Waterfowl Populations of Conservation Concern

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Waterfowl Populations of Conservation Concern
Mottled Duck Ecology and Conservation – The State of our Understanding
Ronald R. Bielefeld*, Florida Fish and Wildlife Conservation Commission, Sebastian, FL
32958, USA ([email protected])
Michael G. Brasher, Ducks Unlimited, Inc., Gulf Coast Joint Venture, Lafayette, LA 70506,
USA ([email protected])
Extended Abstract: The mottled duck (Anas
fulvigula) is a non-migratory dabbling duck
species endemic to peninsular Florida (FL)
and the Western Gulf Coast (WGC). Recent
analyses have demonstrated distinct genetic
structuring between FL (A. f. fulvigula) and
WGC (A. f. maculosa) birds, leading to their
recognition and management as independent
populations. Due to their restricted
distributions, relatively small population sizes,
loss and degradation of key habitats, and in
Florida, introgressive hybridization, mottled
ducks are considered a species of conservation
concern throughout their range.
Mottled ducks are among the least studied
North American Anatini. Their occurrence in
low densities within poorly accessible habitats
presents challenges to rigorous scientific
investigation, and their limited distribution
translates into a relatively small “interest”
base from which to garner support and
funding for major research and management.
Surveys suggest breeding population density
in FL has remained relatively stable since
1984, with a breeding population size of
approximately 53,300 (Florida Fish and
Wildlife Conservation Commission 2011).
Long-term, range-wide estimates of mottled
duck breeding population size are not
available for the WGC, although local surveys
and large-scale indices suggest a declining
trend in Texas and a stable trend in Louisiana
and the entire WGC (Bielefeld et al. 2010).
Estimates from a recently implemented rangewide breeding population survey of mottled
ducks in the WGC indicate a breeding
population of 129,000 – 172,000 individuals.
Conversion and degradation of habitats are
likely the greatest impediments to sustaining
mottled duck populations at desired levels,
especially in the WGC, whereas introgressive
hybridization with feral mallards (Anas
platyrhynchos) is the most serious threat to the
mottled duck in FL. The extent to which
hybridization threatens WGC mottled ducks
has not been quantified, but it is believed of
lesser concern than in FL. Other concerns for
mottled ducks include the continued, yearround exposure to legacy lead shot in LA and
TX marshes; accelerated habitat loss and
degradation driven by a declining rice
industry, urban expansion, and relative sealevel rise; questions about sustainable harvest
levels; and potential for climate change and
increased frequency of extreme weather to
exacerbate effects of habitat loss and the
general ability of the mottled duck to adapt.
Conservation plans were recently developed
for WGC and FL mottled ducks to encourage
coordinated approaches for conserving and
managing this species. These plans
summarize prevailing hypotheses of
population limitation, provide guidance for
conservation actions, identify ecological and
data uncertainties, and recommend priority
science needs for refining conservation
strategies. The GCJV Mottled Duck
Conservation Plan identified recruitment as
most likely to limit population growth, with
nest success, brood survival, and breeding
propensity of greatest concern; survival is
believed to play a smaller role, although these
conclusions were derived largely from expert
opinion (Wilson 2007). In contrast, life stage
projection matrices have suggested WGC
mottled duck population growth rates are most
sensitive to variation in annual survival.
Recent studies have documented lowest
survival during breeding and hunting periods,
but within the range of estimates for other
monochromatic duck species. Primary causes
of mortality during these periods are poorly
understood. Rigorous and large-scale studies
of mottled duck recruitment remain elusive;
thus, limited information is available to
measure the importance of reproductive
parameters. Others studies have revealed
aspects of habitat use, local and long-range
movement, molt site fidelity, brood survival,
nest site selection, nest success, and breeding
propensity, although small samples and
limited spatial scales for some studies
constrain inference.
The FL mottled duck conservation plan
contains objectives focused on population
management, hybridization reduction, and
habitat management. However, the greatest
threat is genetic swamping by feral mallards.
A major research emphasis currently is
focused on minimizing introgressive
hybridization. Strictly speaking, determining
and managing other population limiting
factors matters little if the bird being managed
no longer exists. High research prioritization
given to the genetic threat is justified further
by recent research suggesting FL mottled
ducks have adapted well to habitat conversion
(Bielefeld unpublished data, Varner
unpublished data).
To combat the genetic threat, FL has banned
mallard releases and conducted wide-ranging
public education programs aimed at reducing
new releases and support for existing ducks.
However, a more direct approach to reducing
feral mallard and hybrid numbers is needed.
To initiate an intensified approach (if
approved), an understanding of numbers and
distribution of mottled ducks, mallards, and
hybrids in FL must be obtained. Additionally,
resource managers must have an efficient and
effective way of discriminating mottled ducks
from hybrids in the field. Recent FL mottled
duck genetics and development of field
identification key has brought these
capabilities to bear.
Although much remains to be learned about
FL and WGC mottled duck populations,
significant advancements over the past decade
have enabled a deeper understanding of
mottled duck ecology and population
limitation and allowed managers to address
some of the threats. Additional efforts,
including ambitious research investigations
and commitment to an adaptive management
approach for evaluating effectiveness of
conservation actions, will be needed to further
refine our knowledge of population limiting
factors and develop conservation programs to
ensure sustainability of mottled duck
populations at desired levels.
Literature Cited:
Bielefeld, R.R., M.G. Brasher, T.E.
Moorman, and P.N. Gray. 2010. Mottled
duck (Anas fulvigula), The Birds of North
America Online. A. Poole, editor. Ithaca:
Cornell Lab of Ornithology. Retrieved from
the Birds of North America Online:
Florida Fish and Wildlife Conservation
Commission. 2011. A Conservation Plan for
the Florida Mottled Duck. Tallahassee, FL.
31 pp.
Wilson, B.C. 2007. North American
Waterfowl Management Plan, Gulf Coast
Joint Venture: Mottled Duck Conservation
Plan. Albuquerque, NM. 27 pp.
