Geological Survey

In FY 94 the Fish and Wildlife Service and the National Park Service Arctic research programs were transferred to the National Biological Survey (later National Biological Service) (NBS), a new bureau constituted by combining the biological research functions of a number of Department of the Interior (DOI) bureaus. As a result of the FY 97 Appropriations Act, the NBS was transferred to the U.S. Geological Survey and became the Biological Resources Division (BRD).

The BRD conducts research in the Arctic to generate information that will help DOI agencies in Alaska meet their resource management responsibilities. These responsibilities include the conservation of migratory birds, certain marine mammals, endangered species, anadromous fishes and all biota inhabiting National Wildlife Refuges and National Parks and Preserves. Research addresses the effects of development, disturbance, hunter harvest and natural environmental cycles on fish and wildlife populations. Other research seeks to develop improved census and survey methods that will better detect trends in populations. All research has the ultimate goal of providing information that will lead to better management decisions and actions to promote conservation of living resources in the vast ecosystems of the Arctic. Fish and wildlife populations in the U.S. Arctic are extensively shared with Canada and Russia, and a portion of the research effort is directed toward treaty and other international requirements to jointly manage shared resources.

Bull caribou in fall looking out on its winter range, northern edge of Denali National Park and Preserve, Alaska.

Most Arctic research of the BRD is conducted from the Alaska Biological Science Center (ABSC), Anchorage, and the Cooperative Research Unit at the University of Alaska Fairbanks. Some additional research is performed by others of the 15 national research centers or the more than 50 cooperative research units, each of which has special capabilities that may be applicable to problems in Arctic research.

Ecological research in Arctic ecosystems is difficult, given the harsh conditions, frequently inaccessible habitats and often wide-ranging movements of Arctic biota. It is also very costly. Since it has often been necessary to develop new methods of obtaining information, some of the most advanced technologies have been developed for, or first applied to, research in the Arctic. Satellite-linked biotelemetry and molecular genetics are but two of many new techniques that have been successfully applied to the problems of fish and wildlife conservation in the Arctic.

Wildlife Ecology

Research on the unmanipulated wolf/prey community of Denali National Park and Preserve (DNPP) has continued unabated since 1986. BRD scientists, in cooperation with the National Park Service (NPS), are currently studying the population dynamics and predator/prey relationships of gray wolves and caribou and are planning in FY 98 to launch new research on moose, the other major prey of wolves in DNPP. To date, the studies have provided new information on the population dynamics, predation behavior, social structure and genetic relationships of wolves; the population dynamics, reproductive performance and calf survival patterns for caribou; and the influences of weather and landscape use patterns on wolf/ caribou relationships. During these studies, wolf density increased from below 4.0 wolves/1000 km² during 1986-87 to 7.8 wolves/1000 km² by 1990, with the onset of a six-year period of above-average snowfall. Caribou numbers increased from 1986 to 1989, reaching about 3200, then declined precipitously to around 2000 animals by 1993 as a result of high losses of calves to predation (primarily wolves and grizzly bears) following the severe winters and increased mortality of adults during the severe winters. Since 1993, wolf numbers have declined to about 5.5 wolves/1000 km² with the decline in caribou and a return to near-average snowfall, while the caribou numbers have stabilized at 2000. Although biologists only conducted moose censuses every five years during this period, it appears that moose numbers have stayed relatively stable.

Denali National Park and Preserve also supports a naturally regulated grizzly bear population that has not been subject to harvest for at least 80 years. Grizzly bears are an important visitor attraction in DNPP, and the impact on bears from efforts to improve visitor access to the park is a primary concern. NPS managers suspect that current human access alters grizzly bear distribution within some portions of the park. Public pressure for more access into Denali along current routes is constant, and alternative access points are proposed on both the north and south sides of the park. Continued human developments adjacent to the eastern boundary of the park are fragmenting bear habitat. Sport harvest of grizzly bears east of the park has been very intensive in the past, and reduction in bear density is the objective of the current harvest program in the State of Alaska's Game Management Unit 13, southeast of the park. There is concern that intensive harvest and habitat fragmentation may eventually alter natural gene flow. Grizzly bears are specifically mentioned in the park's enabling legislation, and protection of the grizzly bear population is an important concern of park administrators. This combination of threats and responsibilities resulted in the need to:

• Understand grizzly bear population ecology and identify intrinsic and extrinsic factors that drive bear population dynamics, especially those that could be altered by human activities;
• Identify the natural variation in population parameters to assist in identifying human-caused perturbations; and
• Develop cost-effective, non-invasive methods to monitor the grizzly bear population.

Beginning in 1991, NPS and BRD biologists chemically immobilized grizzly bears from a helicopter and placed radio collars on 28 female and 30 male bears, not including dependent young. The female age distribution was bimodal, with no females between the ages of 9 and 16. Annual survival rates of independent bears were highabove 95% for both males and females. The average litter size of newborn cubs was high (2.2 cubs), and the average age of young at the time of family break-up was typical for Alaska grizzlies (3.0 years). The average annual survival rate of dependent newborn cubs and yearlings was unusually low, however, and is the subject of ongoing research. Naturally regulated grizzly bear populations may be characterized by high but variable dependent bear mortality, periodic recruitment and a dynamic female age structure, at least in sub-Arctic environments such as interior Alaska.

