USGS at The Wildlife Society: From sea-ice change to contaminants to predators and prey
Polar bear habitat preferences and prey availability in a changing sea ice environment:
In the Beaufort Sea, polar bears (Ursus maritimus), ringed seals (Phoca hispida), and bearded seals (Eriginathus barbatus), inhabit a seasonably dynamic environment that has experienced climate-induced changes. During most seasons polar bears prefer mixed ice habitats near ice edges in shallow waters over the continental shelf. In past decades, polar bears could maintain this habitat preference for nearshore ice, but in recent years, extensive ice melt has forced most polar bears to summer in deepwater ice habitat more than 200 km from the mainland coast. A smaller segment of the population is forced to use shoreline habitat. Other research suggests that prey resources may be diminished for polar bears force to occupy land and the deep water pack ice during summer. For example, the winter and spring distribution of ringed seals, the most important prey for polar bears, reflects the general distribution of polar bears. During summer, while some ringed seals may track the ice edge as it retreats north, others may have an open water life style and thus would be unavailable to polar bears. Bearded seals, due to their bottom-feeding habits, have not been available to polar bears summering over deep-water habitats during recent summers. In addition, a changing sea ice environment may affect reproduction of both predator and prey. Many pregnant polar bears in Alaska den on the active sea ice, the thinning of which brings into question whether winter ice has the stability necessary for successful denning. Seals also depend on sea ice for birth and hence are also susceptible to changes in the composition of sea ice. George Durner and Steven Amstrup, Session 33, Tuesday, Sept. 26, 8:40-9:00 a.m.
Survival and population size of polar bears in western Hudson Bay in relation to earlier sea ice breakup:
Researchers estimated survival and population size for polar bears (Ursus maritimus) in western Hudson Bay, Canada, from data collected 1984-2004, and handling data for polar bears that entered the community of Churchill, Manitoba, adjacent to the study area. The size of the Western Hudson Bay polar bear population significantly declined from about 1194 in 1987 to 935 in 2004. Survival of prime-adult polar bears (age 5-19 years) was stable over the course of the study for both females and males. However, survival of juvenile, subadult, and old adult polar bears was associated with the timing of sea ice breakup, which was variable between years and occurred about two weeks earlier in 2004 than at the beginning of the study in 1984. The researchers propose that this correlation provides evidence for a causal association between earlier sea ice breakup (due to climatic warming) and decreased polar bear survival. It may also explain why Churchill, like other communities along the western coast of Hudson Bay, has experienced an increase in the number of human-polar bear interactions in recent years. Earlier sea ice breakup may have resulted in a larger number of nutritionally stressed polar bears, which are encroaching upon human habitations in search of supplemental food. Because western Hudson Bay is near the southern limit of the polar bear's range, these findings may foreshadow how more northerly polar bear populations will respond to the continued warming that is projected for many parts of the Arctic. Eric Regehr, Session 13, Sunday, Sept. 24, 1:20-1:40 p.m.
Polar bears, canaries, and declining sea ice – wildlife managers or wildlife historians?
Research efforts of the past few decades have given wildlife professionals the tools necessary to address past and present polar bear management challenges. Now, however, climate changes appear to threaten the sea ice itself – the floating platform upon which polar bears depend for nearly all of their life history needs. As a universal symbol of the Arctic, polar bears have been heralded as the "canary in the coal mine" of global climate change, and recent reports suggest their Arctic ice habitat may be gone in 100 years. Some researchers have even suggested there is nothing we can do to prevent disappearance of the summer sea ice. As the apex predator in the Arctic, polar bears reflect the status of the ecosystem supporting them and are one of the best harbingers of the future of the Arctic ecosystem. Still, polar bears did somehow survive a period in the Holocene between 5 and 10 thousand years ago when temperatures were substantially warmer than they are now. These facts alone suggest there is reason to continue to study polar bears. Because current predictions of increasing temperature are based upon a relatively short time line there is uncertainty about what the future may bring. By knowing how polar bears respond to diminishing ice, resource managers and scientists will have the best chance of predicting where polar bears may continue to survive in a diminished ice environment and of adapting management strategies to reconcile the needs of bears with their altered habitat. This will maximize opportunities to assure the long-term survival of polar bears throughout whatever the future brings. Steven Amstrup, Session 13, Sunday, Sept. 24, 1:20-1:40 p.m.