Informing American Black Duck Population and Habitat Management
Patrick Devers*, U.S. Fish and Wildlife Service, Laurel, MD, 20708 ([email protected])
Rod Brook, Ontario Ministry of Natural Resources, Peterborough, ON, K9J 7B8
Min Huang, Connecticut Department of Environmental Protection, North Franklin, CT 06254
Tim Jones, U.S. Fish and Wildlife Service, Laurel, MD, 20708
Dan McAuley, U.S. Geological Survey, Orono, ME 04469
Conor McGowen, U.S. Geological Survey, Auburn, AL, 36849
Guthrie Zimmerman, U.S. Fish and Wildlife Service, Sacramento, CA 95819
Extended Abstract: Historically, the
American black duck (Anas rubripes;
hereafter black duck) was the most abundant
dabbling duck species in eastern North
America. The black duck experienced a
drastic (>50%) and long-term decline
between the 1950s and1990s. Researchers
and managers proposed several hypotheses
to explain the historic decline of black ducks
including over-harvest, competition and
hybridization with mallards (Anas
platyrhynchos), decrease in quality and
quantity of wintering and breeding habitat,
and environmental contaminants (Rusch et
al. 1989, Longcore et al. 2000, Nudds et al.
1996, Conroy et al. 2002). Research into
each of these hypotheses has provided
valuable insight into black duck ecology and
management. However, the black duck
community has not reached consensus
regarding the cause of the population decline
or current limiting factors. In fact, it is
almost certainly impossible for researchers
and managers to identify a single causative
factor for the decline of the black duck
population using a strict hypotheticodeductive approach (Conroy et al. 2002).
Although the population recovered some
from the lows of the 1980s, today, the black
duck population remains below the North
American Waterfowl Management Plan
(NAWMP) continental population goal and
has been identified as a Species of Greatest
Conservation Need by 23 states in the
Mississippi and Atlantic Flyways. More
importantly, indices of abundance and
productivity paint a mixed picture of
population growth, especially in the
Mississippi Flyway, making the future status
and sustainability of the black duck
population uncertain.
To inform management and improve our
understanding of black duck ecology, the
Black Duck Joint Venture (BDJV) is
developing a decision framework that
integrates both habitat and population
management (Fig.1). The decision
framework is being developed to address the
common and often repeated question “how
many hectares do we need to restore black
ducks?” The anticipated output will be an
optimal policy (that accounts for uncertainty
about the system and partial controllability),
detailing the number of hectares to be
protected and or restored at the regional
(e.g., BCR) level (Table 1). The decision
framework will be developed on a 5-year
time step to reflect a realistic process for
developing and implementing habitat
management actions. The resulting habitat
goals will be communicated to BDJV habitat
partners, including Habitat Joint Ventures,
provincial, state, and federal wildlife
agencies for implementation. The decision
framework will contrast support for 2
competing hypotheses: density dependent
productivity vs. density dependent postseason survival. Uncertainty regarding
which model is correct will be addressed via
model weights and model averaging.
In addition to informing regional habitat
goals, this decision framework will be used
by the BDJV to set monitoring and research
priorities. The development of a predictive
model forces researchers and managers to
explicitly state assumptions, identify
information gaps, and evaluate the
sensitivity of the decision to individual
parameters. Key parameters, assumptions,
and information gaps will be investigated
via the BDJV research and monitoring
programs. For example, the BDJV and its
partners in the Mississippi and Atlantic
Flyways and Canada are currently testing a
2-season banding program to obtain
seasonal (i.e., August-December and
January-July) survival estimates. The
resulting estimates will be critical to
developing and testing the density
dependent post-season survival hypothesis.
Ratti, editor. Seventh International
Waterfowl Symposium. Institute for
Wetland and Waterfowl Research,
Memphis, TN USA.
Figure 1. Conceptual diagram of black duck
integrated decision framework.
Literature Cited:
Conroy, M. J., M. W. Miller, and J. E.
Hines. 2002. Identification and synthetic
modeling of factors affecting American
black duck populations. Wildlife
Monographs 150.
Rusch, D. H., C. D. Ankney, H. Boyd, J. R.
Longcore, F. Montalbano, J. K.
Ringelman, and V. D. Stotts. 1989.
Population ecology and harvest of the
American black duck. Wildlife Society
Bulletin 17:379-406.
Longcore, J. R., D. G. McAuley, G. R.
Hepp, and J. M. Rhymer. 2000. American
black duck (Anas rubripes). In A. Poole
and F. Gill, editors. The Birds of North
America, No. 481. The Birds of North
America, Inc., Philadelphia, PA, USA.
Nudds, T. D., M. W. Miller, and C. D.
Ankney. 1996. Black ducks: Harvest,
mallards, or habitat? Pages 50-60 in J. T.
Table 1. Hypothetical example of optimal
policy for black duck habitat management
for a 5-year period.
Region
N. Atl.
Mid Atl.
Boreal
Season
Winter
Winter
Breeding
Habitat Goal (No. ha)
Protected
Restored
3,000
2,000
7,000
3,000
6,000
Dynamics of Northern Pintail Populations and Role of Habitat Conservation Programs
James H. Devries,* Institute for Wetland and Waterfowl Research, Ducks Unlimited Canada,
Oak Hammock Marsh, Manitoba, R0C 2Z0 ([email protected])
Extended Abstract: Through the 1980s and
into the 1990s, northern pintail (Anas acuta;
hereafter, pintail) populations declined to
record low numbers (Fig. 1). Since then,
pintail populations have increased slowly
but they remain well below the North
American Waterfowl Management Plan goal
of 5.6 million birds. Historically, the
number of pintails that settled on the prairies
had a consistent and positive relationship
with numbers of prairie wetlands. Since the
decline, however, the strength of this
relationship has weakened greatly,
especially in prairie Canada, suggesting a
persistent change in the populationenvironment interaction. Understanding
biological mechanisms that drove the pintail
decline, the failure to recover, and what
management actions are appropriate has
become a priority goal for the North
American waterfowl management
community.
7.0
Pintail Population (Millions)
6.0
Alaska and Northern Canada
Northern U.S
5.0
Prairie Canada
Total
4.0
3.0
2.0
1.0
0.0
Year
Figure 1. Comparison of pintail population trajectories in
Alaska/Northern Canada, Southern Canada, and Northern
US states, 1961-2012 (source: USFWS/CWS)
Just over a decade ago, waterfowl scientists
and managers gathered to review the plight
of the pintail and chart a course for research
and habitat conservation to better understand
driving mechanisms and reverse the decline
(Miller et al. 2003). Participants debated
and synthesized current knowledge of pintail
demographics, identified likely causes of the
pintail problem, recommended management
actions, and outlined research needs.
