Substrate age influences species richness and community composition of calicioid lichens and fungi on wooden buildings

摘要

Identifying processes that drive epiphytic lichen diversity and succession is important for directing conservation efforts and developing forest management plans for the maintenance of biodiversity and forest health. Stand age has been implicated as a key factor in driving epiphytic species diversity and community composition. However, understanding the influence of substrate age, independent of the many confounding variables that affect live and dead wood substrates in a forest habitat, can be difficult. To test the hypothesis that substrate age has distinct effects on lichen community assembly independent of surface area, we sampled communities of calicioid lichens and fungi growing on wooden buildings that ranged from 2 to 82 years old. We found a total of 17 species, with a strong positive correlation between species richness and substrate age. We also tested the effects of surface area on species richness and found no relationship between the two variables. Our results indicate that substrate age influenced community composition; non-lichenized calicioid species acted as early colonizers and six calicioid species were recorded only on the oldest substrate. Old-growth associate species were found on substrates of varying ages, implying that additional variables may also be responsible for the colonization of old-growth associate species.