NWT RESEARCH DATABASE

Regions: Dehcho Region, North Slave Region, South Slave Region

Tags: biology, vegetation, ecology, plant communities, non-native plants

Objective(s): To investigate the relative invasibility of different regrowth stand types post-fire; and To complete river surveys of invasive plants downstream of Hay River and Fort Liard.

Project Description: This licence has been issued for the scientific research application No. 5608. Objectives: To investigate the relative invasibility of different regrowth stand types post-fire; and, To complete river surveys of invasive plants downstream of Hay River and Fort Liard. Burns: To assess the invasibility of different regrowth stand types, samples will be taken along transects running perpendicular to roads. The aim is to sample eight transects of each major regrowth type (i.e., spruce, jack pine, deciduous) in the south-west NWT. Plots (1 m2) will be placed along these transects up to a maximum of 250 m from the roadside. The first plot will be placed in the road verge, the second will be placed immediately within the forest edge, and additional plots will be added at set distances from the edge (5, 10, 20, 40, 60, 80, 100, 125, 150, 175, 200, 225, 250 m) until two consecutive plots contain no non-native plants (37,44). The edge will be defined based on remnant snags left after the fire. Non-native and native plant occurrence and Braun-Blanquet cover estimates at the species level will be collected for each plot, and aspect, elevation, and verge width measurements will be taken for each site (34). Burn age and lowland/upland variables will be drawn from geospatial data from the NWT Centre for Geomatics. Data will be analyzed using generalized linear models to capture the hierarchical structure of this data. Rivers (as per methods in 2022 permit): Boat-based surveys will be undertaken along the Liard River and the Hay River. Methods are designed with broad-scale detection of downstream spread as the objective. Surveys will be visual and focused on six non-native target plants (scentless chamomile (Tripleurospermum inodorum), narrow-leaf hawksbeard (Crepis tectorum), white and yellow sweet-clover (Melilotus albus and M. officinalis), field sow-thistle (Sonchus arvensis), and red clover (Trifolium pratense)). The communities of Hay River and Fort Liard will serve as the starting points for surveys and proceed downstream. As patches are located, insofar as is possible (i.e., respecting crew safety), the boat will be landed, and the patch extent documented by walking. Total distance covered per survey will be determined by the distance that can reasonably be traveled by motorboat during a day trip from the community, rather than, for instance, the maximum water dispersal distance of the target species (approximately 20-25km downstream, based on 2022 surveys completed). Data and results will be shared with the GNWT for their biodiversity records and to support objectives related to non-native species monitoring and research articulated in ENR’s strategic plan and knowledge agenda. Data will also be shared with the Liidlii Kue First Nation and Parks Canada, in accordance with their licensing requirements. I anticipate sharing progress and results at community-directed opportunities offered to researchers by organizations like Ecology North and Aurora Research Institute. Additional public presentations will be pursued as requested and as opportunities arise. More broadly, the plan is to present research at annual conferences of the Canadian Society of Ecology and Evolution, the Ecology Society of America, or the Wildlife Society, and to publish results in a peer-reviewed journal. The fieldwork for this study will be conducted from: July 01 - July 31, 2023