Bryological and Lichenological Section/ABLS
Evans, Shelley A. , Nelson, Cara R. , Saracco, James F. , Dovciak, Martin , Halpern, Charles B. .
Persistence of forest-floor bryophytes in a structural-retention experiment: effects of level and pattern of overstory retention.
RELATIVELY little is known about the effects of forest management practices on bryophytes. On federal “matrix lands” in Washington, Oregon, and northern California — an area that coincides with the range of the northern spotted owl and is managed under the Northwest Forest Plan — clearcut logging has been replaced by green-tree or structural retention harvest. Partial retention of the overstory is hypothesized to moderate microclimatic conditions and to enhance species’ survival and recovery. At four locations in western Washington, we examined short-term responses of forest-floor bryophytes to a range of retention levels (100, 75, 40, and 15% of original basal area) and spatial patterns (dispersed vs. aggregated in 1-ha patches). Declines in bryophyte cover and frequency were comparatively large at 40 and 15% retention. Pattern of retention had little effect on the magnitude of decline although declines in richness tended to be greater in aggregated treatments. Declines in species frequency and richness were consistently greater in the harvest areas of aggregated treatments than in dispersed treatments. Forest aggregates appear to be influenced by edge effects: within aggregates of the 15% treatment, richness declined relative to the controls. In addition, within aggregates of the 40% treatment, richness and abundance of liverworts declined with proximity to the forest edge; mosses did not show a similar response. For conservation of bryophytes in forests managed with structural retention, larger aggregates and dispersed trees at levels considerably higher than current retention standards are likely to be required.
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Site describes the DEMO (Demonstration of Ecosystem Management Options) experiment
1 - University of Washington, College of Forest Resources, Box 352100, Seattle, Washington, 98195-2100, USA
2 - The Institute for Bird Populations, P.O. Box 1346, Pt. Reyes Station, California, 94956-1346, USA
Presentation Type: Poster:Posters for Sections
Location: Auditorium/Bell Memorial Union
Date: Tuesday, August 1st, 2006
Time: 12:30 PM