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Patterns in Habitat and Fish Assemblages within Great Lakes Coastal Wetlands and Implications for Sampling Design
Citation:
TREBITZ, A. S., J. C. BRAZNER, M. S. PEARSON, G. S. PETERSON, D. K. TANNER, AND D. L. TAYLOR. Patterns in Habitat and Fish Assemblages within Great Lakes Coastal Wetlands and Implications for Sampling Design. CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES. NRC Research Press, Ottawa, Canada, 66(8):1343-1354, (2009).
Impact/Purpose:
The objectives are to examine fine-scale patterns of fish composition and habitat use across a much larger study area (across the Great Lakes basin), with a focus on the entire fish assemblage.
Description:
Discerning fish - habitat associations at a variety of spatial scales is relevant to evaluating stressor responses and assessment protocols in Great Lakes coastal wetlands. NMDS ordination of electrofishing catch-per-effort data identified an overriding influence of geography and anthropogenic stressors on water clarity, vegetation structure, and fish composition at whole-wetland and within-wetland spatial scales across the basin. Protected lacustrine type wetlands were generally internally homogeneous in fish composition, while riverine or barrier-beach lagoon wetlands were more heterogeneous, especially if they had substantial tributary flows, lake-exposed mouth areas, complex morphology, or strong internal contrasts in vegetation structure. A tendency towards lower richness, more turbidity tolerant taxa, and fewer nest guarding and vegetation spawning taxa described both more disturbed relative to less disturbed conditions across wetlands and open water relative to vegetated areas within wetlands. Because aquatic vegetation is a primary habitat element for fishes and both hydromorphology and disturbance substantially influence its structure, standardizing fish sampling protocols by microhabitat across broad spatial, temporal, or disturbance gradients may be difficult. We recommend distributing sampling effort across vegetation zones available, and show that both fish and habitat are adequately sampled using numbers of stations or points that can be covered in a single field day.