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Communication at the NABS Annual meeting, Keystone, 2000
(107) EFFECTS OF FOREST CANOPY COVER ON TROPHIC LEVEL BIOMASS PATTERNS IN STREAM FOOD WEBS.
B. VandenEeden and A. Turner. Department of Biology, Clarion University, Clarion, PA 16214
It is well documented that periphyton production in streams is often limited by light availability, and that irradiance is spatially heterogeneous in stream corridors. However, few studies examine how variation in primary productivity, driven by heterogeneity in irradiance, propagates up through stream food webs. We compared the standing crops of periphyton, macroinvertebrates, and fish in open canopy and closed canopy reaches of three cold-water streams in the Allegheny National Forest. We found that fish standing stocks were, on average, two-fold higher in reaches with open canopies than in reaches with closed canopies. In contrast, periphyton and macroinvertebrate standing crops did not differ consistently between reaches with open and closed canopies. These data suggest that increased primary productivity filters up through stream food webs to accumulate at the highest trophic levels, and that fish standing stocks in streams may be tightly linked to variation in periphyton productivity.
Presented at 11:30 AM on Tuesday, May 30, 2000 in Food Webs and Communities II
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