In 2020, additional information about limiting factors were added to the SWAP database for RSGCN.
While all species have unique vulnerabilities and stressors that are responsible for declining populations, species and threats associated with aquatic habitats are strongly represented through the RSGCN list. Aside from issues of habitat availability and quality, many of these species have been negatively impacted by poor water quality, and projected hydrologic shifts with climate change are expected to make it more difficult to secure these species in the future.
Similarly, many species have threats associated with their wintering strategy, either because winter habitat management may disturb them during dormancy or because winter conditions are changing both in temperature and in precipitation.
Along with these general findings, the database now includes information about threats like predation, incidental and intentional take, disease, and threats due to loss of genetic diversity and dependencies on other species. We also have information about food dependencies (69% of vertebrate RSGCN are invertivores.) Habitat associations and requirements are also identified for each species. These requirements vary by habitat type but include things like age class, downed woody debris, and canopy density for forests, gradient and temperature for streams and rivers, and fire return intervals for grasslands.
Numbers of RSGCN occurring in each state.