| The Wildlife Society’s 13th Annual
Conference & Trade Show is being held September 23–27, 2006 in downtown
Anchorage, Alaska at the William A. Egan Civic and Convention Center. Additional
information about the Wildlife Society conference can be found online at
www.wildlife.org/conference/index.cfm. |
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/.
For more information on surf scoter studies contact John Takekawa at (707)
562-2000 or john_takekawa@xxxxxxxx,
or Gloria Maender at (520) 670-5596 or gloria_maender@xxxxxxxx.
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. |
