Stream benthic macroinvertebrates of nine selected catchments of the GEOMON network

Geoscience Research Reports 41, 2008 (GRR for 2007), pages 160–166

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Abstract

This project examined relationships between stream physical and chemical characteristics, whole-stream metabolism, and the associated biotic communities in 9 small, selected headwater streams of the GEOMON network. This paper documents the benthic macroinvertebrates found at each site. At each catchment, a 100-m reach was established and 3 replicate samples were collected from each major habitat type (pool, riffle, run), for a total of 9 samples per site. Benthic macroinvertebrates were collected using a net and by scrubbing all rocks and disturbing sediment within 1 ft of the net frame. Specimens were usually to the family level. Stream pH at the time of sampling ranged from 4.0 (LYS) to 7.7 (PLB). As expected, taxa richness declined with increasing acidity (R2 = 0.83; p < 0.001). The lowest biodiversity (9 taxons) was at LYS, the highest (22 taxons) at SAL (Fig. 10). The flies (Diptera) from families Chironomidae (midges) and Simuliidae (black flies), the stoneflies (Plecoptera) from families Leuctridae and Nemouridae, the caddisflies (Trichoptera) from families Limnephilidae and Polycentropodidae, and the worms from class Oligochaeta were present in all streams. However, acid-sensitive taxa such as mayflies (Ephemeroptera) were absent from the two most acidic streams.