Forest Investment Account

Abstract of FIA Project 6080009

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Avian community dynamics in a coastal forest landscape: clearcuts, grouped retention, old-growth benchmarks, progress report, final copy

Author(s): Preston, Michael I.
Imprint: Victoria, B.C. : Westcam Consulting Services, 2003
Subject: Forest Investment Account (FIA), Bird, survey, Birds, Effect of Habitat Modification On, British Columbia
Series: Forest Investment Account (FIA) - Land Base Investment Program


This project is intended as part of a Master's of Science program at Simon Fraser University that will commence in 2003 under the supervision of Dr. Alton Harestad. This study, which uses birds as response variables, was completed in "Block 2" of TFL 39 of Weyerhaeuser Corporations' forest tenure. Three hypotheses were developed to compare differences between species abundance and presence in traditional clearcuts, grouped variable retention harvest sites, and uncut old-growth benchmark forests. Two specific methodologies were developed to make comparisons of site usage by different species at two scales: the treatment level and the site level. For treatment comparisons, 12 sites were selected for each of the clearcut, grouped retention, and old-growth benchmark categories. Within each site, five point count stations were established. Each point count station was surveyed three times, thus yielding 540 point counts. There were 2,293 total detections (45 species), with 439 in clearcuts (31 species), 821 in grouped retention (39 species), and 940 (25 species) in old-growth benchmarks. The Chestnut-backed Chickadee and Golden-crowned Kinglet had significantly greater average abundance in old-growth than in grouped retention and clearcut sites. Mean abundance of Hammondís Flycatcher and Red-breasted Sapsucker in variable retention sites was significantly greater than in clearcuts, but did not differ significantly from old-growth. The Pacific-slope Flycatcher and Brown Creeper had significantly greater abundance in old-growth than in clearcuts, but similar to values found in variable retention sites. For the species mapping component, 73 point count stations were arranged in a 50 x 50 m grid throughout grouped retention cutblock R799. A total of 219 surveys yielded 1,057 observations of 27 species. Sufficient sample sizes for American Robin (n = 291), White-crowned Sparrow (n = 254), Spotted Towhee (n = 87), Song Sparrow (n = 80), Dark-eyed Junco (n = 56), and Red-breasted Sapsucker (n = 52) were enough to suggest that the feasibility of carrying out this project in more detail was warranted. Two plots, one for each of American Robin and Winter Wren, were produced for the purpose of visualizing the distribution and frequency of use three dimensionally. Further analysis will require comparisons between availability of habitat types and their actual frequency of use by individual species to determine if use intensity is different from what would be expected by chance alone. In early 2003, discussions with project supervisor Dr. Alton Harestad will focus on developing specific attributes for the thesis project. Discussions with Pierre Vernier (University of British Columbia) will emphasize the incorporation of data from the thesis project into a second study on developing habitat suitability index models for species at the landscape level. The criteria for both projects will meet the goals of the Adaptive Management Working Group.

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Updated August 02, 2006 

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