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Weekly Highlights for 7-26-2012
I. Departmental/Bureau News
A. Upcoming Events
No Upcoming Events highlights for this week
B. Current
USGS Alaska Science Center scientists, together with international authors, contributed to the article "Polar and brown bear genomes reveal ancient admixture and demographic footprints of past climate change", release online in The Proceedings of the National Academy of Sciences. The research presents the most comprehensive analysis of polar bear DNA to date and suggests that polar bears evolved as a distinct species as many as 4-5 million years ago, rather than on the much earlier timeline suggested by previous studies. The analysis also revealed signatures of repeated hybridization with brown bears. The study used state-of-the-art high throughput sequencing methods similar to methods that facilitated the completion of the Human Genome Project, and is one of the first of its kind for a wildlife species. A major conclusion of the paper is that effective population size of polar bears increased with cooler climate periods and decreased in warmer periods. USGS scientists, and the USGS Office of Communications and Publishing, have worked with the lead authors' institutions on outreach related to this publication; the USGS is not issuing a news release but has participated in the formulation of a press release being issued by the University of Buffalo and Penn State University.
Contact:
Sandra Talbot
Anchorage, AK, (907) 786-7188
From about July 29 - August 7, a team of scientists from the U.S. Fish and Wildlife Service, University of Alaska, and U.S. Geological Survey will visit St. Matthew and Hall islands in the central Bering Sea to conduct an inventory of their biological and archaeological resources. These remote islands are rarely visited and while their avian and mammalian faunas and botanical resources are fairly well-known, other aspects of their natural history have not been described. The expedition is expected to yield new information on seabirds, fish, plants, aquatic and terrestrial invertebrates, diatoms, cyanobacteria, and archaeology.
Contact:
Anthony (Tony) DeGange
Anchorage, AK, (907) 786-7046
On July 26, USGS Alaska Science Center Research Statistician Rebecca Taylor will present a Webinar to a national group of biometricians at the Natural Resources Biometrics meeting titled "Population Dynamics of the Pacific Walrus in a Changing Arctic". The ultimate goal is to guide future data collection for Pacific walruses by evaluating what demographic changes are most likely to affect walrus population size and growth rate, and by generating field-testable predictions regarding the demographic effects of harvest and diminishing sea ice. Notably, loss of sea ice may change the factors that limit walrus populations, which historically, was thought to be harvest. In particular, the loss of sea ice, which walruses use as a resting platform between bouts of foraging for benthic vertebrates, is predicted to reduce access to food, and through nutritional stress, may lower reproduction, juvenile survival and possibly adult female survival. On August 17, Taylor will present the same talk at the Alaska Chapter of the American Statistical Association's Annual Meeting, being held here in Anchorage.
Contact:
Rebecca Taylor
Anchorage, AK, (907) 786-7004
The Changing Arctic Ecosystems initiative is refining forecasts of future wildlife distribution and status in the Arctic, as key habitats respond to climate change. Summer sea ice has been decreasing in the Chukchi Sea, which covers the continental shelf between Alaska and Russia and provides seasonal habitat for most of the Pacific Walrus population. In the past 5 years, sea ice has started retreating beyond the continental shelf, and increasing numbers of walruses have begun using coastal haulouts. This change in behavior could affect energy requirements and condition of walruses as well as viability of localized prey populations. Little is known about walrus food requirements, and direct measurements are nearly impossible to obtain because walruses are remotely distributed and forage on the sea floor. To fill this critical information gap, USGS and University of California researchers collaborated to develop the first bioenergetics model for walruses. The model used published values of physiological parameters for walruses and closely related pinnipeds to provide bioenergetics-based estimates of energy requirements and suggested that increased use of coastal haul-outs may increase energy requirements. These findings will be used to refine a comprehensive USGS forecasting model, linking changes in sea ice to changes in walrus population status and will be published in a forthcoming issue of Marine Ecology Progress Series (abstract available at http://www.int-res.com/abstracts/meps/v460/p261-275/.
Noren, S. R., M. S. Udevitz, and C. V. Jay. 2012. Bioenergetics model for estimating food requirements of female Pacific walruses (Odobenus rosmarus divergens). Marine Ecology Progress Series 460:261-275.
Contact:
Mark Udevitz
Anchorage, AK, (907) 786-7083
Scientists from the USGS Alaska Science Center and the Moscow State University have recently published a paper in the upcoming issue of Condor. The Rock Sandpiper (Calidris ptilocnemis) is endemic to the Bering Sea region and unique among shorebirds in the North Pacific for wintering at high latitudes. The nominate subspecies, the Pribilof Rock Sandpiper (C. p. ptilocnemis), breeds on four isolated islands in the Bering Sea and appears to spend the winter primarily in Cook Inlet, Alaska. Due to its small estimated population size and relatively restricted range, the Pribilof Rock Sandpiper is considered a species of high conservation concern in numerous conservation planning documents, but an accurate population estimate was lacking for the subspecies. This study represents a rare opportunity not only to systematically survey a bird population of conservation concern across its entire breeding range but also to investigate variation in its density with respect to anthropogenic and environmental factors. We estimated the total population at 19,832 birds, ranking it among the smallest of North American shorebird populations. Densities were up to four times higher on the uninhabited and more northerly St. Matthew and Hall islands than on St. Paul and St. George islands, which both have small human settlements and introduced reindeer herds. Differences in density, however, appeared to be more related to differences in vegetation than to anthropogenic factors, raising some concern for prospective effects of climate change. To determine the vulnerability of Pribilof Rock Sandpiper to anthropogenic and stochastic environmental threats, future studies should focus on determining the amount of gene flow among island subpopulations, the full extent of the subspecies' winter range, and the current trajectory of this small population.
Ruthrauff, D. R., T. L. Tibbitts, R. E Gill, Jr., M. N. Dementyev, and C. M. Handel. 2012. Small population size of Pribilof Rock Sandpipers confirmed through distance-sampling surveys in Alaska. Condor, In Press. (early online manuscript now http://www.jstor.org/stable/10.1525/cond.2012.110109
Thermal and hydrological observations near Twelvemile Lake in discontinuous permafrost, Yukon Flats, interior Alaska, September 2010-August 2011. (2012) Jepsen, Steven M.; Koch, Joshua C.; Rose, Joshua R.; Voss, Clifford I.; Walvoord, Michelle A. USGS Open-File Report: 2012-1121 http://pubs.er.usgs.gov/publication/ofr20121121
Contact:
Daniel Ruthrauff
Anchorage, AK, (907) 786-7162
II. Press Inquiries/Media
On July 23, Sandra Talbot, Research Wildlife Geneticist with the USGS Alaska Science Center (ASC), was interviewed by Emily Schwing, with KUAC in Fairbanks (Alaska Public Radio FM 89.9), regarding the Miller et al. (2012) paper, discussing a new genetic study by an international team of scientists, including three scientists from the USGS ASC, using nuclear DNA, recently published in The Proceedings of the National Academy of Sciences. To listen to the full interview and view the paper visit http://www.alaskapublic.org/2012/07/23/study-says-polar-bear-species-older-than-previously-thought/.
Contact:
Sandra Talbot
Anchorage, AK, (907) 786-7188
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