Berry availability and quality may be factors driving grizzly bear population dynamics on the north flank of the Alaska Range. Fall nutritional status affects both female bear fecundity and cub survival. In this area, fall nutritional status is largely dependent on berry availability. The primary berry sources in the study area are blueberry, crowberry and soapberry. The objectives of this study are to determine the distribution patterns for these plants, measure the interannual variation in berry crops, and determine the nitrogen content and relative importance of plant nitrogen fixation to bear diet. This study is part of a larger ABSC grizzly bear ecosystem research project in DNPP. Biologists are using the data to evaluate the relationship between berry availability and bear population dynamics. The primary study area covers 1750 km² in the western part of the park on the north flank of the Alaska Range. BRD biologists used aerial surveys of the study area, ground checks and data on bear movements and foraging from radio-collared bears to assess the distribution patterns of soapberry, blueberry and crowberry plants and to select areas for monitoring berry crops. They specifically looked at the distribution of soapberry plants in relation to moraines and outwash of known age of the Muldrow and Foraker Glaciers. They established 29 permanent transects to measure soapberry, blueberry and crowberry crops. Soapberries, blueberries and crowberries were collected near the transects and divided into a whole berry sample and a seed sample. These samples were analyzed for total nitrogen and stable nitrogen isotope ratios. The study area contains extensive stands of soapberry plants on neoglacial moraines of the major glaciers and smaller stands on glacial outwash. Blueberry and crowberry plants are abundant throughout the study area and include patches with up to 1000 m² of continuous blueberry cover. The soapberry crop was consistently good in 1994-1997. Berry counts on transects showed considerable variation among bushes, but individual bushes had similar crops each year. Overall observations of the blueberry and crowberry crops and counts along transects in 1994-1997 showed small productive patches within a matrix of unproductive bushes. The blueberry crop was 50% higher in 1995 than in 1994; the crop was poor in 1996, followed by a large crop in 1997. Crowberries were virtually absent throughout the study area in 1994 but had good crops in 1995-1997. Soapberries may be important to bear fall nutritional status in this area. In 1994 both soapberries and blueberries were available in the study area, but grizzly bears fed primarily on soapberries from late July until snowfall. Soap berries in this area offer efficient foraging and a relatively high protein content. The large soapberry stands occupy a unique place in space and time in the study area ecosystem. They occur on relatively recent glacial moraines, where they are the primary nitrogen fixers. This successional pattern differs from many other areas of Alaska, where alders or Dryas sp. are the primary nitrogen fixers.

BRD biologists investigated the effect of vehicle traffic on the Denali Road in DNPP on Dall sheep seasonal migration during 1995-1997. Several sections of the park road intersect sheep migration corridors between the Alaska Range and the Outer Range. Sheep leave typical escape terrain and travel up to 10 km through valley shrub habitat and conifer forest to reach these seasonal ranges. Occasionally road traffic has interrupted the sheep's attempts to cross the road. This study was conducted to determine the timing of migration; the number, sex and age class of migrating sheep; sheep and vehicle driver behavior at road crossings; and whether thwarted attempts to cross the road occur often enough to alter or jeopardize migration patterns. Aerial surveys were conducted to determine sheep abundance before, during and after spring migration. Biologists documented migration attempts through daily observation of staging areas and known migration trails and recorded detailed information on sheep-vehicle interactions at the road. To supplement direct observations, they used infrared-triggered cameras and time-lapse cameras to photograph sheep traveling on trails through migration corridors. Spring migration attempts were observed as early as 12 May 1996 and as late as 7 July 1997. Group size ranged from 1 to 62 individuals. Generally, group composition was either ewes with younger animals or rams, although occasionally adult rams traveled with ewe groups. Sheep that migrated prior to mid-June were ewe groups of 1-4 individuals or rams. Larger ewe groups with lambs initiated migration during the third week of June. Overall, spring migrations occurred at various times of the day, with sheep approaching the road between 0400 and 2000 hours. Unsuccessful migration attempts, in which sheep retreated from the road and returned to their winter range, were observed each spring. In most cases these sheep were successful in later attempts to cross the road. Observed fall migration attempts occurred between 23 August and mid-October. Group size ranged from 1 to 32 individuals. Ewe and ram groups migrated separately. Sheep approached the road at various times of the day between 0800 and 2100 hours. Although there were no thwarted attempts to cross the road during fall migration, ram groups were delayed by the road for up to 7.5 hours due to traffic.

For the 10th consecutive year the NPS, in cooperation with the BRD Forest and Rangeland Ecosystem Science Center (FRESC), Corvallis, Oregon, collected data on the reproductive characteristics of golden eagles in DNPP in 1997. Using two aerial surveys, biologists monitored 72 golden eagle nesting areas in the northeastern portion of DNPP. Territorial pairs occupied 63 nesting areas, resulting in an occupancy rate of 88%. Laying rate was 71%, with 45 territorial pairs producing eggs. Nesting success, measured as the number of laying pairs raising one fledgling, was 73%. Thirty-six successful pairs raised 57 fledglings. The overall population production, measured as the number of fledglings per territorial pair, was 0.90. This was the second highest year for golden eagle productivity in the study area in 10 years. Since 1988 the overall annual reproductive output of golden eagles in DNPP was influenced most strongly by the proportion of pairs that lay eggs. Laying rates for golden eagles in DNPP are highly correlated with numbers of snowshoe hare and willow ptarmigan observed on the study area.

