Nocturnal moths use of novel habitats : a case study on a power line in a forest-mire mosaic in boreal Sweden

Detta är en Master-uppsats från SLU/Dept. of Wildlife, Fish and Environmental Studies

Sammanfattning: Biodiversity and pollinators are declining all over the world, and a factor thought to cause this decline is destruction of natural habitats. One new way that has been discussed in an effort to try to mitigate the effects of declining habitats is to understand and use novel habitats, which are habitats created when, for example, building roads, railways, and power lines. This study aims to investigate if a novel bog habitat created by a narrow power line corridor in northern Sweden have another abundance, species richness or the assemblage structure of nocturnal moths than two natural bog habitats. I also analyse if environmental factor such as vegetation type and tree stand structure are different in the power line and try to link which environmental factors can be correlated to the assemblage structure of nocturnal moths. This was done by monitoring nocturnal moths for 38 days using bait traps and light traps in a nature reserve outside of Umeå. The traps were set in three different types of bog habitats (novel power lines, sparse bog, and dense bog) within a boreal forest-mire mosaic. Generalised linear models (GLM) were used to analyse abundance and species richness of nocturnal moths. Simpsons diversity index and Shannon-wiener index were used for analysing the alpha diversity and a non-metric multidimensional scaling (NMDS) were used to illustrate the assemblage structure in the habitats. The results showed no significant difference between the two different natural bog habitats and the novel power line for neither abundance, species richness, species diversity nor assemblage structure. Further, the results showed that the environmental factors of deciduous dwarf shrubs and vegetation diversity correlated with assemblage structure of nocturnal moths but could not be linked towards a specific habitat. Dwarf shrubs and deciduous trees was the two substrates mostly used as host plants and could be important structures for nocturnal moths in a forest-mire mosaic environment. However, due to the low sample size, the results should be interpreted with caution, but my results indicate that the novel open bog habitats created by power lines function as habitats for nocturnal moths equally as natural bog habitats with partially closed and closed tree canopy.

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