Local Infrastructure Induces Edge Effect in Nocturnal Insects—A Case Study in the Donau-Auen National Park (Austria)

In protected areas, fragmentation and artificial light at night are usually present alongside changes in land type, from natural to agricultural or urban. We explored the intensity of edge effects on light trap responses of nocturnal insects at the margin of the floodplain forest in the Donau-Auen National Park in Central Europe, Austria. Specifically, we examined the abundance and biomass of nocturnal insects and characterized the community composition and diversity of moths with respect to the local habitat. In this study, 58 species were observed, with 21 unique records on the forest edge and nine in the interior. Traps in the forest interior harbored significantly higher nocturnal insect biomass. However, moth assemblages were more diverse at edge sites due to many singletons, attributed to individuals attracted from areas with open vegetation. Nine species (15.5% of total) were recorded later than expected given their summer flight periods, potentially reflecting the effects of ongoing climate change associated with warmer autumns. Overall, we observed higher moth species diversity at the forest edge, and insect biomass and moth abundance were higher within the forest. These findings underscore the urgent need to incorporate local anthropogenic landscape and climate change as synergically evolutionary drivers in future population and community-focused research.