The application of resource selection functions in polar bear research and management:
Resource selection functions (RSF) provide a powerful tool for understanding wildlife habitat associations and explaining wildlife distributions. Knowledge of the status and distribution of polar bear populations is necessary for managers to effectively address issues regarding hunting, industrial expansion, contaminants, international treaties, and sea ice degradation from climate change. While telemetry data can describe the general distribution and discreetness of polar bear populations, RSFs help to explain why polar bears occur where they do, allowing predictions of likely population status and distribution based on sea ice composition. RSFs may be employed in a number of research and management endeavors directed towards polar bears. Applying RSFs to near-real time satellite imagery will aid in the design of aerial surveys and mark-recapture research to increase the effectiveness of polar bear field research. A polar bear RSF can help managers to assess the potential impacts of human-caused perturbations, such as industrial expansion and oil spills, by an understanding of the sea-ice characteristics surrounding the perturbation and the expected response of polar bears to those characteristics. Sea-ice degradation due to climate warming will have the largest future impact on polar bears and their prey. RSFs employing long-term forecasting of likely sea-ice scenarios will allow predictions of polar bear distribution resulting from climate change and will be a first step in assessing impacts on the population. If Arctic sea ice continues on a trend toward thinner ice and a longer ice minima season, RSFs will assist in an adaptive management strategy for harvest recommendations and the management of human populations to accommodate a changing polar bear population. In a warming Arctic, RSFs will be necessary to identify high Arctic refugia where persistent sea ice would allow the continued survival of a remnant population of polar bears. George Durner, Session 27, Monday Sept. 25, 2:00-2:20 p.m.
Decline of the glacier murrelet, a Pleistocene relict in an age of global warming:
The birth of a cooler climate in the late Pliocene was accompanied by rapid increase in seabird species, particularly in the auk family. Several new species of murrelets evolved, including the marbled murrelet (B. marmoratus), which nests in coastal old-growth conifers from California to Alaska, and the Kittlitz's murrelet (B. brevirostris), which developed an unusual and intimate association with glacial ice during the Pliocene and subsequent Pleistocene ice ages. Surveys conducted by USGS, USFWS and NPS in areas containing the bulk of their numbers in Alaska indicate that populations of glacier murrelets have declined by more than 80 to 90 percent during the past 20 years. This corresponds to an almost universal and increasingly rapid recession of glaciers and ice fields throughout Alaska, which itself is likely to be the result of global warming. Kittlitz's murrelets usually nest in high alpine on recently de-glaciated mountain peaks and forage in glacially modified marine waters. Today, the "glacier murrelet" is found only in areas with extensive ice sheets (e.g., Glacier Bay, Prince William Sound), remnant glaciers (e.g., Aleutian Islands), and in a few areas that once contained extensive ice fields, but are now glacier-free (e.g., Seward Peninsula). The fate of Kittlitz's murrelet likely hinges on the fate of Alaska's glaciers. Impacts of human activities, such as by-catch in nets and mortality from oil spills, will likely hasten their decline. On the positive side, genetic studies suggest that a few remote sub-populations may be less dependent on glacial environments than those found in core breeding areas. John Piatt, Session 22, Monday, Sept. 24, 3:50-4:10 p.m.
Elk calf mortality following wolf restoration in Yellowstone National Park:
With wolves having been restored to Yellowstone National Park, many people believed that these newcomers would be the main source of mortality for newborn elk calves. True, elk form the main part of the wolf's diet in the park. However, studies by the U.S. Geological Survey, Yellowstone National Park, and the University of Minnesota show that wolves only accounted for about 15 percent of newborn calf deaths whereas grizzly and black bears caused about 60 percent of their deaths. Calves with higher gamma globulin levels, a possible indicator of superior condition, survived better than those with lower levels. Thus environmental factors are also important contributing factors to predation and survival with Yellowstone elk calves. Shannon M. Barber-Meyer, University of Minnesota (St. Paul), and David Mech, USGS, Session 24, Monday, Sep 25, 2006, 1:20- 1:40 p.m.
