Bryophytes and Lichens of North America: Diversity, Function and Importance
Campbell, Jocelyn , Bradfield, Gary, E. , Prescott, Cindy, E. , Fredeen, Arthur, L. .
Expanding the realized niche for cyanolichens in wet-temperate forests of interior British Columbia.
The wet-temperate forests of interior British Columbia are hotspots of cyanolichen diversity. Centuries of ecological continuity and high precipitation have resulted in unparalleled diversity in the wetter sub-boreal spruce biogeoclimatic subzones. Extensive effort has been invested in determining the abiotic conditions that define the realized niche for cyanolichens within these forests. Studies show that regional floristic differences are determined by prevailing abiotic conditions, but recent research suggests that site-scale patterns may be due to positive biotic interactions. Facilitation in plant ecology has been demonstrated to increase species diversity and to result in an expansion of the realized niche for stress-intolerant species. To test the importance of facilitation to cyanolichens in sub-boreal spruce forests, lichens were documented on conifer saplings beneath poplar, paper birch, subalpine fir, hybrid spruce and Douglas-fir. To document changes in facilitative interactions along an increasingly stressful environment, comparisons were made at 9 sites along a climatic gradient from very-wet to moist SBS forests. Moisture was selected as the dominant abiotic factor because cyanolichens require full hydration for physiological activity and distribution patterns are commonly attributed to moisture regime. In the drier forest types, cyanolichens were consistently more diverse and abundant when observed under poplar than under any other tree species. Gel cyanolichens were observed only when under poplar at these sites. At the very-wet sites there were no differences in cyanolichen diversity between any tree species. These data support the concept of moisture-limitations being an important determinant of cyanolichen communities, but also provide support for a facilitative relationship. Cyanolichen communities, through association with poplar trees, are able to become established in drier forest types. Poplars can thus been perceived as nurse-plants; facilitating an expansion of the realized niche for cyanolichens from a comparatively narrow band of wet interior forests, and contributing to islands of high cyanolichen biodiversity
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1 - University of British Columbia, Faculty of Forestry, 2424 Main Mall, Vancouver, British Columbia, V6T 1Z4, Canada
2 - University of British Columbia, Botany Department, 3529-6270 University Boulevard, Vancouver, British Columbia, V6T 1Z4, Canada
3 - University of Northern British Columbia, Ecosystem and Science and Management Program, 3333 University Way, Prince George, British Columbia, V2N 4Z9, Canada
sub boreal spruce forest.
Presentation Type: Symposium or Colloquium Presentation
Date: Tuesday, July 29th, 2008
Time: 2:00 PM