In 1997 the FRESC and NPS biologists began to examine the behavior and movements of juvenile and subadult golden eagles from natal areas in DNPP. Using satellite radiotelemetry they are collecting data on eagle movements during post-fledgling periods, migration, winter and subsequent summers. In late July and early August 1997 (after nestlings were more than 60 days of age) they deployed 22 satellite radio transmitters (PTTs) on juvenile golden eagles. PTTs were deployed on 12 females and 9 males at 14 nests (14 siblings, 7 singles). PTTs were attached to juvenile eagles using a backpack harness constructed of Teflon ribbon. The entire package weighed about 102 grams (less than 3% of the total body weight of the eagles). The duty cycle for all PTTs is 8 hours on and 72 hours off; PTT life is estimated at 3 years. They are using the Service Argos Data Collection and Location System to obtain locations of the radio-tagged eagles. The ABSC is assisting with data collection.

An integrated watershed approach to long-term ecological monitoring has been under development at DNPP since 1992. The DNPP monitoring program is being developed as a prototype for other parks in the sub-Arctic. Because of minimal information on variability and interactions among sub-Arctic biota and different environment variables, a multidisciplinary sampling approach has been used. Early efforts have been concentrated in and around a single watershedRock Creek, a readily accessible headwater stream near park headquarters. Pilot studies have tested techniques and documented variability for methods in air quality, weather, stream water chemistry, hydrology, soils, vegetation, stream invertebrates, and bird and small-mammal populations. These individual efforts have provided significant insight into what might be effective approaches to monitoring within single watersheds.

Current research is focused on integrating watershed findings and scaling to additional watersheds. Additional approaches to monitoring key biological and environmental changes at various levels of scale from the watershed to the full six-million-acre park and beyond are also being investigated. In addition, stronger links between the long-term environmental monitoring program and tactical short-term management needs are being forged.

A coastal brown bear study in Katmai National Park and Preserve (KNPP) was recently completed after seven years of field work. The project was a cooperative effort of the Alaska Department of Fish and Game, the NPS and the BRD. Research objectives included an estimate of the bears' reproductive histories and population dynamics, their movements and distributions, and habitat relationships. Preliminary data analyses have identified significant differences in the population dynamics of this population of unhunted bears compared to nearby hunted areas, where at KNPP there are more adult males to females, adults have a higher mean age, cubs experience a lower survival rate and females are less productive (litter size). Additionally, biologists have found KNPP bear densities to be the highest ever reported (550/1000 km²), and although home ranges for some KNPP female brown bears are the smallest ever reported (less than 10 km²), some of KNPP's female bears traveled less than 240 km annually to and from summer ranges. KNPP brown bears exploit a wide range of food resources, including mussels, clams and a host of invertebrates exposed only at low tides. Biologists also conducted studies that focused on bear-habitat relationships. Preliminary findings support the notion that bear habitat quality is chiefly a function of nutrient resource availability and that nutrient resource maps may prove acceptable indicators of bear habitat suitability. Additional work at KNPP has focused on bear-human interactions at various backcountry locations. Findings have shown that although human activity may highly influence bears' patterns of use, bears are able to adequately access salmon resources. Work is ongoing to map vegetation communities, salmon resource availability, and other nutritional resources so that managers can better understand bear-habitat relationships.

Research conducted on the Arctic coastal plain of the Arctic National Wildlife Refuge (ANWR) in northeastern Alaska addressed the potential impacts of petroleum development on the ecology of this unique wilderness environment. Biologists designed research at the landscape level to encompass the 2.5-million-acre coastal plain of ANWR. The Porcupine Caribou Herd uses this area as its primary calving ground. Snow geese breeding on Banks Island stage in this area in the fall. Polar bears den on the area's Beaufort Sea shoreline. The area hosts a resident population of muskox. The research incorporated the relationships of these fauna to the habitat of the coastal plain. Using remote sensing, biologists developed a vegetation map of the coastal plain from Landsat thematic mapper and ground survey checks. This map, which has 16 land cover types, has been the basis for assessing habitat use and value. Additionally, remotely sensed data on vegetation growth rates from the normalized difference vegetation index (NDVI) derived from the advanced very high resolution radiometer (AVHRR) on polar-orbiting satellites provide the opportunity to assess the habitat conditions of the coastal plain for caribou and other species during the non-winter period. These data allow biologists and managers to link growing-season vegetation changes with caribou habitat selection. With the growing concern over global climate change, these landscape-level relationships could provide the basis for monitoring changes that may be occurring. Preliminary analysis of NDVI and caribou calf survival shows a marked relationship (85%) between onset and rate of spring growth and neonatal mortality. Additional analyses and continued research will be necessary to determine the causal relationship inferred and to predict the impacts of vegetation changes engendered by global warming.