The effects of sylvatic plague on black-footed ferret recovery:
The black-footed ferret (Mustela nigripes) is one of the most highly endangered mammals in North America. Once thought to be extinct, a captive breeding and recovery program was established for ferrets in 1987. Although the breeding program has been highly successful and ferret populations (about 500 animals) have been established in several western states, the recovery effort is seriously threatened by sylvatic plague, caused by the bacterium Yersinia pestis. Research indicates that there may be a partial management solution to this problem in vaccinating both black-footed ferrets and prairie dogs against plague. A plague vaccine for prairie dogs that can be delivered via oral baits has been shown to be efficacious in laboratory experiments and may provide a better method of managing the disease for both prairie dogs and ferrets. Plague was introduced into U.S. seaports in the early 1900's via commensal rodents and quickly spread into native rodent populations, including prairie dogs (Cynomys species). Mortality in plague-infected prairie dog colonies often reaches 95-99 percent, and the disease frequently results in local extinctions and population reductions followed by partial recovery. Plague in prairie dog towns significantly impacts black-footed ferret survival by destroying their primary prey base. In addition, the black-footed ferret is susceptible to the disease, suffering high mortality rates upon plague infection in captivity and in the laboratory. In 2005, a plague outbreak killed numerous black-tailed prairie dogs (Cynomys ludovicianus) in South Dakota about 30 miles south of Conata Basin, where the largest population of black-footed ferrets (about 250) resides. More than 300,000 individual prairie dog burrows in Conata Basin were dusted with pesticides to kill fleas, but pesticide application is a labor-intensive and costly solution and difficult to sustain for a long period of time. Some ferrets were also vaccinated against plague to prevent infection, but protection from the disease won't prevent the loss of their prey base. Tonie E. Rocke, Session 32, Tuesday, Sept. 26, 10:30-10:50 a.m.
Food of surf scoter duck possibly linked to abundance of oyster bars in Chesapeake Bay:
Reports of the Atlantic coast surf scoter (Melanitta perspicillata) populations have indicated steady declines in recent decades, which have necessitated further research on their populations. One of the primary wintering areas for surf scoters is the Chesapeake Bay. While wintering on the Bay the ducks primarily prey on bivalves, such as clams and mussels. Over the last 50 years, the habitat quality for these prey items has undergone drastic changes. The decline in oyster bars and the resultant decline in availability of mussels may be causing the surf scoters to switch to more prolific food items or to move to different coastal areas. USGS Researcher David Kidwell determined a direct correlation in the availability of prey and the density of seaducks in his study sites in the Bay. As winter progressed there was a steady decline in mussel densities in scoter feeding areas, indicating that scoters were depleting their primary food source. If large-scale oyster restoration efforts take place in the next ten years, providing more habitat for mussels, then there could be a recovery seen in the scoter populations that winter on the Chesapeake Bay. David M. Kidwell and Matthew Perry, Session 9, Sunday, Sept. 24, 4:10-4:30 p.m.
Frogs as sentinels of mercury contamination:
Extensive areas of northern California have been mined for mercury and gold, and releases of mercury from these areas to downstream aquatic environments are of concern for fish, wildlife, and human health. Mercury concentrations found in amphibians (post-metamorphic bullfrogs, foothill yellow-legged frogs, and Pacific treefrogs) from eight watersheds confirmed the presence of significant sources of mercury, especially at mercury-mining sites, and, to a lesser extent, in areas impacted by gold mining. Mercury concentrations in certain amphibians, especially bullfrogs in the Cache Creek Watershed in the Coast Range Mountains, were commonly higher than the Environmental Protection Agency's criterion for issuance of health advisories for fish consumption. Since the bullfrog is a sport species whose legs are frequently consumed by humans, the elevated concentrations found in bullfrogs from Cache Creek pose a serious concern for human health. Concentrations of mercury in amphibians were closely correlated with those in aquatic insects, fish, and cliff swallow eggs from the same sites, confirming the usefulness of amphibians as indicators of mercury contamination, especially in fishless areas. Roger Hothem, Session 48, Wednesday, Sep 27, 2006, 8:00 a.m. -12:00 p.m.
