552 items found
Fishing
Research
Fact sheet
Fishing
Research
Fact sheet
Hierarchical model
Individual variation
Population-level
Predation
Telemetry
Wildland-urban interface
Hierarchical model
Individual variation
Population-level
Predation
Telemetry
Wildland-urban interface
Background
While many species have suffered from the detrimental impacts of increasing human population growth, some species, such as cougars (Puma concolor), have been observed using human-modified landscapes. However, human-modified habitat can be a source of both increased risk and increased food availability, particularly for large carnivores. Assessing preferential use of the landscape is important for managing wildlife and can be particularly useful in transitional habitats, such as at the wildland-urban interface. Preferential use is often evaluated using resource selection functions (RSFs), which are focused on quantifying habitat preference using either a temporally static framework or researcher-defined temporal delineations. Many applications of RSFs do not incorporate time-varying landscape availability or temporally-varying behavior, which may mask conflict and avoidance behavior.
Methods
Contemporary approaches to incorporate landscape availability into the assessment of habitat selection include spatio-temporal point process models, step selection functions, and continuous-time Markov chain (CTMC) models; in contrast with the other methods, the CTMC model allows for explicit inference on animal movement in continuous-time. We used a hierarchical version of the CTMC framework to model speed and directionality of fine-scale movement by a population of cougars inhabiting the Front Range of Colorado, U.S.A., an area exhibiting rapid population growth and increased recreational use, as a function of individual variation and time-varying responses to landscape covariates.
Results
We found evidence for individual- and daily temporal-variability in cougar response to landscape characteristics. Distance to nearest kill site emerged as the most important driver of movement at a population-level. We also detected seasonal differences in average response to elevation, heat loading, and distance to roads. Motility was also a function of amount of development, with cougars moving faster in developed areas than in undeveloped areas.
Conclusions
The time-varying framework allowed us to detect temporal variability that would be masked in a generalized linear model, and improved the within-sample predictive ability of the model. The high degree of individual variation suggests that, if agencies want to minimize human-wildlife conflict management options should be varied and flexible. However, due to the effect of recursive behavior on cougar movement, likely related to the location and timing of potential kill-sites, kill-site identification tools may be useful for identifying areas of potential conflict.
[show more]AIS
Boating
Inspection
AIS
Boating
Inspection
ANS
Fishing
ANS
Fishing
Contact InformationPhone: (970) 482-1141Email: tracy.davis@state.co.us
Education
- Partial M.S., Zoology/Physiology — University of Wyoming, (coursework & research completed) 2000
- B.S., Zoology — Colorado State University, 1993
- Associates, Petroleum Technology — Colorado Northwestern Community College, 1983
Current or Recent Positions
- Fish Research Hatchery Technician III — Colorado Parks and Wildlife, 2014–Present
- Captive Wildlife Health Research Technician IV — Colorado Parks and Wildlife, 2001-2014
- Biological Technician — National Black-Footed Ferret Conservation Center, U.S. Fish and Wildlife Service, 1996-2000
- Research Animal Attendant — University of Wyoming Cooperative Fish and Wildlife Research Unit, 1995-1996
Current or Recent Research Projects
Research support for the following projects:
- Development of Whirling Disease Resistant Brood-stock
- Strain Formalin Sensitivity – Hatchery Practices
- Boreal Toad Conservation
- Greenback Cutthroat Trout Recovery
- Iodine Concentration Effects on Salmonid Egg Hardening
- Fog Incubation Techniques on Greenback Cutthroat Trout Eggs
- Energetics
- Terrestrial Wildlife Disease
- Chemical Immobilization Techniques
- Fertility Control
- Ungulate and Black Footed Ferret Nutrition
- Testing New Technologies; transmitters, traps, etc.
Areas of Interest/Expertise
Support aquatic and terrestrial research through sound fish culture and improved, evolving animal husbandry techniques. Collaborate with researchers, managers, and veterinarians, to provide happy healthy animals, functioning facilities, and management systems, to protect and promote the integrity of good research while meeting/exceeding animal welfare needs.
