Case study: Yellowstone to Yukon corridor — lessons from North America's largest connectivity initiative

Habitat fragmentation threatens more than 1 million species globally, yet one conservation initiative has demonstrated that reconnecting landscapes at continental scale is not only possible but measurably effective. The Yellowstone to Yukon Conservation Initiative (Y2Y) stretches 3,200 km along the spine of the Rocky Mountains, has helped protect more than 500,000 km² of habitat across two countries, and has documented a 30% recovery in grizzly bear populations within its priority connectivity zones (Y2Y Conservation Initiative, 2025). This case study unpacks the strategy, science, partnerships, and lessons behind North America's largest wildlife corridor programme.

Why It Matters

Wildlife corridors are the circulatory system of biodiversity. When roads, agriculture, and urban expansion sever migration routes, populations become genetically isolated, food webs destabilize, and ecosystem services such as pollination, water filtration, and carbon storage deteriorate. The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES, 2024) estimates that land-use change has already reduced the integrity of terrestrial ecosystems by 30% relative to pre-industrial baselines. Corridors reverse this trend by allowing species to move between core habitat patches, access seasonal resources, find mates, and shift ranges in response to climate change.

Y2Y is the world's most advanced test of corridor-scale conservation. Spanning from the greater Yellowstone ecosystem in Wyoming and Montana to the northern Yukon, it crosses five Canadian provinces and territories and five U.S. states, traverses Indigenous territories of more than 70 First Nations and Tribal governments, and encompasses some of the most intact temperate ecosystems remaining on Earth. Its outcomes offer a replicable blueprint for practitioners designing connectivity strategies elsewhere.

Key Concepts

Landscape connectivity refers to the degree to which landscapes facilitate or impede movement of organisms, genes, and ecological processes across space. Structural connectivity describes the physical arrangement of habitat patches, while functional connectivity accounts for species-specific movement behaviour and habitat quality.

Wildlife corridors are linear or stepping-stone habitat features that link core protected areas. They range from narrow riparian buffers a few hundred metres wide to landscape-level conservation mosaics spanning tens of thousands of square kilometres.

Umbrella species are organisms whose habitat requirements encompass those of many co-occurring species. Grizzly bears, wolves, and caribou serve as umbrella species in the Y2Y region because protecting their movement pathways simultaneously benefits hundreds of plants, birds, amphibians, and invertebrates.

Transboundary governance involves coordinating conservation policy and management across political jurisdictions. In Y2Y's case, this means aligning municipal land-use plans, provincial and state wildlife regulations, federal park mandates, and international agreements between Canada and the United States.

The Challenge

When Y2Y was formally established in 1997, the Rocky Mountain corridor faced accelerating threats. The Trans-Canada Highway and other major roads bisected critical valley-bottom habitat used by grizzly bears, elk, and wolves during seasonal migrations. Resource extraction, including forestry, mining, and oil and gas development, was expanding into headwater basins that served as source habitats for wide-ranging carnivores. Residential subdivision in gateway communities around Banff, Canmore, Jackson Hole, and Bozeman was converting private ranchlands that historically provided winter range and connectivity (Hilty et al., 2020).

Grizzly bear populations in several management units had declined to fewer than 50 individuals, well below the minimum viable population threshold estimated at 200 to 500 bears. Genetic analyses by Proctor et al. (2012) revealed that highway corridors had already fragmented populations into semi-isolated subunits, with the Trans-Canada Highway in Banff National Park acting as a near-complete barrier for female grizzlies. Caribou herds in British Columbia were declining at 5% per year due to habitat loss and increased predator access along logging roads. Climate change added urgency: the average temperature in the Canadian Rockies rose 1.4°C between 1950 and 2020, shifting alpine habitat upward and compressing the range available to cold-adapted species (Parks Canada, 2024).

