Solar parks provide heterogeneous habitats for winter-active ground-dwelling predatory arthropods

Winter-active ground-dwelling spiders and ground beetles mainly inhabit
non-crop habitats (e.g., grasslands and forests) with complex-structured
vegetation and stable microclimates. In spring, they migrate from non-crop
habitats into crop fields, contributing to pest control. Nowadays, there
is an increasing number of solar parks in agricultural landscapes.
However, the role of solar parks as habitats for winter-active
ground-dwelling spiders and ground beetles, and thus their potential
contribution to pest control, has not been studied yet. We investigated
how different habitat types (i.e., forest, grassland, habitat between and
under solar panels, and abandoned farmland) are associated with variation
in microclimatic conditions (i.e., air temperature and humidity) and with
the diversity of ground-dwelling spiders and ground beetles across 50
sites in western Hungary. Using pitfall traps, we collected 957
ground-dwelling spiders belonging to 69 species, and 327 ground beetles
belonging to 40 species. We recorded microclimatic conditions using data
loggers simultaneously with arthropod sampling. We showed that patterns in
arthropod assemblages likely reflect differences in microclimatic
conditions across habitat types. Solar parks hosted species of different
habitats (e.g., forest, grassland, wetland) with a relatively strong
preference for humidity. Solar parks also supported a high abundance of
agrobiont ground-dwelling spiders (i.e., species dominant in
agroecosystems). In contrast, grasslands and abandoned farmlands exhibited
the most extreme microclimatic conditions, supporting mainly dry-habitat
species. Our results demonstrate for the first time that solar parks can
serve heterogeneous habitats for diverse assemblages of winter-active
ground-dwelling spiders and ground beetles and may positively contribute
to biocontrol and biodiversity conservation.