Do diversity gradients and wildfires interact to facilitate tree range expansion across a broad latitudinal scale?
Principal Investigator: Reid, Kirsten (2)
Licence Number: 16325
Organization: Memorial University of Newfoundland and Labrador
Licensed Year(s): 2019 2018
Issued: Jun 06, 2018
Project Team: Kirsten Reid, Carissa Brown, Lucas Brehaut, Katie Goodwin

Objective(s): To determine what conditions facilitate tree range expansion across the western Canadian boreal-tundra ecotone.

Project Description: The overarching research goal of this project is to determine what conditions facilitate tree range expansion across the western Canadian boreal-tundra ecotone. Using a biogeographical, multi-trophic level approach The main objectives are: 1) to Determine how multi-trophic level species composition changes across the tundra and which conditions dictate these changes; and, 2) to determine the constraints, driven by community structure, trophic interactions, and disturbance, on tree establishment for boreal-tundra ecotone tree species (Picea mariana and Larix laricina) at different latitudes. The Principal Investigator (PI) will employ a large-scale, multi-factorial sampling effort by establishing three latitudinal transects that cover low, mid and high latitudes respectively (Transect 1: Dawson City to Eagle Plains, YT; T2: Eagle Plains, YT to Fort MacPherson, NT; T3: Fort MacPherson to Tuktoyaktuk, NT). Within each transect, the PI will sample sites across high and low elevation, as well sites that are dominated by both forest and tundra vegetation. To gain an understanding of community composition and diversity throughout the boreal-tundra ecotone, the PI will assess community composition, species diversity, and species abundance at five trophic levels (invertebrates, vertebrates, vascular plants, non-vascular plants, and soil microbiota). All sites will be instrumented with pit-fall traps, track tubes, and animal trap cameras to provide quantitative data on invertebrate and vertebrate communities. Vascular and non-vascular plants will be identified in five 1m2 quadrats at each site. Soil samples will be taken next to each quadrat. The PI will obtain a quantitative measure of microbial groups within the soil samples using Phospholipid Fatty Acid Analysis at Memorial University. At each site, the PI will measure active layer depth (ALD), air and soil temperature, snow depth, and soil properties. ALD will be measured yearly in late summer to ensure maximum thaw depth. Soil properties to be assessed include organic layer thickness, soil pH, soil moisture, and soil nutrients. Stations measuring snow depth and air and soil temperature will be installed at each site. Through assessing community composition and diversity and measuring site-specific variables, the PI will be able to determine the physical site factor(s) that dictate(s) species composition and diversity as well as how the driving factor changes with latitude. To test the constraints on tree seedling establishment, thus informing treeline range expansion, at different latitudes, the PI will establish a seeding experiment using Picea mariana, Larix laricina seeds, and Picea glauca and will measure the same physical site conditions as above. The PI will individually test the role of seed limitation, herbivory, and disturbance in a multi-factorial seeding experiment. The role of herbivory will be tested with enclosure cages. The PI will test the role of disturbance in two ways. First, the PII will sow seeds at sites that burned in 2017. Second, in sites that have not been naturally disturbed, the PI will manually scarify the substrate. Paired burned-scarified plots will be used to test how well scarification treatments represent burned conditions. We are interested in having ARI students or community members join us out in the field to learn about what we are doing and to share knowledge. Incorporating a traditional ecological knowledge component and learning from community Elders is something that we would like to incorporate into our project. We will use the following approaches to engage with community members. We will contact local communities and Band’s prior to our arrival in the NWT to find out if and how we can work in and around their community and to what level they would like to be involved. Additionally, we will aim to be actively involved with ARI throughout our time in the Inuvik region and will be interested in participating in any ARI research events or workshops. Given the field methodology that the team are planning to implement, a continuing commitment to northern capacity building would be to establish these sites as long-term monitoring sites. This would provide a reciprocal benefit as the team would train community members in methods of ecology and environmental science, while providing critically needed long-term data on northern ecosystem change. Sites close to communities would provide knowledge on ecosystem change in systems that are directly affecting community members by examining changes in biodiversity and community composition over time. Throughout the time in the NWT, if it is of interest to the communities, the research team will make yearly presentations in the communities near where the team are working (i.e., Inuvik, Fort McPherson, Tsiigehtchic). The team will seek to inform community members of what is being studied and how the team expect the results to be applicable and of interest to them. For previous work that the team has completed throughout the NWT and Yukon, these community presentations have involved showing pictures of sites and explaining the methodology and what the team hope to learn as a result of the project. The research team would like to make connections with the Gwich’in Renewable Resource Board and Aurora Research Institute. The team would plan to be actively involved with these stakeholder groups and would work with them to create meaningful results for communities in the NWT and to share and communicate the results. The research team will be cognisant of meeting any requirements that are held by Bands or communities in exchange for working on their land. The research team will contribute to research reports or information pamphlets that are distributed by any group or community. At the conclusion of the project (2021), the research team will provide a written report to all NWT and Yukon stakeholders in the research. Finally, the team will provide copies of all peer-reviewed scientific publications that arise as a result of this research. The fieldwork for this study will be conducted from June 7, 2018 to August 31, 2018.