Predator-Prey Studies Through the Years (keynote):
Wolves, cougars, grizzly bears and other carnivores are returning to much of the United States where they have not lived for decades. Thus studies of predators and their prey are taking on a new significance. Do predators control their prey? What determines predator numbers? Do predators tend to kill primarily inferior prey? What role does weather play in predator-prey relations? Does predator control work to increase prey numbers? What do we know about the cascading effects of predators in ecosystems? These are among the many questions researchers have been exploring over the years, and the answers are far from simple. L. David Mech, Session 33, Tuesday, Sept. 26, 8:00- 8:20 a.m.
Foraging habitat of harbor seals relative to cruise ship routes in Glacier Bay National Park.
Glacier Bay National Park has historically supported one of the largest populations of breeding harbor seals in Alaska. However, the number of seals has declined by nearly 15 percent per year since 1992. During the same period, the number of cruise ships that have entered the park has increased by 25 percent and may increase up to another 30%. Although the park has initiated restrictions on cruise ships to minimize disturbance of seals at important breeding locations (including terrestrial and ice haul-outs), the extent of overlap between important foraging habitat of seals and areas used by cruise ships was unknown. This study identified foraging areas used by seals, and compared fish densities in these areas with areas used by cruise ships. For two years, researchers tagged 46 seals, and observed the behavior of 36 of them by observing their foraging behavior on 74 occasions. Seals using terrestrial haul-outs foraged predominantly in nearshore habitats within 3.1 miles of haul-outs. Seals captured in ice habitats likewise foraged nearshore but traveled farther from haul-outs to forage (range 0-63 miles). Only 11 percent of foraging bouts of seals observed by researchers were within areas used by cruise ships, and fewer than 17 percent of all foraging bouts were within 1.2 miles of ship routes. Furthermore, after accounting for differences in water temperature, depth, and distance to haul-out, prey densities (including forage fish) from mid-water trawls were similar in areas where seals foraged outside of cruise ship routes compared to areas within cruise ship routes. These results suggest that forging locations of harbor seals were a function of choice, rather than displacement. Foraging habitat of seals appears to be sufficiently protected from cruise ship disturbance, although the effects of other vessel classes on foraging seals is yet unknown. Scott Gende and Jamie Womble (National Park Service) and Mayumi Arimitsu (USGS), Session 20, Monday, Sept. 24, 8:40 a.m.-9:00 a.m.
Assessing bird occurrence and migration in the context of wind development: Two Projects: Coastal and offshore seabird populations.
Offshore wind-generated electricity promises to be an important source of renewable energy for the future; however, wind energy development may be in conflict with coastal and offshore seabird populations. Information on seabird distribution is needed to allow regulatory agencies to evaluate placement of proposed wind energy projects. To address these information needs, seabird occurrence, biophysical parameters, and oceanographic data are being gathered for the Atlantic waters of the eastern United States, a focal area for wind energy development. This information will be used to map seabird occurrence patterns, predict distribution, and to identify potential areas of conflict between birds and proposed wind energy development. Allan F. O'Connell, Jr., Session 21, Monday, Sept. 25, 8 a.m.-5 p.m. (poster session)
Migrating birds and bats. Concerns have arisen about the potential impacts of wind power development in the Appalachians on migrating birds and bats, creating a critical need for information on their distribution and flight characteristics as they pass through the region. We are studying the distribution and flight patterns of birds and bats that migrate nocturnally. Weather surveillance radar data are being analyzed to provide a broad view of spring and fall migration through the Appalachians, and to assess the response of migrants to mountain ridges or other prominent landforms. We also are conducting acoustic monitoring at 29 sites scattered through the central Appalachians, recording the calls made by migrating birds in flight to index their abundance and species composition at different locations. The acoustic monitoring is supplemented with portable radar sampling at three sites, to provide additional data on the passage of migrants, and their flight altitudes and directions. The data will be used to model the effects of topography, weather, and other variables on migrant abundance and flight in order to assess where and when migrants might be at risk from wind power development. Deanna K. Dawson, Session 21, Monday, Sept. 25, 8 a.m.-5 p.m. (poster session)
