Research

Research Goals

The Fate of the Caribou Project aims to understand how climate change and habitat factors like vegetation productivity (1a), wildfire impacts on lichen growth (1b), insect harassment (2), and snow and ice conditions (3a and 3b) interact with increasing human development and resource extraction (4a and 4b) to influence caribou populations and movements. We leverage strong, well-established relationships with Arctic community partners, including Indigenous led co-management governance boards, and an unprecedented collection of caribou monitoring data amassed by our partners in territorial and federal agencies across northern Canada and Alaska to answer ecological questions about caribou at a large spatial scale. Our team has expertise in remote sensing, land-change modelling, behavioral, and population modelling. Additionally, a central strategy for the Fate of the Caribou team is to follow the leadership of Indigenous governments and other local stakeholders in developing research questions, because Indigenous knowledge can lead to the most relevant ecological insights at the largest spatial and temporal scales.

Ongoing Research

Delineating calving grounds & synchrony

Three white adult caribou and a caribou calf walk across a patch of snow.

This project seeks to understand how climate change and local weather patterns from the previous year affect the timing and synchrony of calving within and between caribou herds, and to better define what a "calving ground" is. Female caribou who experienced adverse weather during the previous winter (for example deep, soft snow that is difficult to move through) may not reach the traditional calving grounds before their calf is born, which may result in lower calf survival. The "calving ground" of a caribou herd is the area where most of the herd gives birth each year. However, there have been many approaches to defining and mapping calving grounds, which makes it difficult for caribou managers and land use planners to know which areas to protect from development or other land use so that calving is not disrupted. Using statistical modeling and a comprehensive literature review, this project aims to understand the mechanisms driving the timing of calving, and to develop a consistent method for delineating calving grounds. The final results from this work are under review.

Lead: Dr. Ophélie Couriot

Ros

Changes in vegetation through remote sensing

A close-up of a map with green and white gradients, and a point labeled "Fairbanks".

This project is part of a multi-stage effort to map changes in the composition and biomass of vegetation across a broad spatial extent of Arctic Alaska and Canada using satellite imagery, co-supported by NASA's Arctic-Boreal Vulnerability Experiment and the DoD'sStrategic Environmental Research and Development Program. As the climate warms and wildlife populations shift, many ecological mechanisms are interacting to change the prevalence and geographic distribution of different Plant Functional Types (PFTs; for example, deciduous shrubs, graminoids and lichens). Maps of PFT changes developed thus far will form the basis for expanding the mapping extent across north-central Canada, augmenting those maps to include aboveground biomass, and working with the FotC team to explore how these shifts in PFTs are affecting caribou demographics and migration patterns.

Lead: Dr. Scott Goetz, Dr. Logan Berner

A brown and white caribou lays on a snow-covered hillside.

Spatial, climate, and behavioral drivers of survival

This research uses data from the Western Arctic Caribou Herd (WACH), located in northwestern Alaska, as a case study to examine how climate patterns, space use, and migratory behavior impact caribou survival. The WACH has declined in numbers in recent years, and researchers have observed changes in their migration pattern in response to roads, timing of the spring thaw, and other factors. So far, we see that caribou who stray far away from the core of the herd tend to have higher mortality rates, especially during the calving and post-calving periods. The final results of this project are still in development.

Lead: Dr. Elie Gurarie

Tobias Bjørkli

Caribou antlers on a grass-covered hillside. Snowy mountains are in the background.

Modeling caribou population dynamics

The goal of this project is to build a so-called "synthetic" model of caribou demographics, meaning that the model will simulate population fluctuations without needing input of new data from real caribou. Using known population birth, death, immigration, and emigration rates from existing caribou data, integrated population models allow researchers to explore how different factors might affect populations in the future, or what might be causing observed patterns in historical data. This portion of our research will begin during the summer of 2022.

Lead: Dr. Bill Fagan

Kyle Joly

A group of brown caribou are gathered on a patch of snow.

Impact of insect harassment on sociality

Barren-ground caribou are extremely social. Spring migrations and calving, notably, are largely synchronized in space and time. During periods of peak insect harassment during the summer, massive, dense aggregations of caribou can form. We are interested in using measures of caribou sociality to assess the impacts of insect harassment, even as climate change is leading to longer, warmer summers and potentially longer and more intense insect harassment seasons.
To do this, we are developing “sociality indices,” measuring the distance among individual collared caribou, and are linking these with indices of increased insect harassment. The highest peaks and fastest variations in sociality occur during mid-summer, when insect harrasment (from mosquitoes and parasitic warble flies) can drive caribou to seek shelter in mass aggregation. The potential increase of insect harassment and increased duration of insect harassment seasons due to climate change may have impacts on caribou health and reproduction, and is a concern of high interest throughout the Arctic.
Learn more about this work on Dr. Gurarie's blog.
Lead: Dr. Elie Gurarie

Kyle Joly