Fisheries Research
Fisheries biologists from the ABSC are conducting a detailed study of the ecology and survival of chum salmon in Yukon River tributaries in Alaska. This research was initiated in 1996 in response to an information need of Federal and state land managers for a better understanding of the factors controlling chum salmon production. Some runs in the Yukon River watershed have diminished to the point where important commercial and subsistence fisheries have been limited in recent years. The primary hypothesis being tested is that, in general, the severity of winter weather determines the number of chum salmon smolts moving downstream each spring. To evaluate the hypothesis, biologists are intensively studying sections of selected Yukon River tributary streams to assess the number of adults entering the sections, the density of healthy eggs and fry incubating within the sections, and the number of fry emigrating from the sections. Estimates of stage-to-stage survival will be made from these observations. The survival estimates can then be correlated with environmental variables (for example, temperature, snowfall, ground ice and extent of upwelling subsurface water) to examine to what extent the environment determines freshwater production of chum salmon. Research will continue through 2000 so that annual variation can be assessed. The results should improve the capabilities of Federal and state fisheries biologists in predicting run sizes, allowable harvests and optimal spawner escapements.

Migratory Birds
The black brant is a sea goose that depends on coastal habitats from high Arctic nesting sites in Canada, Alaska and Russia to primary wintering areas in the Pacific coastal states, the Baja California peninsula and mainland Mexico estuaries. Concern about the species stems from a long-term downward trend in winter populations and the degradation and loss of important staging and winter estuarine habitats from commercial and recreational development and disturbance. Other factors that may be limiting population recovery include harvest and predation at nesting colonies in Alaska.

The ABSC, in cooperation with the FWS, the Canadian Wildlife Service, Nature Reserves (Russia), the Bureau of Land Management, and the University of Alaska Fairbanks, has been working on various aspects of the life history of black brant for over a decade. More recently the Japanese Association for Wild Geese Protection (a private conservation organization), Ducks Unlimited Inc., and Ducks Unlimited (Mexico) have joined this international effort to understand the population dynamics of black brant. Several studies were recently completed, including an assessment of the demographic characteristics of molting brant on Alaska's North Slope, and seasonal and annual survival of adult brant.

Brant that lose their clutches or do not nest undertake a molt migration, usually in late June, to secluded areas in the high Arctic. They congregate in large numbers on molting areas for a month or more until new flight feathers are grown. Important molting areas have been discovered on Alaska's North Slope near Teshekpuk Lake and Wrangel Island, Russia. These areas, dominated by large freshwater lakes and ocean estuaries, provide essential habitat for tens of thousands of brant from many nesting colonies during the annual wing molt. A six-year capture-mark-recapture study of brant that molt in the Teshekpuk Lake area revealed that brant originated from ten nesting colonies in Canada and Alaska. The captured birds were 76% adults and 57% males. Ninety-one percent of known-age recaptures were less than six years old. Fewer one-year-olds and more two-year-olds were present than expected. Sixty-one percent of adult females were failed breeders. Brant that were captured in more than one year showed high site fidelity to lakes where they were originally banded, a behavior that may have evolved if survival is enhanced because of few predators, low human disturbance and abundant food and cover. These criteria are met in the Teshekpuk Lake area, where few predators of brant exist, anthropogenic disturbances are limited, extensive grass-sedge foraging sites providing nutrient-rich foods are abundant, and escape cover is extensive. The Teshekpuk Lake brant molting area is within a larger block of land in the National Petroleum Reserve-Alaska that is under consideration for petroleum leasing.

An eight-year study of seasonal and annual survival of adult brant was based on resightings of leg-banded birds at nesting colonies in western Alaska; at major spring and fall staging habitats on the Alaska Peninsula, the Strait of Georgia in British Columbia, and Humboldt Bay, California; and wintering areas in Baja California. Seasonal survival was the same for males and females. The mean monthly survival rate was lowest in late spring migration (mid-April to early June)the period of greatest subsistence harvest on the breeding grounds in Alaskaand highest in winter (early January to early March)the period of greatest sport harvest. The annual survival rate did not vary among years, averaging 0.840 from 1986 to 1993. Biologists concluded that subsistence harvest likely is the most important factor controlling the size of the population, and reductions in the harvest on the Yukon-Kuskokwim Delta, Alaska, would result in an increased number of breeders and geese in the population.

Brant demographic and survival studies were made possible because more than 40,000 birds have been marked with alphanumeric-coded plastic leg bands. Incidental to these studies was the discovery of a previously unknown wintering area for Alaska birds. Colleagues working on Hokkaido and Honshu Islands in Japan observed three brant with leg bands that had been affixed to hatching-year birds from a nesting ecology study on the Yukon-Kuskokwim Delta in western Alaska. In addition, an after-hatching-year bird from the Prudhoe Bay area of Alaska was discovered among flocks on Kokkaido Island. Biologists examined weather patterns and speculate that these brant take a westward transoceanic flight route from their primary fall staging area at Izembek Lagoon, Alaska, to the islands of Japan, where they mix with wintering birds from high-Arctic Russia.

