Species composition of shoreline wolf spider communities vary with
salinity but their diets vary with wrack inflow
Wolf spiders are typically the most common group of arthropod predators
on both lake and marine shorelines, because of the high prey
availability in these habitats. However, shores are also harsh
environments due to flooding and, in proximity to marine waters, to
toxic salinity levels. Here, we describe the spider community, prey
availabilities and spider diets between shoreline sites with different
salinities, albeit with comparatively small differences (5 vs. 7‰).
Despite the small environmental differences, spider communities between
low and higher saline sites showed an almost complete species turnover.
At the same time, differences in prey availability or spider gut
contents did not match changes in spider species composition but rather
changed with habitat characteristics within region, where spiders
collected at sites with thick wrack beds had a different diet than sites
with little wrack. These data suggest that shifts in spider communities
are due to habitat characteristics rather than prey availabilities, and
the most likely candidate restricting species in high salinity would be
saline sensitivity. At the same time, species absences from low-saline
habitats remain unresolved.