Satellite radio tags allow researchers to quantify walrus haul-out behavior on Bering Sea ice for the first time:
Researchers used remotely deployed satellite-linked transmitters to obtain locations and chronologies of the haul-out status of individual Pacific walruses (Odobenus rosmarus divergens) in sea ice of the Bering Sea during early spring of 2004, 2005 and 2006. These data were matched with weather data from NOAA's National Centers for Environmental Predictions and used to assess relations between haul-out status and environmental and behavioral factors, providing the first quantitative analysis of walrus haul-out behavior in sea ice habitat. Such information is especially important with the recent substantial decline of arctic sea ice because identifying factors associated with haul-out status will lead to more accurate population estimates and provide more information about walrus behavior and sea ice usage. Walruses spent the majority of their time in water, averaging only about 20% of their time hauled out on sea ice. Their behavior was similar to that of other pinnipeds, in that the probability of being hauled out increased with temperature and barometric pressure and decreased with wind speed. The study also found that the probability of being hauled out varied among walruses, increased with the proportion of other walruses hauled-out concurrently, and was higher for walruses that were hauled-out at the previous time-point. These results are being used to help develop an estimate of the Pacific walrus population size. Mark Udevitz, Session 20, Monday, Sept. 25, 11:10-11:30 a.m.
Dall's Sheep responses to military overflights in interior Alaska:
High-speed low-level military training flights have the potential to affect the behavior, habitat use and population characteristics of wildlife. USGS, National Park Service, and University of Alaska (Fairbanks) researchers investigated the effects of military flying operations on Dall's sheep in interior Alaska over a four-year period. Low-level, high-speed overflights near sheep were rare even during major flying events. The scientists found that daily flights over Dall's sheep did not significantly influence their activity patterns. Further, they observed no significant effects of the increased number of military aircraft sorties associated with major flying events on total distance moved; home range size; or habitat use of sheep. However, because the studied sheep had been exposed to military overflights for about 20 years, they may have acclimated to the military activity. If the nature, intensity, or frequency of military flights in interior Alaska changes substantially compared to the conditions observed in this study, then sheep may respond differently. Brad Griffith, Session 35, Tuesday, Sept. 26, 2006, 8 a.m.-5 p.m. (poster)
What's been learned from nearly 40 years of studying sea otters, sea urchins, and kelp (keynote)?
The trophic interaction among sea otters, sea urchins, and kelp is one of the earliest and best-known examples of a "trophic" cascade, thanks to the large-scale ecosystem disturbance of the near extinction and subsequent recovery of sea otters from the Pacific maritime fur trade. Throughout much of the coastal northeast Pacific Ocean, otter-dominated ecosystems are characterized by kelp forests whereas otter-free systems are characterized by deforested sea urchin barrens. Adding sea otters to the otter-free systems or removing them from the otter-dominated systems, results in a strongly punctuated shift. Jim Estes will discuss the mechanisms underlying these transitions, the influence on other species and ecosystem processes, the unexpected recent collapse of the sea otter-kelp forest ecosystem in southwest Alaska, and insights and conclusions that have emerged from almost 40 years of work on the interaction dynamics between sea otters and kelp forests and the potential relevance of these insights to other large predator-prey ecosystems. Jim Estes, Session 33, Tuesday, Sep 26, 2006, 9:20 a.m. - 9:40 a.m.
Mercury in giant garter snakes:
Habitat destruction is the main factor in the decline of giant garter snake populations, but the effects of contaminants are unknown for this threatened endemic of wetlands of the Central Valley of California. To contribute to the recovery of these snakes, the USGS has been studying the life history and habitat use of giant garter snakes since 1995. From specimens of dead giant garter snakes encountered in the field, researchers have conducted analyses for mercury and a variety of other elements to determine if mercury or other trace element contamination may be affecting giant garter snake populations. Although contaminants in snakes have been poorly studied, and it is difficult to know threshold values of toxins, mercury concentrations in these samples indicate that the effects of mercury on giant garter snakes should be studied further. Glenn Wylie, Session 48, Wednesday, Sep 27, 2006, 8:00 a.m. -12:00 p.m.
