'ghost' hedgerows (57.9 ± 14.1 Mg C ha⁻¹). In the fields adjacent to hedgerows, SOC stocks were only slightly (and insignificantly) increased compared to stocks in fields with grass strips (56.4 ± 6.3 vs 55.6 ± 5.0 Mg C ha⁻¹) with an exponential decay up to 30 m from the margin. This trend was still limitedly detectable in 'ghost' hedgerowbordered fields, however stocks were not elevated anymore (53.9 ± 6.1 Mg C ha⁻¹). Since 1960, 4 957 ± 1 664 Mg C from the soil alone were released back into the atmosphere due to hedgerow removal in the study area. The implementation of a strict hedgerow conservation policy would thus be a highly effective climate change mitigation measure in agricultural landscapes.
ContextTo safeguard insect pollinators and their pollination services, we need to understand how landscape structure regulates the distribution of resources that sustain pollinator populations. However, evidence of how pollinator communities benefit from the variety of resources distributed across different habitat types is scarce.Objectives
To explore complementary resource provision, we conducted a field study to examine the resources available to pollinators in fruit orchards and woody semi-natural habitat.Methods
We studied 13 landscapes containing both habitat types in Flanders, Belgium. In every habitat element, we surveyed nesting resources, floral resources and wild pollinators (i.e. wild bees and hover flies) during three consecutive time periods in the season (once before- and twice after mass-flowering of the fruit orchards).ResultsWe concluded that the composition of nesting resources for wild bees was clearly different between both habitat types. Woody semi-natural habitat also provided more diverse- and a higher cover of floral resources compared to fruit orchards. In addition, the composition of these floral resources became more and more distinct between the two habitat types as the season progressed. Based on the plant − pollinator network we identified key plant species for inclusion in management schemes to support pollinators.Conclusions
Our study highlights that fruit orchards and woody semi-natural habitat provide a set of different, complementary resources during the flight season, for pollinating insects. Due to the higher diversity and abundance of resources in woody semi-natural habitat, conservation of woody semi-natural habitat is essential for the support of pollinators in agricultural landscapes.
Background: There is considerable uncertainty about the actual size of the global soil organic carbon (SOC) pool and its spatial distribution due to insufficient and heterogeneous data coverage.
Aims: We aimed to assess the size of the German agricultural SOC stock and develop a stratification approach that could be used in national greenhouse gas reporting.
Methods: Soils from a total of 3104 sites, comprising 2234 croplands, 820 permanent grasslands and 50 sites with permanent crops (vineyards, orchards) were sampled in a grid of 8 × 8 km to a depth of 100 cm in fixed depth increments. In addition, a decade of management data was recorded in a questionnaire completed by farmers. Two different approaches were used to stratify cropland and grassland mineral soils and derive homogeneous groups: stratification via soil type (pedogenesis) and via SOC‐relevant soil properties.
Results: A total of 146 soils were identified as organic soils, which stored by far the highest average SOC stock of 528 ± 201 Mg ha ⁻¹ in 0–100 cm depth. Of the mineral soils, croplands and permanent crops stored on average 61 ± 25 and 62 ± 25 Mg ha ⁻¹ in 0–30 cm (topsoil) and 35 ± 30 and 44 ± 28 Mg ha ⁻¹ in 30–100 cm (subsoil), while permanent grasslands stored significantly more SOC (88 ± 32 and 47 ± 50 Mg ha ⁻¹ in topsoil and subsoil). Overall, topsoils stored 67 ± 14% and subsoils 33 ± 14% of total SOC stocks. Soil C:N ratio, clay content and groundwater level were major factors that explained the spatial variability of SOC stocks in mineral soils. Accordingly, Podzols, Gleysols and Vertisols were found to have the highest SOC stocks.
Conclusions: Stratification via soil properties yielded the most comparable cropland and grassland strata and is thus preferable for estimating land‐use change effects, e.g ., for greenhouse gas inventories.
