Flowing forward : freshwater ecosystem adaptation to climate change in water resources management and biodiversity conservation

Abstract

The impacts of climate change on freshwater ecosystems will be complex and hard to predict. These impacts will lead to changes in the quantity, quality, and timing of water. Changes will be driven by shifts in the volume, seasonality, and intensity of precipitation; shifts from snow to rainfall; alteration of surface runoff and groundwater recharge patterns; shifts in the timing of snowpack melting; changes in evapotranspiration; increased air and water temperatures; and rising sea levels and more frequent and intense tropical storm surges. Together, these will lead to a number of key eco-hydrological impacts on freshwater ecosystems: 1) increased low-flow episodes and water stress in some areas; 2) shifts in the timing of floods and freshwater pulses; 3) increased evaporative losses, especially from shallow water bodies; 4) higher and/or more frequent floods; 5) shifts in the seasonality and frequency of thermal stratification of lakes; 6) saltwater encroachment in coastal, deltaic, and lowlying ecosystems, including coastal aquifers; 7) generally more intense runoff events leading to increased sediment and pollution loads; and 8) increased extremes of water temperatures. Changes to the freshwater flow regime will be the most significant and pervasive of the impacts of climate change on freshwater ecosystems.