An Anuran-Based Biotic-Integrity Index for Prioritizing Wetland Conservation Sites in Rwanda

We introduce an index based on the composition of amphibian communities that can be used to assess and monitor over time the biotic integrity of wetlands and to evaluate the priority of these sites for conservation. The Rwanda Anuran-based Biotic-Integrity Index (RABI) integrates three sub-indices, which reflect the conservation priority of species based on their distribution in Rwanda, their conservation status, and their susceptibility to habitat alteration. The functionality of the RABI was tested on 51 wetland sites distributed over the five ecozones of Rwanda. The wetland sites showed a wide range of RABI values, with marked differences between the different ecozones. The RABI reliably identified sites with a high number of threatened, range-restricted, and habitat-sensitive species and sites with high species richness. Although wetlands in agriculturally exploited areas often had high anuran-species numbers, their assemblages contained mostly widespread generalist species, resulting in lower RABI values compared to sites with lower species numbers but with threatened, specialized species. Wetlands within the four Rwandan national parks had particularly high RABI values, confirming that these areas require special protection. We identified five sites with high conservation value outside the national parks that should be considered for future protection.