National Park Service

Southwest Alaska Network (SWAN)

Terrestrial Wildlife

Moose, Kenai Fjords National Park
Moose, Kenai Fjords National Park

Resource Briefs

Protocol Documents

Monitoring Reports

Published Articles

For more information contact: Tammy Wilson

Justification and Issues

All SWAN parks possess intact, naturally functioning terrestrial ecosystems with their historic complement of species, including large carnivores. Such ecosystems containing historic levels of biodiversity are becoming extremely rare globally and supply a resource of great value locally and internationally. Some key wilderness-dependent mammals in SWAN are wolverines, wolves, and brown bears. These species do not require wilderness habitats per se, but they require wilderness to avoid conflicts with humans and to avoid human-caused mortality. They also depend on populations of free-roaming, naturally cycling prey such as moose and caribou.

Some terrestrial animals serve important ecological functions across systems. For instance, brown bears influence coastal intertidal community structure when they forage on salt marsh vegetation and clams, transfer nutrients from rivers to the land when they feed on spawning salmon, and influence plant distribution and nutrient availability when they dig in montane meadows. Bald eagles are keystone predators on avian and fish populations in both freshwater and marine nearshore systems. Eagles move salmon and other carcasses into riparian areas, and ravens and crows cache salmon bits in trees and under grass and rocks. Such marine-derived nutrients have the potential to significantly affect annual nutrient budgets and to maintain the long-term productivity of coastal river systems.

Large terrestrial herbivore-predator interactions are an intrinsic property of intact functioning ecosystems and are a flagship ecological feature of SWAN parks. Selective foraging by herbivores, such as caribou, can alter ecosystem functioning, change species composition, and modify nutrient cycling and plant productivity. Wolves are functionally important in this interaction because they exert top-down control of herbivores. Because caribou and wolf populations oscillate through time, herbivore-predator population cycles play an important role in maintaining a heterogeneous distribution of resources, or habitat mosaic. Caribou and moose also are important subsistence and cultural resources to local native Alaskans and provide significant recreational opportunities for resident hunters.

Bald eagle, Kenai Fjords National Park
Bald eagle, Kenai Fjords National Park

Resource Brief — Bald eagle monitoring

Resource Brief — Bald eagle survey methods

Protocol Documents

Monitoring Reports

Published Articles

For more information contact: Tammy Wilson

Importance/Issues

Bald eagles (Haliaeetus leucocephalus) are keystone predators on avian (e.g., seabirds) and fish (e.g., salmon) populations and hence serve an important ecological role in freshwater and marine coastal systems in SWAN parks. Their occurrence and reproductive performance may be influenced by weather conditions, toxic contaminants, food availability, human-related impacts, and climate. Bald eagles may not attempt to nest or their attempt may fail if breeding conditions are unsuitable during a given year. Thus, their nest occupancy and reproductive rates may be useful indicators of both current condition and long-term change (variability) of freshwater and marine coastal systems. KATM, KEFJ, and LACL all contain large breeding populations of bald eagles, and this species is specifically mentioned in enabling legislation for LACL. Bald eagle populations are under continuing threat from human-related impacts such as ecotourism, sport and commercial fishing, timber harvest, potential mining activities adjacent to the parks, and potential oil spills or other accidents along marine coastlines. Further, global climate change will have an unknown effect on their forage base and nesting habitat.

Current and Future Work efforts

Regular surveys of breeding eagles are critical to monitoring the health of this indicator species. The goal of the bald eagle monitoring program is to develop a rigorous survey design for long-term monitoring that will standardize data collection and facilitate comparisons of eagle nest occupancy and productivity between KATM, KEFJ, and LACL. KEFJ began field testing updated eagle survey methods in 2009; work to finalize data collection and analysis protocol is ongoing. After a lapse of 20 yrs, eagle surveys were reiterated in KATM in spring 2011 based on the KEFJ methods. LACL plans to modify survey methodology in 2012 to facilitate comparison with KATM and KEFJ data, while also maintaining continuity with the valuable long-term data on known eagle nests within LACL.

Brown bear, Katmai National Park and Preserve
Brown bear, Katmai National Park and Preserve

Resource Brief — Brown Bear

Protocol Documents

For more information contact: Tammy Wilson

Importance/Issues

Brown bears (Ursus arctos) are an integral part of SWAN parks and are specifically mentioned in the enabling legislation of Aniakchak, Katmai, and Lake Clark. These animals play important ecological roles as top predators influencing population dynamics of other species and as means of nutrient transfer from spawning salmon (Oncorhynchus spp.) to the terrestrial system . Moreover, Alagnak, Aniakchak, Katmai, and Lake Clark support high densities of brown bears; in fact, estimated densities of brown bears along the KATM coastline are the highest reported in North America. Brown bears are drawn to these areas because of the abundant salmon runs, which also draw sport fishing enthusiasts from around the world. The presence of the bears has begun to draw larger numbers of bear viewers during the past two decades. In addition, the Alaska Board of Game is interested in opening more bear hunting opportunities on state and federal land adjacent to these parks. The impacts of high numbers of back-country anglers, hunters, and recreationalists on bear foraging behavior, habitat use, and survival are largely unknown, particularly at coastal sites, where bears feed heavily on salt marsh vegetation in addition to fish. Further, brown bears in Alagnak, Aniakchak, Katmai, and Lake Clark are subject to subsistence hunting and are available for sport hunting in the preserves.

Moose, south central Alaska
Moose, south central Alaska

Resource Brief — Moose

Protocol Documents

For more information contact: Tammy Wilson

Importance/Issues

Moose (Alces alces) are an integral component of terrestrial systems in Alagnak, Aniakchak, Katmai, and Lake Clark. During cycles of high abundance, this species has the potential to influence structure and function of terrestrial systems both through its browsing effects on vegetational communities and through its role as a prey species. Thus, tracking abundance and distribution of moose provides important information on dynamics of terrestrial systems. Further, the bull:cow ratio is useful for monitoring their reproductive potential. Moose also are an important subsistence and cultural resource to local Native Alaskans and provide significant recreational opportunities for resident hunters. Changes in numbers and distribution of moose are anticipated in response to climate induced changes in their habitats.

Current and Future Work Efforts

NPS staff have worked in cooperation with ADF&G to conduct annual fall surveys of moose in established trend count areas (TCAs) since the 1970s. However, aerial surveys of moose TCAs sometimes lacked consistent application of methods and did not account for sightability. More rigorous surveys are needed to minimize sampling error and enhance comparability of long-term data for the purpose of managing moose harvest and understanding plant-herbivore-predator interactions.

Last Updated: September 25, 2017 Contact Webmaster