In total, 2.5 Pg C are stored in the upper 100 cm of German agricultural soils, making them the largest organic carbon pool in terrestrial ecosystems of Germany. This bares a large responsibility for the agricultural sector and society as a whole to maintain and, if possible, enhance this pool.
Hedge density, structure, and function vary with primary production and slope gradient and are subject to other diverse factors. Hedgerows are emerging ecosystems with both above- and belowground components. Functions of hedges can be categorized as provisioning, regulating, cultural, and supporting ecosystem services; these functions include food production, noncrop food and wood production, firewood production, pollination, pest control, soil conservation and quality improvement, mitigation of water flux and availability, carbon sequestration, landscape connectivity and character maintenance, and contributions to biodiversity. Urban hedges provide a relatively equitable microclimate and critical connections between green spaces and enhance human health and well-being through contact with biodiversity. Soil and water conservation are well researched in tropical hedges but less is known about their contribution to pollination, pest control, and biodiversity. Establishing a minimum hedge width and longer intervals between cutting of temperate hedges would enhance biosecurity and promote carbon sequestration and biodiversity. Hedges have a global role in mitigating biodiversity loss and climate change, which restoration should maximize, notwithstanding regional character.
Expected final online publication date for the Annual Review of Ecology, Evolution, and Systematics, Volume 51 is November 2, 2020. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
ContextHedgerows are highly important for maintaining the biodiversity in deforested landscapes. Especially for habitat specialists such as several forest plants they can provide important refuge habitats.Objectives
This study aims to examine whether there is an extinction debt for forest plants in hedgerows.Methods
In a study area in Northern Germany that had lost 47% of the hedgerow network over the past 120 years, hedgerows were mapped for the presence of forest vascular plants. In a multi-model approach, we compared the explanatory power of present and historical landscape variables and habitat quality on diversity patterns.ResultsThe change in landscape configuration had no effect on the species richness of forest plants in hedgerows, i.e. there was no sign of an extinction debt. The best explanatory variable was the hedgerow width with more species found in wider hedgerows. This demonstrates the importance of including local habitat variables in the study of extinction debt. For ancient woodland indicator species models including both the landscape configuration and habitat variables were superior to simple models. The best models included the historical distance to the nearest forest, suggesting an extinction debt. Counterintuitively, a high density of hedgerows had a negative influence on species richness, most likely because hedgerows are narrower in areas with higher densities due to land-saving measures by farmers. There was also a negative correlation between hedgerow density and the hedgerow proximity to forests.Conclusions
The effects of important covariates may obscure species-area relationships and undermine extinction debt analyses.
Linear landscape elements such as hedgerows and road verges have the potential to mitigate the adverse effects of habitat fragmentation and climate change on species, for instance, by serving as a refuge habitat or by improving functional connectivity across the landscape. However, so far this hypothesis has not been evaluated at large spatial scales, preventing us from making generalized conclusions about their efficacy and implementation in conservation policies.
Here, we assessed plant diversity patterns in 336 vegetation plots distributed along hedgerows and road verges, spanning a macro‐environmental gradient across temperate Europe. We compared herb‐layer species richness and composition in these linear elements with the respective seed‐source (core) habitats, that is, semi‐natural forests and grasslands. Next, we assessed how these differences related to several environmental drivers acting either locally, at the landscape level or along the studied macro‐ecological gradient.
Across all regions, about 55% of the plant species were shared between forests and hedgerows, and 52% between grasslands and road verges. Habitat‐specialist richness was 11% lower in the linear habitats than in the core habitats, while generalist richness was 14% higher. The difference in floristic composition between both habitat types was mainly due to species turnover, and not nestedness. Most notably, forest‐specialist richness in hedgerows responded positively to tree cover, tree height and the proportion of forests in the surrounding landscape, while generalist richness was negatively affected by tree height and buffering effect of trees on subcanopy temperatures. Grassland and road verge diversity was mainly influenced by soil properties, with positive effects of basic cation levels on the number of specialists and those of bioavailable soil phosphorus on generalist diversity.
