Effects of landscape and mesoclimate on biodiversity in agricultural landscapes in western France

Abstract: Global biodiversity is declining due to habitat loss, climate change and human
activities, with agricultural landscapes particularly affected by land-use change, loss of seminatural habitats and reduced heterogeneity. Climate change further alters environmental
conditions and therefore influences species diversity differently, selecting only a fraction of
biodiversity. Understanding the effects of landscape structure and mesoclimate on agricultural biodiversity is therefore crucial. This study examines the effects of landscape heterogeneity (compositional and configurational), the quantity of semi-natural habitats (hedgerows and grasslands) and mesoclimate on plants, carabids and birds across 3 major habitats (crops, grasslands and hedgerows), while accounting for dispersal capacity as a vulnerability factor. It relies on a long-term experimental design of 30 landscape windows selected along independent gradients of heterogeneity and habitat quantity. Within each landscape window we monitored landscape parameters, hourly temperatures and biodiversity surveys. Preliminary results show mixed, taxa-, habitat- and dispersal-dependent effects of heterogeneity and semi-natural habitats on diversity. Using GLMs, we assess landscape and mesoclimate effects on species assemblages. Our work will provide useful knowledge for guiding agricultural management in favor of biodiversity conservation under climate change.