Refuge Notebook
Peninsula Clarion Article
Dated
11 February 2000
Animals,
as well as Humans, Get Stranded on the KenaiPeninsula
by Ted Bailey
The recent avalanches that stopped people from traveling
to and from the Kenai Peninsula are a reminder how isolated the Kenai Peninsula
is from mainland Alaska. Travel by air was still possible, but people using ground
transportation were stopped in their tracks. A similar situation applies to certain
species of wildlife trying to leave, or to find, the peninsula. Because birds
travel by air, they have little difficult finding and leaving the peninsula, but
mammals have more difficulty, because they travel on the ground. Picture wildlife
somewhere on the Kenai Peninsula with no knowledge of geography, no "road"
system, and an urge to travel. How long would it take them find their way off
the peninsula? Or picture wildlife under the same conditions somewhere north of
Anchorage with an urge to travel. What are their chances of finding the Kenai
Peninsula? Translocated animals often attempt and some succeed in returning to
their "home areas." But long-term radio-collar monitoring of native
wolves, bears, and lynx on the peninsula show how difficult it is for certain
species to leave - and probably more difficult to find - the peninsula. Consider
the lynx for example.
Most resident lynx spend most of their lives in a
well defined area whose size varies according to their sex, age, reproductive
status, and their cyclic food supply - the snowshoe hare. However, some lynx,
often young males, eventually leave their natal or birth areas and search out
distant areas to settle in. These non-resident lynx are known as "dispersers."
Dispersing lynx are capable of traveling great distances in a continuous habitat.
Three lynx initially tagged in the Yukon Territory were later trapped in eastern
Alaska and others were trapped in the Northwest Territories (now Nunavut), British
Columbia, and Alberta. One Yukon-tagged lynx was trapped a record distance of
687 miles from its capture location. These Yukon-tagged dispersing lynx traveled
through continuous habitat.
In contrast, the Kenai Peninsula is almost
disconnected from mainland Alaska. Lynx traveling between the Kenai Peninsula
and the rest of Alaska must follow narrow, forested corridors in steep mountain
valleys. They must cross open alpine habitats or a wide zone of nearly treeless
wetlands at the head of Turnagain Arm, and traverse through human-populated areas
surrounding Anchorage. Lynx prefer to travel in dense or forested cover, and unlike
wolves that will cross open areas, lynx are reluctant to cross wide, open treeless
areas. Consider the following specific, but typical, example of the movements
of one dispersing lynx.
We did not know where young male lynx #113 was
born or where he spent his first year of life. It will forever remain a mystery.
But we do know where he went, and where and when he died. We captured him one
dark, snowy afternoon in late October 1996 south of Chick Lake in the northern
portion of the Kenai National Wildlife Refuge near the Moose Research Center.
He was an average young male lynx that weighed 19 pounds, and like other lynx
we had captured, we attached a small radio collar before releasing him in order
to monitor his movements, home range, habitat use, and survival.
Nearly
a month later we found #113 about 20 miles away, along the coast of Cook Inlet
at Point Possession near the very northern tip of the Kenai Peninsula. He could
go no further north or west because of the large expanse of water. From there
he turned back to the south and returned to the area where he was captured - possibly
his area of birth - that encompassed the entire Swanson River Canoe System. His
movements traversed back and forth across this area until May 1997 when he departed
again in the opposite direction, to the southeast, and crossed the Kenai River
above from Skilak Lake sometime in mid-June. By early July his travels had taken
him deep into the Kenai Mountains and high up into a spruce-alder valley southeast
of Upper Russian Lake, near Goat Lake. We found him there near yet another barrier
to his wandering movements, but this time it was glaciers and ice - the Harding
Icefield. By early August he had turned back again to the west, left the mountains
behind and was traveling southwest across the Kenai Benchlands north of Tustumena
Lake. He most likely skirted the west end of Tustumena Lake, crossed the Kasilof
River, and by early September was east of Homer on the north side of Kachemak
Bay overlooking yet another barrier of water to his movements further to the south.
He turned back north.
In late September 1997, nearly a year after his capture
and after wandering the length and breath of the Kenai Peninsula and encountering
the Cook Inlet and Harding Icefield, #113 apparently had found a place to his
satisfaction on the southwestern forested slopes of the Caribou Hills. He settled
there and established himself as a stay-at-home resident, his wandering days apparently
over. He remained there for over a year until he was taken in a coyote snare by
a trapper in December of 1998. A microscopic section of the cementum layers in
one of his canine teeth confirmed that he was three years old at the time of his
death, and therefore just over a year old when we captured him back in October
of 1996.
The movements of this particular lynx are typical of dispersing
lynx we have monitored and demonstrate that it is very difficult for lynx to find
their way off the Kenai Peninsula, and probably even more difficult for mainland
Alaska lynx to find their way onto the Kenai Peninsula. We have monitored the
movements of many dispersing lynx on the western Kenai Peninsula and have found
similar movement patterns. Despite a dispersing lynx's ability to travel, it is
very difficult to find its way off the peninsula. Of well over 100 lynx captured
and monitored on the refuge over more than 15 years, we have only one documented
record, years ago, of a tagged lynx successfully dispersing off the Kenai. This
was also a male lynx that was eventually captured near Chitna, over 200 straight-distance
miles from his last known Kenai Peninsula location. Male lynx are apt to disperse
more frequently and to greater distances than females. And of well over 100 lynx
radio-collared in mainland Alaska and in northwestern Canada, in the 1980's and
1990's, none ever made it to the Kenai Peninsula.
This knowledge of lynx
movements and the movements of other mammals such as wolves and brown bears on
the Kenai Peninsula is of significance because it relates to a tenet of animal
ecology known as "island biogeography." Basically, island biogeography
states that animal populations on islands, or in isolated blocks of habitat, are
more at risk and susceptible to extinction than populations that are surrounded
by other similar populations. The smaller the island and the more isolated from
nearby populations, the greater the risk. The scientific literature is replete
with examples of populations declining or going extinct on islands or within isolated
or small fragments of once-continuous habitat. Specific examples also include
the Kenai Peninsula.
Caribou, another great wanderer, were once native
to the Kenai Peninsula but were extirpated by man in the early 1900's. Caribou
had to be re-introduced to the Kenai in the mid-1960's and 1980's. Had they not
been re-introduced, we would probably still be waiting, after nearly 100 years,
for caribou from mainland Alaska to find and "naturally colonize" the
peninsula again.
Evidence suggests that it took mainland Alaska wolves
about 50 years to find and colonize the Kenai Peninsula after they were also extirpated
from the peninsula in the early 1900's. As wildlife habitat shrinks on the peninsula
and more human-created barriers to wildlife movements to and from the peninsula
are erected in their paths, the more difficult it is for mainland Alaska and Kenai
Peninsula wildlife populations to intermix, share genetic traits, and maintain
themselves through emigration and immigration. The known history of Kenai Peninsula
wildlife populations, as well as radio-collar studies of dispersing wildlife on
the peninsula, and ecological information on the risks associated with isolated
populations in general, all clearly indicate that certain wildlife populations
on Kenai Peninsula need to be managed more carefully than mainland Alaska populations.
---------------------------
Ted Bailey, a supervisory wildlife biologist,
has been responsible for the Kenai National Wildlife Refuge's biological programs
for more than 20 years. He and his staff monitor and conduct studies of a variety
of wildlife populations. He and his wife, Mary, live near Soldotna. Previous Refuge
Notebook columns can be viewed on the Web at www.r7.fws.gov.
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