SS3.07 Headwater Ecosystems in Forested Landscapes and Beyond
Date: Wednesday, June 12, 2002
Time: 9:45:00 AM
Location: View Royal
 
MacIsaacEA, Fisheries & Oceans Canada, Burnaby, Canada, macisaace@pac.dfo-mpo.gc.ca
Macdonald, J, S, Fisheries & Oceans Canada, Bunaby, Canada, macdonaldst@pac.dfo-mpo.gc.ca
Beaudry, P, G, P. Beaudry and Associates Ltd, Prince George, Canada, pbeaudry@bcgroup.net
Herunter, H, , Fisheries & Oceans Canada, Burnaby, Canada, herunterh@pac.dfo-mpo.gc.ca
Bothwell, M, , Environment Canada, Nanaimo, CANADA, bothwellm@pac.dfo-mpo.gc.ca
 
EFFECTIVENESS OF RIPARIAN BUFFERS FOR MAINTAINING HYDROLOGIC, THERMAL, AND BIOLOGIC FUNCTIONS OF SMALL HEADWATER STREAMS IN NORTHERN BRITISH COLUMBIA
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Under current BC forest practices regulations, small headwater streams (<3-m) have no mandatory riparian buffer reserves, allowing a variety of riparian vegetation treatments to protect stream functions. We evaluated the effects of three different 30-m riparian buffer treatments on small headwater streams in the northern Interior of BC: 1) all merchantable riparian timber harvested, 2) only large merchantable timber harvested, and 3) a “patch cut” with the top 40% of the stream clear-cut. Relative to the control streams, none of the buffer treatments were effective at eliminating stream temperature increases (mean, maximum and range) or at moderating increases in peak spring discharges. Short-term increases in suspended sediments were also apparent in the streams. Benthic invertebrates showed marked changes in abundance and diversity in the most aggressive harvesting treatments, with reductions in detritivore and shredder functional groups. In general, changes in the hydrologic, thermal, and biologic characteristics of the streams varied with the amount of riparian vegetation left in reserve, but none of the treatments completely protected the streams from the effects of the surrounding clearcuts.