MIGRATION CORRIDORS UNDER THREAT

©By Susan B. Eirich, Ph.D.

We here in Teton Valley are the southernmost anchor for the only remaining intact mountain ecosystem in the world, ranging 2000 miles from our valley all the way north to the Yukon. It is the last great refuge for many species, a Noah’s arc. This huge vibrant wilderness sends fingers of vitality down into Teton Valley in the form of forested creeks that serve as wildlife corridors connecting to the Teton River: North Leigh, South Leigh, Fox Creek, Trail Creek, Badger Creek and others give wildlife food and cover. 

We are in the midst of a breakthrough in understanding how nature works, thanks to the huge amounts of data we can now process with computers. Some of the results are practical and encouraging. We have discovered the absolute need, and astounding distance, individual animals may travel to survive and to keep their populations vibrant and vital. Lynx 700 miles. Wolverine 700 miles. Antelope nearly 200 miles twice a year. We have seen that two hundred years of chopping and dividing land into squares with roads, houses, dams, railroads, has resulted in a devastating loss of wildlife. One of the major reasons is that animals cannot survive in boxed areas, even those the size of Yellowstone. We are lost without the ability to travel, without our highways and byways, without the ability to refuel and resupply on the way; take alternate routes if there is a disaster.  Animals need their own  “animal highways” to be able to move; to survive drought, landslides, diseases; to find food during the different seasons; to find mates. Fish need connecting tributaries and streams to spawn. This holds true  for larger areas such as the Yellowstone to Yukon corridors, but also for smaller areas such as our own Teton Basin. Corridors are critical. Without animal highways we will eventually lose wildlife in that area. And migrating birds need areas to drop in and rest during their migrations, especially in the arid west. Without these rest stops they die of exhaustion or starvation. 

BUT – we have also discovered that to a surprising degree we can develop AND have wildlife if we keep these critical interconnecting corridors open between larger areas of habitat. For us in Teton Valley, it is those fingers of vitality, those forested creeks that connect the Tetons to the Teton River that are critical. There are areas that can be developed with relatively little impact and areas at great cost to wildlife. For example, we live in a high valley that already experiences harsh winter conditions. The interruption of creek corridors by development costs wildlife the opportunity to escape the even harsher rigors of high country winter by moving down to our relatively milder conditions. Our bighorn sheep no longer have access to windswept open country to get to grasses and shrubs. Forced to live near timberline, they feed on what rough forage is available, wearing their teeth down prematurely. As a consequence, their lives are shortened and their isolation prevents their genes from mingling with other populations, further weakening the population through inbreeding. The more we develop in the few remaining stream corridors, the more we disrupt the paths wildlife can travel to crucial winter range. 

Most of the forested creeks connecting the Tetons to the Teton River have been developed to the point they are no longer useful to much wildlife. But our valley wildlife biologists have identified South Leigh as the last best of these corridors in the Upper Valley; a top priority for conservation. It is the least fragmented riparian corridor in the Upper Valley that connects big game summer habitat on the west slope of the Tetons with winter range along the Teton River.South Leigh Creek is travel route and winter habitat, or home, rest stop, food source, and highway to water for moose, mule deer and white tail deer, elk, and black bears. Lynx and wolverine have been spotted in the upper reaches of the corridor. It is home to small mammals, game and non game birds, and breeding songbirds. It has the largest known wintering concentration of great gray owls in the lower 48 states. It still has nesting raptors, hawks, great horned owls, woodpeckers, bluebirds, chickadees and neotropical migratory songbirds. It serves MacGillivray’s warblers, yellow warblers, dusky flycatchers, will flycatchers, calliope hummingbirds and ruffed grouse. It is the best habitat for riparian dependent songbirds in Teton Basin. Bald eagles roost and nest there. Nests built by raptors are used by eleven species of hawks including the northern goshawk, and owls, eagles and other birds. Bohemian waxwings feed and roost and rest by the thousands on remnant berries and there is a self-sustaining population of our native cutthroat trout with the possibility of connecting them once again to the Teton River. Biologists conducting waterfowl surveys in 2001 and 2002 found that the corridor provides significant breeding habitat for duck species such as mallard, widgeon, and cinnamon teal. There are two rare world-class plant communities…the black cottonwood-red osier dogwood and the black cottonwood black hawthorne community, additionally important because the hawthorne berries are a food source in fall for bears, deer, small mammals and birds. The cottonwood bottoms include a complex understory which provide a rich diversity of homes for an amazing range of creatures, many more than we ordinarily are aware of. Cottonwood bottoms offer more breeding habitat than any other part of the Valley. Without breeding there is no regeneration. It is rest stop to thousands of spring and fall migrating birds. These cottonwood riparian bottoms are most valuable remaining habitat in the valley floor.

A development group from California has purchased a vital 120 acre section of the South Leigh corridor running from Highway 33 at Hatch’s Corner due east to the Tetons. Their plan, to be presented for initial Planning and Zoning approval on January 11, is to build 32 houses, many directly in the cottonwoods, each with individual wells and septic systems, and a commercial area as well. This proposed South Leigh Ranch Subdivision is not just development of 120 acres. It is a critical 120 acres. As 1/8” inch taken out of an artery leading to a heart is critical. It doesn’t matter that you don’t touch the rest…it disconnects the flow of life blood. If a bridge is washed out it isn’t just the bridge that is affected. All the land and resources on the other side are now unavailable because you can’t get there. Highway 33 is already a barrier to wildlife. But developing from there due east along the corridor towards the Tetons will be an insurmountable barrier to many species. We can ease the Highway 33 barrier, as both the Teton Regional Land Trust and Earthfire Institute have been exploring, by building a wildlife over or underpass as has been done successfully in other areas. But we cannot ease the damage that building in the corridor will do. Yes, some animals will adapt and remain and others increase– especially animals that can adapt to human interference such as coyotes, foxes, starlings. But many will not.

The proposed development will be devastating to the corridor and its wildlife. But the developers have indicated that they would like to do a “green” development. As development pressures increase it is especially important to remember to take wildlife needs into consideration BEFORE we build, as individuals, as developers and as a community. Many private landowners are looking for ways to keep their land healthy, and in this picture of a larger system, every developer and every person counts. The actions of a single homeowner can make a crucial impact. In a vivid example there are places along the antelope migration route in Wyoming where access to Jackson Hole boils down to a single pathway which every antelope must walk two times a year. In other places it is not a house itself but the human activities that are the problem, such as free-ranging dogs or cats. Homeowners can invest time in local planning and zoning efforts, offering educated opinions and voicing development concerns. Many people simply don’t realize the impacts of their actions or inactions and would be glad to take wildlife needs into consideration given the right information and the larger picture. 

There is an opportunity for us to come together as a community to decide how we will work with the developers for the best possible outcome, and an opportunity to educate ourselves about the value of wildlife corridors to our way of life. Can we use this chance and come together to protect this last best corridor, while preserving the consortium’s right to develop property?  Legally there is little to stop this plan – there are no ordinances on the books in Teton Valley to protect wildlife.  But legal options are a last resort. Far better to come together to do the best thing for all of us, humans and wildlife.

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