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Abstract Detail

Bryological and Lichenological Section/ABLS

Holt, Emily [1], McCune, Bruce [1], Neitlich, Peter [2].

Grazing impacts on macrolichen communities of the Seward Peninsula, Alaska.

DO reindeer and caribou grazing simply reduce lichen biomass, or can lichen community composition be altered as well? Extensive research demonstrates that grazing, including both consumption and trampling, negatively alters lichen communities in Arctic environments. These findings are consistent: grazing reduces lichen cover and biomass. Little research, however, investigates grazing impacts on community composition and species diversity. Some studies describe predictable shifts in lichen community composition associated with grazing. Based on these results, we hypothesized that reindeer grazing on the Seward Peninsula, Alaska, would alter lichen community structure. Using multi-response permutation procedure, we compared lichen community composition, species richness, height, and cover from heavily grazed to lightly or ungrazed areas throughout the Seward Peninsula. We also sought environmental factors to best explain these lichen attributes with nonparametric multiplicative regression. Lightly grazed areas had, on average, taller lichens and greater total lichen cover than heavily grazed sites. Lichen species richness and community composition, however, were roughly equal in heavily and lightly grazed sites. The single variables that best explained lichen height and cover were Sphagnum cover and longitude, respectively. Sphagnum cover, however, did not vary significantly with grazing intensity while longitude did. Geographic differences within the Seward Peninsula may confound potential grazing effects, perhaps mediated by differences in climate and history. Overall, grazing does not appear to have greatly affected lichen community composition or diversity on the Seward Peninsula, yet a reduction in lichen height may be associated with grazing. -DU

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1 - Oregon State University, Department of Botany & Plant Pathology, 2082 Cordley Hall, Corvallis, Oregon, 97331-2902, USA
2 - National Park Service, 41 A Wandling Road, Winthrop, Washington, 98862, USA

Arctic tundra.

Presentation Type: Oral Paper:Papers for Sections
Session: 21-5
Location: 304/Bell Memorial Union
Date: Monday, July 31st, 2006
Time: 2:30 PM
Abstract ID:33

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