Re-introduction of Trumpeter Swans to Utah
The Effects of Spatial Pattern on Predator-Prey
Dynamics
Swift Fox on the Pinon Canyon Maneuver Site, Colorado:
Population ..Ecology and Evaluation of Survey Methodologies
Visual Encounter Rate Model for Pelagic
Piscivores
Habitat Selection in Five Species of Cavity Nesting
Birds in the Uinta Mountains, Utah
Mapping Aquatic Habitat in Strawberry Reservoir
Salmonid Production and Survival in Strawberry
Reservoir
Impact of Introduced Lake Trout in Yellowstone
Lake
Modeling Lake Trout Predation on Kokanee in Flathead
Lake
Limnological Effects on Walleye Production in Three
Mid-elevation Reservoirs in Central Utah
Funding Sources:
Utah Division of Wildlife Resources
U.S. Fish and Wildlife Service
Ducks Unlimited
Project Location: Bear River Migratory Bird Refuge and vicinity
Project Duration: September 1996 - July 1999
Investigators:
John A. Kadlec
Katia Engelhardt
Technicians:
Renee Chi
Gregory Wattley
Goals and Objectives:
In order to reestablish a migratory route towards southern wintering grounds
for the Rocky Mountain population of Trumpeter swans (RMTSP), Trumpeter swans
will be introduced to the Bear River Migratory Bird Refuge (BRMBR). However,
the introduction of Trumpeter swans to BRMBR and the establishment of a migratory
route can only be successful if BRMBR meets Trumpeter swan staging habitat
requirements, and negative direct and indirect interactions with Tundra swans
(Cygnus columbianus) and hunters do not affect Trumpeter swan viability.
Our objectives therefore are (1) to examine quantity and availability of
sago pondweed (Potamogeton pectinatus), the preferred food resource of swans
in general, (2) to examine mechanisms for coexistence between Trumpeter swans
and Tundra swans, and (3) to examine Trumpeter swan interactions with
hunters.
Progress to Date:
We took infrared aerial photographs of BRMBR and vicinity to examine the
distribution of sago pondweed at the field site. These photos will need to
be digitized and analyzed with the geographical information system (GIS)
in the near future. Sixty-four transects (200m long, 10 stations per transect)
were established systematically/randomly at the field site. At every station
a soil core was taken which was then divided into 5cm sections. The soil
samples are currently analyzed in the lab to quantify sago pondweed tuber
biomass and distribution within the soil column.
Overall, 57 Trumpeter swans were caught at Harriman State Park, Idaho, in
November and December. They were immediately transported to BRMBR where they
were equipped with neck collars, tarsal bands, and some with transmitters.
Transmitters were either attached to the collar or with a special glue to
the back feathers of the swans. Forty-six swans were hard-released and nine
were soft released. We decided to soft release some birds in order to observe
them more closely for potential health problems, transmitter problems, and
behavior. Additionally, five Tundra swans were captured at Harriman State
Park and the refuge which were also equipped with collars, tarsal bands and
transmitters. After release, birds were tracked by radiotelemetry and through
visual observation. Interactions between as well as within both swan species
was observed and foraging behavior was recorded.
A swan hunter checking station located at the entrance of BRMBR was manned
in November. Esophagi and gizzards (52 total) were collected from swan hunters
to determine diet selection of Tundra and Trumpeter swans foraging on the
refuge. Whenever a Trumpeter swan was shot (8 total) additional information
was acquired.
Daily migrations of Tundra swans were counted in November to quantify the
trade-off between food resources and predation risk. Numbers of swans within
every impoundment on the refuge and vicinity were counted every week by air
craft to establish the number of swan days the refuge was used during the
fall migration and to measure the change of impoundment use by swans during
the season.
Waterfowl managers were contacted in Idaho, Nevada and California to evaluate
the establishment of a migratory route.
Future Plans:
Marked Trumpeter and Tundra swans will be tracked and observed until they
can no longer be located on BRMBR and vicinity. We will locate birds when
they migrate through BRMBR during the spring migration.
Tundra swans will be captured on the refuge during the spring migration to
measure differential mortality of the two swan species during the next swan
hunting season. We also may capture Trumpeter swans during late summer so
that Trumpeter swans get accustomed to the area before the hunting season
starts. Newly released birds are more susceptible to hunting than birds which
are accustomed to the area.
