Forest edge-induced damage of cephalo- and cyanolichens in northern temperate rainforests of British Columbia

Abstract

Retention of trees after logging is a method of preserving epiphytic lichens; however, epiphytes’ responses to logging disturbance are insufficiently known. We aimed to characterize four viability measures - effective PSII yield (ΦPSII; a proxy for photosynthesis), maximal photosystem II efficiency (FV/FM; a proxy for photoinhibition), chlorophyll a content, chlorophyll a/b-ratio, - and the functional parameter specific thallus mass (STM; a proxy for water storage) in sympatric populations of two old-growth lichens (Lobaria retigera, L. oregana) and the less old-growth dependent L. pulmonaria along recently-logged forest edge gradients of retained forest patches. All species experienced substantially reduced chlorophyll contents near edges, whereas ΦPSII was lower in the two old-growth lichens than in L. pulmonaria. STM, and thus lichen water storage, did not respond to logging, probably because chlorophyll degradation reduced the carbon-gain required for necessary acclimation. Reported edge effects on lichen viability were so strong that the epiphytic lichens in most of the retained forest patches were affected. Measured viability variables improved linearly with distances up to ≈120 m from the edge. To avoid logging-induced adverse impacts on the threatened epiphytic lichens of these old-growth rainforests, there is a need to retain forest patches wider than 240 m.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author