Rarity status of endemic and vulnerable fish species in a Brazilian Atlantic Forest protected area

Rare and endemic species can be good indicators for monitoring the success of biodiversity management in protected areas. Rarity status can be checked using relatively simple quantitative methods. We used species frequency of occurrence, abundance and biomass to identify rare fish species in a Brazilian Atlantic Forest protected area. We also analyzed the abundance of a vulnerable and endemic species, Isbrueckerichthys epakmos, using general linear models and predictor variables related to instream environmental structures (substrate types, mesohabitats, water velocity and depth). Nine rare species were found, disregarding an exotic specimen. I. epakmos was endemic to PEJU, highly abundant and widely spread species. Its abundance was strongly related to higher proportions of coarse substrate, pools and riffles. The combination of biological information and rarity rates is a useful tool for indicating failures in conservation management, but also for suggesting more effective actions.