Doctoral Dissertations

Robert J. Cox

Date of Award

3-1988

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major Professor

Dewey L. Bunting

Committee Members

E.C. Bernard, G.S. Sayler, G.A. Vaughan

Abstract

This study Involved an examination of the microinvertebrate communities associated with aquatic bryophytes in two lower order mountain streams having different lengths and different watershed areas. An attempt was made to identify some of the environmental factors influencing those communities. The effect of growth form on the accumulation of water-borne particulate material was examined by determining the amount and size distribution of material collected by bryophytes having different growth forms and artificial substrates chosen to mimic those plants. The bryophytes examined were Eurhynchium riparioides, a mat-forming moss found in Crabapple Branch, and Fontinalis novae-angliae, a "streamer" found in Crabapple Branch and the shorter Hog Jaw Branch. The Eurhynchiummimic was a 10x10 cm square of indoor/outdoor carpet. The Fontinalis mimic was an acrylic yarn "mop." The macroinvertebrate communities examined were composed of the smaller insects, mites, crustaceans, annelids, nematodes, rotifers, and tardigrades. The numbers of individuals, numbers of genera, and diversity were determined for each group and for the entire community.

All environmental parameters for both streams exhibited significant differences over time. Flow rate and suspended solids load, factors closely linked to stream length and watershed area, were greater for the longer Crabapple Branch than for Hog Jaw Branch.

Comparison of all substrates in both streams in terms of both detrital and biological parameters revealed that the models resembled each other more than they resembled their respective mimics and vice versa. Different substrates within a stream were less similar than the same substrates within different streams. It appears that growth form may strongly influence the microinvertebrate community associated with these substrates. Differences between substrates within a stream reflect different growth forms and/or interactions between growth form and environmental parameters. Differences between the same substrates in different streams may reflect differences between streams. Some of these differences may be linked to local geography and be site specific.

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