Are contaminants from winter areas affecting surf scoter reproduction?
During 2005, a USGS-led team tracked a surf scoter from its coastal wintering area in the San Francisco Bay to pinpoint its nest 2000 miles away in the vast northern boreal forest of interior Canada. By tracking these migratory birds to their nests, scientists are learning about effects of contaminants accumulated by the ducks from southern wintering regions on their reproduction. Understanding such cross-seasonal linkages may also help in detecting emerging threats to surf scoters in their northern breeding areas. To check out the travels of marked surf scoters in 2006, visit the maps at www.werc.usgs.gov/sattrack/. Susan Wainwright-De La Cruz will discuss cross-seasonal implications of mercury and selenium bioaccumulation by wintering surf scoters and the tracking effort through the 2005 nesting season. Susan Wainwright-De La Cruz, Session 40, Tuesday, Sep 26, 2006, 5:10 - 5:30 p.m.
Productivity of tundra swans breeding on the lower Alaska Peninsula:
The density of tundra swan (Cygnus columbianus columbianus) breeding pairs at Izembek National Wildlife Refuge (NWR) on the Lower Alaska Peninsula has decreased by nearly 75 percent over the past 25 years. Swans breeding in this area are unique because they are the most southwesterly breeding population of tundra swans and are the only known population of tundra swans to exhibit non-migratory behavior. Growing concerns about the status of swans breeding on the Alaska Peninsula, the unique behavior and characteristics of the Izembek population, and concerns regarding an increase in development and harvest pressure on or near Izembek NWR have prompted an assessment of past data. During the 20-year span of field studies, extensive aerial surveys of pairs and nests were conducted and the fate of over 500 nests and associated cygnets were monitored. We analyzed data collected between 1980 and 1987 to examine factors affecting nest, egg, and cygnet survival rates. We considered possible relationships between reproductive success and year, season date, cygnet age, neck collars, weather variables, nesting location, and brown bear densities. Nest survival rates for nests located in a portion of our study area known as the Cold Bay road system were considerably higher than for those in the remaining portion of our study area. Brown bears are the main predator of tundra swan nests on our study area and the density of bears on the road system was more than 3 times lower than in adjacent areas. We believe that the relatively low density of bears on the road system is a major factor in explaining the higher nest survival rates in that area. Brandt Meixell (Institute of Arctic Biology and Department of Biology and Wildlife, Univ. Alaska, Fairbanks) and Paul Flint (USGS) and others, Session 17, Monday, Sept. 25, 2006, 10:50-11:10 a.m.
Polycyclic aromatic hydrocarbon (PAH) exposure in seaducks, eastern Aleutian Islands:
As an indicator of hydrocarbon exposure, scientists measured enzyme reaction (cytochrome P450 IA induction) in Steller's eiders and harlequin ducks captured and released at industrial and non-industrial sites at Unalaska, Popof, and Unga Islands, in winters 2002-03. They also measured PCBs in seaduck bloods as a confounding factor of P450 induction, and PAHs and other organic contaminants in prey and habitat. Seaducks captured at industrial sites had high measurements of P450 induction (relative to those from non-industrial sites) that were more strongly correlated to concentrations of PAHs in invertebrate prey than PCB concentrations in the seaducks' blood. Keith Miles will discuss these and additional results from this study. Sea ducks are being studied because of evidence indicating widespread declines in this group. Pollution or exposure to environmental contaminants in wintering areas may be a potential contributing factor in these declines. Keith Miles, Session 40, Tuesday, Sep 26, 2006, 4:10 - 4:30 p.m.
Spatial and trophic variations in environmental contaminants among Aleutian Islands birds:
Persistent organochlorines and mercury are elevated throughout the coastal food chain of the Aleutian Archipelago but the sources of these contaminants are unclear. Scientists used seabirds and a terrestrial bird species along a natural longitudinal gradient across the western and central Aleutian Islands (Buldir, Kiska, Amchitka, Adak), and additional seabird species representing different foraging and migratory bird groups from Buldir Island to evaluate westward increases in contaminant concentrations. Their study results suggest non-point source input, point source input from former military installations, and bioaccumulation in the food chain. Mark Ricca will discuss these contaminants analyses and what they indicate regarding contaminants sources and the increases in contaminants in animals higher in the food chain. Mark Ricca, Session 40, Tuesday, Sep 26, 2006, 3:50 p.m. - 4:10 p.m.