Satellite telemetry has proven to be an effective tool in tracking long-distance migrants during annual flights from nesting to wintering areas. The ABSC has pioneered the use of this technique to better understand migration timing, migration routes and corridors, staging habitat locations and migrant survival. Tundra swans nest in western Alaska (on the Alaska Peninsula, the Yukon-Kuskokwim delta and the Seward Peninsula) and across the Arctic Coastal Plain from Barrow east through the Canadian high Arctic. Even though the swans are conspicuous, biologists and managers have a poor understanding of tundra swan migration pathways. The movements of satellite-marked tundra swans were tracked during autumn and spring migration between the outer Yukon-Kuskokwim delta and wintering areas in California. Marked swans migrated eastward across the delta during early October. After crossing the Alaska Range, swans stopped briefly on the Susitna Flats of Upper Cook Inlet. They then migrated eastward into the Yukon, Canada, and from there flew southward, paralleling the Wrangell Mountains through the interior of the Yukon to a staging area in northeastern British Columbia. They gradually migrated through central Alberta and southwest Saskatchewan and across Montana to a staging area in southeastern Idaho. Swans remained in Idaho from mid-November until early December, when they migrated across Nevada to the Sacramento-San Joaquin delta of California. Spring migration routes were similar to those used in autumn.

The Colville Research Station, a effort between the FRESC and the FWS, has operated as a remote field camp on the Colville River delta in northern Alaska since 1987. Its primary mission is to provide scientific information needed in the conservation and management of Arctic-breeding birds and the ecosystems on which they depend. The Colville River delta provides some of the best habitat for breeding waterbirds (tundra swans, geese and loons), breeding shorebirds and fall-staging shorebirds in northern Alaska. FRESC biologists have completed studies on tundra swan productivity, habitat use and parental care; mating strategies of the rock ptarmigan; spectacled eider productivity and habitat use; and the use of wetlands by grazing waterfowl. Ongoing studies include developing monitoring protocols for nesting shorebirds and Lapland longspurs; comparative demography and breeding ecology of red-throated, Pacific and yellow-billed loons; and the breeding ecology, survival and dispersal of shorebirds. FRESC biologists are working with the FWS and the Conservation of Arctic Flora and Fauna (CAFF) program to initiate Alaska- and world-wide monitoring of tundra-breeding birds and the tundra ecosystem.

Marine Mammals
The FWS has trust responsibility for managing three species of marine mammals: polar bears, Pacific walruses and sea otters. Polar bears and Pacific walruses are apical carnivores in Arctic regions. The BRD has responsibility for conducting research to satisfy FWS information needs for these two species. The U.S. shares both species with Russia, and polar bears are also shared with Canada. The international nature of the populations requires the U.S. to coordinate research programs with both Russia and Canada. The focus of current research relates to international actions necessary to conserve shared populations. Both species are subject to legal harvests by Alaska Natives, and research seeks to develop methods for defining and monitoring populations to establish sustainable population goals. Resource development in the Arctic habitats and their potential impacts on populations of polar bears and Pacific walruses are also topics of research interest.

The research program on Pacific walruses is focused on the trophic ecology and use of terrestrial haulouts of Pacific walruses in Bristol Bay. The development of an international Pacific walrus database, which includes data from Russian and American scientists concerning census, harvest and habitats, is nearing completion. Drugging protocols have been refined, and effective immobilization agents have been found for Pacific walruses. The use of isoflurane gas for extending the effective marking period was partially successful, but the unreliability of currently available intubation procedures for walruses limits the utility of the gas. Attachment procedures for satellite tags have been improved, and units were deployed on 30 adult male walruses in Bristol Bay during the summers of 1996 and 1997. Telemetry data indicate movements between all primary land-based haulouts in Bristol Bay, with some evidence of haulout fidelity between years. The movement data also indicate that walruses are traveling between land-based haulouts to particular regions of the southern Bering Sea, presumably for feeding purposes. Time-depth recorders were deployed on five walruses during the summer of 1997, and the units were recovered by recapturing the animals six weeks later. These units collected detailed dive profile data for the five individuals. Data analysis is underway.

USGS Alaska Biological Science Center researcher weighing a polar bear cub near Prudhoe Bay, Alaska, in April. Heavy cubs are significantly more likely than lighter cubs to survive the first few months in the rigors of the Arctic environment, and heavy cubs usually are born to heavier females.

BRD biologists have completed satellite telemetry studies of movement patterns of adult female polar bears, and data analyses are underway. The movements of adult females marked in the Chukchi population are extensive, and annual ranges often exceed 400,000 km². Maternity denning occurs primarily in Russian territory, with the majority on Wrangel and Herald Islands. Survey methodologies for aerial censuses of polar bears in western Alaska have been developed, but budget limitations and the continuing economic crisis in Russia have delayed implementation of this survey. The aerial surveys used by Russian scientists on Wrangel and Herald Islands have been revised based on a joint U.S.-Russia workshop. The revised methodologies were tested on Wrangel Island during the spring of 1998 by a U.S.-Russia team of scientists. Present movement data for polar bears are limited to adult females. A pilot study to determine if subcutaneously implanted satellite transmitters could be used to monitor the movements of adult male polar bears was initiated in the spring of 1996. Detailed movement data have been collected for seven adult males during the spring and summer months. Preliminary data analyses indicate that adult males have a tendency to be more sedentary that adult females during the same period. Technical difficulties caused the satellite transmitters to fail before animals could be recaptured the following spring, and the effort during the spring of 1998 focused on resolving this problem.

