Lichen epiphyte abundance controlled by the nested effect of woodland composition along macroclimatic gradients

Abstract

Abstract Understanding species climatic sensitivity is a central theme in biodiversity conservation. However, climate, and the response to climate change, is one component in a multiplicity of drivers which interact to control the occurrence of lichens. This paper investigates patterns of lichen species occurrence and abundance (for Degelia spp., Lobaria pulmonaria and Sphaerophorus globosus ) in response to the simultaneous and interacting nested effect of macroclimate and local habitat quality. We show that for a very steep climatic gradient in Scotland occurrence is delimited by a climatic threshold, but also that abundance within a suitable locale is controlled by an interaction with local habitat quality. This interaction between cross-scale drivers – climate and local habitat – provides a powerful conservation tool, enabling predictive management to optimise habitat conditions, in order to offset the possible negative impacts of larger-scale environmental stress (e.g. climate change).