Vegetatively reproducing crustose lichens in neotropical lowland rain forests

The plan of the project is a taxonomical treatment of vegetatively reproducing crustose lichenized fungi of neotropical lowland rain forests with the aim to circumscribe for the first time the morphology, anatomy, and secondary chemistry of the taxa involved. It can be regarded as a valuable contribution to the knowledge about biodiversity of tropical lichenized fungi, as detailed data on sterile crustose epiphytic lichens will become available for the first time for calculations of alpha-diversity of tropical lowland rain forests. Project description: Crustose corticolous vegetatively reproducing lichens of tropical lowland rain forests are among the most badly known lichens on the world, although they are very common and widely distributed and may even dominate in understory habitats. Within this framework such species will be investigated from selected neotropical lowland rain forest sites (near the Pacific coast, the Atlantic coast, and from inland). The taxa involved will be characterized by their morphology, anatomy and secondary chemistry. Additionally, the different modes of vegetative reproduction of crustose lichens in neotropical lowland rain forests will be classified. Detailed analyses regarding taxonomy and phytogeography will focus on the Thelotremataceae. This family is one of the dominating lichen families in the understory of rain forests, and contributes most of the sterile corticolous crusts. Sterile crusts other than Thelotremataceae from the investigated forest plots will also be treated. Aims: The main goal of this study is to find ways to make sterile crustose lichen species of tropical lowland rain forests seizable, to show their species diversity, and to elucidate their taxonomic relationship and to prepare a key which should allow to determine these lichens. Furthermore a scheme of the modes of vegetative reproduction applicable to lowland rain forest lichens will be built up. The project will include a world wide monographic treatment of vegetatively reproducing taxa of the Thelotremataceae. Methods: Field work is planned to be undertaken at forest sites in Panama and Costa Rica. In Panama also a tower crane will be used, which makes it possible to explore the rain forest canopy zone. Own specimens resulting from field work in Venezuela in connection with an earlier project and borrowed material will be studied in the laboratory by applying mainly light microscopy and chromatographical techniques (TLC, HPLC).

Also in tropical lowland rain forest the diversity of sterile lichens is so high, that the number of species involved at this point is almost impossible to overlook. Sterile lichens are considered to be taxonomically difficult, especially in tropical areas. As attempts to determine such specimens in the most cases were hopeless, sterile lichens were so far widely ignored by collectors, even in biodiversity surveys. This ommission gives the missleading impression that sterile species play an inferior role in tropical lowland rain forests. However, own field observations during previous rain forest studies have shown, that also in tropical lowland rain forests vegetatively reproducing lichens cover a substantial part of the bark surface. In addition, preliminary observations suggested that members of a certain species rich lichen family, the Thelotremataceae, are hidden behind numerous sterile taxa in this habitat. This family is codominating among the epiphytic lichens in the understorey of tropical rain forests. The main aim of this FWF-project was a taxonomic treatment of this poorly known group of vegetatively reproducing cortical crustose lichens in neotropical lowland rain forests and to show that this type of lichens contributes considerably to the total diversity of lichenized fungi. For this purpose, field studies were performed in Costa Rica, both in the Esquinas rainforest (`Tropenstation La Gamba`) and the surroundings of the village Golfito. Further material for the study originates from field work undertaken in connection with previous FWF-projects in Venezuela (Surumoni crane plot and in the surroundings of La Esmeralda) as well as in Panama (Ft. Sherman crane plot). Additional specimens were received on loan from foreign herbaria. As a first screening of the material had shown that the number of sterile species is overwhelming and the time was limited, detailed studies were restricted to species showing a certain mode of vegetative reproduction (soredia). Any collections exhibiting characters typical for Thelotremataceae were selected. Special emphasis was given to character states of thallus and the vegetative organs for reproduction as well as secondary compounds. Secondary chemistry proved to be extremely helpful to separate taxa and, in some cases, to place a sterile species into a genus. The project so far resulted in 3 publications including descriptions of 23 species and 1 variety of Thelotremataceae new to science.