Sea-Ice Decline and Permafrost Thaw Create Goose Habitat in Arctic Alaska
Warming temperatures are leading to the creation of high-quality habitats for geese along the Arctic coast of Alaska, according to scientists with the U.S. Geological Survey (USGS). This effect is in contrast to the deleterious impacts that warming global temperatures are having on the habitats of animals that depend on sea ice, such as polar bear and walrus. In response to the new habitats, goose distributions are shifting from inland lakes to coastal marshes. Additionally, geese are expanding their range beyond the area historically used to assess their numbers.
The USGS research findings—reported in the journal Environmental Research Letters in December 2013 and the Journal of Field Ornithology in January 2014—focus on Black Brant geese (Branta bernicla nigricans). These birds migrate by the thousands each summer to the Arctic Coastal Plain of Alaska to undergo their wing molt, during which they are flightless for three weeks. While they are molting, the birds require extensive open-water areas where they can escape from predators and high-quality food to give them the energy necessary to replace worn feathers.
Since the 1970s, the U.S. Fish and Wildlife Service has noted a shift in the distribution of Black Brant geese near Teshekpuk Lake, a large lake southeast of Barrow, Alaska, in the center of the Arctic Coastal Plain and within the National Petroleum Reserve. The most obvious change has been that geese are moving away from large inland lakes to coastal salt marshes.
“This was a case where we knew from the long-term survey data that geese were shifting their molting distribution, but ‘why’ was the question,” says Paul Flint, a research wildlife biologist with the USGS and one of the authors of the new reports.
The answer, according to Flint, is that the shift of Black Brant from inland lakes to coastal areas results from creation of new habitat along the coast rather than degradation of inland habitat. The USGS investigations also discovered new molting areas outside the historic range. Results from the research suggest that Black Brant are dispersing from the Teshekpuk Lake area into new coastal habitats, while simultaneously redistributing within the Teshekpuk Lake area. Surveys conducted in new coastal molting habitats documented a 50-percent increase in the population size of molting Black Brant along the Arctic Coast. The authors conclude that continued reductions in sea ice and associated permafrost melting may continue to alter coastal areas, creating more salt marshes and thus facilitating further changes in goose distributions.
“The bottom line is that there is now an abundance of high-quality goose forage along the coast; therefore, we expect this process to continue and populations of Black Brant and other goose species to increase,” said Flint.
Future investigations planned by the USGS will determine if the changes driven by sea-ice-and permafrost decline are resulting in an overall increase in the high-quality coastal vegetation used by geese or if habitat is simultaneously being lost to coastal erosion.
“This kind of information has been very helpful in identifying areas that may need special considerations when planning for potential industrial development on the North Slope,” said Debbie Nigro, wildlife biologist with the Bureau of Land Management in Fairbanks, Alaska.
Complete citations for the recent publications by the USGS scientists and their colleagues from the University of Alaska, Fairbanks, and the U.S. Fish and Wildlife Service are:
Tape, K.D., Flint, P.L., Meixell, B.W., and Gaglioti, B.V., 2013, Inundation, sedimentation, and subsidence creates goose habitat along the Arctic coast of Alaska: Environmental Research Letters, v. 8, no. 4, 9 p., doi:10.1088/1748-9326/8/4/045031.
Flint, P.L., Meixell, B.W., and Mallek, E.J., 2014, High fidelity does not preclude colonization—Range expansion of molting Black Brant on the Arctic coast of Alaska: Journal of Field Ornithology, v. 85, no. 1, p. 75–83, doi:10.1111/jofo.12051.
in this issue:
Warmer Conditions Create New Goose Habitat in Arctic Alaska