Catrin Westphal

Landscape heterogeneity is a key driver of biodiversity, ecosystem functioning, and resilience. However, its multiple components—compositional, configurational, vertical, and temporal— are rarely analysed together at broad spatial scales. Compositional heterogeneity refers to the number and proportions of different elements, configurational heterogeneity to their spatial arrangement and shape, vertical heterogeneity to variation in vegetation height, and temporal heterogeneity to interannual variation in land cover and management. Here we examine relationships among these components across forests, croplands, and grasslands using nationwide geospatial data from Germany. We show that compositional and configurational heterogeneity (Shannon diversity vs. edge density) are positively correlated, although their relationship varied with land-cover proportions. Contrary to common assumptions, configurational heterogeneity does not enhance habitat connectivity. Vertical and temporal heterogeneity are largely independent from horizontal heterogeneity. Forests are the main contributors to landscape heterogeneity across land-cover types, whereas croplands contribute little or even negatively. These findings highlight the importance of considering land-cover proportions and multi-dimensional heterogeneity when assessing landscape structure. Our results have broad implications for environmental monitoring and planning for biodiversity and ecosystem assessments, offering a framework to avoid hidden collinearity and consider multi-dimensional perspective and socio-ecological context.

Pollination is a key ecological process sustaining biodiversity and food security, yet global patterns of plant–pollinator specialization remain unresolved. Using a global dataset of quantitative plant–pollinator networks (>3,400 networks, >110,000 interactions), we show that specialization is latitudinally structured, but not as a single directional pattern. We find no consistent monotonic increase or decrease in specialization towards the Equator. Instead, network-level and pollinator specialization peak at low northern latitudes near the tropical–subtropical boundary, whereas plant specialization is hemispherically asymmetric. Climate is most often the best-supported predictor of specialization compared with latitude, biodiversity and environmental productivity. Network-level specialization declines with increasing mean annual temperature, with strong group-specific differences. Precipitation exerts nonlinear effects: plant specialization peaks at intermediate precipitation but is lower at the wettest sites, whereas pollinator specialization is lower at intermediate precipitation, although often in interaction with temperature. Pollinator groups diverge strongly, especially in contrasting precipitation-related patterns between birds and insects. These findings show that global plant–pollinator specialization is structured by latitude and climate in complex and taxon-specific ways, with implications for uneven responses of pollination networks to future climatic change.

Calcareous grasslands are important habitats for many pollinators including wild bees but have declined dramatically in habitat quantity and quality due to land use changes at local and landscape scale. Such developments might be mitigated by local management, such as low‐intensity land use and landscape measures, including the conservation of calcareous grasslands and the establishment of biodiversity‐friendly farming practices like agri‐environment schemes (AES). Yet, the effectiveness of these measures for conserving pollinator communities is still poorly explored and might depend, for example on the landscape context or the AES type (productive vs. non‐productive). Using transect walks, we investigated how local and landscape‐scale management affects bee communities in 96 calcareous grasslands in three European countries (Estonia, Germany, Spain), covering three biogeographic regions (boreal, continental, Mediterranean). Over a period of 2 years, we recorded 6716 individuals from 235 species across our study regions, underpinning the importance of calcareous grasslands for wild bee conservation. According to a local land use intensity index, we found that both long‐term abandonment and intensive management reduced wild bee species richness and abundance, either directly or indirectly through effects on floral resource availability. At the landscape scale, cover of calcareous grassland and AES in the surroundings benefited wild bee communities, though the effectiveness of AES often depended on the AES type and the landscape cover of calcareous grasslands. In Germany, for example productive AES increased wild bee abundance and richness only in landscapes with higher calcareous grassland cover, while non‐productive AES were most effective if landscape calcareous grassland cover was lower. However, landscape effects varied across study regions. Synthesis and applications . Conserving wild bee diversity in these grasslands requires avoiding long‐term abandonment and intensive management, while promoting local management at low to moderate intensity. Moreover, it is essential to conserve and restore calcareous grasslands in the surroundings. This may be complemented by implementing AES in the landscape, depending on the AES type, landscape and regional context. Our findings stress that future restoration and conservation planning should combine local and landscape management measures to successfully conserve wild bees in European calcareous grasslands.

Global farmland biodiversity is declining rapidly, threatening both natural ecosystems and agricultural production. Although agri‐environmental schemes incentivize farmers to adopt environmentally friendly measures, the spatial mismatch between their local implementation and the landscape‐scale habitat requirements of farmland species has been criticized. Landscape‐scale agri‐environmental schemes (LAESs) are a promising approach for promoting biodiversity effectively through collaboration among multiple farmers. The success of such collaboration for biodiversity conservation relies substantially on well‐functioning social networks and economic profitability for participating farmers. For an LAES to be an effective tool, it is crucial to capitalize on potential synergies among social, ecological, and economic benefits arising from collaborative implementation of LAESs and to promote positive feedback loops. We identified six potential synergies originating from the combined benefits of LAESs based on participatory workshops, expert discussions, and scientific evidence, focusing on intensive agricultural systems in Western Europe. Governance structures, such as a coordinating institution, bottom‐up approaches, and adaptations to policy frameworks, can promote synergies and help overcome current challenges and trade‐offs. The identified synergies and governance structures will be crucial for shaping future European agricultural policies that promote sustainable farmland biodiversity conservation and may serve as a model for transferring LAESs to other global regions.

Tropical rainforests harbor exceptional biodiversity and function, but are increasingly threatened by agricultural expansion. Whether landscape heterogeneity mitigates these impacts, as in temperate systems, remains unclear. Here, we quantified how local land use and landscape heterogeneity shape multidiversity and ecosystem multifunctionality, using 34 biodiversity metrics and 21 functions across 128 plots in Sumatra. Relative to rainforests, plantations reduced multidiversity and multifunctionality by ~25%, with stronger aboveground declines, lower plant and animal but higher microbial diversity. Contrary to temperate systems, landscape heterogeneity did not buffer local land-use effects but exacerbated declines in multidiversity and multifunctionality, and benefits of surrounding-rainforest cover were confined to rainforest fragments rather than plantations. Our results highlight the irreplaceability of continuous tropical rainforests, and the limited transferability of temperate-based landscape conservation strategies.