Efficacy of Terrestrial Protected Areas for Conserving Taxonomic and Functional Diversity of Fishes in Nepal: The Critical Role of Large Glacier‐Fed Rivers

ABSTRACT

Protected areas (PAs) are a cornerstone of terrestrial biodiversity conservation, but their effectiveness for the conservation of freshwater biota remains poorly understood. We evaluated the effect of protection status (PA, buffer zone and unprotected) and river type (glacier‐fed vs. spring‐fed) on the taxonomic and functional diversity, size spectra and turnover of fish communities in Chitwan and Bardiya national parks in Nepal. PAs provided limited conservation benefits for fishes: Mean fish size was higher within PAs, but abundance, richness and functional diversity did not differ among PA, buffer and unprotected sites. River type had stronger effects than protection status, such that glacier‐fed rivers supported higher fish abundance and lower species turnover than spring‐fed rivers, despite similar richness and functional diversity. Large glacier‐fed rivers may provide stable refugia from fishing pressure and habitat degradation and should be incorporated as priority ecosystems in conservation planning. Our findings indicate that Chitwan and Bardiya national parks in Nepal, celebrated for successful megafauna conservation, inadequately protect fish biodiversity and fish population abundance. In the face of intensifying climate and anthropogenic pressures, conservation of freshwater ecosystems in Nepal will require a shift from top‐down management towards local, watershed‐level management that effectively integrates community‐based governance and enforcement.