Master thesis: Understanding the effects of structure and dynamics of agricultural landscape

An analysis of solitary bee and earthworm data collected within the framework of the Farmland Biodiversity Observatory

Abstract

Among the main drivers of biodiversity loss are agricultural practices and landscape change. This study investigates immediate and long-term effects of agricultural landscape and related farming practices on biodiversity. I focused my work on two taxa, solitary bees and earthworms, monitored in a participatory national monitoring scheme involving farmers. I used hurdle models to assess the link between solitary bee nest-building or earthworm abundance and both farming practices and landscape variables. Local farming practices is strongly linked to earthworm abundance but not to solitary bee reproduction. Crop rotation correlates with solitary bee reproduction at a landscape scale, while it correlates with earthworm abundance at the field-level. Landscape floral resources, in particular rapeseed field area in the previous year and permanent meadow area, is strongly linked to solitary bee reproduction. Earthworm abundance correlates with permanent crop cover. To assess the impacts of agriculture on biodiversity and thus to design favourable cropping systems and agricultural landscapes, we must take into account agricultural variables at different temporal (current year, previous year, three last years) and spatial (field, landscape) scales. To promote biodiversity, we must focus both on crop rotation and related farming practices at the field level and at the landscape scale.

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