Most of the refuge is a vast,
flat wetland/tundra complex interspersed by countless ponds, lakes, and
meandering rivers. The refuge's most productive wildlife habitat is the coastal
region bordering the Bering Sea. This narrow strip of land is unquestionably
the most productive goose nesting habitat in North America. Refuge vegetation
is primarily subarctic tundra, underlain by permafrost, and includes a variety
of scrub, peatland, heath meadow, marsh, and bog habitats. Tall scrub and
forest habitats are found in the eastern interior areas. Alpine tundra occurs
in the mountainous areas at higher elevations. Most of these habitats remain
essentially untouched by man.
Less than five percent
of the refuge is forested. Narrow bands of riparian, black spruce-hardwood,
mixed black spruce-balsam poplar, and balsam poplar woodlands extend onto the
delta along the Yukon and Kuskokwim rivers and their tributaries. None of the
wooded areas contain commercially harvestable timber.
The refuge supports
one of the largest aggregations of water birds in the world. Over one million
ducks and half a million geese breed here annually and in some summers, up to a
third of the continent's northern pintails can be found on the refuge. In
addition, nearly 40,000 loons, 40,000 grebes, 100,000 swans and 30,000 cranes
return to the refuge each spring to nest. Millions of shorebirds use the refuge
for both breeding and staging. In terms of both density and species diversity,
the delta is the most important shorebird nesting area in the country, and the
vast intertidal zone is the most important wetland for post-breeding shorebirds
on the west coast of North America.
The refuge hosts
approximately 80% of the continental breeding population of black brant and
nearly all emperor geese. Cackling Canada and Pacific greater white-fronted
geese number over 175,000 and 420,000, respectively. Undoubtedly, these four
species have been a significant factor in shaping the coastal ecosystem.
Principal species of
ducks that occur on the refuge include northern pintail, greater scaup, and
wigeon. Harlequin ducks breed in many of the watersheds draining the Kuskokwim
Mountains, as well as other suitable habitats. Common eiders are locally
"common" in the vicinity of some brant colonies. The formerly abundant
spectacled eiders have declined precipitously over the last 25 years.
eider nesting is nearly non-existent on the refuge, the adjacent waters are
extremely important to a large fraction of this Pacific population. Tens of
thousands stage each spring on Kuskokwim Shoals along the refuges southern
coastline prior to moving to their arctic breeding grounds, and tens of
thousands migrate south past Cape Romanzof in the fall. In addition, several
thousand molt each fall on Kuskokwim Shoals and along the shoreline of Nunivak
Nineteen species of
raptors have been recorded on the refuge, including golden eagles, bald eagles,
and peregrine falcons. The Kisaralik River is among the most important areas on
the refuge for nesting raptors, and supports one of the densest breeding
populations of breeding golden eagles in North America.
occurred on the Yukon-Kuskokwim Delta in large numbers and were the most
abundant ungulate. Numbers peaked in the 1860's and during this period, caribou
ranged over much of the refuge. Caribou subsequently disappeared from the
region with the exception of small, remnant herds in the Kilbuck and Andreafsky
Mountains. In recent years, up to 40,000 animals from the Mulchatna Caribou Herd
have migrated onto the eastern portions of the refuge during the fall and
Bering Sea marine
mammals add an interesting diversity to the refuge's wildlife and provide a
vital subsistence resource for coastal villages. Pacific walruses, spotted
seals, ringed seals, and Pacific bearded seals are hunted on the ice in spring,
and some seal hunting continues during summer in bays and estuaries. Small
numbers of threatened Stellers sea lions haul out on the rocks at Cape Romanzof
and on Nunivak Island. Other marine mammals include harbor and Dall porpoises,
northern fur and harbor seals, and beluga, gray, and minke whales.
Including the Bering Sea, refuge waters
provide habitat for at least 40 species of fishes. The Yukon and Kuskokwim
rivers, support regionally and internationally significant salmon fisheries.
Other important freshwater resident species include several species of
whitefish, sheefish, Alaska blackfish, burbot, northern pike, Dolly Varden,
rainbow trout, and grayling. Nearshore ocean habitats harbor Pacific herring,
halibut, tomcod and starry flounder..