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Accueil du site → Doctorat → Allemagne → Diversity and Ecology of wood-inhabiting fungi in Khonin Nuga, Westkhentey, Mongolia

Georg-August Universität zu Göttingen (2009)

Diversity and Ecology of wood-inhabiting fungi in Khonin Nuga, Westkhentey, Mongolia

Sunjidmaa, Renchin

Titre : Diversity and Ecology of wood-inhabiting fungi in Khonin Nuga, Westkhentey, Mongolia

Diversität und Ökologie holzbewohnender Pilze in Khonin Nuga, Westkhentey, Mongolei

Auteur : Sunjidmaa, Renchin

Université de soutenance : Georg-August Universität zu Göttingen

Grade : Doktorgrades 2009

Résumé partiel
The present work deals first with diversity and ecology of wood-inhabiting fungi of Mongolia. The study area Khonin Nuga is located in the West Khentey region of Northern Mongolia, which belongs to the buffer zone of the Strictly Protected Area of Khan Khentey. In the present study investigations were done on the following topics : 1. The study of fungal occurrence, species diversity, abundance and species composition of wood-inhabiting fungi in the characteristic vegetation types of the study area, which can be categorised into the following habitat types : The Light taiga of the lower montane belt (HTU), The Dark Taiga of the lower montane belt (DTU) and The Dark taiga of the upper montane belt (DTO). 2. The study of fungal occurrence, species diversity, abundance and species composition in forests, which vary widely across their fire history. Three forest types that were differentially affected by fire in 1996 (F1996, fire eleven years ago), in 2002 (F2002, fire five years ago) and in 2007 (F2007, freshly burned) were selected for investigation. As a control site, the forest HTU with only minor traces of fire occurrence and having a history of more than 15 years of not being subjected to burning was selected. 3. The investigations on the succession of fungal colonization in the initial phase of decomposition by the Manchurian birch (Betula platyphylla) in Larix-Betula forest for the first three years. For investigations and sampling, 60 plots in each of the habitat types - HTU, DTU and DTO were selected. This amounted to six transects each measuring one km within each habitat type. In each of the three fire affected forests and in the control forest, 40 plots were selected. There were four transects each measuring one km within each habitat type. In each plot, living trees and standing deadwood were investigated using angle count samples. Individual counts of logs and stumps were carried out within a radius of 15 meters around the plot center. The records of fungi fruit bodies were registered on all recorded trees and deadwood objects. The recorded species were Polyporoide and Corticioide Basidiomycetes and a few species of Ascomycetes, which formed relatively hard fruit bodies. For observing the succession trend during the initial phase of fungal colonization, in September 2004, fifteen healthy birch trees with a diameter of about 20 cm were cut. Thereafter the fungal colonization during a three year time period (2005 2007) was investigated. The study showed a total record of 152 species of wood-inhabiting fungi out of which 111 fungi were identified at species level. The evidence of more than 80 new species of wood-inhabiting fungi is not only significant for the fungal flora of the Khentey area, but also for the entire fungal flora of Mongolia. The two dark taiga habitat types showed a high degree of similarity in terms of fungal species composition. The HTU was clearly different from the two dark taiga habitat types, but with respect to their fungal floral composition was found to be rather similar to the DTU. Apart from the composition of the occurring tree species, there were also other crucial environmental factors such as the slope, the proportion of coniferous trees and the altitude level which determined the fungal species composition. The species composition in the fire-affected forests and in control forest not only differed from each other, but there was a clear succession in terms of occurrence of fungal species.

Mots clés  : Wood-inhabiting fungi ; species diversity ; species composition ; ecology ; forest fire ; succession ; logs ; stumps ; standing dead trees ; Betula platyphylla ; Larix sibirica ; Khonin Nuga

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