Synthesis and applications. We demonstrate that linear landscape elements provide a potential habitat for plant species across Europe, including slow‐colonizing specialists. Additionally, our results stress the possibility for land managers to modify local habitat features (e.g. canopy structure, subcanopy microclimate, soil properties, mowing regime) through management practices to enhance the colonization success of specialists in these linear habitats. These findings underpin the management needed to better conserving the biodiversity of agricultural landscapes across broad geographical scales.
The global role of tree-based climate change mitigation is widely recognized; trees sequester large amounts of atmospheric carbon, and woody biomass has an important role in the future biobased economy. In national carbon and biomass budgets, trees growing in hedgerows and tree rows are often allocated the same biomass increment data as forest-grown trees. However, the growing conditions in these linear habitats are different from forests given that the trees receive more solar radiation, potentially benefit from fertilization residuals from adjacent fields and have more physical growing space. Tree biomass increment and carbon storage in linear woody elements should therefore be quantified and correctly accounted for. We examined four different hedgerow systems with combinations of pedunculate oak, black alder and silver birch in northern Belgium. We used X-ray CT scans of pith-to-bark cores of 73 trees to model long-term (tree life span) and short-term (last five years) trends in basal area increment and increment in aboveground stem biomass. The studied hedgerows and tree rows showed high densities (168-985 trees km⁻¹) and basal areas (22.1-44.9 m² km⁻¹). In all four hedgerow systems, we found a strong and persistent increase in stem biomass and thus carbon accumulation with diameter (long-term trend). The current growth performance (short-term trend) also increased with tree diameter and was not related to hedgerow tree density or basal area, which indicates that competition for light does not (yet) limit tree growth in these ecosystems. The total stem volume was 82.0-339.7 m³ km⁻¹ (corresponding to 18.8-100.7 Mg aboveground carbon km⁻¹) and the stem volume increment was 3.1-14.5 m³ km⁻¹ year⁻¹ (aboveground carbon sequestration 0.7-4.3 Mg km⁻¹ year⁻¹). The high tree densities and the persistent increase in growth of trees growing in hedgerow systems resulted in substantial wood production and carbon sequestration rates at the landscape scale. Our findings show that trees growing in hedgerow systems should be included when biomass and carbon budgets are drafted. The biomass production rates of hedgerow trees we provide can help refine the IPCC Guidelines for National Greenhouse Gas Inventories.
Background and aims
Hedgerows have been shown to improve forest connectivity, leading to an increased probability of species to track the shifting bioclimatic envelopes. However, it is still unknown how species in hedgerows respond to temperature changes, and whether effects differ compared to those in nearby forests. We aimed to elucidate how ongoing changes in the climate system will affect the efficiency of hedgerows to support forest plant persistence and migration in agricultural landscapes.
Methods
Here we report results from the first warming experiment in hedgerows. We combined reciprocal transplantation of plants along an 860-km latitudinal transect with experimental warming to assess the effects of temperature on vegetative growth and reproduction of two common forest herbs (Anemone nemorosa and Geum urbanum) in hedgerows vs forests.
Key results
Both species grew taller and produced more biomass in forests than in hedgerows, most likely due to a higher competition with ruderals and graminoids in hedgerows. Adult plant performance of both species generally benefitted from experimental warming, despite lower survival of A. nemorosa in heated plots. Transplantation affected the species differently: A. nemorosa plants grew taller, produced more biomass and showed higher survival when transplanted at their home site, indicating local adaptation, while individuals of G. urbanum showed larger height, biomass, reproductive output and survival when transplanted northwards, likely owing to the higher light availability associated with increasing photoperiod during the growing season.
