Effectiveness of swamp rabbits as indicator species for wildlife in bottomland hardwood forests

Indicator species have been widely used to monitor ecological integrity and guide habitat restoration and management decision making. Although swamp rabbits (Sylvilagus aquaticus) have been identified as a potential indicator species of wildlife habitat quality in bottomland hardwood (BLH) forests, the effectiveness of swamp rabbits as an indicator species has not been tested quantitatively. We hypothesized that if swamp rabbits were a good indicator species, their responses to habitat components should represent responses of other taxa. Using wildlife presence-absence data collected in 2019 in southern Illinois, USA, we used a hierarchical multi-species occupancy framework to assess occupancy by wildlife and a correlation analysis to assess the relationship between species richness and swamp rabbit habitat components. Swamp rabbits preferred areas closer to upland forest, with high canopy closure, dense vertical obstruction and herbaceous ground cover, and high forest cover. Overall, 47.5 % of herpetofauna and 44.4 % of avifauna responses to habitat components were similar to swamp rabbits. Amphibians used habitat most similar to swamp rabbits, while facultative-wetland avifauna were the least similar. Although swamp rabbits alone did not represent the entire BLH wildlife community, similarities in occupancy trends between swamp rabbits and other taxa suggested that swamp rabbits could be used as an indicator species. Although management for closed canopy cover would benefit the greatest number of species, conserving other swamp rabbit habitat components, including dense vertical obstruction and herbaceous ground cover, would benefit amphibian, wetland-dependent avifauna, and some neotropical migratory bird species including species of conservation concern.