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Presented at the NABS Annual meeting, Vancouver, British Columbia, 2004
in Small Streams and Forestry 2
Environmental factors shaping fish and macroinvertebrate assemblages in streams of southeastern Michigan
D.M. Infante1, J.D. Allan1, S. Linke2, and R.H. Norris2. 1School of Natural Resources and Environment, University of Michigan, Ann Arbor, Michigan, USA, 2Cooperative Research Centre for Freshwater Ecology, University of Canberra, Canberra 2601 AUSTRALIA
We investigated 43 first- and second-order tributaries of the Huron and Raisin Rivers of southeastern Michigan to determine whether fish and macroinvertebrates respond similarly to landscape and habitat variables. Similarities among biological assemblages were investigated by cluster analyses using relative abundances and excluding rare taxa, resulting in 5 clusters for fish and 4 clusters for invertebrates. Taxa important in formation of clusters generally shared morphological characteristics and/or had similar tolerance values. Biological clusters were related to stream habitat and landscape measures using principle axes correlations (PCC). Fish clusters were most strongly related to landscape variables, whereas macroinvertebrates showed stronger relationships to local stream habitat features. Biological groupings were again related to environmental variables using discriminant function analysis (DFA), which supported the findings of the PCC: fish clusters showed relationships to landscape measures, particularly extent of the catchment that was in wetlands or used for agriculture , while invertebrate clusters responded more strongly to local habitat including small substrate, stream siltation, and bank stability. Our results suggest that landscape variation influences the biota through multiple pathways, and the importance of landscape and local habitat may vary depending on taxonomic focus.
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