Consequences of Global Climate Change for Stream Biodiversity and Implications for theApplication and Interpretation of Biological Indicators of Aquatic Ecosystem ConditionEPA Grant Number: R834186
Title: Consequences of Global Climate Change for Stream Biodiversity and Implications for theApplication and Interpretation of Biological Indicators of Aquatic Ecosystem Condition
Investigators: Hawkins, Charles P. , Jin, Jiming , Tarboton, David G.
Institution: Utah State University
EPA Project Officer: Hiscock, Michael
Project Period: September 1, 2009 through August 31, 2012 (Extended to July 31, 2013)
Project Amount: $789,532
RFA: Consequences of Global Change for Water Quality (2008) RFA Text | Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , Global Climate Change , Water and Watersheds , Ecosystems , Climate Change , Water
The main objective of our proposed research is to assess how changes in stream temperature and hydrology associated with global/regional climate change will influence (1) site- and regional-scale biodiversity of stream ecosystems and (2) the performance and interpretation of biological indicators, which are used to determine if streams are meeting the biological water quality goals of the Clean Water Act.
Our study area includes all streams and rivers within the contiguous United States. To address our objectives, we will (1) predict the regional and local changes in climate conditions that will likely occur as a consequence of global climate change by down-scaling predictions from general circulation models (GCMs), (2) model how ecologically important aspects of stream temperature and hydrology should change in response to these regional/local changes in climate conditional on relatively fixed differences (topography, geology, soils) among watersheds, (3) model the changes in reach-level and regional stream macroinvertebrate biodiversity (taxa composition and richness) that should occur in response to local and regional changes in temperature and hydrology, (4) determine under what conditions (e.g., stream size, topography, geology, size of biogeographic regions, etc.) changes in biodiversity are expected to be most pronounced, and (5) assess the consequences of the predicted changes in macroinvertebrate assemblage composition and structure for the application and interpretation of biological indicators.
The results of our study will provide critically needed information for aquatic resource managers who will have to anticipate (1) how aquatic biodiversity and the biological indicators used to assess biological integrity (that we have derived from natural patterns in biodiversity) will likely change in response to climate change and (2) where those changes are likely to be most pronounced. Many states have invested heavily in developing biological assessment programs to determine if water bodies are meeting the aquatic life use goals of the Clean Water Act. All biological indicators are based on comparison of observed metric values with those expected to occur under natural conditions. Data collected at reference sites are used to predict the expected metric values at assessed sites, hence inferences regarding the biological condition at assessed sites are conditional on the assumption that conditions at reference sites are dynamically stable (i.e., no long-term directional trends). If climate change alters the biological assemblages at reference sites, managers will have to consider how such changes will affect interpretation of future assessments and how they can best modify their programs to account for these effects.