Paving paradise? Effects of the urban interface on wildlife

Data from 9 GPS-collared caribou show how they move along the refuge boundary as they migrate from their wintering grounds in the eastern Kenai Lowlands to their calving grounds near the mouth of the Kenai River during 2006-08.

While helping out at a ski meet this past weekend, several of us mostly middle-aged parents were gloating about what a great place we live in. Our healthy and hopefully well-educated kids were skiing through a well-groomed lighted trail system, adjacent to a well-maintained high school just off a segment of the Alaska highway system, within spitting distance of the Kenai National Wildlife Refuge, 2 million acres set aside by Congress for wildlife and recreation. The Kenai Peninsula really is a spectacular place to call home with an abundance of natural resources, plenty of outdoor space to recreate in, and clean air and water.   


For better or worse, we’re not the only ones who know this poorly-kept secret. Since the Sterling Highway was completed in 1951, the residential population in the borough, mostly on the Peninsula, has increased by about 1,000 new residents each year, currently adding 1.5 housing units per day! More than 1.7 million vehicles annually now travel the highway east of Sterling, an average of 2.7 vehicles per minute. And our road system on the Peninsula is much more than the 200 miles of the Seward and Sterling Highways. We are blessed with over 3,000 miles of paved and unimproved roads to access the 238,800 acres of private lands, currently divided into 55,000 parcels, that we call home.

But everything has a down side. Joni Mitchell sang how “(we) paved paradise to put up a parking lot.” But it’s not the actual pavement I’m concerned about — after all, we’ve all got to live somewhere. Rather, it’s the indirect impacts of a rapidly urbanizing landscape abutting against an otherwise natural Alaskan landscape. 

This wildland-urban interface, stretching for 175 miles along the western boundary of the Refuge, is already a problem that will only become more so with time. If you fly south from Point Possession to the headwaters of Kachemak Bay along this interface, you’d see three platted subdivisions north of the Spur Highway, the towns of Nikiski, Kenai, Sterling, Funny River and Kasilof, and eventually the cabin-dotted Caribou Hills as you look westward toward the Cook Inlet. If you look eastward along this interface, you’d see the black spruce, birch and extensive peatlands in the Kenai Lowlands, white spruce and subalpine shrubs reaching above Tustumena Lake into the Benchlands, the standing and fallen beetle-killed spruce amidst Calamagrostis grasslands in the Caribou Hills, and finally Sheep Creek as it flows out of the Kenai Mountains.

So what’s the big deal? This urbanizing landscape along the Refuge boundary greatly increases the likelihood of bears killed in defense of life or property (DLP), litter, wildlife-vehicle collisions, noise and air pollution, wildlife disturbance, poaching, trespass by ATVs, introduction of invasive species including wildlife diseases, human-caused fire ignitions and, ironically, the suppression of wildland fires. Needless to say, all of the above concerns Refuge law enforcement officers, biologists, and fire managers.

Impacts to vegetation on the Refuge may be one of the more subtle impacts of the urban interface. Historically, wildfire sweeps black spruce forests on the Peninsula every 80 years, and white and Lutz spruce forest every few hundred years. Fire that burns down to mineral soil typically converts softwood forest to birch and aspen, setting the stage for abundant moose browse 10-25 years after the fire. While this is a really desirable outcome if you like moose, nobody wants to see their house burn down either.

The default management action for natural fires on Congressionally-designated Wilderness, roughly two-thirds of the Refuge, is to let them burn. Unfortunately, almost 40 miles of the urban interface also serves as a boundary for both Refuge and Wilderness. For example, the 2005 Fox Creek Fire burned 26,000 acres of beetle-killed spruce in designated Wilderness. The fire would have burned more (and should have by policy), but firefighters were forced to use aerial- and hand-ignition methods to flank the fire when it started turning toward recreational cabins in the Caribou Hills just outside Refuge boundaries. We will almost certainly see more wildfires put out (and perhaps fewer moose) as the urban interface develops further.

Disease transmission from domesticated and feral animals is another thorny problem. Canine parvovirus, canine distemper virus, and biting dog lice showed up in wolves and coyotes back in the late 1970s and 1980s that were almost certainly transmitted by domestic dogs roaming the urban interface. The two viruses are known to kill wolves and coyotes, and lice can significantly reduce the commercial value of fur pelts. I have often wondered if red fox populations on the Kenai failed to recover after commercial fox farming operations ended in the 1930s, presumably because of the coincidental invasion of coyotes (which will kill fox) onto the Peninsula in 1926, but perhaps because of the subsequent spread of these diseases from domestic dogs.

I worry too that chickens, or perhaps escaped pheasants and turkeys, may introduce avian diseases. For example, Newcastle virus was suspected of killing an entire cohort of double-crested cormorants that breed on Skilak Lake in 1999.

And, of course, the urban interface can be a double-edged sword for wildlife. Not surprisingly, bears tend to die when they enter the urban interface, either unintentionally or in pursuit of human garbage. Of 247 brown bear DLPs recorded between 1965 and 2008, more than half occurred on private lands west of the Refuge. On the other hand, many moose cows calve in the urban interface, and many cows and calves winter there despite the relatively high collision rate with vehicles. As any homeowner knows, the ornamental shrubs and trees in our backyards serve as food for moose in lieu of post-fire browse during the winter.

Addressing the collective impacts of the urban interface will almost certainly occupy future managers of the Kenai Refuge. This is a fertile area for research now so we can lay the groundwork for smart management in years to come.    


John Morton is the supervisory biologist at Kenai National Wildlife Refuge. You can find more information about the Refuge at or


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