To successfully conserve and restore agrobiodiversity, it is essential to understand the impact of multiple drivers and interlinkages across multiple taxa that occur above, across, and below the soil interface. Based on data from six agricultural landscapes in Central Germany, with 16 sampling plots per landscape, we used structural equation models to disentangle the impacts of climate, land-use, and soil factors on the diversity of multiple taxonomic groups. We expected belowground communities (soil bacteria and fungi) to be more driven by soil variables, mobile aboveground groups (wild bees, ground beetles) to be more driven by climate and land use, and vascular plants, that have an above- and belowground component, to respond to a combination of all factors.According to our expectations, climate and land-use variables had an important role in shaping aboveground and plant communities. In contrast to our expectations, soil characteristics were of lesser importance for belowground organisms. Moreover, climatic factors had a strong impact on the soil microbiome, but this effect was indirect, modulated by soil pH. We also found indications for cascading effects of environmental factors via interlinkages within and among the above- and belowground communities. Our results highlight the importance of direct and indirect effects of multiple drivers on the diversity of multiple taxonomic groups and support recent calls for a multifunctional approach for sustainable landscape management and nature restoration, suggesting to focus on the promotion of semi-natural habitats but also considering the climatic context.
Human-induced disturbances to ecosystems cause a direct loss of biodiversity, and also alter the inherent processes that shape ecosystems even after the main disturbance has ceased. Therefore, is it important to understand the ongoing consequences of past and present land use practices on both above- and belowground components of agroecosystems. Our study takes a detailed investigation of what shapes communities in semi-natural grasslands under long-term management as either pastures or meadows. We investigated the relative importance of land use (land management (LM) and land use intensity (LUI)) and abiotic conditions (soil, topographic, climatic) across five grassland sites in central Germany in explaining species occurrence patterns of vascular plants and soil fungi. Analyses included a hierarchical joint-species distribution modeling approach to uncover the role of possible drivers shaping the local communities. Our results show that abiotic factors are of particularly high importance compared to LM and LUI for both vascular plant and soil fungal communities. In general, the relative importance of explanatory variables was similar across both taxon groups, however, for plant communities, local climate conditions were more important, while for fungal communities the soil variables (e.g., soil acidity and fertility including soil carbon and potassium concentrations) played a more prominent role. Species-specific responses to the respective variables showed some similarity across the taxon groups, however less so than expected given the long legacy of past LM. Here we found that approximately 50% of the plant and fungi species had clear LM preferences and responses to LUI. More plant species were positively related to pasture than meadow management, while the opposite was found for fungal species. Our findings advance the understanding of how abiotic conditions and human land use impact local species communities in managed semi-natural grasslands, aiding further research and policy development for conserving multitrophic diversity within these biodiversity rich habitats. Our results highlight the importance of controlling for soil and climate in studying the impact of land use, and of considering the environmental context at both small and larger spatial grains when making land management and biodiversity conservation decisions. In so doing, the complexity of ecological processes within managed systems are accounted for and prioritized, promoting both conservation and ecological functioning of the agroecosystem.
The global recognition of modern agricultural practices’ impact on the environment has fuelled policy responses to ameliorate environmental degradation in agricultural landscapes. In the US and the EU, agri-environmental subsidies (AES) promote widespread adoption of sustainable practices by compensating farmers who voluntarily implement them on working farmland. Previous studies, however, have suggested limitations of their spatial targeting, with funds not allocated towards areas of the greatest environmental need. We analysed AES in the US and EU—specifically through the Environmental Quality Incentives Program (EQIP) and selected measures of the European Agricultural Fund for Rural Development (EAFRD)—to identify if AES are going where they are most needed to achieve environmental goals, using a set of environmental need indicators, socio-economic variables moderating allocation patterns, and contextual variables describing agricultural systems. Using linear mixed models and linear models we explored the associations among AES allocation and these predictors at different scales. We found that higher AES spending was associated with areas of low soil organic carbon and high greenhouse gas emissions both in the US and EU, and nitrogen surplus in the EU. More so than successes, however, clear mismatches of funding and environmental need emerged—AES allocation did not successfully target areas of highest water stress, biodiversity loss, soil erosion, and nutrient runoff. Socio-economic and agricultural context variables may explain some of these mismatches; we show that AES were allocated to areas with higher proportions of female producers in the EU but not in the US, where funds were directed towards areas with less tenant farmers. Moreover, we suggest that the potential for AES to remediate environmental issues may be curtailed by limited participation in intensive agricultural landscapes. These findings can help inform refinements to EQIP and EAFRD allocation mechanisms and identify opportunities for improving future targeting of AES spending.
Abstract Land management is known to have consequences for biodiversity; however, our synthetic understanding of its effects is limited due to highly variable results across studies, which vary in the focal taxa and spatial grain considered, as well as the response variables reported. Such synthetic knowledge is necessary for management of agroecosystems for high diversity and function. To fill this knowledge gap, we investigated the importance of scale‐dependent effects of land management (LM) (pastures vs. meadows), on plant and soil microbe diversity (fungi and bacteria) across 5 study sites in Central Germany. Analyses included diversity partitioning of species richness and related biodiversity components (i.e., density of individuals, species‐abundance distribution, and spatial aggregation) at two spatial grains (α‐ and γ‐scale, 1 m2 and 16 km2, respectively). Our results show scale‐dependent patterns in response to LM to be the norm rather than the exception and highlight the importance of measuring species richness and its underlying components at multiple spatial grains. Our outcomes provide new insight to the complexity of scale‐dependent responses within and across taxonomic groups. They suggest that, despite close associations between taxa, LM responses are not easily extrapolated across multiple spatial grains and taxa. Responses of biodiversity to LM are often driven by changes to evenness and spatial aggregation, rather than by changes in individual density. High‐site specificity of LM effects might be due to a variety of context‐specific factors, such as historic land management, identity of grazers, and grazing regime. Synthesis and applications: Our results suggest that links between taxa are not necessarily strong enough to allow for generalization of biodiversity patterns. These findings highlight the importance of considering multiple taxa and spatial grains when investigating LM responses, while promoting management practices that do the same and are tailored to local and regional conditions.
Background: Cyclopia is endemic to regions of the Cape Floristic Region across the Eastern and Western Cape provinces of South Africa and is commonly known as honeybush. Honeybush has historically been used as an herbal tea, and has proven medicinal properties. Honeybush biomass and extracts are used in the functional foods and cosmetics sectors, both locally and overseas. The growing demand for honeybush calls for increased agricultural production and a shift away from the predominantly wild harvested supply. Objectives: The current study aimed to address the lack of baseline knowledge on honeybush phenology and its associated arthropod community to advance sustainable production of commercially valued plants in the genus. Method: The study was conducted on wild and cultivated Cyclopia species (Cyclopia maculata and Cyclopia genistoides) at respective sites in the Overberg region. Sampling took place from April 2014 to April 2015 using qualitative methods for recording seasonal honeybush phenology and suction sampling for aboveground arthropods. Focal insect taxa (Coleoptera, Hemiptera, Thysanoptera, Lepidoptera and Hymenoptera) were sorted and identified to family level and classified into functional feeding guilds. Results: Qualitative phenology observations of wild C. maculata and cultivated C. genistoides indicated a high level of congruency in seasonality of phenophase stages. Associated arthropod assemblages contained a diversity of families per functional feeding group, namely phytophagous, zoophagous and omnivorous taxa, with high seasonal variability. Conclusion: Findings highlight the complexity of ecological elements to be taken into consideration for ecologically sound honeybush cultivation. Outcomes can be applied to land management practices and governance policies promoting sustainable agroecosystems in honeybush production areas.