Continued analysis of movement data generated by satellite radio-collared female polar bears suggests that polar bear populations in the Beaufort and Chukchi Seas are largely discrete. Some Beaufort Sea polar bears did temporarily leave their "home areas," however, and were most likely to do so during late winter and spring. Because polar bears breed in the spring, biologists hypothesized that bear populations of the Chukchi and Beaufort Seas, which appear from movement data to be discrete, may not be discrete genetically. New molecular genetics data support that hypothesis. Based on eight microsatellite loci in tissue extracted from approximately 300 polar bears, there appear to be no significant genetic differences between Beaufort and Chukchi Sea bears. Hence, there is a contrast between radiotelemetry data suggesting a high degree of fidelity and molecular genetics data suggesting no differences. Also, this pattern appears to contrast with that in the Canadian high Arctic, where polar bear populations living closer together than do the bears of the Beaufort and Chukchi Seas had relatively distinct genetic patterns.

BRD research has shown that the patterns of maternal denning in Alaska tend to reduce the vulnerability of denning bears to human disruptions. Nonetheless, conflicts with denning polar bears remain a concern because bears in dens are more vulnerable to disturbance than at any other time in their life cycle and because both denning on land and the extent of human activities are increasing. Hence, ongoing research seeks to characterize denning habitats and test whether state-of-the-art thermal detection devices can allow dens to be located before human activities occur. If preferred habitats predictably can be mapped, and if denned bears can be detected with the aid of infrared scanners, biologists and managers will have a management tool that will eliminate conflicts between human activities and denned bears.

The concentration of polar bears in the central Beaufort Sea region in late summer and autumn and the larger population that exists now has the potential to increase interactions between humans and polar bears at times other than denning. For example, in 1997, 50 polar bears were trapped on the beach when the sea ice suddenly retreated north in August. The central Beaufort Sea is the home of the most productive oilfields in North America, and several stranded bears ended up hanging around oilfield facilities, where they posed a constant threat to the safety of oilfield workers. As oil exploration and development and other human activities expand to the east and west of present development centers, biologists expect conflicts between polar bears and humans to be more frequent. Similarly, 20-30 of those trapped bears spent the late summer and fall near the coastal village of Kaktovik, where they became accustomed to feeding on the scraps left by subsistence whaling activities and they learned that humans need not be feared.

To properly manage human-bear interactions, we must have better knowledge of polar bear foraging strategies and the ecological importance of near-shore habitats. In response to that need, the ABSC plans to initiate research to answer questions such as: When and why can polar bears be expected to concentrate in near-shore areas where their opportunity to conflict with humans is greatest? What limiting factors at sea may be encouraging larger numbers of bears to remain on land for longer periods than in the past? What is the importance of land-based foods such as beach-cast marine mammals and human waste relative to ringed seals, which are thought to be the main component of their diet? Answers to these and other questions will help assure that humans and polar bears can continue to coexist in Alaska's Arctic.

Cooperative Research

The Alaska Cooperative Fish and Wildlife Research Unit supports a wide variety of research in Arctic and sub-Arctic regions of Alaska, Canada and Eurasia. Aquatic studies are presently concentrated on the energetics of Dolly Varden char in Noatak National Park and Preserve (NPP); the water quality of lakes in Gates of the Arctic NPP and Katmai NPP and in Lake Becharof; and migration and habitat use of broad whitefish in the Prudhoe Bay watershed. Landscape-oriented projects are focused on environmental changes in the Kobuk Sand Dunes; the status of rare plants in the Bering Land Bridge region; habitat use and remote sensing of caribou in northern Alaska and the Yukon Territories; and vegetation response/nutrient cycling in relation to climate change in the Arctic. Studies of birds and mammals constitute the majority of Alaska Unit studies in the Arctic. These include the habitat of red-legged kittiwakes on St. George Island; the population ecology of black brant and lesser snow geese; habitat use of peregrine falcons in the upper Yukon River; sampling protocols for small mammals in Denali NPP; the biogeography of Arctic hares in northwest Alaska and eastern Russia; habitat mapping of muskoxen on the Alaskan North Slope; and the interaction of muskoxen and reindeer on the Seward Peninsula.

Additional research in Arctic regions of Alaska and Canada is being conducted by BRD scientists at Cooperative Fish and Wildlife Research Units in Minnesota, Wisconsin, New York, Missouri, Washington and Louisiana. Most of this work answers questions pertinent to the management of migratory waterfowl and wetlands habitats on breeding grounds in the Arctic, migratory flyways and wintering grounds to the south. All of these projects are tightly linked to program objectives of cooperators in several Canadian and U.S. government agencies, many state natural resource agencies, flyway councils and private organizations.

Mineral Resources Program

The regional geology and mineral resource potential of frontier areas, the geology of known mineralized terranes and the geoenvironmental behavior of mined and unmined mineral deposits and occurrences are major themes for research in Alaska as part of the Mineral Resources Program. In addition, compilation of geological, geochemical and geophysical databases into easily accessible and manipulatable digital formats is a major ongoing effort.

