Restoration of aquatic habitat complex extends the foraging window of terrestrial consumers

Abstract

Cross-ecosystem linkages benefit generalist consumers by providing prey fluxes from donor habitats, but these trophic connections are highly vulnerable to human influences. Evidence shows that restoring degraded habitats can re-establish these linkages; however, the potential interaction between restored and remnant donor habitats remains poorly understood. Here, we show that constructed wetlands synergize with adjacent remnant streams by supplying spatial subsidies (emerging aquatic insects) asynchronously, effectively extending the foraging window for terrestrial consumers. While stream insects primarily emerged in spring to early summer, constructed wetlands exhibited a distinct peak in mid-summer, creating resource waves that terrestrial consumers may exploit over an extended period. Indeed, increased bat activity was observed in a restored site with a constructed wetland adjacent to a remnant urban stream. However, this positive effect diminished when a constructed wetland was located in a closed forest canopy area, where dense canopies may reduce prey accessibility for bats. These findings illuminate the context-dependent synergy between restored and remnant habitats in sustaining cross-ecosystem linkages, highlighting the importance of spatial design in restoration projects.