Periphyton and Macroinvertebrate Assemblage Structure in Headwaters Bordered by Mature, Thinned, and Clearcut Douglas-Fir Stands
Authors: Danehy, Robert J.1; Chan, Samuel S.1; Lester, Gary T.1; Langshaw, Russell B.1; Turner, Ted R.1
Source: Forest Science, Volume 53, Number 2, April 2007 , pp. 294-307(14)
Abstract:
We examined the structure of periphyton and macroinvertebrate assemblages in 18 Oregon Coast Range perennial headwater streams bordered by mature (6), clearcut (5), and thinned (7) forest treatments. Summer base flow discharge ranged from 0.02 to1.98 l/s (mean − 0.5 l/s). Periphyton was almost entirely diatoms (72 species) and assemblage characteristics were most strongly influenced by substrate characteristics. Mature treatment sites had fewer species of diatoms and less biomass than other treatments. Diatom richness was highest at sites with higher unit area discharge. Diatom assemblages were dominated by a single species (Achnanthes lanceolata [Brébisson] Grunow), which composed more than 50% relative abundance of the assemblage at nine sites. Macroinvertebrate assemblages were rich, with 194 taxa collected across all sites and 42 taxa found at a single site. Macroinvertebrate assemblages differed across treatments with higher abundance, more Chironomidae taxa, and more biomass at the clearcut treatment sites. We observed no difference in functional feeding group percentage composition across treatments, with collector-gatherers and shredders composing at least 50% abundance at all treatments. We found little difference in either periphyton or macroinvertebrate assemblages between thinned and mature treatments.Keywords: Oregon; periphyton; diatoms; macroinvertebrates; headwaters; hydrology; logging
Document Type: Research article
Affiliations: 1: Robert J. Danehy, Weyerhaeuser Company, Springfield, OR 97405—Phone: (531) 741-5219; Samuel S. Chan, Oregon State University, Sea Grant Extension, 307 Ballard Hall, Corvallis, OR 97331—Phone: (503) 679-4828; Fax: (541) 737-3039; samuel.chan@oregonstate.edu. Gary T. Lester, EcoAnalysts Inc., 105 East 2nd St., Suite 1, Moscow, ID 83843—Phone: (208) 882-2588; Fax: (208) 883-4288; glester@ecoanalysts/com. Russell B. Langshaw, Weyerhaeuser Company, Springfield, OR 97405—Phone: (504) 754-0500; Fax: (509) 754-5012; rlangsh@gcpud.org. Ted R. Turner, Weyerhaeuser Company, Springfield, OR 97405—Phone: (531) 741-5597; Fax: (541) 741-5343; ted.turner@weyerhaeuser.com., Fax: (541) 741-5343, Email: bob.danehy@weyerhaeuser.com.
