Does pollinator-dependency in vascular plants affect the elevational range expansion of species in the northern Scandinavian mountains?
Master thesis
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https://hdl.handle.net/11250/3172876Utgivelsesdato
2024-11-20Metadata
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- Master theses [294]
Sammendrag
Rising temperatures have led to the number of species increasing on mountain peaks across Europe. A greater increase in species richness leads to more competition for resources on the mountains which threatens local species. Simultaneously, pollinating insects, which are an integral part of the reproduction of many vascular plant species, have been detected to be on the decline. Consequently, there could be changes in species composition on the mountain peaks based on the reproductive strategy of each vascular plant species. It is important to grasp how ecosystems are changing across the world and the lower abundance of pollinators could play a part in changes in species composition for plants. This study aims to assess how reproductive strategy plays a part in changes in mountain peak ecosystems over time by analysing samples collected from the same peaks at different time intervals. To enable this, I used samplings from northern Scandinavia conducted by J. M. Norman in 1890 as well as a resampling of these mountains from 2010 to 2015. Then I supplied these datasets by resampling six of the mountains a third time in 2023. By comparing the ratio and local extinction of pollinator-dependent species to pollinator-independent species over time on the top 30 meters of the mountains, I found no trend suggesting that reproductive strategy plays a part in which species establish themselves or thrive on the mountains. This could be explained by several factors such as high-alpine pollinators still being active with local pollinator dependent-plants as well as visiting the novel pollinator-dependent plants in the mountains. Another possibility is that lowland pollinators are parallelling the upward shift of lowland pollinator-dependent plants. Lastly, some species might have adapted to selfing when faced with few pollinators, which has been shown to happen in earlier studies. Despite the lack of trends, a continued monitoring of the mountains is important. To further understand these changing ecosystems future research should investigate the species composition below the peaks as well as the abundance of each species, which could help us understand trends in what species settle on the summits.