Tectonics and gold mineralization in south-central Alaska
Studies of the large expanse of oceanic rocks and associated plutons along the southern Alaska margin have led to the development of a new model for the generation of gold veins and have helped to resolve the tectonic history of the northern Pacific Ocean basin. Patterns of magnetic anomalies reflect the existence of three oceanic plates in the northern Pacific in early Tertiary time, separated by three spreading ridges. One of the ridges, between the Kula and Farallon plates, headed in the general direction of the North American margin, but exactly where it intersected the margin cannot be discerned from marine magnetic anomalies because all direct evidence has been subducted. The location of this triple junction is revealed, however, by a suite of Paleocene and Eocene near-trench plutons in southern Alaska. The near-trench magmatic pulse was diachronous, beginning around 63-65 Ma at Sanak Island in the west and progressing to about 50 Ma at Baranof Island to the east. Near-trench plutons are thought to have been generated as a result of subduction of the Kula-Farallon ridge below the southern Alaska margin. The triple junction evidently migrated along that margin some 2200 km in 13-15 million years. Near-trench plutonism was only one of several geologic effects of ridge subduction. In addition, the accretionary wedge was cut by numerous normal and strike-slip faults, some of which host gold-quartz veins. ⁴⁰Ar/³⁹Ar ages on sericite show that mineralization was coeval with near-trench magmatism and, by implication, due also to ridge subduction. Prior to this study, gold mineralization had been attributed only to a poorly defined metamorphic event. We can now relate mineralization to a very specific tectonic setting and use this as a new guideline for gold exploration in frontier areas around the world where ridge subduction may have occurred.

Frontier studies in the Kuskokwim mineral belt
The quality of regional geologic knowledge in Alaska lags far behind that in the conterminous U.S. Not only is the mineral resource potential of vast tracts in the state unknown, but the basic geologic data used to determine mineral potential, such as the age and thermal history of the bedrock, have not been collected. One of the most poorly understood parts of the state is the 190,000-km² Kuskokwim mineral belt, which stretches through southwest Alaska. The area is a frontier in two ways: the geologic framework is extremely poorly understood, and it contains a gold-bearing deposit type that is not well documented in Alaska or elsewhere. Coordinated geologic mapping, geochemical sampling and geophysical studies have refined regional geologic and metallogenic models for the belt. Regional geology is dominated by extensive sedimentary rocks intruded by late Cretaceous-early Tertiary igneous complexes. Precious-metal and related deposits are associated with the igneous complexes. Detailed mapping, analysis of structural features (faults and folds), analysis of features in sedimentary rocks, and preliminary isotopic results indicate that the igneous complexes, gold deposits and mercury deposits apparently all originated at about the same time in an intracontinental strike-slip basin system. The strike-slip basins formed over a protracted period of time behind the western Alaska Range segment of the circum-Pacific volcanic arc. Geologic studies are continuing, using this model as a guide, to identify the extent of the belt, a metallogenic model for the region, and an estimate of the region's mineral potential.

Environmental impacts of mercury and arsenic
An understanding of the geochemical behavior of arsenic and mercury surrounding developed mineral deposits and in geologic environments with naturally elevated levels of arsenic and mercury is of critical importance in predicting natural and anthropogenically induced environmental impacts and establishing scientifically sound mitigation efforts.

In the Fortymile Mining District in east-central Alaska, determining the natural levels of arsenic and other metals in the watershed versus the levels resulting from placer mining (dredge operations) is required to establish risk assessment protocols for discharge permitting by Federal and state agencies. Parts of the historic Fortymile Mining District are being evaluated by BLM for possible inclusion as part of the Nation's Wild and Scenic River System. Recreational visitor usage of Fortymile River and its tributaries has increased 40% since the mid-1970s, and there is concern about conflicting land use. Extensive areas of Fortymile River systems have been mined since 1886, and much of the area along the river system consists of currently patented mining claims. The area contains mineral deposits such as vein gold (plus silver, lead, copper, zinc and antimony), stratabound volcanogenic massive and/or disseminated sulfides, porphyry copper and others. During the preparation of a series of Environmental Impact Statements for the area (beginning in 1974), anomalously high levels of arsenic were found in soil, sediment and surface water. It is unknown, however, how arsenic is mobilized and whether its presence poses a threat to aquatic life, wildlife or humans. The initial research effort focused on water quality in the vicinity of active mining operations. Chemical and turbidity studies were undertaken to evaluate the impact of placer mining.

The water chemistry data collected in the vicinity of mining operations give values roughly equal to or lower than the regional average concentrations of dissolved metals, based on 25 samples. Turbidity values fall within the range of turbidity values found for currently mined areas of the Fortymile River system and its tributaries. The highest turbidity value was measured in an unmined stream. The preliminary study identified no appreciable difference in turbidity values between mined and unmined areas in the river system.

Further efforts in this study area will evaluate:

• The importance of water-rock interactions as a determining factor in water quality;
• The fate and transport of the elements of interest; and
• The flux and biogeochemical cycling of arsenic between terrestrial and aquatic environments.

