Habitat Connectivity is a Critical Part of Wildlife Conservation
When Ian Tyson once sang about a pack of wolves longing for their former home, dreaming of the sound of another pack answering their calls, he imagined the leader of the pack lamenting, “I’m a long, long way from the Yellowhead, here in Yellowstone”. It’s possible that Ian Tyson’s wolf wasn’t actually thinking about the possibility of a connected route from Wyoming back to his former home in the wilderness of the British Columbia-Alberta border; however, thanks to a large conservation initiative, that kind of connected wilderness is precisely the goal. In fact, those wolves might have travelled from Yellowstone all the way to Yukon.
“We must build a coherent view of what the 21st century ought to look like, and at the heart of that must be wild nature.” – Harvey Locke, Y2Y founder
I’m a little late to the party on learning about this initiative, but while reading the January/February 2017 issue of Canadian Geographic, I came across an article on the Yellowstone to Yukon (Y2Y) Conservation Initiative. The magnitude and incredible potential of the project immediately struck me as something truly amazing for wildlife on this continent. Although I was coming across the initiative for the first time, Y2Y has been working with over 300 partners since 1993 to create an “interconnected system of wild lands and waters stretching from Yellowstone to Yukon, harmonizing the needs of people with those of nature”. Since it began, Y2Y has made important advancements in securing core habitat for a suite of wildlife, which include the purchase of 200 000 hectares of private lands and 7 150 hectares of additional lands in British Columbia. In addition, Y2Y was involved in establishing two additional National Park reserves in the Northwest Territories and a 6.5 million hectare are of protected lands in British Columbia.
Why is habitat connectivity so important for North American conservation?
We have some outstanding organizations and initiatives throughout North America dedicated to the conservation of species, habitats, wild and public lands, and the interests of various user groups. I’m a member of a number of them and I appreciate the work they do. Often, however, our conservation efforts are limited by arbitrary political divisions that have been imposed on this continent in the form of provincial, state, and national borders. In terms of conservation, these borders are arbitrary because they were not designed to follow ecological, geological, or hydrological features. They were not designed based on watersheds, mountain ranges, ecosystem types, climate zones, wildlife migratory pathways, or other natural landscape features. As we all know, however, water, wind, and wildlife are not constrained by political borders. As a result, environmental management of a landscape is often distributed between multiple jurisdictions, which often results in a lack of coordinated effort in decision-making.
One of the greatest environmental legacies of European colonization and settlement in North America has been dramatic land cover and habitat changes that accompanied the spread of agricultural and human development throughout the continent. Human developments such as roads, railways, transmission lines, dams, urban infrastructure, and agricultural fields have broken up once connected ecosystems into a patchwork of disconnected, fragmented habitats. According to WWF-Canada, 61 of 167 sub-watersheds across the country are highly or very highly fragmented.
In addition to direct habitat conversion for human needs, climate change and other environmental changes have the potential to increase habitat fragmentation. For example, sea ice in the Canadian Arctic is an important habitat that provides a platform for the movement and dispersal of species such as fox, wolves, and caribou. Sea ice loss due to climate change may result in Arctic wildlife populations that find themselves living in increasingly fragmented habitats. Habitat fragmentation has become one of the most important conservation issues affecting North American wildlife.
In terms of the effects of habitat fragmentation on wildlife, when populations are confined to small and disconnected patches of habitat, they are more vulnerable to events that threaten their survival, such as natural disasters (referred to by ecologists as “stochastic events”). For instance, wildlife populations rely on genetic interchange, the process through which individuals of local populations travel to new areas and breed with individuals of other populations, to maintain resistance against diseases and pass on heritable strengths. Without the ability to travel and breed, the effect is that small, restricted populations of wildlife are increasingly vulnerable to local extinctions.
The flip side of habitat fragmentation is referred to as habitat connectivity: linkages between different sections of habitat cover. However, the importance of habitat connectivity goes beyond simply individual animals moving between, for example, a bedding and feeding area. Connectivity is important for both the structure (physical components of habitats) and function (the ability of an ecosystem to carry out the processes that keep it healthy) of ecosystems.
