Quantifying the impact of environmental factors on arthropod communities in agricultural landscapes across organizational levels and spatial scales

TLDR

In landscapes shaped by intensive agriculture, understanding how environmental factors influence arthropod community composition and function across spatial scales is crucial for biodiversity conservation. The authors examined five arthropod taxa across 24 4 × 4 km landscapes in seven European countries, using hierarchical variability partitioning of country, land‑use intensity, landscape structure, and local habitat properties across regional, landscape, and local scales. Regional processes dominated community composition, but after accounting for them, landscape‑scale factors—especially land‑use intensity and connectivity—explained most variation in species, body size, and trophic guilds, indicating that targeting these factors can enhance diversity. The study synthesizes findings and discusses applications.

Abstract

Summary In landscapes influenced by anthropogenic activities, such as intensive agriculture, knowledge of the relative importance and interaction of environmental factors on the composition and function of local communities across a range of spatial scales is important for maintaining biodiversity. We analysed five arthropod taxa covering a broad range of functional aspects (wild bees, true bugs, carabid beetles, hoverflies and spiders) in 24 landscapes (4 × 4 km) across seven European countries along gradients of both land‐use intensity and landscape structure. Species–environment relationships were examined in a hierarchical design of four main sets of environmental factors (country, land‐use intensity, landscape structure, local habitat properties) that covered three spatial scales (region, landscape, local) by means of hierarchical variability partitioning using partial canonical correspondence analyses. Local community composition and the distribution of body size classes and trophic guilds were most affected by regional processes, which highly confounded landscape and local factors. After correcting for regional effects, factors at the landscape scale dominated over local habitat factors. Land‐use intensity explained most of the variability in species data, whereas landscape characteristics (especially connectivity) accounted for most of the variability in body size and trophic guilds. Synthesis and applications. Our results suggest that management effort should be focused on land‐use intensity and habitat connectivity in order to enhance diversity in agricultural landscapes. Since these factors are largely independent, specific conservation programmes may be developed with regards to socio‐economic and agri‐environmental requirements. Changes in either of these factors will enhance diversity but will also result in specific effects on local communities related to dispersal ability and the resource use of species.