Abstract
Biological invasions in northern regions are an emerging issue, with increasing occurrences of non-native flora in disturbed areas. Whether biotic factors inhibit establishment of alien plant populations in these regions remains unknown. I present evidence supporting the hypothesis that ground cover composed of native cryptogams and phanerogams limits establishment of non-native plants in the subarctic Churchill, Manitoba region of Canada. Though field experiments did not clearly show negative effects of ground cover presence on establishment of non-native plants, I found a significant negative effect of ground cover on germination and survival of non-native plants in greenhouse experiments. Through these experiments, I also investigated how environmental changes caused by ground cover affect non-native plant species and found evidence that changes in moisture and access to soil may be involved.
This project marks one of the first experimental investigations of plant invasions in northern biomes and offers insights for conservation, as well as for understanding the early stages of invasion.