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Central Alaska Network:

Vital Signs:

Wolves: Central Alaska Network Resource Brief

Wolf monitoring,
Yukon-Charley Rivers

Denali • Wrangell-St. Elias •

Yukon-Charley Rivers

Wolf Monitoring Status and Trends: Yukon-Charley Rivers

Roughly 10 to 12 wolf packs include a significant part of Yukon-Charley Rivers National Preserve (YUCH) in their home ranges. In 14 years of consecutive monitoring, the number of wolves in the preserve has never been lower than in the spring of 2007.

Wolves can be located by finding and following tracks in the snow during winter flight surveys. Specialized devices, such as radio/GPS collars, have greatly increased the success and decreased the cost of wolf monitoring. Despite a winter characterized by low snowfall and poor flying conditions, researchers replaced or newly fit radio collars on 9 wolves from 8 packs during the 2006/2007 monitoring season.

One of the year’s most striking discoveries was a decrease in the average number of wolves per pack from 5.4 to 2.3 over the course of the winter. The survey conducted in April 2007 revealed an all time low for the preserve’s wolf population (about 17) since monitoring began in 1993. Subsistence harvest was responsible for the death of 4 wolves, though this is not unusual for YUCH. In addition, a few historical packs have disappeared and home ranges have shifted for a number of other packs. Finally, birth and survival of wolf pups has dropped.

» Photo:
aerial wolf
darting

» Graph:
wolf mortality
YUCH

» Photo:
biologists
with wolf

In 2006 the average litter size was 4.3. In 2007 this number shrank to 3.2. In total, 19 pups from 6 packs were counted during the fall survey, while 2 packs appear to have lost their offspring.

The highly controversial wolf management program in the areas surrounding YUCH did not appear to impact the preserve during the 2006/2007 season. While 11 wolves were shot in the control area adjacent to the preserve, none of them were from YUCH. This could easily change in the future, since monitoring has revealed that all of the preserve’s wolf packs regularly travel far outside its borders.

Monitoring Importance:

Wolves (Canis lupus), are one of six keystone large mammal species in interior Alaska and are specifically identified in the enabling legislation and management objectives of all three CAKN parks. Wolves are good indicators of long-term habitat change within ecosystems because they depend on healthy populations of large ungulate prey (such as moose and caribou), which in turn respond to vegetation, weather and other habitat patterns across the entire landscape. As a top predator, wolves may play a key role in influencing prey populations, and as a result may influence vegetation patterns and ungulate harvest by humans on NPS parks and preserves in Alaska. Wolves are of great importance to park visitors because of the unique opportunities to view wolves in Alaska’s parks. Information on wolf populations will allow managers to protect wolves in a variety of ways. Examples include locating and isolating active dens from disturbance; determining whether wolves are being impacted by activities (such as wolf control) outside park boundaries; and evaluating the long-term changes in Alaska populations using genetic data gathered during monitoring.