Lichens in forested ecosystems

We are analysing the functional and genetic diversity of lichens in forested ecosystems and developing new methods for assessing environmental change.

Lichens are characteristic elements of temperate and tropical forests.

We are studying the spatial patterns of lichen species richness and community composition along different scales, from individual trees up to the landscape level. We are focusing on species in the UK (New Forest National Park) and the tropics (Costa Rica, Sri Lanka and Malaysia) in order to understand differences in spatial distribution of species and their relation to habitat structure and conditions.

With this data we can address:

• the relationship between lichen species' distribution and the structure and condition of forests
• the effect of fragmentation of forested areas on lichen species richness.

We identify species in the traditional way, using simple field methods to assess environmental continuity and air pollution.

However, DNA barcoding has now shown that in certain groups of lichens cryptic and semi-cryptic species or unrelated lookalikes frequently occur. We therefore aim to develop a methodology using modern taxonomy for the assessment of environmental change in forested ecosystems.

Methods

• Multivariate analysis of data from randomised sampling of lichen communities on trunks and leaves at various spatial scales, from individual trees to one-hectare plots and large landscape units separated by more than 50 kilometres.
• DNA barcoding and phylogenetic analysis of lichen species within selected higher level groups (Graphidaceae, Ramalinaceae, Arthoniales).
• Development of a new methodology to assess environmental change in forests using revised taxon concepts and functional groups.

Preliminary results

Data analysis is ongoing but preliminary results have shown that:

• lichen species richness is associated with increasing structural complexity and greater age of the site
• species richness is lower in plantations and logged forests
• specialist lichen communities are associated with certain tree species
• fragmentation of forests in both temperate and tropical conditions plays a crucial role in the loss of specialist lichen communities.