The United States National Forest Service, in its National Forest Management Act (2012), draws attention to the broad importance of connected habitats that contain linkages that facilitate the exchange of abiotic (or non-living) habitat components, such as water flow, sediments, and nutrients; the movements of wildlife, both within their home ranges and on larger scales that allow for genetic exchange between populations (a key biological factor in maintaining healthy and resilient populations); and longer distance range shifts that allow species to expand into new habitats and regions.
“Any comprehensive strategy for conserving biological diversity requires maintaining habitat across a variety of spatial scales and includes the maintenance of connectivity, landscape heterogeneity and structural complexity.” – Planning for Connectivity, 2015
Habitat connectivity has been identified by the Convention on Biological Diversity (CBD) as an important global conservation need. The CBD developed a collection of 20 global biodiversity targets to be addressed from 2011-2020 (known as the “Aichi Biodiversity Targets”). Aichi Biodiversity Target 11 positions the expansion of Protected Area networks as one of the cornerstones of conservation action to improve the status of global biodiversity and specifically identifies the need for “an increased focus on representativity, connectivity and management effectiveness” in biodiversity protection worldwide. Since their inception as a deliberate conservation strategy, Protected Areas have been the cornerstone of conservation in North America. As a recent example of the impacts of Protected Areas to conservation, a bison reintroduction program in Banff National Park (Alberta, Canada) has successfully led to the births of 10 bison calves, the first bison born in the park in 140 years.
The challenge facing a global Protected Areas network is in creating an interconnected system of habitats across landscapes. Protected Areas are typically planned by distinct political and administrative jurisdictions and often opportunistically, rather than with a landscape level focus on creating large, continental networks. Habitat connectivity is a particular need for large animals, and especially large carnivores. In North America, flagship species for promoting habitat connectivity have often been grizzly bears and caribou, which both require large areas of habitat and intact corridors, and which have both experienced population declines as a result of degraded habitat quality.
A recent study of habitat connectivity and tigers in India illustrates the importance of Protected Areas in safeguarding and increasing habitat quality for a large carnivore species. India is considered the hotspot for global tiger conservation. Tigers currently occupy only 7% of their historic range in India, largely as a result of massive land conversion throughout the country in response to growing population, which has resulted in a significant reduction in forest cover throughout India. Only 5% of India is part of a Protected Area network, but perhaps more important than the actual percentage of area that is protected are the size of Protected Areas relative to the habitat requirements of tigers and the connectivity between these areas. In the case of tigers, the size of individual Protected Areas is often insufficient for their needs, meaning that connections between tiger habitats are critical for both species dispersal and population recovery, and these habitat connections need to be strengthened.
A 2015 study of the functionality of Protected Area networks in facilitating species dispersal specifically identified transboundary (across political borders) connectivity as an important aspect of biodiversity conservation. Unfortunately, the study found that transboundary connectivity is in need of improvement, requiring better cooperation between governments. To bring this back to a North American context, the Y2Y Conservation Initiative is specifically addressing this kind of transboundary connectivity with a 3 500 km corridor of Protected Areas that spans multiple jurisdictions.
The moral of this story is that conservation on a national, continental, and global scale needs to be ecologically-based, focused on maintaining the structures and functions of ecosystems through connected habitats. If the Protected Area system is going to continue to be an important part of our conservation strategy, which it is, then it has to be based on the needs of wildlife populations and ecosystems and the realities of environmental pressures confronting conservation today. In Canada, we have committed to expanding both our terrestrial and marine Protected Area networks by 2020. It is commitments and work on the scale of the Y2Y initiative that could very well be the key to the future health of thousands of wildlife species in this country.
To be successful, I think that conservation needs to be a part of our everyday lives, realities, and landscapes. Conservation can’t only be that thing that occurs at a distance, removed from humans, behind the fancy gates of parks, or as some static ideal that we hear news clips about once in a while. To me, conservation is something that we should be surrounded by, not something we visit. We need to learn firsthand what it means for landscapes to be connected, both to other landscapes and to ourselves. Long-term, large-scale connectivity, then, is about more than only linkages between patches of ground. To me, the quest to create habitat linkages is also somewhat of a metaphor for the integrated nature of how I think we should connect and live with conservation.