Afognak and Raspberry Island Project
Background
Brown bears (Ursus arctos) have important, sport, economic, subsistence and ecological value for residents and non-residents of Alaska. Brown bears are the only large mammal endemic to the Kodiak Archipelago, and have been genetically isolated from other bear populations for approximately 12,000 years. Due to abundant food, particularly salmon, bears on the Kodiak Archipelago are among the largest brown bears in the world.
Brown bears use diverse landscapes including open and forested habitats. Their use of harvested timber stands can be influenced by several factors including bear physiology, season, and landscape structure. Logged areas can provide increased forage availability; however, increased risk can result in brown bear avoidance of these areas. Understanding factors potentially influencing brown bear distribution and abundance, and how they vary among forest successional stages, is critical for developing effective forest management strategies which incorporate brown bear resource requirements.
Commercial logging on Afognak Island occurred in the 1930s and became extensive since 1979, resulting in a mosaic of forest stands of varying age. However, the effects of this habitat alteration on brown bears is unknown. In addition to forest management practices, brown bears can influence elk calf survival as well as elk distribution and resource use. Therefore, a secondary area of study includes characterizing potential impacts of logging on brown bears in relation to elk space use.
Our overall goal is to identify habitat conditions and forest management practices that can enhance wildlife habitat and provide sustainable wildlife harvests. We will examine brown bear distribution, space use, and resource abundance on Afognak and Raspberry Islands in unharvested and harvested forest stands to identify resource attributes important to these species. Information gained through this project will be used to develop a long-term management strategy that incorporates sustainable logging, responsible wildlife management, and continued sport and subsistence hunting opportunities.
Objectives
- Estimate spatial and temporal availability of resources and their effects on brown bear space use.
- Examine brown bear movements and energetic costs across varied landscapes.
- Estimate diet of brown bears as part of an archipelago-wide study.
- Investigate brown bear space use relative to forest management, and elk movements.
- Formulate resource use models to develop recommendations for long-term management of sustainable logging, brown bear populations, and sport and subsistence harvest opportunities.
Study Area
The Kodiak Archipelago consists of 25 islands comprising 13,882 km2 south of mainland Alaska. The largest island in the archipelago is Kodiak (57.4912° N, 153.4950° W; 9,311 km2). Kodiak and surrounding islands have a subarctic maritime climate with average annual high and low temperatures of 7.9°C and 1.9°C, respectively. Archipelago-wide average annual rainfall is 198.2 cm and snowfall is 173.0 cm. Elevations on Kodiak Island range from 0 to 1,362 m. The island is heavily forested in the north and east, with open tundra in the south. About 13,500 people live on Kodiak Island, with 7,000 in the city of Kodiak. Commercial fishing is the dominant industry and includes 5 species of Pacific salmon (Onchorynchus spp.), Pacific halibut (Hippoglossus stenolepis), and crab. Numerous rivers are famous for salmon fishing and island-wide annual escapement counts typically range from 4.6 to 5.9 million salmon. Logging, ranching, fish processing, and copper mining also occur on Kodiak Island. The island supports native brown bears as well as introduced populations of mountain goats (Oreamnus americanus), black-tailed deer (Odocoileus hemionus), bison (Bison bison), and captive elk.
Afognak Island (58.3279° N, 152.6415° W; 1,809 km2) is the second largest island in the Kodiak Archipelago and is located 5 km north of Kodiak Island. The island has varying terrain ranging from steep mountains rising to 739 m along the western side, to generally flat and rolling hills in the interior and east. It has rocky shores and Sitka spruce (Picea sitchensis) is the dominant tree species. Devil’s club (Oplopanax horridus), blueberry (Vaccinium ovalifolium), salmonberry (Rubus spectabilis), and willow (Salix spp.) comprise much of the understory. Afognak Island has about 200 year-round residents located primarily in two logging camps. The island was set aside by President Benjamin Harrison in 1892 as a fish culture, forest, and wildlife preserve. Pacific salmon spawn throughout several of the island’s streams and lakes. The average annual salmon escapement for the island ranges from 414,000 to 510,000. Black-tailed deer were released on Kodiak Island in the early 1900s and expanded their range to Afognak Island by the 1950s. Eight Roosevelt elk were released on Afognak Island in 1929 and the current population is about 840 individuals. Elk hunting on Afognak Island is by permit only. Brown bears are common on Afognak Island, but the population size is unknown.
Raspberry Island (58.0708° N, 153.1876° W; 197 km2) is located 1 km southwest of Afognak Island and 5.6 km north of Kodiak Island. The highest elevation is 1,006 m and the island is dominated by alder (Alnus spp.), salmonberry, grasses, and scattered Sitka spruce forests. Along with a herd of about 210 Roosevelt elk, black-tailed deer and brown bears are common. Pacific salmon spawn throughout several of the island’s streams and lakes. Land ownership of Afognak and Raspberry Islands includes native corporations (64%), state government (27%), and federal government (9%).
Sitkalidak Island Project
Background
Research conducted on Sitkalidak Island will be incorporated into our Kodiak Archipelago-wide study on brown bears. Since 2008, 34 female brown bears were captured and received VHF radio collars. These bears were monitored and observed intermittently each year to estimate cub recruitment and survival.
In 2018 we deployed 13 additional GPS radio collars as part of our overall study to compare brown bear space use, movements, and aspects of demography throughout the Archipelago. Additionally, we will estimate brown bear diet across the Archipelago in relation to dominant food resources.
Our study will provide important information to Old Harbor Native Corporation landowners as they consider implementing eco-tourism opportunities (e.g., brown bear viewing) into land management plans for Sitkalidak Island.
Objectives
- Estimate spatial and temporal availability of resources and their effects on brown bear space use.
- Estimate diet of brown bears as part of an archipelago wide study.
- Assess cub survival and recruitment rates of brown bears.
- Formulate resource use models to develop recommendations for long-term management of brown bears.
Study Area
Sitkalidak Island (57.1030° N, 153.2356° W; 300 km2) is the third largest island in the Kodiak Archipelago and is separated from the eastern shore of Kodiak Island by a strait 320–3,200 m wide. Average annual rainfall is 270 cm, average annual snowfall is about 168 cm, and average annual high and low temperatures are 8.9°C and 3.6°C, respectively. The island does not have permanent residents but supported Alutiiq people from over 7,500 years ago until Russian occupation in the late 1700s. The village of Old Harbor (215 residents) is immediately across Sitkalidak Strait and villagers regularly visit the island to collect subsistence resources. Sitkalidak Island has deep fjords and steep mountains that are covered with grasses and alder (Alnus spp.). Several streams provide spawning habitat for Pacific salmon. The island also supports a population of black-tailed deer. A cattle ranch was present from the 1900s through the early 1980s, and bears were frequently killed to protect livestock, causing an apparent population decline. Population size of brown bears on Sitkalidak Island is unknown. Old Harbor Native Corporation owns Sitkalidak Island and public access is granted by purchasing a land use permit in Old Harbor. Bear hunting is by permit only.