Conclusions
These findings demonstrate that some forest herbs can show phenotypic plasticity to warming temperatures, potentially increasing their ability to benefit from hedgerows as ecological corridors. Our study thus provides novel insights into the impacts of climate change on understory plant community dynamics in hedgerows, and how rising temperature can influence the efficiency of these corridors to assist forest species’ persistence and colonization within and beyond their current distribution range.
Questions
How do contrasting environmental conditions among forests and hedgerows affect the vegetative and reproductive performance of understorey forest herbs in both habitats? Can hedgerows support reproductive source populations of forest herbs, thus potentially allowing progressive dispersal of successive generations along the linear habitats?
Location
Hedgerows and deciduous forest patches in agricultural landscapes across the European temperate biome.
Methods
First, we assessed differences in environmental conditions among forests and hedgerows. Next, we quantified plant performance based on a set of functional life‐history traits for four forest herbs (Anemone nemorosa , Ficaria verna , Geum urbanum, Poa nemoralis ) with contrasting flowering phenology and colonization capacity in paired combinations of forests and hedgerows, and compared these traits among both habitats. Finally, we assessed relationships between plant performance and environmental conditions in both habitats.
Results
All study species showed a higher aboveground biomass in hedgerows than in forests. For P. nemoralis and G. urbanum , we also found a higher reproductive output in hedgerows, which was mainly correlated to the higher sub‐canopy temperatures therein. The ‘ancient forest herb’ A. nemorosa , however, appeared to have a lower reproductive output in hedgerows than in forests, while for F. verna no reproductive differences were found between the two habitats.
Conclusions
This is the first study on such a broad geographical scale to provide evidence of reproductive source populations of forest herbs in hedgerows. Our findings provide key information on strategies by which forest plants grow, reproduce and disperse in hedgerow environments, which is imperative to better understand the dispersal corridor function of these wooded linear structures. Finally, we highlight the urgent need to develop guidelines for preserving, managing and establishing hedgerows in intensive agricultural landscapes, given their potential to contribute to the long‐term conservation and migration of forest herbs in the face of global environmental change.
The significant contribution to the global carbon budget made by soil organic carbon (SOC) inspired the “4 per 1000” initiative. It promotes agricultural practices aimed at raising SOC stocks 0.4 % annually over 20 years. However, the response of topsoil and deep soil profiles to agroecosystem changes is largely unknown at present. Our work aims to quantify deep SOC accumulations in stabilized croplands and grasslands of northeast Italy and identify the best management practices to increase those stores. Soil profiles were collected to 70 and 90 cm depths from three well-established long-term experiments. A total of 1242 soil samples were analyzed for SOC concentrations as a function of soil type, soil management practice, and cropping system. SOC stocks were quantified using the equivalent soil mass method. Results show that SOC stocks averaged 23.2 Mg ha⁻¹ in sandy Arenosol, 59.3 Mg ha⁻¹ in silty loam Cambisol, 111.6 Mg ha⁻¹ in clay loam Gleysol, and 383.5 Mg ha⁻¹ in peaty Histosol. Substantial SOC stocks were found in the subsoil beneath the tilled layer, ranging between 59 % and 74 % in sandy and clay loam soils. Among the considered managements, the SOC accumulation rate of permanent meadow topsoil was higher than croplands (0.299 Mg ha⁻¹ yr⁻¹), which fell to 0.256 Mg ha⁻¹ yr⁻¹ when estimated along the full soil profile. In contrast, organic carbon added through manures and residues, coupled with minimum tillage practices, led to increased average SOC stock rates in the topsoil (0.205 Mg ha⁻¹ yr⁻¹) and throughout the full soil profile (0.386 Mg ha⁻¹ yr⁻¹), suggesting that some translocation dynamics occurred. The long-term adoption of permanent meadow, along with manure or residue addition under minimum tillage, made it possible to achieve “4 per 1000” goals to great depths in naturally poor-SOC sandy and silty loam soils. In SOC-rich soil, only in the topsoil layer achieved this.