Cooperative Research Units

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The Cooperative Research Units Program conducts research on a wide range of disciplines related to fish, wildlife, and natural resource management. Our 40 Units collectively conduct research on virtually every type of North American ecological community. 

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Filter Total Items: 104
Date published: November 9, 2020

Migration Corridors of Mule Deer in the Paunsaugunt Plateau Herd in Utah

The Paunsaugunt Plateau in southern Utah is home to a prolific mule deer herd numbering around 5,200 individuals in 2019. In early October, these mule deer begin their migration from the Plateau traveling south distances up to 78 miles to winter range in the Buckskin Mountains near the Utah-Arizona border. Approximately 20-30% of the Paunsaugunt Plateau herd reside in northern Arizona durin...

Date published: November 9, 2020

Winter ranges of mule deer in the Pequop Mountains, Nevada

The Area 7 mule deer population is one of the state’s largest deer herds with an estimated population of about 11,000 in 2019. This deer herd is highly important to Nevada from an economic and ecological perspective. It’s one of the longest distance deer migrations in the state of Nevada with some animals known to migrate over 120 miles during a single migration. A subset of th

Date published: November 9, 2020

Migration stopovers of mule deer in the Izzenhood herd, Nevada

Mule deer in the Izzenhood herd are part of a larger population known in Nevada as the “Area 6” mule deer population. They primarily reside on winter ranges in the Izzenhood Basin and upper Rock Creek drainages in western Elko County and northern Lander County. From their winter range, mule deer in this sub population migrate approximately 70 miles to summer ranges in the north

Date published: November 9, 2020

Migration Routes of Moose in the Jackson Herd in Wyoming

Moose in the Jackson herd make an elevational migration in the southern portion of the Greater Yellowstone Ecosystem. This small herd of approximately 500 animals winters primarily in the Buffalo Valley just east of Jackson Lake. During migration, animals travel an average one-way distance of 33 miles, with some animals migrating as far as 67 miles. In the spring, most moose migrate north i...

Date published: November 9, 2020

Winter ranges of mule deer in the Sheep Creek Range, Nevada

Mule deer in the Sheep Creek sub herd are part of the larger Area 6 herd that occupies portions of Elko, Lander, and Eureka counties. The primary winter range of this population is located along the eastern flank of the Sheep Creek Range and the west side of Boulder Valley. Most deer migrate approximately 30 miles from winter ranges in upper Boulder Creek and Antelope Creek drainages to summe...

Date published: November 9, 2020

Migration corridors of mule deer in the South Tuscarora Mountains, Nevada

Mule deer in the South Tuscarora herd are part of the larger “Area 6” deer population that reside in the southern and eastern portion of this big game Management Area (MA 6). The winter range for this sub population is located along the western slopes of the Tuscarora Mountains and the Dunphy Hills. The spring migration route for this deer herd traverses north along the toe

Date published: November 9, 2020

Migration Corridors of Elk in the Interstate 17 Herd in Arizona

The Interstate 17 (I-17) elk herd primarily resides in Arizona’s GMU 6A and 11M south of Flagstaff. The population estimate for elk in GMU 6A was 6,500 in 2019. Their summer range consists of gentle topography with ponderosa pine forest and interspersed riparian-meadow habitat. Annually, the I-17 elk herd migrates an average of 24 miles to lower-elevation winter range dominated by

Date published: November 9, 2020

Wyoming Game and Fish Department stopovers of mule deer in the Baggs Herd, Wyoming

The Baggs Mule Deer Corridor was officially designated by the Wyoming Game and Fish Department (WGFD) in 2018 (fig. 24). The Baggs Herd is managed for approximately 19,000 animals, and the corridor is based on two wintering deer populations: a northern and southern segment. Animals in the north segment occupy a relatively small winter range along a pinyon-juniper ridge that runs alo

Date published: November 9, 2020

Migration Routes of Mule Deer in the Wyoming Range South Population in Wyoming

Mule deer in the southern Wyoming Range population winter north of Evanston in the relatively low mountains between Kemmerer, Wyoming, and Woodruff Narrows Reservoir along the Utah border. Many deer in this population migrate north more than 100 mi (161 km) to summer ranges in the Wyoming Range surrounding Afton, Wyoming. Migrations in this population are not limited to Wyoming, with

