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REGIONAL-SCALE FISH ECOLOGY IN NORTHEASTERN USA LAKES USING A PROBABILITY-BASED SURVEY DESIGN
Citation:
Whittier, T R. REGIONAL-SCALE FISH ECOLOGY IN NORTHEASTERN USA LAKES USING A PROBABILITY-BASED SURVEY DESIGN. Presented at North American Benthological Society meeting, LaCrosse, WI, June 3-8, 2001.
Description:
Historically, most fish ecology has been done at local scales. As these data accumulate, the need to set this knowledge into landscape, regional, and historical context grows. There are important broad-scale issues (e.g., non-point source pollution, biodiversity loss, alien species, climate change) that can not be effectively addressed by local studies. However, it is a non-trivial task to acquire and combine existing data, of unknown representativeness, to produce a useful regional-scale assessment. The Environmental Monitoring and Assessment Program (EMAP) used a probability-based design to select and sample lakes (1? 10,000 ha) in the northeastern USA. Fish assemblages data were collected during 1992-1996 at 187 randomly-selected lakes and impoundments. Only an estimated 21% of the population of Northeast lakes retained an all-native fish assemblage. An estimated 14% of lakes had more introduced species than native while introduced individuals outnumbered natives in 31% of lakes. Ecoregionally, the Adirondacks was more heavily invaded by non-native fish, than were the Lowlands or the remaining Uplands. The population of impoundments had more non-native fish than did the population of natural lakes. Data indicate that non-native predators, especially basses and sunfish, have adversely affected native brook trout and minnow assemblages.