Primary hypotheses that emerged from that
effort included reduced nest survival due to
land use change/predation (especially in
prairie Canada), reduced breeding
propensity, disease (e.g., botulism), and
adult breeding season survival. The report
went on to recommend a suite of
conservation actions and research priorities.
In the ensuing years, progress on many of
the recommended actions from that meeting
has been great and has provided information
to address and revise original hypotheses.
For example, relatively recent estimates
from the Texas Gulf Coast region suggest
overwinter survival, at least in some places,
may be a greater concern than originally
thought (Anderson 2008). At the same time,
prairie breeding-ground research has
supported the negative recruitment
consequences of cropland nesting at local
and landscape scales (T. Kowalchuk pers.
comm., J. Devries unpubl. data). Further,
several new analyses of non-breeding pintail
movement, habitat use and survival have
shed light on important staging areas and
downplayed the role of changing survival
rates in pintail decline or failure to recover
(Miller et al. 2005, Haukos et al. 2006, Rice
et al. 2010, Fleskes et al. 2007).
The Miller et al. (2003) review
recommended large-scale habitat programs
focused on reducing the area affected by
annual or spring tillage within key pintail
breeding areas, and maintenance of key
staging and wintering habitats, especially
rice agriculture. The conversion of springseeded cropland to more pintail-friendly
agricultural uses (e.g., winter wheat, forage
crops) and maintenance of existing
grasslands in key pintail breeding
landscapes was of the highest conservation
priority. Conservation efforts have included
direct land securement and enhancement
efforts, agricultural partnerships, and
agricultural policy initiatives. While
considerable progress in these efforts has
been made over the last decade, land use and
agricultural drivers continue to threaten
progress. As well, new information on the
magnitude and scale of wetland loss,
especially in prairie Canada, suggests
additional habitats threats not considered in
original discussions.
In concert with these activities, an
unprecedented effort was initiated in 2007 to
build habitat-linked regional and continental
life-cycle models for pintails that integrate
the effects of habitat and harvest
management (Mattson et al. 2011). Current
modeling efforts are focused on developing
regional submodels directly linking habitat
change and management efforts to
demographic vital rates in key breeding and
wintering regions.
Literature Cited:
Anderson, J. T. 2008. Survival, habitat use,
and movements of female northern pintails
wintering along the Texas coast. MS
Thesis Thesis, Texas A&M University,
Kingsville, TX.
Fleskes, J. P., J. L. Yee, G. S. Yarris, M. R.
Miller, and M. L. Casazza. 2007. Pintail
and mallard survival in California relative to
habitat, abundance, and hunting. Journal of
Wildlife Management 71: 2238-2248.
Haukos, D. A., M. R. Miller, D. L. Orthmeyer,
J. Y. Takekawa, J. P. Fleskes, M. L.
Casazza, W. M. Perry, and J. A. Moon.
2006. Spring migration of northern pintails
from Texas and New Mexico, USA.
Waterbirds 29: 127-136.
Mattsson, B. J., M. C. Runge, J. H. Devries,
G. S. Boomer, J. M. Eadie, D. A. Haukos, J.
P. Fleskes, D. N. Koons, W. E. Thogmartin,
and R. G. Clark. 2012. A modeling
framework for integrated harvest and habitat
management of North American waterfowl:
case-study of northern pintail
metapopulation dynamics. Ecological
Modelling 225: 146-158.
Miller, M. R., D. C. Duncan, K. L. Guyn, P. L.
Flint, and J. E. Austin. 2003. The northern
pintail in North America: The problem and
a prescription for recovery, Sacramento, CA.
Miller, M. R., J. Y. Takekawa, J. P. Fleskes,
D. L. Orthmeyer, M. L. Casazza, and W. M.
Perry. 2005. Spring migration of northern
pintails from California's Central Valley
wintering area tracked with satellite
telemetry: routes, timing, and destinations.
Canadian Journal of Zoology 83: 13141332.
Rice, M. B., D. A. Haukos, J. A. Dubovsky,
and M. C. Runge. 2010. Continental
survival and recovery rates of northern
pintails using band-recovery data. Journal
of Wildlife Management 74: 778-787.
Review of Scaup Population Hypotheses: Do they fit recent trends?
Jean-Michel DeVink* Canadian Wildlife Service, 115 Perimeter Road, Saskatoon, SK, Canada,
S7N 0X4, [email protected]
TSA Bpop Estimate ('000,000)
Extended Abstract: Scaup (both lesser and
greater) population dynamics have proven an
enigma of sorts. Following their late 1970s
peak in excess of 7 million breeding birds in
the Traditional Survey Area (TSA), scaup
began their gradual decline to a record low in
2006 of less than half that number (Fig 1).
Since then, population estimates appear to be
rebounding, particularly in the western boreal
forest – their traditional breeding stronghold.
9
8
7
6
5
4
3
2
1
0
1955
1966
1977
NAWMP
Boreal
1988
1999
2010
TSA
Prairie
Figure 1. Scaup breeding population estimates
from the TSA and by biome of the May Breeding
Waterfowl Survey, 1955-2012, in relation to the
North American Waterfowl Management Plan
(NAWMP) objective.
Population models suggest that survival of
hens and reproductive success are the
principle model parameters that are limiting
scaup population growth (Koons et al. 2006),
and most hypotheses have focused on effects
related to these parameters. Here I provide a
brief review of hypotheses and provide
context for each in light of recent biomespecific population trends.
The Spring Condition Hypothesis (SCH)
posits that reduced body condition during
migration and pre-breeding has negatively
affected survival and productivity of scaup.
Wetlands in the upper Midwestern US, among
other places, have suffered from loss and
degradation. Concomitantly, scaup body
condition is lower there than historic levels
(Anteau and Afton 2004), but conflicting body
condition results from the boreal has led to
debate about the degree of impact these
changes have had on scaup productivity,
particularly in northern breeding areas.
