Alaskan Coastal Wolves: Living Life on the Edge in More Ways Than One
By Austin Kozlowski
As our human population continues to grow, we are increasingly faced with issues of balancing our resource needs with the need to conserve natural ecosystems. One clear example that illustrates this challenge can been seen in southeastern Alaska on the Prince of Wales Island, a hotspot for commercial scale logging and coastal wolf populations.
How did the conflict arise?
For over 12,000 years, coastal wolves have roamed Prince of Wales Island and flourished in the rich Alaskan ecosystem. In the 1950’s, commercial logging practices were brought to the island, and since then over 93% of the island’s old growth forests have been clearcut, in effect, altering the habitat of the wolves and their prey species, which include mostly Sitka black-tailed deer and salmon. The loss of old growth forests changes the natural ecosystem that the wolves rely on to support food sources and provide shelter by altering the landscape to one with clearcut areas and those with post clearcut stages of growth. Logging also alters the health of streams that support salmon and creates roads that further disrupt the wolves. Thankfully, work is being done to help minimize the impact of logging on wolves and help promote an ecosystem that can support the needs of both humans and native wolf populations.
Understanding the ecosystem
Old growth forests consist of diverse species and a varied tree canopy, which allows enough light to reach the forest floor for a healthy understory of shrubs, forbs, and lichens, optimal forage for deer. After an area is clearcut, shrubs and forbs do grow back in the first 30 years, that is, during the early successional stages after a clearcut, and so do still provide some deer forage. But after about 30 years, these later successional areas become habitats with all same-age trees and a thick canopy that blocks light to understory areas, so shrubs and forbs cannot grow. Hence, forage for deer has been severely limited in these later successional areas.
Understanding the wolves
To better understand how coastal wolves adapt to their altered ecosystem, several researchers with the Alaska Fish and Game set out to study their seasonal habitat selection with the understanding that wolves choose areas where prey is available. The researchers conducted a study on the island that consisted of tracking seven wolf packs via global positioning collars on 13 individuals and analyzing what types of habitat they spent their time in. The researchers then compared wolf movements with those of their prey and how this was affected by logging operations.
Where are the wolves?
Wolves choose habitat types based largely on how well that habitat supports prey sources. Therefore, since Prince of Wales Island wolves rely on deer as their main source of food, it is not a surprise that they frequent sparse old-growth forests, as well as early successional clearcuts during most seasons. However, during some seasons wolves move to and utilize other habitats with other prey sources. During the denning season from the end of March to late July, the wolves shift their selection of habitat and establish their dens in remote areas, away from logging operations, regardless of the successional stage of the forest. This illustrates that instead of selecting areas that have large deer populations, the wolves choose areas far from human disturbances in an effort to ensure the safety of their pups. During this time, wolves also shift to other sources of prey, such as beavers, to make up for moving out of optimal deer habitat. In fact, wolf dens are often located within close proximity to freshwater streams that support beaver populations. During the late summer months and into early fall, the wolves are found to frequent areas near rivers and streams as the seasonal salmon run becomes an important factor in their diet. Past studies have in fact shown that salmon consists of over 19% of these wolves’ annual diet.
Other effects of human disturbance
Logging operations often bring new roads to otherwise undisturbed regions. These new roads mean an increase in human presence and disturbance in wolf habitat. For the wolves, these roads have both negative and positive effects. During the denning season and early summer when the pups are still young, wolves will avoid busy roads in an effort to protect their pups. However, when heavy snow covers the ground in the winter months, wolves often increase their presence along roadways. This is because it is easier for the wolves to travel cleared roads rather than travel through deep snow. Deer also follow this way of thinking, which increases the opportunity for hunting for the wolves as well.
What does all this mean for the wolves and logging?
There is a great deal of positivity looking forward for these wolves, even with increasing logging practices. Not only are they able to switch prey sources based on availability but they have also learned to adjust to and sometimes utilize human disturbances such as roads. This flexibly indicates the possibility for wolves to adjust to and coexist with humans on Prince of Wales Island and surrounding regions in Alaska. However, there is still much to learn. Past efforts to artificially thin areas of old-growth clearcuts on the island in order to keep them in earlier post cut successional stages, and therefore a more optimal habitat for deer forage, has not resulted in the use of these areas by wolves, showing that their habitat selection may not be as simple as we think. Nevertheless, coastal wolves are incredibly resilient creatures, and with continued close study and adequate changes to human practices as we learn more about their ability to adapt, they can continue to flourish on Prince of Wales Island for years to come.
Roffler, et al. “Resource Selection by Coastal Wolves Reveals the Seasonal Importance of Seral Forest and Suitable Prey Habitat.” Forest Ecology and Management, vol. 409, 2018, pp. 190–201.