Disputation: Lichens in Mountain Rainforests of Tanzania: Studies of Usnea and Calicioids

  • Datum:
  • Plats: Zoom
  • Doktorand: Stella Gilbert Temu
  • Arrangör: Department of Organismal Biology
  • Kontaktperson: Stella Gilbert Temu
  • Disputation

Stella Gilbert Temu försvarar sin avhandling Lichens in Mountain Rainforests of Tanzania: Studies of Usnea and Calicioids.

Abstract: 

Lichens occur in various habitats. They often have narrow niches and are sensitive to environmental changes leading to their use as bioindicators of environmental disturbances and conditions; air and heavy metal pollution, agricultural toxins, assessing forest continuity and drought tolerance. Lichenological studies in Africa, particularly in Tanzania, have been scarce, and those available have been mainly based on morphology and chemistry data.   The aim of my doctorate was to investigate lichens, in particular Usnea and calicioid lichens in mountain rain forests in Tanzania, using both traditional and molecular approaches.

Paper I and II explored Usnea subgenus Eumitria. In paper I, molecular, morphological and chemical methods were utilized. A phylogeny of Eumitria from Tanzania based on a four-markers data set supported monophyly of Eumitria, where sixty-two new sequences were reported. In paper II additional specimens of the Usnea pectinata aggregate from Tanzania and São Tomé and Príncipe were studied, and forty-two specimens were examined by an integrative approach (molecular, morphological, chemical data). The U. pectinata aggregate was monophyletic, containing several subclades, some characterized morphologically and chemically.

 Paper III and IV focused on calicioids. Paper III summed up earlier information on Tanzanian calicioids along with new discoveries (twenty-six species), with notes on their habitats and distributions. Chaenothecopsis kilimanjaroensis was described as new, Chaenotheca hispidula and Pyrgillus cambodiensis new to Africa: Calicium lenticulare and Chaenothecopsis debilis new to Tanzania. In paper IV, Coniocybe was revised and emended to include along with its type C. furfuracea, also C. brachypoda and C. confusa. A three marker phylogeny was used to infer its phylogenetic position and Coniocybe eufuracea was described as new.

This thesis contributes to the knowledge of the lichens in Tanzania and Africa at large by building capacity in lichenology and its applications for future research. It provided integrated data for Usnea species from Africa, adding to the knowledge of this difficult group (only two sequences of Usnea from Africa have previously been published). It provided new information on calicioid lichens in Tanzania and by uncovering a rich diversity in both of the groups studied provided a foundation for further investigations of lichen biodiversity.

Zoom link: https://uu-se.zoom.us/j/2686946260