Changes in wetland conditions on staging
areas would not likely result in divergent
population trends among biomes due to mixed
spatial use of staging areas by various
breeding populations. Therefore, further
research investigating changes in body
condition among biomes using a consistent
approach would be required to better test the
SCH given recent population trajectories.
The Contaminants Hypothesis states that
environmental contaminants have impacted
scaup survival and productivity. Recent
increases in scaup use of exotic bivalve
mollusks that bioaccumulate contaminants
may have facilitated exposure to industrial
effluents, particularly on wintering grounds.
Studies have documented relatively high
concentrations of some contaminants,
particularly selenium, in scaup. However,
there has been a lack of evidence supporting
reproductive effects or reduced survival due to
contaminants both in the wild and in captive
settings (DeVink et al. 2008). It is unlikely
contaminants could also result in divergent
population trends among biomes.
Climate Change: Two related hypotheses
associated with climate change have been
proposed to explain scaup population
dynamics. The Mismatch Hypothesis purports
The Predation Hypothesis states that shifts in
predator abundance and communities, through
natural or anthropogenic causes, are one
contributing factor to population declines in
parts of their range. Systematic removal of
mammalian predators does increase nest
success of waterfowl in the prairies. However,
a lack of information about predator
community dynamics from the boreal has
limited the scope of this hypothesis to explain
population declines there between 1980 and
2006.
Harvest Impact Hypothesis: Hunting mortality
of scaup has been debated as a source of
additive or compensatory mortality, and one
that may have contributed to population
declines. Analyses of scaup harvest and
population trajectories have suggested that
harvest is not an important factor in driving
past population declines (Afton and Anderson
2001). Despite restrictive bag limits set in
2008, harvest in the US has remained
relatively stable since 2006 (Fig. 2), which
suggests that it is unlikely to have influenced
the recent population increases in the boreal.
1000
Harvest ('000s)
that earlier spring phenology and warmer
water temperatures of the ecosystems in which
scaup breed have caused invertebrates to
advance their reproductive cycles, reducing
their availability to scaup later in the season
(Drever and Clark 2007). Periodic changes in
local climate and concomitant food
availability could result in differing population
trends among biomes. Current research is
evaluating this hypothesis against population
trends. The Habitat Hypothesis posits that
wetland habitat changes due to climate change
have reduced the quality or quantity of
breeding habitat available for scaup. Little
work has been completed to test this
hypothesis on a large scale, though evidence
of loss and changes to wetlands in Alaska
supports a key premise of this hypothesis.
800
600
400
200
0
1961 1971 1981 1991 2001 2011
US
CA
Figure 2. Estimates of scaup harvest in US and
Canada 1961-2011.
To date, the SCH and Mismatch hypotheses
have shown the greatest support in explaining
continental scale population trends, though the
former is limited in its ability thus far to
explain recent divergent trends among biomes.
As scaup numbers now exceed the long-term
average, some question the need to further
invest in scaup research. Building on our
recent efforts, particularly during this recent
period of increase, could provide important
insights about scaup population dynamics and
build on our general knowledge about
waterfowl ecology.
Literature Cited:
Afton, A.D., and M.G. Anderson. 2001. Journal
of Wildlife Management 65:781-796.
Anteau, M.J., and A.D. Afton. 2004. Auk
131:917-929.
Drever, M. C., and R. G. Clark. 2007. Journal
of Animal Ecology 76: 139-148
DeVink, J.-M., R. G. Clark, S. M. Slattery, and
M. Wayland. 2008. Environmental Pollution
150:116-122
Koons, D.N., J.J. Rotella, D.W. Willey, M.L.
Taper, R.G. Clark, S.M. Slattery, R.W.
Brook, R.M. Corcoran, and J.R. Lovvorn.
2006. Avian Conservation and Ecology 1:6.
Scaup Conservation Action Plan: Linking models to conservation actions and the
revisioned NAWMP
Jane E. Austin*, U.S. Geological Survey, Northern Prairie Wildlife Research Center, 8711 37th
Street SE, Jamestown, ND 58401, USA ([email protected])
G. Scott Boomer, U.S. Fish and Wildlife Service, Division of Migratory Bird Management, 11510
American Holly Drive, Laurel, MD 20708-4016, USA ([email protected])
Robert G. Clark, Environment Canada, Prairie and Northern Wildlife Research Center, 115
Perimeter Road, Saskatoon, SK S7N 0X4, Canada ([email protected])
David W. Howerter , Ducks Unlimited Canada, Institute for Waterfowl and Wetlands Research,
Oak Hammock, MB ROZ 2Z0, Canada ([email protected])
James E. Lyons, U.S. Fish and Wildlife Service, Division of Migratory Bird Management, 11510
American Holly Drive, Laurel, MD 20708-4016, USA ([email protected])
Stuart M. Slattery, Ducks Unlimited Canada, Institute for Waterfowl and Wetlands Research,
Oak Hammock, MB ROZ 2Z0, Canada ([email protected])
Extended Abstract: The combined breedingseason populations of North American greater
scaup (Aythya marila) and lesser scaup (A. affinis)
(hereafter, scaup) declined from estimates of 5.7–
7.6 million birds in the 1970s to a record low of
3.25 million birds in 2006 before showing signs of
recovery in recent years; an estimated 5.24
million scaup were reported for 2012. Scaup
populations have remained 17–48% below the
goal of 6.3 million scaup set in the first North
American Waterfowl Management Plan
(NAWMP). Concerns about the population’s
status have been exacerbated because there are
many uncertainties about factors limiting scaup
populations; therefore, appropriate management
actions are unclear. Possible effects of ecosystem
change on habitat carrying capacity and the role
of harvest in scaup population dynamics are two
sources of uncertainty that have led to
considerable debate in the waterfowl-management
community. Furthermore, stakeholders are
concerned about declining opportunities for scaup
hunting and the future of diving duck hunting
traditions.
We used a structured decision-making process
to develop a biologically based framework to
guide scaup conservation actions. Our early
efforts focused on problem framing (resource
allocation) and identifying fundamental
objectives of scaup conservation planning.
