Lost before found? On systematics and conservation of lichen genus Micarea Fr. (Pilocarpaceae, Ascomycota)

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Sammanfattning

The lichenized genus Micarea Fr. (Ascomycota) comprises ca. 100 species. All species in the genus are crustose and mostly inconspicuous. The species are known from wide range of habitats, where they can cover large surface areas. Many of them are epiphytes on bark or wood, but several are also frequently encountered on rocks or soil. Some of the species are specialized living in old-growth forests or in strict microhabitats, and these species may be sensitive to forest management practices. Micarea includes one of the largest groups of congeneric obligate lignicoles depended entirely on dead wood. In addition, many species are regarded as facultative lignicoles.

Micarea prasina group is a monophyletic subgroup within the genus, including the type species of the genus Micarea prasina Fr. At the moment, the group includes 28 species. Challenges in species delimitation within this group are often noted. For example, the type species M. prasina is known for its phenotypic variability and taxonomic difficulties.

The aim of this thesis was to investigate the deficiently known lichen genus Micarea focusing especially on the M. prasina group. Moreover, the aim was to gather new information on the distribution, taxonomy, systematics, and evolution of wood-dependency within this group. We also studied the conservation biology of wood dependent communities of Micarea and decomposer fungi, and underline the importance of cooperation between taxonomists and ecologists. The specimens for the thesis were collected from several European countries and from the USA. In addition, herbaria collections were examined.

The main results are: 1.) We present a three-loci phylogeny of the Micarea prasina group and circumscribe nine new species based on phenotypic characters and phylogenetic analysis. Crystalline granules are studied as a novel character for the species. They are shown highly relevant in linking the old type specimen of M. prasina to fresh material. Also, a new species for North America is discovered. 2.) We bring new insights to the evolution of wood-inhabiting Micarea species and their reproduction. We suggest that lignicolous substratum requirement has evolved multiple times independently, and that obligate lignicoles are usually anamorphic. 3.) We show that local forest continuity is important for species rich Micarea communities. These communities seem to depend on dead standing pine trees that have been available continuously for long periods. However, local continuity did not explain diversity of decomposer fungi.

Our results indicate that species diversity is still rather poorly known even in the relatively well-studied areas of Europe. Understanding species boundaries is a necessity for reliable conclusions in habitat requirements and threat status of the species. Two of the new species described in this study are likely obligate lignicoles occupying strict microhabitats. Intense forest management can pose a real threat to these species.
Originalspråkengelska
Tilldelande institution
  • Helsingfors universitet
Handledare
  • Myllys, Leena, Handledare
Tilldelningsdatum14 sep 2018
UtgivningsortHelsinki
Förlag
Tryckta ISBN978-951-51-4429-4
Elektroniska ISBN978-951-51-4430-0
StatusPublicerad - sep 2018
MoE-publikationstypG5 Doktorsavhandling (artikel)

Vetenskapsgrenar

  • 1181 Ekologi, evolutionsbiologi

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