Breeding and wintering sites will be visited because we suspect that mechanisms
for Trumpeter and Tundra swan coexistence occur during the life cycle when
resources are scarce. Both species appear to select the same diet (sago pondweed)
and generally appear to prefer the same habitats.
Funding Source: Quinney Graduate Fellowship
Project Location: Utah State University and northern Utah
Project Duration: Spring 1997 - Spring 2000
Investigators:
John A. Bissonette
Lisa A. Nordstrom
Goals and Objectives:
This project will investigate the relationship between the spatial arrangement
of habitat patches and predator-prey dynamics. Our objective is to identify
certain spatial pattterns that allow the stabilization of predator-prey dynamics.
A laboratory experiment, based on Huffaker's mite experiments, will be conducted
to experimentally manipulate landscape pattern. The information will be used
to construct a spatially explicit model. The model will then be tested in
the field to determine if the results can be applied to a larger spatial
scale.
Progress to Date: The project is currently in the planning and design stage. Research will begin in Spring 1997.
Funding Source: U.S. Department of Defense (Army)
Project Location: Pinon Canyon Maneuver Site, southeastern Colorado
Project Duration: FY 1996 to FY 2000
Investigator: Eric M. Gese
Technician: Edward R. Schauster (Graduate Research Assistant)
Project Goals:
Progress to Date:
Graduate student has completed one quarter of course work at USU and planned
out study proposal. Required permits and protocols have been approved.
Future Plans:
Student will begin field work this winter: capturing and radio collaring
foxes, and conducting radiotelemetry and surveys.
Funding Source: New Faculty Research Grant
Project Location: Utah State University, Logan Utah
Project Duration: June 1996 - June 1998
Investigators:
Jason Vogel
David A. Beauchamp
Technicians:
Jeff Godfrey
Jason Van Tassell
Project Goals, Objectives, and Progress:
Pelagic piscivores forage by visually detecting prey dispersed over large
volumes of water. Therefore optimal conditions and prey visibility will determine
encounter rates between piscivores and their prey. The purpose of this study
was to estimate reaction distance between predators and prey fish as a function
of prey size, light intensity, and transparency in laboratory troughs. Reaction
distances by predators were calibrated against parallel measurements of detection
distances by /scuba divers and video, then detection distances by divers
were measured in western lakes with different optical characteristics at
different depths and times of day to estimate the shape and size of detection
volumes around model prey fish. Reaction distances of fish ranged 0-2m, and
increased asymptotically with increasing light. Detection envelopes around
model fish in different lakes considerably in size but were generally consistent
in shape. Downlooking detection distances were considerably shorter than
lateral and uplooking distances. This study represents the initial steps
toward understanding the capability of visually- feeding pelagic, predatory
fishes to search for, detect, and capture prey fishes, determining how these
capabilities change in response to changing biotic conditions, and developing
a model to predict how the influence of visually- feeding piscivores n the
structure and dynamics of ecological communities changes under different
conditions.
Future Plans:
During the upcoming year we will continue measuring reaction distances of
salmonids with different prey sizes and transparency levels. We will also
continue our SCUBA diving efforts and add different times of the day as well
as other systems(i.e. Lake Tahoe, Flaming Gorge, Lake Powell, etc.). With
this added information we will continue to develop the foraging model.
Funding Source:
U.S.D.A. Forest Service
National Biological Service
Project Location: Uinta Mountains, Utah
Project Duration: January 1997 - January 1999
Investigators:
Thomas C. Edwards, Jr.
Joshua Lawler
Goals and Objectives:
The study investigate habitat associations for five cavity nesting birds
(Mountain Chickadees, Mountain Bluebirds, Red-naped Sapsuckers, Tree Swallows,
and Northern Flickers) by building and testing predictive models at two spatial
scales.
Progress to Date:
One set of predictive models has been built using habitat data collected
in 1994 and 1995. In 1996 five new field sites were searched for nests. Habitat
measurements were made at all nest sites and a random sample of non-nest
sites. This data has been used to test the predictive models. A refined
explanatory model has been produced, defining a suit of habitat characteristics
associated with nest-sites of the five cavity nesting birds.
An additional set of predictive models is currently being built at a larger spatial scale, using landscape pattern characteristics such as percent habitat type, amount of edge, degree of fragmentation, and habitat diversity. These larger scale models are being constructed with the help of GIS and a spatial analysis program.
Future Plans:
Data collected in 1996 will be used to test the completed larger scale models.