This process involved >50 scientists and
decision-makers over the course of three
workshops. Participants 1) defined the
problem and objectives, 2) identified potential
management actions and measures of success,
3) contributed information on vital rates, 4)
identified key uncertainties about scaup
population dynamics, and 5) identified urgent
issues for conservation planning. Early in the
process, we identified the need to integrate not
only objectives for scaup populations and
habitat but also scaup hunter populations.
Ultimately, the final goal and objectives (Fig.
1) are consistent with the revisioned NAWMP
(NAWMP Committee 2012).
The decision framework is supported by two
linked population models that integrate scaup
and scaup hunter demography. First, we
developed an annual life-cycle model that
incorporates population estimates and vital
rates for each of three breeding regions:
boreal forest and prairie potholes (lesser
scaup) and tundra (greater scaup). We
structured the model to be consistent with the
spatial and temporal scales outlined by the
objectives and the set of potential
management actions. Second, we developed a
model to represent changes in scaup hunter
numbers as a function of key factors affecting
their recruitment and retention. These two
models were then directly linked through a
harvest rate parameter.
The scaup life-cycle model includes the
necessary structure to represent alternative
hypotheses about scaup population dynamics
and response to different management
alternatives. The model also can be used to
explore the potential impacts of large-scale
system change on scaup reproduction and
carrying capacity. Ultimately, the scaup
models provide the necessary framework to
perform decision analyses to evaluate the
estimated costs and benefits of specific
management actions and to make transparent,
informed trade-offs among multiple
objectives.
We have successfully developed an initial
framework to support scaup conservation
planning. As part of our decision analyses for
optimal conservation action and monitoring,
current tasks include the finalization of a baseline
parameterization, completion of formal sensitivity
analyses, and specification of utility functions to
describe stakeholder values.
The scaup conservation modeling framework is
the first to encompass the revisioned NAWMP
goals – integrating objectives for waterfowl
populations, habitat conservation, and societal
needs and desires (here, the scaup hunting
community). This prototype provides a tool to
evaluate linkages among management actions,
environmental change, scaup populations, and
hunter community dynamics. The framework was
designed to support decision analyses that identify
the best areas and actions for scaup conservation
while providing a basis for learning about the
consequences of management actions.
Literature Cited:
North American Waterfowl Management
Plan Committee. 2012. North American
Waterfowl Management Plan 2012:
People conserving waterfowl and
wetlands. Canadian Wildlife Service and
U.S. Fish and Wildlife Service.
Figure 1. Goal and objectives hierarchy for the scaup conservation action plan.
The Baltic/Wadden Sea Common Eider – a waterbird population of conservation concern
Anthony D. Fox,* Department of Bioscience, Aarhus University, Kalø, Grenåvej 14, DK-8410
Rønde, Denmark ([email protected])
The Baltic/Wadden Sea flyway Common
Eider Somateria mollissima (hereafter
“Eider”) population breeds in Sweden,
Finland, Denmark, Norway, Estonia, the
Netherlands and Germany and winters
mainly in Denmark, Germany, the
Netherlands, Sweden, Norway and Poland.
Despite breeding on remote coastlines and
wintering entirely at sea, this population is
relatively well-studied and has been the
subject of long-term international
monitoring programmes because of its status
as a huntable quarry and recent declines in
abundance. However, we still lack basic
information about the population, making
this an excellent case study for the session.
Annual midwinter censuses of Eiders have
been carried out in some areas on the
wintering grounds as a means of establishing
changes in overall population size.
Coordinated aerial surveys in the Dutch,
German and Danish Wadden Sea show
numbers halved from c.320,000 in 1993 to
c.160,000 in 2007, but count coordination
elsewhere has been less good (Ekroos et al.
2012). Shifts from using the “total count
method” to modern aerial survey methods,
e.g. distance sampling and spatial modelling
to generate density surfaces (and hence area
estimates with associated confidence
intervals; Ekroos et al. 2012) has further
restricted comparisons among annual totals
across their range. As a result, our best
estimates of winter totals for the years 1991,
2000 and 2009 were 1,181,000, 760,000 and
976,000 Eiders respectively. It is difficult to
conclude whether the “increase” between
2000 and 2009 was a real increase in
abundance or due to (i) the changes in
survey methods, (ii) the generation of mid-
winter counts from some states from data
from several winters during 2006-2010 or
(iii) birds short stopping further east in
response to milder winters, where they may
be less well counted (Ekroos et al. 2012).
Wadden Sea declines have been blamed on
commercial shellfish exploitation which has
reduced Eider prey availability, linked to
Eider mass starvation in some years and
regional reductions in numbers (Ekroos et
al. 2012).
After relative stability during 1991–2000,
estimates of overall breeding abundance fell
by 48% during 2000–2009, yet nesting
numbers in Denmark have been more or less
constant for two decades (Ekroos et al.
2012). Causes of declines at specific
colonies vary. Since the 1990s, White-tailed
Sea Eagles Haliaeetus albicilla have
recolonized parts of Finland, taking
incubating females and eggs of Eiders.
Invasive American Mink Neovison vison
have also reduced reproductive success and
female survival in Sweden (Desholm et al.
2002). Increased predator pressure in parts
of the breeding range is thought to have
contributed to changes in adult sex ratio
amongst Eider taken in Denmark, which fell
from 45% females in 1982 to less than 25%
in 2010 (Ekroos et al. 2012).
Some colonies, lacking these predators,
show no such declines, whilst in others,
falling reproductive success and/or colony
size have been linked to low duckling
survival (through density dependent
regulation and viral disease, Finland),
competition with other nesting waterbirds
(Denmark) and poor pre-nesting female
body condition in spring (Denmark).
Falling proportions of first winter birds in
the Danish hunting kill from ca. 70% in
1982 to ca. 30% in 2010 indicate dramatic
structural changes amongst the winter
population overall (Ekroos et al. 2012).