Studies of environmental impacts of mercury in the southwest Alaska mineral belt were designed to document, in a sub-Arctic environment, the levels and distribution of the various mercury species and to identify the geochemical processes that control the distribution, speciation and transport of mercury at selected inactive mercury mines. Identification and discrimination of natural and anthropogenically induced impacts were focused on areas where the environmental impact of mercury is a concern to regulatory, planning and land managing agencies, to the local population, and to the village and regional Native corporations. Mercury levels in stream sediments, stream water and fish were measured. Stream sediments collected near mercury mines are elevated in mercury due to erosion and local transport of cinnabar, a mercury-bearing mineral. Stream sediments in unmined areas showed no significant mercury concentrations. Stream waters collected in the vicinity of mines yielded mercury values above background levels for the region but below the present State of Alaska and EPA-CPC drinking water and in-stream standards. Fish livers and muscle tissue from freshwater fish collected downstream from mercury mines contained elevated mercury, most of which was in the toxic form, methylmercury. However, mercury contents in the edible portions of the fish were below the 1.0-ppm limit established by the Food and Drug Administration (FDA). Mercury contents in muscle tissue of salmon, the primary fish consumed by humans in the area, were well below the FDA limit. The bioavailability of mercury in vegetation and the contribution of mercury from southwest Alaska to the global mercury cycle are areas of ongoing research.

Water Resources

The USGS hydrologic activities in Alaska are divided into three broad categories:

• Collection of hydrologic data;
• Hydrologic appraisals; and
• Basic and applied research in hydrologic topics unique to cold climates.

Hydrologic Data Collection
A wide range of climate directly influences the water resources of Alaska. Precipitation ranges from less than 10 in. per year (principally snow) in Arctic Alaska to 200-300 in. per year (principally rain) in southeast Alaska. Hydrologic data are required for planning and conducting hydrologic appraisals and hydrologic research. In 1997 collecting these data constituted the major part of the Division's efforts in Alaska.

Hydrologic Appraisals
Hydrologic appraisals include studies of water resources in areas that are likely to be or that are being affected by mineral or urban development, investigations of potential hydrologic hazards, and studies of ground- and surface-water contamination on Federal lands.

Alaska has about 36% of the entire Nation's average annual streamflow; if lakes and glaciers are included, Alaska has more than 40% of the entire Nation's surface water resources. Streamflow in southern Alaska alone is comparable to the mean annual streamflow of the Mississippi River. This streamflow does not enter the ocean in the form of one large river but by way of numerous smaller rivers and streams. Alaska has 7 of the 20 largest rivers in the U.S.: the Yukon, Kuskokwim, Copper, Stikine, Susitna, Tanana and Nushagak. Alaska has so many lakes they are essentially uncounted. Nearly 100 lakes are larger than 10 square miles in size. Iliamna Lake is Alaska's largest, with a surface area of about 1000 square miles. Springs throughout the state are found as innumerable small seeps and as warm or mineral waters that support recreational centers. On the North Slope, flows from large springs produce widespread icings in winter. In 1997 the USGS monitored about 85 surface water sites.

Snow covers most of the state for half to three-quarters of the year. Freezing and thawing of water affects virtually all of the state to some extent. Glaciers cover nearly 30,000 square miles in Alaskaabout 5% of the total area of the statebut produce approximately 35% of Alaska's runoff and 10% of the Nation's runoff. If all the glacial ice melted, it would take a river the size of the Yukon about 150-200 years to drain all the water. Glaciers play a key role in water storage, timing of peak flows and sediment transport.

Ground water is an undeveloped resource in most of Alaska; in many areas, potential development of the resource far exceeds current use. Groundwater conditions are diverse: major aquifers are present in the alluvium of large river valleys (Yukon, Tanana, Kuskokwim, Susitna), in glacial outwash deposits under coastal basins (Cook Inlet) and valleys (Seward and Juneau), and in carbonate bedrock of the Brooks Range. In other areas, however, the fine-grained material of glacial and glacial-lake deposits and the low permeability of consolidated rocks offer a much less promising ground water potential. In addition, the recharge, discharge, movement and thus the availability of groundwater over much of the interior, western and northern parts of the state and on the flanks of the Alaska Range are restricted by permafrost. In 1997 the USGS monitored approximately 50 groundwater sites.

The quality of Alaskan waters is generally acceptable for most uses. However, available data do indicate naturally occurring problems, such as suspended sediment in glacier-fed streams, salt-water intrusion and undesirable concentrations of iron or arsenic in ground water at various locations. Local pollution from septic tank leakage has occurred in several locations. In 1997 the USGS collected water quality data at approximately a dozen sites.

Hydrologic Projects
Hydrologic subjects being studied include the quantity and quality of surface and ground water; hydrologic instrumentation; and glacier, snow and ice dynamics.

The Kenai River in south-central Alaska is an economically important salmon river generating as much as $78 million annually in direct benefits. Resource management agencies are concerned that increased sedimentation and loss of streamside cover associated with accelerated erosion rates caused by boat activity may threaten salmon returns to the river. Bank loss and boat activity were characterized during 1996 along 67 miles of the Kenai River, including a segment of the river several miles long where boat activity is restricted to non-motorized uses. Dates of peak boat activity coincided closely with chinook salmon returns to the Kenai River and with peaks in measured bank erosion. The boat activity period began in late May, peaked on weekend days in mid-July, and declined in early August. Several types of bank protection measures were evaluated along the Kenai River for their ability to reduce or eliminate bank erosion. These include complex engineered systems of coconut-fiber biodegradable logs attached to the bank with live willow sprouts and covered with elevated walkways, simple series of spruce trees cut down and cabled to the bank, rock riprap piled against the bank, and vertical wooden retaining walls.