Glacial retreat, human-bear conflicts, and adaptive management in Glacier Bay National Park and Preserve:
Glacial retreat over the past 200 years in Glacier Bay, Alaska, has created lush upland meadows along the shoreline that are desirable to both humans and bears (Ursus arctos and Ursus americanus). As the number of backcountry campers has increased over the past 30 years, so have the number of bear-human conflicts. In response to these conflicts, including a human fatality in 1980, two large areas of shoreline have been closed to camping since the 1980's. In the 1990's, park managers joined with USGS bear researchers to identify key research needed to determine bear habitat characteristics and activity patterns in Glacier Bay with the goal of ultimately minimizing bear-human conflict. Two research projects have subsequently been conducted including a risk assessment of campsites in Glacier Bay, and an assessment of bear habitat and activity in areas of management concern, which included the areas closed to camping. As bear research commenced, park managers made changes to educational content and safety trainings based on preliminary findings from the field. For example, bear safety messages now encourage people to look for signs of recent bear activity, keep control of their gear at all times, and to stand their ground during bear encounters. Consequently, the number of bear-human conflicts decreased. Research is now completed and the park is incorporating findings into new management policies and a bear management plan. Tania Lewis (NPS) and Tom S Smith (USGS), Session 34, Tuesday, Sept. 26, 8 a.m.-5 p.m.
Declining northern bobwhites in a longleaf pine landscape: how movement affects survival:
Bobwhite populations and fire-maintained longleaf pine forests have been declining for at least the last 4 decades. We studied survival and movement of northern bobwhites in fire-maintained longleaf pine forests in south-central Alabama. We found that daily survival probabilities of bobwhites were most influenced by daily movements and that the farther they had to move, the more their survival rates decreased. In turn, daily mobility of bobwhites varied with respect to the time that had passed since the last fire, season of year, and whether or not an individual was near a wildlife opening. These findings indicate that longleaf pine forests managed with growing season fire and provision of unburned areas interspersed within forests will lead to increased survival of bobwhites. James B. Grand, Session 17, Monday, Sept. 25, 9:20 a.m.
The Farm Bill and breeding birds: not the same-old, same-old. Numerous studies have demonstrated the enormous value in terms of wildlife habitat that the Conservation Reserve Program provides. Much policy was based on research conducted in the early years of CRP. USGS scientists Douglas Johnson and Lawrence Igl use results from a long-term study in Montana, North Dakota, South Dakota, and Minnesota to show that bird use of CRP fields has changed dramatically during the past 17 years. Reasons for these changes involve variation in precipitation, ecological succession, and management. Decisions should be based on current information; the use of "old" data may lead to decisions best suited for conditions that no longer apply. Douglas H. Johnson, Session 46, Sept. 27, 9-9:20 a.m.
Mercury exposure in California black rails in San Francisco Bay:
Little is known of the ecology of secretive or special status species such as the California black rail, but mercury contamination in San Francisco Bay may degrade the value of existing or restored tidal marshes for these species. Understanding the relationships of resident species such as black rails and risk of methylmercury (a more toxic form of mercury) exposure will aid in the restoration and management of tidal wetlands at San Francisco Bay. To determine movements and food habits of black rails in relation to mercury and methylmercury exposure, scientists radio-tracked black rails at three independent tidal marsh sites in northern San Francisco Bay in spring and summer 2005 and 2006, and collected blood and feathers and invertebrate food prey for mercury and methylmercury analyses. Danika Tsao Melcer will discuss what was learned from the radio-tracking efforts and contaminants analyses. Danika Tsao Melcer, Session 40, Tuesday, Sep 26, 2006, 2:00 - 2:20 p.m.
Last reviewed: By John M. Grohol, Psy.D. on 30 Apr 2016
Published on PsychCentral.com. All rights reserved.