Beetles in hedgerows

Research Invasive species H. armigera outbreaks in cotton fields Landscape pollen index and hoverflies Fields hedgerows and ground beetles Dwelling beetles in North China grasslands My main skills Where I worked

Importance of hedgerows in ground beetles community structure in northern France agrosystems Keywords: Hedgerows - Ground beetles - Activity-density - Rarefied richness - Bocage - Openfield - Northern France Human activities as well as climate change are shaping ecosystems. Most of the time the new shape of the ecosystem corresponds to a degraded state where interactions between organisms and ecological processes like ecosystem services are impeded. Studies show that the sparse natural patches of intensive agrosystems are crucial for natural enemies. Fields margins like hedgerows constitute suitable habitats for arthropods predators like ground beetles of agrosystems. Hedgerows may also serve as corridors for forest ground beetles crossing their natural habitat – forest to fields where they can regulate aphids and slugs populations (Burel, 1989). In this study, we investigate the effect of hedgerows on ground beetles community structure (activity-density and species richness) in two contrasted landscapes (bocage and openfield) in the North of France. Ground beetles were grouped according to their ecological habitat: Openfield, forest and ubiquitous species. I spent six months last year in the research unit EDYSAN at Amiens, my role in this study as a post doctoral researcher was to analyse data and write the article. Ground beetles had been sampled in 2013, in bocage and openfield agricultural landscape using pitfall traps. Bocage is characterised by polyculture and grassland patches with a dense network of hedges and many small forest fragments. Unlike bocage, open field landscapes are characterized by large fields and few natural elements. Two main questions drive the study: At local scale, do hedgerow features and quality affect carabid assemblages? At landscape scale, do wood elements (proportion of forest and hedgerow network) affect carabid assemblages? We found that there were more ground beetles (activity-density) in hedgerows of openfield landscapes than in bocage but, in bocage there was more ground beetles species than in openfield hedges. Activity-density according to the ecological groups in the bocage and opendfield landscapes Specific richness according to the ecological groups in the bocage and opendfield landscapes We also found a great variability in the response of activity-density or species richness of ground beetle to hedgerow features depending both to their ecological group and landscape. Local effects were more important than landscape effects. As expected, we found that the connection of hedgerows to forest enhanced forest species richness in the hedgerows. This study highlights the importance of hedgerows as key components of agricultural landscapes. Integrated pest management involving ground beetles should first focus on local scale before considering the landscape context. Hedgerow management should be adapted to the target ground beetles ecological group. Bibliographical references Burel, F., 1989. Landscape structure effects on carabid beetles spatial patterns in western France. Landscape Ecology 2, 215-226. https://doi.org/10.1007/BF00125092