IMPACTS OF CLIMATE CHANGE ON AQUATIC ECOSYSTEM FUNCTIONING AND HEALTH¹

Abstract

We review published analyses of the effects of climate change on goods and services provided by freshwater ecosystems in the United States. Climate‐induced changes must be assessed in the context of massive anthropogenic changes in water quantity and quality resulting from altered patterns of land use, water withdrawal, and species invasions; these may dwarf or exacerbate climate‐induced changes. Water to meet instream needs is competing with other uses of water, and that competition is likely to be increased by climate change. We review recent predictions of the impacts of climate change on aquatic ecosystems in eight regions of North America. Impacts include warmer temperatures that alter lake mixing regimes and availability of fish habitat; changed magnitude and seasonality of runoff regimes that alter nutrient loading and limit habitat availability at low flow; and loss of prairie pothole wetlands that reduces waterfowl populations. Many of the predicted changes in aquatic ecosystems are a consequence of climatic effects on terrestrial ecosystems; shifts in riparian vegetation and hydrology are particularly critical. We review models that could be used to explore potential effects of climate change on freshwater ecosystems; these include models of instream flow, bioenergetics models, nutrient spiraling models, and models relating riverine food webs to hydrologic regime. We discuss potential ecological risks, benefits, and costs of climate change and identify information needs and model improvements that are required to improve our ability to predict and identify climate change impacts and to evaluate management options.

Climate Change Projections for the United States Midwest

“…Warmer temperatures will alter lake mixing regimes and availability of fish habitat (Meyer et al 1999), while annual stream temperatures in the Missouri River and Ohio River basins could increase by 2-5 • C (Mohseni et al 1999). Summer stratification in lakes will last longer under warmer conditions, resulting in deep oxygen-depleted areas in lakes where cold water fish will not be able to survive (Lehman 2002).…”

Possible impacts of climate change on wetlands and its biota in the Brazilian Amazon

“…It is expected that these environments will be affected by changes in precipitation, temperature and evaporation, which would cause changes in the input of nutrients and debris, and the frequency and intensity of droughts and floods (Mulholland et al, 1997;Meyer et al, 1999;Lake et al, 2000;Erwin, 2009). Changes in the hydrological regime might also modify the physicochemical properties of the soil, directly impacting the wetland biota (Carpenter et al, 1992;Burkett and Kusler, 2000;Lake et al, 2000).…”

The role of organisms in hyporheic processes: gaps in current knowledge, needs for future research and applications

“…Predictions of the potential effects of climate changes on river processes are urgently required (Carpenter et al, 1992;Meyer et al, 1999), especially for the hyporheic zone. The consequences of temperature increases on biologically mediated hyporheic processes must be clarified and offered to river managers.…”