Studies on Tasmanian rainforest lichens
Creators: name: Kantvilas, Gintaris
Publisher: name: University Of Tasmania
Year: 2023

description: This thesis deals with the history of lichenology in Tasmania, the composition of the Tasmanian rainforest lichen flora and the ecology of rainforest lichens. The first part (history) provides a context for the floristic and ecological sections and traces the development of lichenology from the first collections to the present. Two periods of lichenological activity are apparent in Tasmania. The first, in the 19th Century, saw the discovery and description of much of the flora. The second, which commenced within the last two decades, has involved the relearning of early knowledge and its reappraisal in terms of modern taxonomic principles. In the present study, 208 species, comprising 128 macrolichens and 80 crustose species, are reported from Tasmanian rainforest. The inventory of macrolichens is considered virtually complete and an identification key for the species is provided. Crustose lichens remain poorly known and only the more common or distinctive species are included. Brief descriptions for all species, as well as habitat and distribution data, are provided. Approximately 60% of the species belong to the \austral cool temperate\" phytogeographical element although the \"Australian\" and \"cosmopolitan\" elements are also well-represented. There are very few endemics and 76% of the flora also occurs in New Zealand. Some lichens are confined to rainforest but many species occur also in other high-rainfall vegetation. Most species are widespread within rainforest but large scale disturbance and the fragmentation of rainforest stands poses a threat to their survival. The vertical distribution of lichens in rainforest is investigated by direct gradient analyses and by the numerical techniques of ordination and classification. Lichens respond to a complex environmental gradient which extends from the forest floor to the canopy. This height gradient entails the components of micro-climate and substrate age with the shadiest oldest substrates near the forest floor and the most exposed youngest substrates in the canopy. The character of the host tree and the local structure of the forest modify the effects of height. Individual lichens mostly have broad overlapping distributions with recognisable optima. Similarly aggregations of species characterise particular habitats along the complex height gradient. Relationships between lichen diversity height and substrate age are also apparent. A classification of lichen vegetation in rainforest at Little Fisher River northern Tasmania is undertaken using phytosociological techniques. 11 communities are described and apart from minor compositional details these are widespread in Tasmanian rainforest. A numerical classification provides supporting evidence for the phytosociological classification and the relative merits of the two approaches are discussed briefly. A scheme of inter-relationships and successional pathways among the communities is proposed. This scheme is supported by an ordination which illustrates the ecological and distributional trends described. Ecological centres of distribution for bryophytes and different lichen growth-habit groups are also illustrated. Three environmental gradients are of particular importance: age of substrate/ height above ground moisture and substrate texture. These results independently support the analyses of environmental gradients in the vertical distribution study. Furthermore the aggregations of species previously identified along the vertical gradient are referable to phytosociological units."