Disease and parasite infestation could also
reduce survival and recruitment and the
species is known to have been adversely
affected by pollutants generally (e.g.
genotoxic polyphenolic hydrocarbons and
organochlorines detected in Finland, Matson
et al. 2004), lead poisoning specifically
(Finland), Avian Cholera outbreaks
(Denmark), intestinal occlusions (males in
Finland) and duckling virus (Finland, see
Desholm et al. 2002). The fitness
consequences of effects of winter
infestations of acanthocephalans and
ecosystem level thiamine deficiency remain
unproven. The population remains a
popular legal quarry species in Denmark,
Norway, Sweden and Finland with up to
115,000 birds shot annually. It is unclear to
what extent current harvest levels are
consistent with sustainable exploitation.
Other man-induced mortality known to
affect the population include by-catch in gill
nets, collisions with high speed vessels and
with offshore structures such as wind
turbines and bridges.
Despite these multiple pressures, our current
knowledge of the size and rate of change in
the Baltic/Wadden Sea flyway Eider
population remains poor and the primary
drivers of change unknown. It is essential
that we generate (i) robust annual population
estimates, (ii) unbiased estimates of annual
immature and adult survival and (iii) annual
assessments of reproductive output if we are
to be able to provide effective advice on
population management. Under present
circumstances, whatever the true rate of
decline, our impression is that the total
flyway population will experience further
declines, unless productivity increases and
the factors responsible for decreasing adult
female survival and productivity are
identified and ameliorated. This
presentation will also prevail upon the
conference audience to help develop
recommendations for improved flyway-level
monitoring and management of Eiders in
this flyway.
Literature Cited:
Desholm, M., Christensen, T.K., Scheiffarth,
G., Hario, M., Andersson, Å., Ens,
B.,Camphuysen, C.J., Nilsson, L., Waltho,
C.M., Lorentsen, S.-H., Kuresoo, A., Kats,
R.K.H., Fleet, D.M. & Fox, A.D. 2002.
Status of the Baltic/Wadden Sea
population of the Common Eider
Somateria m. mollissima. Wildfowl 53:
167-204.
Ekroos, J., Fox, A.D., Christensen, T.K.,
Petersen, I.K., Kilpi, M., Jónsson, J.E.,
Green, M., Laursen, K., Cervencl, A., de
Boer, P., Nilsson,L., Meissner, W.,
Garthe, S. & Öst, M. 2012. Declines
amongst breeding Eider Somateria
mollissima numbers in the Baltic/Wadden
Sea flyway. Ornis Fennica 89: online
early.
Matson, C. W., Franson, J. C., Hollmén, T.,
Kilpi, M., Hario, M., Flint, P. L. &
Bickhamn, J. W. 2004. Evidence of
chromosomal damage in common eiders
(Somateria mollissima) from the Baltic
Sea . Marine Pollution Bulletin 49: 10661071.
Sea Duck Joint Venture: Evolution of a JV Model for Conservation of Declining Waterfowl
Timothy D. Bowman,* U.S. Fish and Wildlife Service, 1011 East Tudor Road, Anchorage,
Alaska 99503, USA ([email protected])
Stuart M. Slattery, Ducks Unlimited Canada, Box 1160, Stonewall, Manitoba, ROC 2Z0,
Canada ([email protected])
Kathryn Dickson, Environment Canada, Canadian Wildlife Service, 351 St. Joseph Boulevard,
Hull, Quebec, K1A 0H3, Canada ([email protected])
W. Sean Boyd, Environment Canada, Science and Technology Branch, RR#1, 5421 Robertson
Rd, Delta, BC V4K 3N2, Canada ([email protected])
The Sea Duck Joint Venture (SDJV) was
established in 1999 to advance sea duck
conservation. The perception was that sea
ducks were declining for unknown reasons
and research was needed to fill key
information gaps to enable sound
management, which became the SDJV’s core
function. The SDJV’s multi-species mandate,
limited knowledge of sea duck biology and
population status, and the inherent difficulty in
studying this group of birds in remote arctic
and marine environments have and continue to
impose special challenges to conservation.
However, the SDJV’s coordinated
international approach, mainly between U.S.
and Canada, and a continental perspective,
have been essential to advancing conservation
for these species.
The SDJV’s initial research program was
diverse and opportunistic, reflecting the
plethora of knowledge gaps and a small sea
duck research community. SDJV priorities
were set within, but not among species
because it was felt that the lack of information
about all species precluded prioritizations
among species (Sea Duck Joint Venture
Management Board 2008). Emphasis was
placed on research that provided a
fundamental understanding of population
delineation, ecology, and status. Satellite
telemetry, in particular, provided extensive
data on sea duck ranges, migration patterns,
habitat use, and site fidelity that could not
have been obtained using more traditional
study methods such as banding. Distinct
populations for several sea duck species have
now been identified in North America and
range maps for several species have been
redrawn. Previously unknown ties with
countries outside North America (e.g.,
Greenland, Russia) have been revealed. This
information, along with data on abundance
and trends, has allowed the SDJV to rank
species and research priorities, giving higher
priority to species known or believed to be
declining, species facing significant threats,
and species with high societal values (hunting,
subsistence).
Taken together, the information gained has set
the stage for achieving our ultimate goal to
identify and recommend conservation and
management actions that will most benefit sea
ducks. There have been some successes in
this regard; arctic shipping lanes have been
influenced, harvest regulations amended, and
restrictions on siting of offshore wind power
were changed to protect sea ducks. Despite
these successes, providing sufficient
knowledge on which to base management
actions continues to be a challenge. For
example, an understanding of the key factors
limiting population growth remains unknown
for most species. Reliable, long-term
monitoring data are lacking for most species;
unconventional surveys and new efforts are
needed – at a time when agency budgets are
With the rapid pace of knowledge gains about
sea ducks, the SDJV is taking an adaptive
approach, where progress and priorities are
Sea Duck Joint Venture Management Board.
2008. Sea Duck Joint Venture Strategic
Plan 2008-2012. Available online at:
http://seaduckjv.org
Sea Duck Joint Venture. 2012. Sea Duck Joint
Venture Implementation Plan for April 2012
through March 2015. Available online at:
http://seaduckjv.org
50
1st SDJV Projects Funded
40
STEI
Listed
SPEI
Listed
30
20
Year
Number of peer-reviewed publications on
North American sea ducks, by year.