The two sets of predictive models will then be refined and integrated. The
integrated models with then be tested in the field. In addition there will
be an attempt to link the models with other, vegetation level predictive
models.
Funding Source:
Utah Reclamation, Mitigation, and Conservation Commission
Utah Division of Wildlife Resources
Project Location: Strawberry Reservoir, Wasatch County,
Utah
Project Duration: August 1996 to March 1997
Investigators:
Chad P. Gubala
David A. Beauchamp
Goals and Objectives:
Examine the impacts of reservoir level fluctuations on seasonal habitat
availability for gamefish, undesirable fishes, and the forage base. Construct
a framework for optimizing reservoir management operations within the constraints
of water supply and demand, water quality, and the ecological integrity of
the fishery.
Progress to Date:
A bathymetric map of Strawberry Reservoir was constructed from an extensive
GPS-SONAR survey of the reservoir. Precise relationships between reservoir
stage and depth-specific areas and volumes were developed to link critical
fisheries habitats (wetted surface areas and volumetric estimates of key
strata) to reservoir operation. Hardcopy images and a digital elevation model
(DEM) type GIS files were developed for inclusion in UDWR databases. Strawberry
Reservoir is both an extremely popular trout fishery and a storage reservoir
for water diverted from the Uinta Basin to the Wasatch front. Seasonal changes
in water supply and demand create fluctuating water levels that could be
either potentially harmful or beneficial to aquatic resources and water quality.
Fluctuations can alter the thermal structure, food supply, and availability
of critical habitat for fish and invertebrates. The timing and magnitude
of changing water levels is important in determining whether impacts will
result. Reservoir fluctuations can affect availability and productivity of
benthic invertebrates which represent nearly half of the prey biomass in
the diets of trout. Drawdowns could eliminate critical shorezone cover for
juvenile salmonids, or could render these areas inaccessible due to thermal
incompatibilities. Reservoir levels affect accessibility to spawning and
nursery areas in tributaries, and can change the quality of spawning gravels
by altering sediment deposition/scouring zones and intragravel circulation
patterns. Fluctuations could potentially be used to limit spawning or recruitment
of undesirable non-native Utah chubs and Utah suckers.
Future Plans:
Model refinement will be coordinated with state fisheries representatives.
We intend to extend this approach to multiple-use, multi-reservoir watersheds.
Funding Source:
Utah Reclamation, Mitigation, and Conservation Commission
Utah Division of Wildlife Resources
Project Location: Strawberry Reservoir, Wasatch County,
Utah
Project Duration: July 1996 to January 1999
Investigators:
Casey M. Baldwin
David A. Beauchamp
Technicians:
Jason Van Tassel
Jeff Godfrey
Laura Kuehn
Project Goals, Objectives, and Progress:
As the fishery becomes reestablished in Strawberry Reservoir after the rotenone
treatment in 1990, the trophic interactions within and among species become
increasingly important in determining the structure and dynamics of this
community. The reservoir was restocked with Bear Lake cutthroat trout
(Oncorhynchus clarki utah), sterile rainbow trout (O. mykiss), and kokanee
(O. nerka) to support a popular fishery while increasing resistance to reinvasion
by nonnative, nongame fishes. Our objective was to couple diet analysis with
bioenergetics models to examine the impact of predation on juvenile salmonids,
nongame fishes, and zooplankton. The density of nongame fish has remained
low, whereas juvenile salmonids are relatively more abundant and enter the
reservoir in pulses from both stocking and natural reproduction. Juvenile
salmonids represented a major fraction of the diet following the fall stocking.
For most of the year, Daphnia and other invertebrates were the predominant
prey while salmonids and nongame fishes contributed little to the diets of
adult cutthroat and rainbow trout. Bioenergetic simulations indicated that
piscivory imposed severe mortality on fall-stocked juvenile cutthroat trout.
Consumption demand on Daphnia by the entire salmonid assemblage represented
a small fraction of Daphnia biomass and production for most of the year.
These results suggest that prey supply is sufficient to support the expanding
fish community, but that predation represents a significant loss to recruitment
of juvenile salmonids. These results can be used to model the population
dynamics of gamefish and may be useful in optimizing the timing and integration
of hatchery supplementation with natural reproduction of game fish in the
Strawberry basin.