A further challenge was governance complexity. The Y2Y region encompasses more than 1,000 land management jurisdictions, including national parks, provincial Crown lands, state forests, Bureau of Land Management holdings, tribal reserves, and private ranches. No single authority could mandate corridor protection. Success required voluntary collaboration, science-based persuasion, and creative financing mechanisms.

The Approach

Y2Y adopted a four-pronged strategy that combined science, policy advocacy, land protection, and community engagement.

1. Science-driven corridor mapping. Beginning in the early 2000s, Y2Y funded and synthesized movement ecology research to identify priority linkage areas. Researchers deployed GPS collars on grizzly bears, wolverines, lynx, and caribou, generating over 2 million location fixes that were analyzed using circuit theory and least-cost path models (Clevenger and Wierzchowski, 2006). The resulting connectivity maps pinpointed 16 priority linkage zones where habitat interventions would yield the greatest population-level benefits.

2. Policy advocacy and protected area expansion. Y2Y partners campaigned for new protected areas and Indigenous Protected and Conserved Areas (IPCAs) within priority linkages. Between 2010 and 2025, their advocacy contributed to the establishment or expansion of more than 80 protected areas totalling over 90,000 km², including the Peel Watershed (67,000 km²) in the Yukon and the Bighorn Wildland Provincial Park (5,000 km²) in Alberta (Y2Y Conservation Initiative, 2025). In the United States, Y2Y supported the Northern Rockies Ecosystem Protection Act proposals and worked with the U.S. Fish and Wildlife Service on grizzly bear recovery planning.

3. Wildlife crossing infrastructure. In partnership with Parks Canada and the Alberta government, Y2Y helped secure funding for wildlife crossing structures along the Trans-Canada Highway in Banff National Park. By 2025, the programme had built 6 overpasses and 38 underpasses, representing the most extensive wildlife crossing system in the world. Camera trap monitoring documented over 200,000 wildlife crossings by 11 large mammal species between 1996 and 2024, with highway-related mortality for elk and deer declining by 80% in mitigated sections (Clevenger and Ford, 2024).

4. Community stewardship and private land conservation. Recognizing that nearly 30% of critical habitat in linkage zones sits on private land, Y2Y invested in conservation easements, collaborative ranching programmes, and Indigenous-led stewardship agreements. The Blackfoot Challenge in Montana, a landowner-driven initiative supported by Y2Y, enrolled over 400,000 hectares in conservation easements and coexistence programmes that reduced livestock-grizzly conflicts by 60% (Blackfoot Challenge, 2025). In British Columbia, partnerships with Indigenous governments led to co-managed IPCAs that incorporated traditional ecological knowledge alongside Western science.

Results and Impact

After more than 25 years of sustained effort, Y2Y has produced measurable outcomes across ecological, governance, and economic dimensions.

Habitat protection. Over 500,000 km² of habitat has been formally protected or placed under enhanced conservation management within the Y2Y region, an area larger than Spain (Y2Y Conservation Initiative, 2025). This includes 50,000 km² of new or expanded protected areas established between 2020 and 2025 alone, driven in part by Canada's commitment to protect 30% of its land and water by 2030 under the Kunming-Montreal Global Biodiversity Framework.

Grizzly bear recovery. Grizzly bear populations in priority connectivity zones have grown by approximately 30% since 2005. In Banff National Park and surrounding areas, female grizzly bear detections in crossing structures increased tenfold between 2008 and 2023, indicating improved functional connectivity for the sex that was most impeded by highway infrastructure (Clevenger and Ford, 2024). The Yellowstone grizzly bear population has rebounded to over 1,000 individuals as of 2025, up from an estimated 136 in 1975.

Multi-species benefits. Wolverine, lynx, wolf, elk, moose, and mountain goat populations have all shown positive trends in mitigated corridor sections. Camera trap data from highway crossings document regular use by cougars, black bears, and even small carnivores like martens and fishers.