Date published: November 9, 2020

Migration stopovers of mule deer in the Pequop Mountains, Nevada

The Area 7 mule deer population is one of the state’s largest deer herds with an estimated population of about 11,000 in 2019. This deer herd is highly important to Nevada from an economic and ecological perspective. It’s one of the longest distance deer migrations in the state of Nevada with some animals known to migrate over 120 miles during a single migration. A subset of th

Date published: November 9, 2020

Winter Ranges of Mule Deer in the Ruby Mountains, Nevada

The Area 10 mule deer population is one of the largest deer herds in the state, accounting for roughly 20 percent of the statewide mule deer population. The Area 10 herd is comprised of several sub populations that occupy the majority of the Ruby Mountains, are highly migratory,and exhibit long distance migrations from summer to winter ranges. Several key stopovers occur within the migratio...

Date published: November 9, 2020

Migration Routes of Elk in the Interstate 17 Herd in Arizona

The Interstate 17 (I-17) elk herd primarily resides in Arizona’s GMU 6A and 11M south of Flagstaff. The population estimate for elk in GMU 6A was 6,500 in 2019. Their summer range consists of gentle topography with ponderosa pine forest and interspersed riparian-meadow habitat. Annually, the I-17 elk herd migrates an average of 24 miles to lower-elevation winter range dominated by

Filter Total Items: 2,893
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Year Published: 2020

Conserving transboundary wildlife migrations: Recent insights from the Greater Yellowstone Ecosystem

Animal migrations are ecologically, culturally, and economically important. Ungulate populations in many parts of Africa, Asia, Europe, and the Americas migrate long distances to access seasonally available resources, traversing vast landscapes in large numbers. Yet some migrations are declining, raising concerns among scientists and natural...

Middleton, Arthur D.; Sawyer, Hall; Merkle, Jerod A.; Kauffman, Matthew; Cole, Eric. K.; Dewey, Sarah R.; Gude, Justin A.; Gustine, David D.; McWhirter, Douglas E.; Proffitt, Kelly M.; White, P. J.

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Year Published: 2020

Coldwater periods in warmwater streams: Microhabitat shifts from autumn to winter by Smallmouth Bass

Seasonal and life stage variation in microhabitat use is an important driver of fish survival and bioenergetics, but knowledge of microhabitat selection during colder periods is generally lacking in warmwater streams. Our objective was to examine changes in microhabitat selection by age‐0 (TL ≤ 85 mm) and age‐1+ (TL > ...

Wolf, S.L.; Mollenhauer, R.; Brewer, Shannon K.

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Year Published: 2020

Nonlinear patterns in mercury bioaccumulation in American alligators are a function of predicted age

Mercury is a widespread, naturally occurring contaminant that biomagnifies in wetlands due to the methylation of this element by sulfate-reducing bacteria. Species that feed at the top trophic level within wetlands are predicted to have higher mercury loads compared to species feeding at lower trophic levels and are therefore...

Lawson, A.J.; Moore, Clinton T.; Rainwater, T.R.; Nilsen, F.M.; Wilkinson, P.M.; Lowers, R.H.; Guillett, L.J. Jr; McFadden, Katherine W.; Jodice, Patrick G.R.

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Year Published: 2020

Latitudinal variation in snowshoe hare (Lepus americanus) body mass: A test of Bergmann’s Rule

The relationship between body size and latitude have been the focus of dozens of studies across many species. However, results of testing Bergmann’s Rule – that organisms in colder climates or at higher latitudes possess larger body sizes – have been inconsistent across studies. We investigated whether snowshoe hares (Lepus americanus) follow the...

Gigliotti, Laura C. ; Berg, Nathan D. ; Boonstra, Rudy ; Cleveland, Shawn M.; Diefenbach, Duane R.; Gese, Eric M. ; Ivan, Jacob S. ; Kielland, Knut; Krebs, Charles J. ; Kumar, Alexander V. ; Mills, L. Scott; Pauli, Jonathan N.; Underwood, H. Brian; Wilson, Evan; Sheriff, M.J.

