Biological Projects

One of the establishing purposes of the Nowitna Refuge is to "conserve fish and wildlife populations and their habitats in their natural diversity." To fulfill this mission, refuge biologists need to understand what wildlife species and habitats are found on the refuge (Inventory), how wildlife populations and habitats change through time (Monitoring), and the interaction between those resources and human activities (Management). Click on the links below to learn more about these programs:

Passerines
Passerine monitoring programs at the Koyukuk/Nowitna Refuge Complex are conducted according to statewide and national protocols so that locally collected data can contribute to large-scale efforts to conserve and protect sensitive species. Statewide efforts are coordinated by Boreal Partners in Flight.

Christmas Bird Count: The Audubon Christmas Bird Count (CBC) has provided the longest-term, most extensive and geographically comprehensive ornithological data set in America. A CBC has been conducted in Galena every year since 1982.

North American Migration Count: This national program was initiated in 1992 to provide an annual “snapshot” of spring migration. The count has been conducted in Galena most years.

Monitoring Avian Productivity and Survivorship (MAPS): The MAPS program was established in 1989 by the Institute of Bird Populations to provide long-term demographic data on landbird species throughout North America. The program uses standardized constant-effort mist netting to obtain indices of adult population size, post-fledging productivity, recruitment, and adult survivorship. A MAPS station was established near Galena in 1995, consisting of 10 net sites. The station was operated according to standard protocol for five consecutive summers. Data collected at Galena is being used in an effort to determine the effectiveness and long-term value of the MAPS program in Alaska.

Breeding Bird Survey (BBS): The BBS is a cooperative, continent-wide effort designed to gather and analyze information on breeding bird populations in North America north of Mexico. Surveys provide indices of species abundance based on annual point counts. The refuge complex conducts two complete routes and one half-route annually. The Galena BBS (half-route) incorporates most of Galena's limited road system, and has been run since 1985. The Nikolai Slough BBS is a river-route, surveyed by boat on the Yukon River and a tributary since 1986. The Ruby BBS uses the Ruby-Poorman road which lies approximately 10 miles west of the Nowitna NWR. This route has been conducted since 1994.

Moose

Moose are the largest herbivores in the refuge complex, and play a key role in the boreal forest ecosystem. They are also one of the most important subsistence resources to local residents, as well as popular for sport harvest. These factors make the species a primary focus of wildlife management at the complex. Standardized aerial-survey protocol is used to provide annual indices of moose abundance and population composition. Through aerial data collection, refuge biologists obtain annual trend information on moose, including the relative abundance of cows, bulls, yearlings and calves.

The Service works in cooperation with Alaska Department of Fish and Game (ADF&G) to conduct annual fall surveys of moose in established Trend Count Areas (TCAs). Aerial surveys of the moose TCA's emphasize consistent application of methods and standardized survey areas that are aimed at sampling identical units with minimal variation in conditions to maximize comparability between years. (Survey methods follow the protocols of Gasaway and VerHoef.) These surveys, which focus intensively on the more popular hunting areas, are not able to produce estimates of overall population. The trend information that is collected is, however, vital to making management decisions, including hunting regulations, to ensure that the moose population will remain at healthy levels.

Waterfowl

Wetlands within the refuge complex support large waterfowl populations. The most common breeding duck species include American wigeon, northern pintail, mallard, green-winged teal, northern shoveler, surf scoter, white-winged scoter, common and Barrow's goldeneye, bufflehead, and lesser scaup. Canada geese, white-fronted geese, trumpeter swans, and tundra swans are found on the refuge in moderate numbers. The greatest concentrations of waterfowl occur during spring and fall migrations on large, shallow floodplain waterbodies.

The complex's inventory and monitoring programs for waterfowl include:

Documenting spring weather conditions and waterfowl migration chronology
Duck production surveys (conducted from 1983-1993)
Aerial breeding pair surveys
Duck and goose banding
Aerial molting white-fronted goose surveys
Goose production surveys (conducted by boat on selected rivers and sloughs)

In the last decade, abundance of greater white-fronted geese that nest in the boreal forests and ecotonal areas of western Interior Alaska has declined relative to the tundra nesting populations of the Alaskan and Canadian arctic. Several studies have been initiated to determine why abundance and survival rates differ markedly in these population segments. These projects include radio- and satellite-telemetry to determine migration routes, and collar re-sighting to determine stopover lengths during migration in Canada.