Economic co-benefits. Wildlife tourism in the Y2Y region generates over US$6 billion annually. Reduced vehicle-wildlife collisions in Banff alone save an estimated CA$500,000 per year in emergency response, vehicle damage, and healthcare costs (Parks Canada, 2024). Conservation easements have helped maintain ranching livelihoods while protecting open landscapes.

Lessons Learned

Start with science, but do not wait for perfect data. Y2Y's corridor maps were refined iteratively over two decades. Early versions using expert opinion were sufficient to set priorities; GPS telemetry and genetic analyses validated and sharpened them later. Organizations should begin with the best available data and update as monitoring improves.

Invest in crossing infrastructure at bottleneck points. The Banff wildlife crossings demonstrate that targeted engineering interventions can restore connectivity even across major transportation corridors. The key is identifying the handful of locations where movement is most constrained and concentrating resources there.

Centre Indigenous leadership. The most durable conservation gains in Y2Y have come through partnerships with First Nations and Tribal governments who hold both legal authority and generations of ecological knowledge. IPCAs and co-management agreements create governance structures that outlast political cycles.

Align conservation with economic interests. Conservation easements that compensate ranchers, tourism revenue sharing, and reduced collision costs all create constituencies for corridor protection. Framing connectivity as an economic asset rather than a land-use restriction builds broader support.

Think in decades. Y2Y's 25-year track record demonstrates that landscape-scale conservation requires sustained institutional commitment. Quick wins such as individual crossing structures build momentum, but population-level recovery unfolds over generations.

Key Players

Established Leaders

• Yellowstone to Yukon Conservation Initiative (Y2Y) — Founding organization coordinating science, advocacy, and partnerships across the 3,200 km corridor since 1997.
• Parks Canada — Federal agency managing Banff, Jasper, and other national parks within the corridor; lead funder of wildlife crossing infrastructure.
• U.S. Fish and Wildlife Service — Oversees grizzly bear recovery planning and Endangered Species Act implementation in the American portion of Y2Y.
• Wildlife Conservation Society Canada — Conducts connectivity science and supports boreal and montane conservation planning across Y2Y.
• The Nature Conservancy (TNC) — Funds conservation easements on private lands in Montana, Idaho, and Wyoming linkage zones.

Emerging Startups

• Grizzly Bear Foundation — Canadian nonprofit (founded 2020) mobilizing public engagement and policy advocacy for grizzly recovery and coexistence.
• Niiyaansinaan (Our Land) Alliance — Indigenous-led coalition advancing IPCAs and traditional stewardship within priority Y2Y linkage zones.
• WildCAM Network — Camera trap monitoring network using AI-powered image classification to track corridor usage across British Columbia and Alberta.

Key Investors/Funders

• Wilburforce Foundation — Long-term philanthropic supporter of Y2Y science and capacity building across the Northern Rockies.
• Gordon and Betty Moore Foundation — Major funder of connectivity science and large-landscape conservation in western North America.
• Canadian federal government (Canada Nature Fund) — Provides matching funds for protected area expansion and IPCA establishment under the 30x30 framework.
• Wyss Foundation — Supported the Campaign for Nature and funded land protection projects within Y2Y linkage zones.

Action Checklist

• Conduct a connectivity assessment using movement ecology data (GPS telemetry, genetic sampling, camera traps) to identify priority linkage zones.
• Engage Indigenous and local community leaders early in corridor planning to ensure governance structures reflect diverse knowledge systems and legal authorities.
• Prioritize wildlife crossing infrastructure at transportation bottleneck points where mortality data and movement models converge.
• Secure conservation easements on private lands within identified linkage zones, using financial mechanisms that maintain landowner livelihoods.
• Advocate for policy alignment across jurisdictions, including transboundary agreements, protected area designations, and zoning reforms.
• Establish long-term monitoring programmes using standardized camera trap arrays and genetic sampling to measure corridor effectiveness over decades.
• Communicate results to funders, policymakers, and the public using compelling species recovery narratives backed by quantitative data.

