The effect of grassland management and landscape structure on arthropod communities

Abstract

Insect diversity is declining globally, driven largely by habitat loss and agricultural intensification. Landscapes with low biodiversity offer fewer ecosystem functions and are less resilient to climate extremes. Grasslands can serve as biodiversity hotspots within agricultural areas, but not all are species-rich or multifunctional. Management practices strongly influence grassland species composition, including insect biodiversity, as well as ecosystem functioning. However, it remains poorly understood how specific management practices and use intensity levels affect diverse insect taxa on broad scales. Here, we analyze the effects of grassland management and landscape structure on arthropod diversity in Bavaria, Germany. Most German grasslands are regularly mown, with mowing times varying across parcels. To capture this, we used a high-resolution mowing dataset derived from satellite time series. We also included a hedgerow map for Bavaria, generated from orthophotos using deep learning. This data was linked to a large arthropod dataset (~12,000 BIN species across 450 families), sampled throughout Bavaria. The spatial data were intersected with the point data by calculating spatial statistics (e.g. mean, variance) for hexagons (200 m edge length) surrounding the points. Using Generalized Linear Mixed Effects Models (GLMMs), we analyze the influence of variables related to grassland mowing dynamics as well as landscape features on insect diversity. First results show that the mean mowing frequency has a significant negative influence on the arthropod diversity over all orders. Further analyses focus on the contribution of e.g. early mowing, variance in mowing dynamics or hedges for overall arthropod diversity and various subgroups such as flying or red list insects. With this analysis, we aim to expand our understanding of how grassland management and landscape structure influence insect diversity across a broad range of grasslands.