BC’s Inland Rainforest – Conservation and Community
Not all old-growth is equal: Ecological attributes and lichen biodiversity in an inland temperate rainforest landscape.
David Radies 1, Darwyn Coxson 1, Chris Johnson 1 and Ksenia Konwicki 2
Windward slopes of the inland mountain ranges in British Columbia support a unique temperate rainforest ecosystem. Continued fragmentation and loss of old-growth forests in this globally rare ecosystem, has led to calls for the identification of conservation priorities between remaining stands. We address this question by surveying the relative abundances of 37 canopy macrolichens over a 70-km2 area of remaining old-growth (>140 years) forest in the upper Fraser River watershed, British Columbia, Canada. To ensure adequate representation of landscape-scale old-growth forest characteristics, we divided study plots equally among leading tree species and between broadly defined sites of “wet” and “dry” relative soil moisture. Other variables included: minimum mean annual temperature, mean annual precipitation, solar loading, and canopy openness. We used two statistical techniques: Nonmetric Multidimentional Scaling ordination for analysis of lichen assemblages and logistic regression to evaluate the habitat conditions of a subset of 8 lichen species previously identified as “old-growth associated”. Ordination results suggest that lichen community assemblages were greatly influenced by both the presence and abundance of bipartite cyanolichens. These communities correlated well with increasing levels of relative soil moisture, temperature, precipitation, and canopy openness, with little to no significant effect of tree leading species. Logistic regression models identified relative soil moisture and temperature in all parsimonious models. Leading tree species, in combination with moisture and temperature, were important factors explaining the presence or absence of 5 of 8 modeled lichen species. Our results emphasize the importance of maintaining representative areas of old-growth forests that are potentially less prone to natural disturbances such as fire. Of concern to the maintenance of lichen populations in old-growth inland temperate rainforests is the continued forest harvesting of low-elevation water-receiving sites. We recommend conservation of these wet topographic positioned areas to meet provincially set ecosystem-based old-growth threshold targets for the purpose of maintaining biological diversity and ecological integrity. For further information see: http://wetbelt.unbc.ca/featured-03.htm
1 Ecosystem Science and Management Program, University of Northern British Columbia, Prince George, B.C. Canada, V2N 4Z9
2 Timberline Natural Resource Group Ltd., 1579 9th Ave., Prince George, BC, V2L 3R8
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