FAQ

How long does it take for a wildlife corridor to produce measurable population recovery? Initial changes in animal movement behaviour can be detected within 3 to 5 years of corridor establishment. Population-level recovery, however, typically requires 10 to 25 years because large carnivores like grizzly bears have slow reproductive rates (one litter every 3 to 4 years) and delayed maturation. Y2Y's 30% grizzly recovery unfolded over roughly two decades of cumulative habitat protection and crossing infrastructure investment.

Do wildlife crossings actually work, or do animals avoid them? Extensive monitoring in Banff National Park confirms that wildlife crossings are highly effective. Over 200,000 crossings by 11 large mammal species have been recorded since 1996. Initially, animals may take 1 to 3 years to habituate to new structures, but usage rates increase steadily over time. Overpasses tend to be preferred by grizzly bears and elk, while underpasses are favoured by deer, wolves, and cougars (Clevenger and Ford, 2024).

What is the cost of building a wildlife corridor? Costs vary enormously depending on the approach. Highway overpasses in Banff cost CA$2 to $5 million each, while underpasses range from CA$500,000 to $1.5 million. Conservation easements on private land in Montana average US$500 to $2,000 per hectare depending on agricultural value and development pressure. Protected area designations on public lands can be achieved primarily through policy advocacy at relatively low direct cost, though they require sustained institutional investment in engagement and enforcement.

Can the Y2Y model be replicated in other regions? Yes. The core principles of science-driven corridor mapping, multi-stakeholder governance, crossing infrastructure, and community stewardship are transferable. The European Green Belt along the former Iron Curtain, the Terai Arc Landscape in Nepal and India, and the Great Eastern Ranges initiative in Australia all draw on similar strategies. The key adaptation is tailoring governance structures to local political, cultural, and ecological contexts.

How does climate change affect corridor design? Climate change makes corridors more important, not less. As species shift their ranges to track suitable temperatures and precipitation, corridors provide the pathways for movement. Y2Y's north-south orientation along the Rocky Mountains is particularly valuable because it allows latitudinal and elevational range shifts. Climate-smart corridor design uses projected habitat suitability models to ensure that linkage zones remain functional under multiple warming scenarios (Hilty et al., 2020).

Sources

• Y2Y Conservation Initiative. (2025). 25 Years of Conservation Impact: Y2Y by the Numbers. Yellowstone to Yukon Conservation Initiative.
• Hilty, J. A., Keeley, A. T. H., Lidicker, W. Z., & Merenlender, A. M. (2020). Corridor Ecology: Linking Landscapes for Biodiversity Conservation and Climate Adaptation (2nd ed.). Island Press.
• Clevenger, A. P., & Ford, A. T. (2024). Long-Term Monitoring of Wildlife Crossing Structures in Banff National Park: 1996-2024. Parks Canada Technical Report.
• Parks Canada. (2024). State of Canada's Mountain National Parks: Ecological Integrity and Climate Change Indicators. Parks Canada Agency.
• IPBES. (2024). Thematic Assessment of the Interlinkages among Biodiversity, Water, Food and Health. Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services.
• Proctor, M. F., Paetkau, D., McLellan, B. N., et al. (2012). Population Fragmentation and Inter-Ecosystem Movements of Grizzly Bears in Western Canada and the Northern United States. Wildlife Monographs, 180(1), 1-46.
• Clevenger, A. P., & Wierzchowski, J. (2006). Maintaining and Restoring Connectivity in Landscapes Fragmented by Roads. In K. R. Crooks & M. Sanjayan (Eds.), Connectivity Conservation (pp. 502-535). Cambridge University Press.
• Blackfoot Challenge. (2025). Community-Based Conservation in the Blackfoot Watershed: 2024 Annual Report. Blackfoot Challenge, Ovando, Montana.