Wolves

Wolf abundance is a main concern of wildlife and land managers in Alaska because of the role wolves play in ungulate population dynamics, and their listing as an endangered species in the continental US and Europe. Few wildlife management issues have generated as much controversy as that of wolf management in Alaska. Wolves are a major predator of moose on the Northern Innoko NWR and Nowitna NWR, and of both moose and caribou on the Koykuk NWR. Because moose and caribou are important game species sought by subsistence and sport hunters, hunters and wolves must share the ungulate resource. Wolf abundance data is an important element in scientific management of moose and caribou. We must understant wolf population trends if those ungulate species are to be maintained at healthy and huntable levels.

Annual wolf surveys at the refuge complex use the Sub-Unit Probability Estimator (SUPE) to estimate abundance based on probability sampling of snow tracks occurring in a network of plots surveyed by aircraft. The survey is conducted in late-February and March when good snow cover and light conditions provide suitable tracking conditions. Because of time and funding constraints, units of the Complex are surveyed on a rotating basis, with each refuge surveyed every 2-3 years.

Small Mammals

Rodents (voles) and insectivores (shrews) are abundant throughout interior Alaska and the refuge complex. Most are important sources of food for many predators such as birds of prey, mustelids, and wolves. The distribution and abundance of some predators (e.g. marten and hawk owls) is likely related to the seasonal abundance of rodents. Past research on small mammals on the refuge complex includes 8 years of monitoring as part of a fire/furbearer study, and a 3- year investigation of yellow-cheeked vole populations in burns. Below is an abstract of results from the latter study, which appears in:

Lehmkuhl, K.L. 2000. Microhabitat selection by yellow-cheeked voles (Microtus xanthognathus) in post-fire seres of interior Alaska. Master's thesis, University of Alaska Fairbanks, Fairbanks, AK.

Yellow-cheeked voles occupy early successional habitats in boreal regions, but specific factors influencing the species’ distribution and population dynamics are not well known. Yellow-cheeked voles were studied in three early post-fire habitats in interior Alaska to relate population parameters to habitat characteristics. Voles were live-trapped during June, July, and August of 1997 and 1998, and habitat components were measured within trapping grids. Capture data were analyzed using the robust design to estimate vole abundance, density, survival, and recruitment. Yellow-cheeked voles were most abundant in the floodplain white spruce, where survival was stable and recruitment was high. The white spruce habitat had the greatest cover of preferred forage species, while grasses, large diameter logs and snags provided escape cover. Observed differences in habitat quality may be related to unique successional processes in black and white spruce communities.

Wood Frogs

Recent nationwide concern over high malformation rates occurring in amphibians throughout their range led to the initiation of frog malformation surveys on National Wildlife Refuges in 2000. Amphibians are believed to be an important indicator species due to their complex life cycles and porous skin.

In 2001, a pilot study was begun to monitor wood frogs for malformations at three sites near Galena. The ponds were monitored for egg masses beginning in May, with follow-up monitoring of tadpole development in June and July. Upon returning to one of the ponds in July, biologists found only dead or sickly tadpoles. Several tadpoles were sent to a Wildlife Disease Specialist at the USGS National Wildlife Healthe Center in Madison, WI. A virus of the genus Ranavirus was isolated from one of the tadpoles, suggesting this virus had caused the die-off. This discovery was startling, as it was previously theorized that ranaviruses that kill one species of amphibian are carried by adult amphibians of another species, but there is only one amphibian present in the study area.

Wood frog monitoring was expanded in 2002 to include lakes on the Northern Unit of the Innoko NWR (Kaiyuh). Monitoring is expected to continue through 2006, with the primary focus on lakes in the Kaiyuh.

Last updated: July 22, 2008