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Year Published: 2020

Vulnerability of resource-users in Louisiana’s oyster fishery to environmental hazards

Knowledge of vulnerability provides the foundation for developing actions that minimize impacts on people while maximizing the sustainability of ecosystem goods and services. As a result, it is becoming increasingly important to determine how resource-dependent people are vulnerable to environmental hazards. This is particularly true in coastal...

Humphries, A. T.; Josephs, L.; LaPeyre, Megan K.; Hall, S. A.; Beech, R.D.

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Year Published: 2020

Anthropogenic land‐use change intensifies the effect of low flows on stream fishes

As ecosystems experience simultaneous disturbances, it is critical to understand how multiple stressors interact to affect ecological change. Land‐use change and extreme flow events are two important stressors that could interact to affect fish populations.We evaluated the individual and interactive effects of discharge and land‐use change...

Walker, Richard H.; Girard, Carlin E.; Alford, Samantha L.; Walters, Annika W.

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Year Published: 2020

Identifying important military installations for continental-scale conservation of marsh bird breeding habitat

Degradation of wetland ecosystems has negatively impacted many species, perhaps none more so than marsh birds that breed in vegetative emergent wetlands throughout North America. The U.S. Department of Defense manages approximately 29 million acres of land within the continental U.S., and many military installations contain wetland complexes that...

Stevens, Bryan S.; Conway, Courtney J.

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Year Published: 2020

Juvenile Sandhill Cranes exhibit wider ranging and more exploratory movements than adults during the breeding season

Sandhill Cranes Antigone canadensis exhibit delayed sexual maturity and breeding, and therefore juvenile Cranes searching for suitable territories to occupy have different ecological constraints on movements than adults, which must defend a territory and raise young. We used fine-scale GPS telemetry data to characterize and compare...

Wolfson, David W.; Fieberg, John R.; Andersen, David

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Year Published: 2020

Reproductive ecology and movement of pallid sturgeon in the upper Missouri River, Montana

Successful recruitment of endangered pallid sturgeon has not been documented in the upper Missouri River basin for decades, and research on the reproductive ecology of pallid sturgeon has been hindered by low sample size. A conservation propagation program was initiated in the 1990s, and the oldest age class of hatchery‐origin pallid sturgeon are...

Holmquist, Luke M.; Guy, Christopher S.; Tews, Anne; Trimpe, David J.; Webb, Molly A. H.

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Year Published: 2020

Comparing grasshopper (Orthoptera: Acrididae) communities on tallgrass prairie reconstructions and remnants in Missouri

Tallgrass prairies, which once occupied a large swath of central North America, face the combined challenges of habitat loss and fragmentation. In Missouri, where less than 1% the historical prairie remains, prairies are being reconstructed from agricultural or wooded land.Invertebrates are often assumed to colonise reconstructions if native...

LaRose, J. P.; Webb, Elisabeth B.; Finke, D. L.

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Year Published: 2020

Bridging the gap between salmon spawner abundance and marine nutrient assimilation by juvenile salmon: Seasonal cycles and landscape effects at the watershed scale

Anadromous Pacific salmon are semelparous, and resource subsidies from spawning adults (marine-derived nutrients, or MDN) benefit juvenile salmonids rearing in freshwater. However, it remains unclear how MDN assimilation relates to spawner abundance within a watershed. To address this, we examined seasonal, watershed-scale patterns of MDN...

Joy, Philip J.; Stricker, Craig A.; Ivanoff, Renae; Wipfli, Mark S.; Seitz, Andrew C.; Tyers, Matthew

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Year Published: 2020

Relation of fish intersex to contaminants in riverine sport fishes

Endocrine active compounds (EACs) are pollutants that have been recognized as an emerging and widespread threat to aquatic ecosystems globally. Intersex, the presence of female germ cells within a predominantly male gonad, is considered a biomarker of endocrine disruption caused by EACs. We measured a suite of EACs and assessed...

Grieshaber, C. A.; Penland, T. N.; Kwak, Thomas J.; Cope, W. G.; Heise, R. J.; Law, J. M.; Shea, D.; Aday, D. D.; Rice, J. A.; Kullman, S. W.