The importance of macrolichen traits and phylogeny in forest community assemblage along a high elevation gradient in southwestern British Columbia

Macrolichen community structure and traits were examined across a high elevation gradient in southwestern British Columbia. To our knowledge, the current study is the first to examine lichen phylogeny and community traits along a gradient of elevation. Samples were collected from 13 plots, every 50 m from 1200 to 1800 m at Joffre Lakes Provincial Park. Species richness within this zone had a unimodel distribution from low to high elevation and peaked at an intermediate elevation. Canonical correspondence analysis (CCA) confirmed that a distinct lichen community structure and assemblage of lichens is represented across the gradient of elevation. The covariate for lichen phylogeny explained 9% of the variation in community assemblage along the gradient of elevation. Lichen traits explained 91% of the variation in community assemblage. The first CCA axis distinguishes between alpine and forest lichen communities, and identified important microhabitats and traits used to explain variation in the species associations. The second CCA axis makes a distinction between higher and lower elevations and is strongly correlated with variables such as the presence of specific microhabitats (i.e. rock, wood, or bark), and lichen traits. Within the elevation range assessed, the analysis indicated three distinct lichen communities, one in alpine ecosystems, one in higher elevations forests and one in mid elevation forests. These results provide forest managers with an increased understanding of lichen community structure across elevation gradients and of indicator species and their associated traits, which can assist with management strategies that include the preservation of biodiversity.

► Lichen community structure and traits were examined across an elevation gradient in BC, Canada.
► Lichen traits (91%) and phylogeny (9%) explained variation in community assemblage.
► Species richness was distributed in a unimodel distribution with increasing elevation.
► Three distinct lichen communities exist with indicator species and characteristic traits.
► A useful resource for sustainable forest management and the conservation of lichen diversity.