Physical habitat indicators of the ecological condition of lakes and streams are important approaches for regional ecological assessment. Most physical habitat indicators are quantitative because qualitative indicators are more variable than the quantitative ones, and the measurement process for both is about the same. Biological indicators are the primary sources of information on the ecological condition of surface waters, and measurements of physical habitat indicators are required to interpret this biological information. This research uses habitat data because it can be adjusted to biological expectations resulting from natural geomorphic variation.
Habitat data are useful in assessing possible pathways through which human activities affect biota.
Methods for quantitatively characterizing physical habitat in lakes and streams have been identified and a great deal of pilot research has been conducted through survey programs such as the Environmental Monitoring and Assessment Program. Some general conclusions are that qualitative indicators are more variable than the quantitative ones, and that habitat indicators are among the best predictors of biological condition in lakes and streams. Research in this project will continue on to develop methods to reduce to metric scores the numerous field measurements of physical habitat structure characterize various habitat traits, and to combine these metrics into integrated indices of habitat condition.