Funding Source:
National Park Service
Biological Resources Division, U.S. Geological Survey
Project Location: Yellowstone National Park, Wyoming
Project Duration: July 1996 to December 1999
Investigators:
James R. Ruzycki
David A. Beauchamp
Technicians:
Vance Mumford
Project Goals, Objectives, and Progress:
The establishment of a reproducing population of non-native lake trout poses
a potentially serious threat to the integrity of the Yellowstone Lake ecosystem,
particularly to native Yellowstone cutthroat trout. We used field data on
diet, distribution and size structure of lake trout in a bioenergetics model
to estimate the seasonal and size-specific loss of cutthroat trout that could
be attributed to lake trout predation. Since the abundance of lake trout
is currently unknown, predation was computed as loss in biomass and numbers
of cutthroat trout consumed for every 1,000 lake trout, given the size structure
of predators currently observed in the lake. This analysis identifies the
seasons and sizes of predators and prey that are most heavily involved, and
demonstrates the need for a population estimate of predatory lake trout.
Based on seasonal distribution patterns and size structure of lake trout, we evaluate whether the lake trout population is stable or expanding. By linking the demography and temporal-spatial distribution patterns of lake trout and cutthroat trout, we are developing a conceptual model of cutthroat trout vulnerability to lake trout predation. This model will be used to identify critical periods and locations of predator-prey interactions, and will allow us to predict how interactions are likely to change in response to changes in environmental conditions or predator and prey populations.
Funding Source: Montana Department of Fish, Wildlife, and
Parks
Project Location: Kalispell, Montana
Project Duration: July - December 1996
Investigators: David A. Beauchamp
Technicians:
Jane Chen
Gary P. Thiede
Christine Gemperle
Project Goals, Objectives, and Progress:
Bioenergetic model simulations suggested that lake trout predation imposed
serious losses on the kokanee population in Flathead Lake, accounting for
87% (in the nominal run) of the number stocked within the first year of their
release. The heaviest predation in 1994 occurred during the first month after
stocking in June (351,000 kokanee eaten). Kokanee losses during this acute
predation exceeded total predation losses accrued during July-September (263,000
eaten). Lake trout in the 626-750 mm and 501-625 mm size class were responsible
for more than 64% of the estimated predation, and 376-500 mm lake trout consumed
another 21%. Kokanee disappeared from the diets of progressively larger predators
over time. Kokanee survival over the first year in the lake declined from
13.2% in the nominal run to 4.6% under chronic predation, whereas no kokanee
survived past midsummer under acute predation. Lake trout abundance might
have been underestimated in model simulations, because standard hydroacoustic
methods cannot detect fish less than 1 m from the bottom. Some fraction (e.g.,
10-50%) of the predator population in August 1995 probably was not detected.
When larger lake trout populations were modeled, kokanee survival (from an
initial stock of 800,000) dropped from 13.2% to 4.2% with a 10% increase
in lake trout abundance, and no survival was predicted if the lake trout
population was 50% larger than the acoustic-based estimate. The kokanee
mitigation program cannot meet its goals under the current stocking regime
of releasing 800,000-1,000,000 yearling kokanee in late spring. The simulations
of lake trout predation indicate that predation losses alone can account
for nearly all of the kokanees stocked, but other sources of mortality will
reduce adult recruitment even further. Different stocking strategies should
be tested before the end of the 5-year evaluation program ends. Dispersed,
nocturnal releases in deep, openwater areas are suggested to reduce the observed
functional and numerical responses by predators to easily detected, localized
high densities of stocked kokanees. This experiment would examine whether
dispersed stocking avoids or reduces loss during the acute predation phase,
and if so, whether higher intitial survival holds throughout life, or is
simply converted to higher chronic losses.
Funding Source: Utah Department of Wildlife Resources
Project Location: various Utah reservoirs
Project Duration: Jan 1996 - Dec 1996
Investigators:
Chris Luecke
Michael T. Slater
Technicians:
Phil Wilson
Todd Seamons
Jessica Ruehrwein
Goals and Objectives:
The growth, condition, and size distribution of Walleye (Stizostedion vitreum)
populations were examined in relation to food web status and limnological
characteristics in three mid-elevation reservoirs in central Utah. Abundance
and condition of walleye were greatest in reservoirs with abundant forage
fish populations. Forage fish growth rate was related to zooplankton food
resources, temperature, and oxygen conditions. Physical factors such as water
level fluctuation appeared to explain most of the variation in forage fish
recruitment success. Combining limnological conditions with forage fish
population dynamics provided a means of understanding walleye production
in mid-elevation reservoirs in Utah.
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