Browsing by Author "Huttunen, Oona"

Reindeer herding and climate change are causing notable changes in tundra ecosystems. In this thesis, I examine the impacts of summer reindeer grazing and climate change on Fennoscandian tundra moss and lichen communities at Mt. Saana, North-Western Finnish Lapland. The research questions are whether there have been temporal changes in moss and lichen communities over three decades, if the changes are consistent under different grazing pressures, and if the changes reflect recent climate change. The study is based on permanent plots and long-term time series data from 1990 to 2023 at intervals of about ten years. The results indicate significant correlations between reindeer grazing and moss and lichen abundances and an indication of climate change affecting the vegetation composition. Heavy grazing pressure during summer reduced moss and lichen abundances, particularly affecting lichens, while mosses benefit from moderate grazing pressure. During the study period, mosses had overall increased, while lichens had decreased. A slight recovery of lichens was observed between 2010 and 2023. At Kilpisjärvi, mean temperatures have increased significantly over the study period, affecting vegetation growth conditions. The increase in moss abundance could be related to the warmer temperatures and the lichen dynamics to changes in snow cover, warm winter events and increased competition from vascular plants. The temporal changes are also possible due to variations in grazing pressure. Overall, the findings emphasize the significant effects caused by reindeer grazing and climate change in tundra vegetation. Thus, the effects of reindeer grazing and climate change should be considered simultaneously when studying the changes in vegetation composition in tundra environments.