Determination of decomposer fungal communities in early stages of scots pine ( pinus sylvestris l.) needle- litter decomposition

This thesis was conducted in order to determine the diversity and structure of fungal communities of scots pine (Pinus sylvestris L.) needles during the early stages of its decomposition. In this study, the fungi colonizing the needles that have been exposed to the natural decomposition process using the litterbag method were determined based on isolations after two (D1), four (D2), and six (D3) moths of incubation on the forest floor. Identification of isolated fungi were achieved through both morphologically and ITS sequencing. A total of 47 fungal taxa were identified on pine needles at the early stage of the decomposition process. The Ascomycota constitute of 74 % of the needle mycobiota. The members of class Dothideomycetes were the most common by both numbers of taxa and isolation frequencies, followed by the Leotiomycetes. By the isolation frequencies, the members of Pleosporales, Dothideales, Eurotiales, Phacidiales and Helotiales were dominating the community. The top ten most frequently isolated taxa included; Sydowia polyspora, Phacidium sp., Desmazierella acicola, Xenopolyscytalum pinea, and Herpotrichia spp. .D. acicola, a fungus that is known to be common on pine needle litter, and a recently described fungus X. pinea were recorded for the first time in Turkey. In this study, only the first six months of the decomposition process was treated and during this time, the diversity and structure of the fungal communities of pine needle litter did not differ significantly. On the other hand, according to Chao-1 and Shannon H' index, the diversity of communities at D2 phase (fourth month) which included high numbers of rare taxa, was significantly highest whereas differences between D1 (second month) and D3(sixth month) were not differing significantly. This study was the first to explore the fungi associated with pine needle litter decomposition in Turkey. The decomposition process of scots pine needles in the study area was estimated to last between 5 to 6 years. Considering this long time, and the lack of knowledge on the fungal communities of pine needle litter in the country, it can be suggested to maintain further researches in this area.