Contemporary Dynamics of Forest-Tundra Ecotones in Central NWT

Regions: North Slave Region

Tags: biology, vegetation, climate change, remote sensing, forest ecosystem

Principal Investigator: Danby, Ryan K (1)
Licence Number: 15909
Organization: Queen's University
Licenced Year(s): 2016
Issued: Jun 23, 2016
Project Team: Mitchell Bonney (MSc Student Researcher, Queen's University), Stuart Thibert (Undergraduate Field Assistant, Queen's University), Dr. Gregory M. King (Postdoctoral Fellow, Queen's University)

Objective(s): To understand regional vegetation change over the past 30 years; to determine the timing of tree establishment and the climate influence on tree growth across the forest tundra transition zone over the past 300 years; and, to measure spruce seedling growth across the forest-tundra ecozone in relation to variables that might limit treeline advance.

Project Description: Objectives of this research project are to:
1) analyze Landsat satellite images to understand regional vegetation change over the past 30 years;
2) determine the timing of tree establishment as well as the climate influence on tree growth across the forest tundra transition zone over the past 300 years; and,
3. measure spruce seedling growth across the forest-tundra ecotone in relation to variables that might limit treeline advance.

Following the objectives provided above, three different sets of field methods will be used.

1) To determine the relation between the amount of satellite observed vegetation measured by NDVI and the actual vegetation present on the ground, the research team will establish sampling plots along the route. Plots will be 30x30m along with several smaller subplots across various landscape characteristics (i.e. highland, lowland, rivers, etc.). Plots will be also located across a range of vegetation types (i.e. shrubs, tree patches, etc.). At each plot the research team will use non-destructive methods in order to measure the amount and type of vegetation and the area it covers. These measurements will allow the team to more accurately understand what the satellite observations mean for actual vegetation on the ground.

2. To determine tree age, the research team will count growth rings that each tree produces annually. To collect tree rings the team will sample cores from individual trees using an increment borer. In rare cases where trees cannot be cored a saw or clippers will be used to collect samples. Samples will be collected in a nested plot and transect design with an anticipated 3-4 transects established on the route. The research team will also more intensively sample patches of trees in order to understand how trees are distributed across the forest-tundra ecotone. These samples will be aged to determine when trees became established in an area and provide an idea of if younger forests are located further north. Along with the ages, the size of tree rings can be linked to temperature and precipitation in order to determine what climate patterns influence forest growth.

3. Plots (30x30m) will be established at locations at and beyond treeline. In each plot spruce seedlings will be counted and their annual growth from the last 3 years along with the amount of winter damage will be measured. These measurements will be related to a variety of environmental variables hypothesized to mediate treeline advance, including distance to nearest seed source, amount of shrub cover, and soil types.

In the first year of this research, the research team have reached out to contacts with the Territorial Government, the Wek’èezhìi Renewable Resources Board (WRRB) and the Tlicho Government as a first point of contact in order to gather information on their research interests about the forest tundra transition, hear their thoughts on the initial project aims as well as gathering input and community knowledge related to fire and landscape change in the research area. These discussions will be ongoing as the planning for the project progresses and will hopefully at some stage involve in-person meetings as the research team would like to consider local knowledge in the project.

The best way to convey results to a community is in person and we will endeavour to to present the results to the Wek’èezhìi Renewable Resource Board and/or to the Tlicho Government during one of their winter meetings. The research team are making plans to extensively document the work this summer with pictures and videos and assemble a video of the research expedition, and short presentations on results that can be sent to the communities. The research team will also produce end of field season reports for all of the governments and agencies involved and ensure all individuals are contacted in regards to any publications that arise from this work.

The fieldwork for this study will be conducted from July 10, 2016 to August 20, 2016.