Climate change sensitivity of threatened, and largely unprotected, Amazonian fishes

Abstract

Climate change is poised to have fundamental impacts on the freshwater environments of the Amazon River Basin, and protected areas are routinely proposed as a possible management strategy to conserve freshwater fishes. However, there remains a paucity of information regarding the sensitivity of threatened fish species to climate-induced changes in water quantity and quality. An expert-based survey was used to address the following questions: (1) Are currently threatened fish species in Brazil also sensitive to projected effects of climate change? (2) Does the current conservation status of fish species also reflect their degree of sensitivity to climate change? and (3) What are the specific aspects of climate change that are likely to contribute the most to species sensitivity? Survey respondents evaluated 35 species (11 families) representing 50% of the threatened species in the Brazilian Amazon. The results suggest that the majority of threatened Brazilian fish species are considered highly sensitive to climate change impacts. Climate-induced changes in water quality were, on average, considered a greater threat to species persistence than potential changes in water quantity. Survey results also suggest that fishes exhibit high sensitivity to changes in temperature and dissolved oxygen, and moderate to high sensitivity to changes in high-flow (i.e. flood) and low-flow (i.e. drought) regimes. A considerable mismatch was found between species conservation status and sensitivity to climate change, suggesting that perceptions of present-day extinction risk do not necessarily provide insight into future risks associated with climate change. Species sensitivity to climate change showed no relationship to dispersal ability, indicating that protected areas may serve as important refugia for those species unable to keep pace with climate change. Despite this, the number and size of protected areas in Brazil have decreased over the past decade, largely to support the exploitation of hydropower and mining. Strategic conservation planning that involves existing and new protected areas for those species most at risk to climate change is warranted. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.