Epiphytic Lichens

Within-community species-area relationships were examined for vascular plants and epiphytic lichens on Populus spp within 100 treed patches in an area of less than 4km2 in the aspen parkland of south-central Alberta, Canada. Both plants and lichens were sampled on three scales (patch-scale and two within-patch scales). This study is one of the few to demonstrate scale-dependent species-area relationships at a small scale and highlights the importance of multi-scale sampling in ecology. At the larger patch scale, the relationship between plant species richness and area was positive for both the full plant datasets and the forest habitat specialist subset. For lichens, the species-area relationships were positive at all scales. However, for plants, at small scales, the species-area relationship was negative for all plants, but non-significant for forest habitat specialist species when considered separately. This difference reflects the different mechanisms behind the species-area relationships for the two taxa. For vascular plants, small-scale species richness decreased with patch size due to an edge effect within patches. The species-area relationships for the forest habitat specialist species were unaffected by this edge effect because these species were more common in larger patches. The distribution of lichens within patches was not significantly different from random. Therefore, the positive species-area relationships observed for this taxon reflect a passive sampling effect; where there are more individuals, there are more species.

The paper presents a list of threatened epiphytic macrolichen species found in the upper valley of Bystrzyca Dusznicka river (Central Sudetes Mts.) near Duszniki-Zdrój. Ten species have been recorded, which belong to the group of threatened lichens in Poland: Bryoria fuscescens, Evernia divaricata, Pleurosticta acetabulum, Ramalina farinacea, R. fastigiata, R. pollinaria, Tuckermanopsis chlorophylla, Usnea filipendula, U. hirta and U. subfloridana. The most valuable finding is a new locality of rare and critically endangered species Evernia divaricata.

tSimultaneous assessment of epiphytic lichen diversity by teams from six European countries, followingthe procedures defined in the recently adopted European standard, revealed several sources of error (e.g.location of plot, selection of trees, identification of taxa). Routine training and further improvement ofStandard Operating Procedures (SOPs) are suggested to boost the harmonization process of the Europeanguidelines, which promises to be an effective tool for standardizing the assessment of lichen diversity.