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Lake Shore and Littoral Habitat Structure: Precision and biological Relevance of a Field Survey Method.
Citation:
Hughes, R. AND Phil Kaufmann. Lake Shore and Littoral Habitat Structure: Precision and biological Relevance of a Field Survey Method. Presented at Annual Meeting, Western Div. American Fisheries Society, Jackson, WY, March 26 - 29, 2012.
Impact/Purpose:
IMPACT STATEMENT for Hughes, R.M, and P.R. Kaufmann. 2012. Lake Shore and Littoral Habitat Structure: Precision and biological Relevance of a Field Survey Method. Talk presented at Annual Meeting, Western Div. American Fisheries Society. Jackson, Wyoming March 26-29, 2012: ?Lake Shore and Littoral Habitat Structure: Precision and Biological Relevance of a Field Survey Method? Until recently, lake physical habitat assessment has been an underemployed tool for assessing the ecological condition of lakes and reservoirs. In this manuscript, Kaufmann et al. describe and evaluate a rapid field sampling and analytical approach for quantifying near-shore physical habitat as it was employed in USEPA regional surveys (Environmental Monitoring and Assessment Program, EMAP survey of the Northeastern US, and the Office of Water?s National Lake Assessment, NLA). They conclude that the NLA physical habitat field approach produced metrics and indices with precision that is adequate for regional and national assessments of lake condition. Furthermore, the response of these habitat metrics to anthropogenic stress and their clear association with biotic assemblage composition and structure strongly suggest that these habitat measures quantify biologically relevant characteristics of near-shore lake environments. Using the NLA methods described in our manuscript, the Office of Water and their Federal, State, and Tribal Collaborators concluded that 36% of the lakes in the contiguous U.S. had lakeshore habitat in poor condition, and that those lakes were 3 times more likely to have impaired biotic condition than lakes whose shoreline habitat was not poor. This article confirms the effectiveness and biological relevance of this cost-effective habitat assessment tool for use by EPA, Regions, and States in evaluating the ecological health of lakes, and their compliance with the clean water act.
Description:
Until recently, lake physical habitat assessment has been an underemployed tool for assessing lake and reservoir ecological condition. We outline and evaluate a rapid field sampling and analytical approach for quantifying near-shore physical habitat. We quantified the repeatability of physical habitat metrics based on a random subsample of 90 lakes from a national probability sample of 981 lakes (NLA) and a random subsample of 50 lakes from a probability sample of 185 Northeast USA lakes (NE). We assessed the precision of littoral physical habitat complexity, fish cover, substrate, aquatic macrophytes, riparian vegetation, and shoreline human disturbances. Of the 46 NLA metrics examined, more than 65% had repeat measurement standard deviations <10% of their observed ranges. Precision was generally better (lower repeat measurement standard deviations) in the NLA compared with the NE, largely because the NLA modified the field methods by visually estimating a greater number of % areal cover classes. NLA vegetation and fish cover metrics were nearly twice as precise as NE metrics that estimated cover more coarsely. We evaluated the biological relevance of the habitat sampling approach by examining the association of habitat metrics with near-shore assemblages of fish and birds in NE. Intolerant fish species richness decreased and tolerant fish species increased with increased anthropogenic disturbances and reductions in the abundance and structural complexity of riparian vegetation and littoral cover. The percentage of neotropical migrant birds decreased and the richness of tolerant birds increased with increased anthropogenic disturbances and reductions in the abundance and structural complexity of riparian vegetation and littoral cover. We conclude that the NLA physical habitat assessment produced metrics and indices with precision adequate for regional and national assessments of lake condition. Furthermore, the response of very similar NE habitat metrics