Intra-reach Headwater Fish Assemblage Structure

Large-scale conservation efforts can take advantage of modern large databases and regional modeling and assessment methods. However, these broad-scale efforts often assume uniform average habitat conditions and/or species assemblages within stream reaches.

I examined fish species assemblage structure within two forested headwater stream reaches of the Great Lakes drainage to evaluate the validity of within stream uniformity.

Sample assemblages within stream reaches were not distinct, except for where habitat changed sharply from forest to wetland.

The results support the general assumption that fish assemblages are uniform within stream reaches, for the purposes of coarse scale analyses, but more research is needed to test the consistency of these finding across all headwater streams of a watershed or region.