Anthropogenic Climate Change Is a Present and Future Stressor for Fish Communities in the Amazon Basin

The main reported effect of global climate change on marine fish assemblages has been the movement of species to higher latitudes as ocean waters have warmed. In contrast, the Amazon basin is the largest freshwater system in the world and, here, climate change has created extremes in the annual hydrological cycle: floodplain lakes, which are crucial habitats for Amazonian fish, have now become more isolated from the river in periods of low water; and, in the periods of high water, lakes extend further into the adjacent forest. These events strongly affect the life cycle and reproduction of fish, especially those that require seasonal connectivity between lakes and river channels in order to migrate. Our earlier results indicated that responses are species-specific, with both winners and losers being based largely on trophic level and migratory behavior. This chapter is about predicting changes in fish assemblages based on characteristics of life history. Understanding these impacts caused by climate change is key to preserving aquatic biodiversity and conserving an important food resource for humans in the Amazon. We suggest the need for a more comprehensive, cooperative research program to investigate the abundance and distribution of fish species in floodplain lakes of different regions in the Amazon.