Canopy macrolichen distribution in a very wet oldgrowth forest landscape of the upper Fraser River watershed.

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. This thesis addresses this concern 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. This thesis integrates two statistical techniques: Nonmetric Multidimensional 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 suggested that community assemblages were greatly influence 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. The results of this thesis 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 rainforestsThe original print copy of this thesis may be available here: http://wizard.unbc.ca/record=b151375