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
1990
1989
1988
1987
1986
1985
1984
1983
1982
1981
1980
1979
1978
1977
0
1976
10
1975
To increase its focus, the SDJV undertook
several planning exercises to refine priorities
and better integrate research with management
decisions. The SDJV’s research program
currently emphasizes providing information
most needed by managers to effectively
manage sea ducks. Input from waterfowl
managers and habitat conservationists is being
solicited and higher priority is given to
addressing issues where the cost of making a
wrong management decision based on
inadequate or incorrect information is high.
Current priorities are completing population
delineation for several key species, fostering
development of core monitoring programs,
and recommending strategies to manage
harvest and conserve habitat.
Literature Cited:
1974
At the same time, threats appear to be
increasing. Harvest pressure is growing in
some areas and threats to arctic environments
from climate change and associated
consequences, such as the opening of arctic
shipping routes and increased resource
development, are posing additional threats.
All of these underscore the need for a more
focused approach to information gathering,
and highlight the importance of maintaining
momentum using the SDJV model.
reviewed, adjusted as appropriate, and
reflected in an annual implementation plan
(Sea Duck Joint Venture 2012). The success
of the SDJV to date can be attributed to
several factors, including: 1) dedicated
coordinators and base funding that has helped
accelerate the pace of research and monitoring
programs; 2) an emphasis on partnerships; 3)
representation from both researchers and
managers in decision-making; 4) growing
interest in a group of birds for which exciting
discoveries of basic natural history can, and
are, being made; 5) supporting an international
sea duck conference every three years to
facilitate communication of research findings
and special workshops; and 6) a willingness
to adapt as needed.
No. Publications
dwindling. Advice for coastal habitat JVs and
habitat conservation activities has been limited
due to the difficulty of assessing habitat
requirements and carrying capacity in marine
environments, and uncertainty about how
habitat JVs can influence protection of marine
habitats. We currently have a limited basis for
setting habitat goals based on population
targets, and uncertainty about which
conservation measures will best improve the
status of sea ducks and their habitats.
Changes in Size and Trends of North American Sea Duck Populations Associated with
North Pacific Oceanic Regime Shifts
Paul L .Flint,* U.S. Geological Survey, Alaska Science Center, 4210 University Drive,
Anchorage, Alaska 99508 ([email protected])
Extended Abstract Broad scale, multi-species
declines in populations of North American sea
ducks have occurred for unknown reasons and
are cause for management concern. Oceanic
regime shifts have been associated with rapid
changes in ecosystem structure of the North
Pacific and Bering Sea. Hare and Mantua
(2000) and Overland et al. (2008) considered
suites of biological and climatic variables
recorded over long time frames and concluded
that broad scale regime shifts occurred in the
North Pacific in 1977, 1989 and 1998. These
regime shifts represent complex changes in
the ecosystem processes and differ from long
term cycles (i.e., El Niño) in that they have an
unknown number of states. Regime shifts are
known to alter primary productivity,
invertebrate populations, secondary
consumers and top predators (Lees et al.
2006), yet relatively little is known about
potential effects of these changes in oceanic
conditions on marine bird populations at broad
scales (Agler et al. 1999, Irons et al. 2008).
I examined changes in North American
breeding populations of sea ducks from 1957
to 2011 in relation to oceanic regime shifts
detected in the North Pacific in 1977, 1989,
and 1998. I used population indices from the
traditional survey area of the North American
waterfowl breeding population and habitat
survey. I fit linear models which allowed
population size and trajectory to change
among the various combinations of regime
shifts. I used AIC based model selection
criteria to draw inference.
For eiders, scoters, and long-tailed ducks,
there was only support for regime shifts
affecting these species in 1977 and 1989.
Merganser data showed support for regime
shift effects in 1977 and 1998 and goldeneye
and bufflehead data supported a single regime
shift in 1989. Thus, of the 6 species groups
considered, 4 showed population effects from
the 1977 shift, 5 from the 1989 shift and one
from the 1998 shift. The effects of these
regime shifts differed across species groups
and time. Prior to 1989, 3 of 6 species groups
were declining; however, since the 1989
regime shift, all sea duck species groups show
stable or increasing trends at the continental
scale.
These results support the overall hypothesis
that oceanic regime shifts are correlated with
sea duck population status and trends.
However, these analyses are functionally posthoc correlations and as such there is no strict
inference of cause-and-effect relationships.
In some species, populations immediately
increased following a shift then subsequently
declined, whereas in other cases, populations
initially dropped but then began to increase.
These immediate and large population
responses to regime shifts can likely be
explained by changes in breeding propensity.
However, contrary to my initial expectations,
there was no correlation between changes in
population status and population trends
following a regime shift.
Changes in population status and trends are
functional realizations of changes in survival
and/or productivity. Patterns in sea duck
population response to North Pacific regime
shifts do not clearly fit with either a “change
in survival” or a “change in productivity”
explanation. Sea duck population responses to
oceanic regime shifts are unpredictable and
likely vary among species and locations.
The management implications of these results
are complicated. First, these results suggest
that the primary drivers of sea duck population
trends are processes that we cannot manage or
control and are difficult to monitor. If at-sea
conditions are the primary drivers of
population trends of these species, then the
usual management actions are only useful for
slight changes in trajectory within this larger
influence. Further, oceanic regime shifts can
only be detected 5–10 years after they have
happened. As such, detection of regime shifts
and associated population consequences for
sea ducks will always be retrospective. Case
in point is that perceived population declines
of sea ducks appear to have halted > 20 years
ago and populations have been relatively
stable or increasing ever since. Given these
results, we should reasonably expect dramatic
changes in sea duck population status and
trends with future oceanic regime shifts. Thus,
management objectives and harvest should
probably be re-evaluated any time a shift is
detected.
From a research perspective, these
relationships call for long term monitoring of
survival and productivity. Because regime
shifts are only detected retrospectively,
monitoring data before and after such shifts
are necessary to identify the population
parameters that change in response to oceanic
conditions. I suspect that such changes
represent functional changes in carrying
capacity and the associated population
responses represent density dependent
population dynamics. Under this hypothesis,
regime shifts represent rapid changes in
functional carrying capacities and the
associated population responses are
complicated by population momentum and
transient population dynamics of both sea
ducks and their prey species.
Literature Cited:
Agler, B. A., S. J. Kendall, D. B. Irons, and S.
