A biodiversity-friendly rotational grazing system enhancing flower-visiting insect assemblages while maintaining animal and grassland productivity

摘要

Grazing management is an important tool to preserve insect biodiversity. Although literature hasdiscussed the importance of grazing pressure adjustment to support grassland insect communities forthe ecosystem services they provide, little has been published on the economic sustainability of suchmanagement adjustments to date. This study compared continuous grazing (CG) to an innovativerotational grazing system (the biodiversity-friendly rotation – BR), where a subplot was excluded fromgrazing for two months during the mainflowering period. The effects of grazing two different species(cattle and sheep) within both systems were also evaluated. The aims were to assess the effects onbutterfly, bumblebee, and ground beetle assemblages, along with the impact on herbage mass and animalperformance. The BR enhanced both the abundance and species richness offlower-visiting insectassemblages and it was observed that cattle provided better results than sheep grazing. A multivariateredundancy analysis highlighted that most of theflower-visiting species (including almost all theendangered and locally rare species) were favoured by BR-cattle treatment, mainly due to the highpercentage offlower cover and sward heterogeneity involved in this treatment. However, grazing systemand grazer species did not affect ground beetle species richness or abundance. Moreover, herbage massand animal performance (live weight and body condition score) were comparable between CG and BRthroughout the grazing season. The BR could be a useful management system to enhance grasslandflower-visiting insect assemblages whilst meeting farm production objectives, especially in protectedenvironments where insect conservation is a major target.