Habitat Use Across Multiple Scales Suggests Resilience To Rising Seas For Endangered Island Endemic Compared To Sympatric Invasive Species

Wildlife is increasingly threatened by a suite of anthropogenic factors including climate change, habitat loss from human development, and invasive species. These threats are particularly pronounced on islands where species are more likely to go extinct. To better understand how native and invasive species on islands might respond to these threats, we compared habitat use between the endangered silver rice rat (SRR)Oryzomys palustris natatorand invasive black ratRattus rattusacross multiple scales. We used a specialized camera trap design to survey rodents across the Lower Florida Keys, USA, a region vulnerable to emerging threats, such as rising sea level, and persistent threats, such as human development. Additionally, we used a novel modeling approach to investigate temporal variation in rodent activity as a function of lunar tides. Silver rice rat occurrence was greatest in regularly inundated mangroves that could potentially increase in extent as sea level rises. Black rats were widespread and often co-occurred with SRR, but we observed temporal resource partitioning between these species, which suggests competition may be limited. Of the stressors we investigated, we conclude that contjaceinued urban development is the most substantial threat to SRR, and potentially other island species. Our results highlight island species' disparate responses to different aspects of global change and the potential conservation opportunities that may result.