Naturalist Notebook: Alces alces – Working together for a culturally important species

Photograph courtesy of James Ianni/U.S. Forest Service, Chugach National Forest.

Fall and winter are especially challenging for moose on the Copper River Delta (CRD) due to the variable snow loads and mixed precipitation during the winter months. To prepare, moose need to eat about 50 to 70 pounds of food per day to maintain their large size. Adult moose need to consume almost 10,000 calories a day. To put this into perspective, the average peanut butter and jelly sandwich is around 376 calories, this means a moose needs to eat the equivalent of 27 peanut-butter and jelly sandwiches a day to meet this energy requirement!

The first moose calf named “Kenai” was released on the CRD in 1949. Between 1950 and 1958, an additional 21 calves — 8 male, 13 female — and a female yearling were released. By 1960, the population had grown enough to open the first moose hunting season. The moose population continued to increase steadily until a severe winter in the year of 1971-1972, when approximately 15-20 percent of the CRD moose population died. But by 1996, the CRD moose population had recovered and grown from the original 22 individuals to 570.

As the moose population increased, interest in moose habitat relationships on the CRD began to emerge. However, habitat studies and enhancement projects had never been completed in “this type of Alaska.” A series of scientific studies conducted by a variety of universities, and both state and federal natural resource management agencies began to emerge in the ‘60s. These studies closely examined moose movement, seasonal ranges, activity budgets, food sources and foraging behavior. The information collected built the foundation for our knowledge of moose on the CRD today. Research has shown that CRD moose display differences in their summer and winter habitat preference, and moose prefer willow twigs as their main source of nutrition, especially during the harsh winter season.

Since the 1964 Good Friday earthquake, changes in willow abundance have been noticeable. The earthquake resulted in a new, uplifted landscape that was not previously accessible by upland-associated woody species. Sitka spruce, alder and cottonwood tend to crowd out willow, and have been increasing on the delta. As these woody species expand on the CRD, willow patches, the preferred food sources for moose, are reduced. Food availability is especially important when considering carrying capacity. If carrying capacity is exceeded, enough forage may not be available to support the population. Although exceeding carrying capacity has not yet been observed in moose on the CRD, it is important to consider this possibility and to test preventative measures to ensure that this culturally important subsistence species can be sustained.

“Kenai” the first moose calf released on the Copper River Delta, Alaska, in 1949. Photo courtesy of U.S. Forest Service, Cordova Ranger District Office.

In order to best manage both moose and their habitat on the CRD, the U.S. Forest Service Cordova Ranger District Office and collaborators have been collecting information on moose and their preferred wintering habitats. In 2007, a multi-year project was designed to enhance winter forage availability for CRD moose. The goal was to improve moose winter forage (i.e. willow) through a vegetation treatment plan that encompassed both Native and Federal lands on the West CRD. In 2011, the USFS, in collaboration with the Native Village of Eyak proposed an expansion of the project to include both Native Village of Eyak and the Eyak Corporation lands. The Cordova Ranger District is grateful for the ongoing collaborative effort, between the Native Village of Eyak and the Eyak Corporation, to improve moose winter forage through vegetation treatment.

The preferred method of vegetation treatment is called hydroaxing. Hydroaxing is a method of woody tree and shrub removal that can clear large areas in a short amount of time. The machinery consists of a hydraulically powered cutting blade attached to a tractor, where the blade heights can be adjusted, and can remove any tree or shrub smaller than a 13-inch diameter. Winter is the ideal time for hydroaxing. The ground is frozen reducing any unnecessary damage to the CRD. Trees and shrubs are dormant at this time, so most of their nutrients are stored in root systems, allowing fast regrowth to occur. Willows thrive after physical disturbance and quickly grow lush sprouts after hydroaxing.

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Vegetation communities have been closely monitored each year by U.S. Forest Service biologists to compare plant composition and document willow cover. Areas on the CRD that were mechanically treated by hydroaxe, have shown an increase in willow density and growth, while spruce, cottonwood,and alder have been reduced. Habitat management for the benefit of the local moose population continues on the CRD today. This type of vegetation management not only supplements winter forage for moose, but also helps diversify regrowth that can be beneficial to other wildlife as well.


Melissa Gabrielson is a U.S. Forest Service Wildlife Biologist for the Prince William Sound Zone. She has been heavily involved with many wildlife projects on the Copper River Delta including the moose winter range improvement project; If you have any questions about the project or want up to date information on other wildlife-related projects happening on the Copper River Delta or Prince William Sound Zone, feel free to contact Melissa Gabrielson at melissa.gabrielson@usda.gov or stop in the Cordova Ranger District Office.

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