Grazing and mowing practices drive complex dynamics in the structure of butterfly communities in semi-natural grasslands

Rural abandonment and agricultural intensification are major threats to
the conservation of biodiversity in Europe. Butterflies are excellent
bioindicators of environmental change and can be used to assess the impact
of global change on agroforestry mosaics. We used long-term
spatio-temporal butterfly data to explore how grazing and mowing practices
affect butterfly communities in the Northwest Mediterranean Basin. Changes
in butterfly richness, abundance and habitat indicators were recorded
using standardized transect counts. We focused primarily on the impact of
management practices but also considered their interaction with other
drivers (climate and habitat configuration). The most intensive levels of
grazing did not correspond to the lowest butterfly richness; rather, they
were correlated with lower abundances but supported a greater number of
open habitat specialists. More intense mowing was also associated with low
abundances and communities dominated by common and open-habitat species.
Habitat configuration variables were also influential: open areas favoured
greater butterfly richness and abundance, as well as more grassland
specialists; greener vegetation, as measured by satellite imagery, led to
an increase in butterfly abundance and communities composed of more
generalist and forest species. Our study demonstrates the significant
impact of grassland management on butterfly communities and offers
insights into adaptive rangeland practices. It also indicates that
increased levels of mowing and grazing can alter the composition of
butterfly communities without necessarily affecting their diversity. This
suggests that a dynamic restructuring of butterfly communities may occur
in response to the environmental and habitat changes induced by these
practices.