Fire as a window of opportunity for alien species establishment in the sub-Arctic?

Lake Torneträsk near the Abisko research station.

Beginning:      March/April 2020
Duration:        6 months, unpaid
Credits:           up to 45 ECTS depending upon duration

Background

Alien species can have profound impacts on ecosystems but their effect on polar ecosystems has been little studied, even though their invasion threat is likely to increase in the future. Fires are expected to occur more frequently in the sub-Arctic due to climate change, which may facilitate alien plant establishment. In addition, polar ecosystems warm up quickly, making the previous harsh climate more suitable to a wider range of plant species. At the same time, anthropogenic pressure, mainly in the form of tourism, is increasing rapidly, which increases the chance of alien plant seeds to hitchhike into polar ecosystems. Climate change and human activities together are thus expected to enhance alien plant establishment success, posing a growing threat to native species and ecosystem functioning in the sub-Arctic.

Fires can act as a pulse disturbance by removing dominant native plant species, which may give alien plant species the chance to establish in an otherwise challenging environment. The dwarf shrub Empetrum hermaphroditum is dominant in tundra ecosystems where it forms dense, almost monospecific mats. It produces the phenolic compound batatasin-III, which inhibits germination of other plant species, microbial activity and litter decomposition, hence constructing its own niche. Once E. hermaphroditum is however removed by fire, there may be a chance for other plant species to establish as E. hermaphroditum exhibits slow vegetative re-growth compared to other native and new alien plant species. As such, fire may provide a window of opportunity for alien plant establishment in the sub-Arctic.

Project

In this project you will join a field-based experiment in which we will burn small patches of tundra near the Abisko research station in North Sweden to test whether fire could facilitate alien plant establishment in the sub-Arctic. We will determine germination success of alien plant species during summer in burned and intact tundra patches. Microclimate conditions related to seed germination will be quantified and related to germination success. The regeneration of native plant species in the burned plots will also be determined. In addition, small tundra patches could be burned in the laboratory to be used in germination tests under different climatic conditions.

Requirements

Interest in plant ecology and polar ecosystems is required, as is the ability to work abroad in the summer of 2020. You are able and willing to work in semi-remote regions under challenging weather conditions.

Please note that we as a department cannot fund your travel and accommodation costs.

Contact information

For more information please contact Emily van Loon-van Egmond: e.m.van.loon-van.egmond@vu.nl