Mountain Caribou (Rangifer tarandus caribou) Habitat in the South Selkirks: Zonal Shifts in Dynamic Landscapes

By HarleyJo Holman

Spring 2024

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Advisor, Lisa Shipley, PhD

Mentor, Leah Brueggeman, PhD

School of the Environment

WSU: College of Agricultural, Human, and Natural Resource Sciences

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This Photo by Unknown author is licensed under CC BY.

Vulnerable Ecosystem in Contemporary Times

• ~30% of global forested area
• High fuel load
• Carbon sink -> carbon source
• Projected to experience most warming
• +11C/52F by end of century

Animal Focus

Species: Rangifer tarandus caribou

Ecotype: Deep-snow Mountain caribou

Population: Southern Selkirk Mountain Herd

Photo courtesy of the United States Fish and Wildlife Service

• Last identified population in contiguous US
• The final remaining individual relocated in 2019 – species extirpated
• Greatest Conservation Need

Mountain Caribou

Washington WDFW: $9 billion in recreational spending, ~ $630 million to state general fund, $57 million in license revenue

Thesis Activity

• Assess the S. Selkirk region for a potential climate-induced elevation shift in suitable R. tarandus caribou habitat.
• What extent of managed land remains suitable for R. tarandus caribou?
• Elevation range?
• Climate suitability?

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Habitat Requirements

• Cold, wet climate (Interior Wet Belt)
• Older forests & complex stands
• High slopes
• Distance from artificial pathways
• Isolation from human activity

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Photo courtesy of Wildsight Canada 2024.

Predictions for Suitable Habitat (≥75% )

Climate Suitability ≥75%

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Elevations ≥ 1800m

Total Area <3000ha

Scale-Dependent Ecology of Mountain Caribou

Serrouya, R., et al. (2008)

Precipitation

Snow

NOAA Climate Normals (1981 - 2010)

Prism Climate Group, Oregon State University

Forest Age

Temperature

Prism Climate Group, Oregon State University 2023

U.S. Forest Service Geospatial Data Discovery 2019

Slope

Distance to Agriculture

USGS Earth Explorer Digital Elevation Model 2010

USGS Landcover Dataset 30m 2023

Distance to Urban Area

Distance to Lakes

USGS Landcover Dataset 30m 2023

USGS ScienceBase-Catalog 2012

Distance to Waterways

Distance to Roads

USGS ScienceBase-Catalog 2012

USGS National Transportation Dataset (NTD) 2023

Distance to Rails

Distance to Trails

USGS National Transportation Dataset (NTD) 2023

USGS National Transportation Dataset (NTD) 2023

Climate

Suitability

Index (CSI)

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• Precipitation
• Snowfall
• Temperature
• Weight 0.33%/factor

• ≥75% suitable ~12500 hectares (0.52%)
• 4 individuals (S. Purcell data)
• ≥50% suitable ~320000 hectares (13.3%)
• 113 individuals

Final Suitability Map

• Mean = 2083.84m
• SD = 149.84m
• Range = 439.58m - 2656.71m
• ≥1800m has 90% frequency

Elevational Frequencies in ≥75% Suitable Acreage

Climate Suitability Value in ≥75% Suitable Acreage

• Mean = 83.4% 
• SD = 0.5
• Range = 67.8% - 100%

Conclusions

• Most suitable area is south of Selkirk Range
• Cabinet Mts, MT
• Elevational/Zonal shift
• Decrease in habitat as elevation increased
• Habitat fragmentation

Implications and Applications