P. Klosiewski. 1999. Declines in marine
bird populations in Prince William Sound,
Alaska coincident with a climatic regime
shift. Waterbirds 22:98-103.
Hare, S.R., and N. J. Mantua. 2000.
Empirical evidence for North Pacific regime
shifts in 1977 and 1989. Progress in
Oceanography 47:103-145.
Irons, D. B., T. Anker-Nilssen, A. J. Gaston,
G. V. Byrd, K. Falk, G. Gilchrist, M. Harrio,
M. Hjernquist, Y. V. Krasnov,A. Mosbech,
B. Olsen, A. Petersen, J. B. Reid, G. J.
Robertson, H. Strom, and K. D. Wohl.
2008. Fluctuations in circumpolar seabird
populations linked to climate oscillations.
Global Change Biology 14:1455-1463.
Lees, K., S. Pitois, C. Scott, C. Frid, and S.
Mackinson. 2006. Characterizing regime
shifts in the marine environment. Fish and
Fisheries 7:104-127.
Overland, J., S. Rodionov, S. Minobe, and N.
Bond. 2008. North Pacific regime shifts:
Definitions, issues, and recent transitions.
Progress in Oceanography 77:92-102.
Climate Change Effects on Dispersion of Viable Habitat: Predicting and Preserving
Alternatives in Shifting Landscapes
James R. Lovvorn,* Department of Zoology, Southern Illinois University, Carbondale, IL 62901
([email protected])
Two main expectations of climate change
are a long-term warming trend and increased
weather extremes. The first aspect can
cause directional shifts in the location or
quality of habitats, and the second can cause
increased variability in where habitats occur.
If extreme weather events happen in close
succession, with no chance for a system to
recover in between, habitats may transition
into fundamentally different states that no
longer serve the same habitat functions.
These dynamic processes undermine the
approach of protecting key habitats within
set boundaries, which has been a major
strategy for conserving waterfowl during
winter, migration, and sometimes breeding.
Spectacled eiders winter in pack ice of the
Bering Sea. Designation of extensive
critical habitat for this threatened species
does not preclude human uses of the area.
With warming climate, anticipated
northward expansion of bottom trawl fishing
requires delineation of no-trawl zones that
are adequate to support the eiders but do not
restrict fishing unnecessarily. However, the
location of profitable prey densities can
change in as few as 5 years, and in some
years high ice concentrations can exclude
the eiders from the better feeding areas.
During spring, the eiders migrate through a
variable system of leads (openings in ice) in
the Chukchi Sea. Imminent development of
an offshore oil field will require a pipe to
carry oil across this nearshore migration
corridor. This area is heavily ice scoured,
and in spring is covered with broken ice that
would prevent containment or recovery of
oil leaked from a ruptured pipe. If the
location of foraging areas and their
accessibility through ice change among
years, what placement of this pipe would
minimize exposure of birds to spilled oil?
For eiders during both winter and migration,
one approach is to examine as much
historical data as possible on the dispersion
of prey and ice cover, identify the extremes
of habitat availability, and protect areas
large enough to ensure that at least some
alternative habitat is available in all years.
For non-breeding birds, an important
consideration in such assessments is the
density of prey needed for profitable
foraging. Knowing this threshold under
different conditions provides a criterion for
delineating viable habitat, and for assessing
the area needed to support a given number
of birds. However, giving up densities can
be a complex function of energetic
profitability, anti-predator strategies, and
social interactions within and among
species; thus, they are hard to identify with
field data. Although research continues,
carrying capacity estimates at present
provide only relative rather than absolute
information on habitat adequacy.
For example, in the complex of smaller bays
in the San Francisco Bay system, surf
scoters and scaup move seasonally and
annually among bays in response to
availability of bivalve prey. These bivalves
fluctuate widely with freshwater inflow and
salinity governed by snowmelt in the
Sierras, and with invasions of marine
bivalve predators driven by variable ocean
climate. Detailed models indicate that
different diving duck species have different
profitability thresholds that affect their
carrying capacity. However, modeled
thresholds substantially underestimate mean
prey densities at which one bay is
abandoned for another. Pending better
understanding, conservation cannot focus on
a single bay, but must recognize that all bays
may become critical in some years. Again,
as we try to identify the minimum area of
habitat that is adequate, climate trends and
fluctuations mandate a widening of
geographic and temporal perspective.
In the arid West, breeding wetlands are
highly circumscribed, and often receive
water only after agricultural or municipal
water rights are satisfied. The entire humanenvironment system depends on annual
fluctuations in snowpack, which are strongly
affected by climate trends. Wetlands are
often small enough that their suitability for
different species can make mutually
exclusive shifts. For example, bulrush may
be used as upland cover by Mallards or as
flooded cover by Canvasbacks depending on
the amount of water that exceeds irrigation
needs in a given year. Sustaining regional
populations of both duck species requires
attention to climatic conditions and probable
trends across areas that are large enough to
ensure habitat is available somewhere for
both species in all years.
In response to expected long-term
geographic shifts and greater variability
among habitats, the Department of Interior
is establishing Climate Science Centers in
different regions across the nation.
Research approaches at these centers are just
developing. However, one theme is to link
the physical sciences, which have long been
focused on weather prediction and climate
modeling, to potential effects on biotic
communities. Correlational analyses of past
data will be essential and informative.
However, correlations often will not provide
mechanistic understanding that is needed to
predict “no-analog” communities of the
future, or effects on particular species such
as waterfowl.
For individual species, the current approach
of “climate envelope” modeling overlooks
the truism that different species will not
respond to a changing physical environment
in isolation. Rather, the response of each
species will depend strongly on direct and
indirect interactions with multiple other
species that are each responding in their own
way. For trophic relationships, the main
analytical approach has been network
modeling, which is greatly facilitated by the
Ecopath with Ecosim software. Such
models can consider possible changes in
species composition of communities,
changes in diet and production rates of
different organisms, and direct and indirect
interactions among all species. Although
model predictions are never entirely
accurate, they can indicate food web
elements that are most vulnerable to
environmental changes. Identifying
problems most likely to arise may aid
planning to avoid serious habitat losses in
the future.

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