Selected Publications
Fetherman, E. R., B. Neuschwanger, C. Praamsma, and T. Davis. 2023. Concentration, life stage, feeding, density, flow, and strain effects on formalin sensitivity in rainbow trout (Oncorhynchus mykiss). Animals 13(15):2425. Riepe, T. B., E. R., Fetherman, B. Neuschwanger, T. Davis, A. Perkins, and D. L. Winkelman. 2023. Assessment of vertical transmission of Renibacterium salmoninarum in hatchery-reared Cutthroat Trout (Oncorhynchus clarkii). Journal of Fish Diseases. Fetherman, E. R., B. Neuschwanger, T. Davis, C. L. Wells, and A. Kraft. 2020. Efficacy of Erymicin 200 injections for reducing Renibacterium salmoninarum and controlling vertical transmission in an inland rainbow trout brood stock. Pathogens 2020, 9(7), 547. Williams, T. M., L. Wolfe, T. Davis, T. Kendall, B. Richter, Y. Wang, C. Bryce, G. H. Elkaim, C. C. Willmers. 2014. Instantaneous energetics of puma kills reveal advantage of felid sneak attacks. Science 346 (81):31-38.
Wolfe, L. L., M. Fisher, T. Davis, and M. W. Miller. 2014. Efficacy of a Low- Dosage Combination of Butorphanol, Azaperone and Medetomindine (BAM) to Immobilize Rocky Mountain Elk. Journal of Wildlife Diseases 50(3):676-680.
Pilon, J. L., J. C. Rhyan, L. L. Wolfe, T. R. Davis, M. P. McCollum, K. I. O'Rourke, T. R. Spraker, K. C. VerCauteren, M. W. Miller,T. Gidlewski, T. A. Nichols, L. A. Miller, and P. Nol. 2013. Immunization with a synthetic peptide vaccine fails to protect mule deer (Odocoileus hemionus) from chronic wasting disease. Journal of Wildlife Diseases 49:694-698.
Rhyan, J. C., M. W. Miller, T. R. Spraker, M. McCollum, P. Nol, L. L. Wolfe, T. R. Davis, L. Creekmore, & K. I. O'Rourke. 2011. Failure of fallow deer (Dama dama) to develop chronic wasting disease when exposed to a contaminated environment and infected mule deer (Odocoileus hemionus). Journal of Wildlife Diseases 47 (3): 739-744.
Dreitz, V. J., L. A. Baeten, T. R. Davis, M. M. Riordan. 2011. Testing Radiotransmitter Attachment Techniques on Northern Bobwhite and Chukar Chicks. The Wildlife Society Bulletin 35 (4): 475-480.
Mich, P. M., L. L. Wolfe, T. M. Sirochman, M. A. Sirochman, T. R. Davis, W. R. Lance, & M. W. Miller. 2008. Evaluation of intramuscular butorphanol, azaperone, and medetomidine and nasal oxygen insufflation for the chemical immobilization of white-tailed deer, Odocoileus virginianus. Journal of Zoo and Wildlife Medicine 39: 480-487.
Duncan, C., J. Powers, and T.R. Davis. 2007. Abomasal and uterine adenocarcinomas with ovarian metastasis in a captive elk (Cervus elaphus nelsoni). Journal of Veterinary Diagnostic Investigation 19(5): 560-563. [show more]
Contact InformationEmail: troy.meyer@state.co.us
Current or Recent PositionsHatchery Technician III — Colorado Parks and Wildlife, 2015-CurrentAreas of Interest/Expertise
- Support aquatic and terrestrial research through sound fish culture and improved, evolving animal husbandry techniques.
- Collaborate with researchers, managers, and veterinarians, to provide happy healthy animals, functioning facilities, and management systems
Led By
Estevan Vigil and George Schisler
Study Area
Statewide
Project Status
Completed
Research Objectives
- To understand the potential and current consequences of gill lice on economically and ecologically important fish.
- To determine gill lice distribution in Colorado.
Project Description
In Colorado, gill lice, a parasitic copepod (group of small crustaceans), can infect cutthroat trout, kokanee salmon and rainbow trout, which are ecologically and economically important fish species in Colorado. Gill lice are very host-specific, and thus far, only one species of gill lice (Salmincola californiensis) has been identified in Colorado.
Gill lice attach to and damage the gills of the host fish, interfering with oxygen exchange. As a result, infections can negatively affect fish behavior, immune system function, growth, warm water tolerance and survival.
Fisheries managers are concerned about gill lice in Colorado because the parasite is resistant to chemical treatments and thus very difficult to control. Further, very little research has been conducted on gill lice, making management challenging.
CPW initiated research to learn more about gill lice, specifically gill lice distribution in the state and the impacts of gill lice on Colorado's fish. Currently, CPW is the only agency conducting research on gill lice in Colorado and one of only a few in all of western North America.
With a greater understanding of gill lice, managers will be able to make management decisions that help protect and preserve Colorado's fish populations.
Associated Publications
Vigil, E. M., K. R. Christianson, J. M. Lepak, and P. J. Williams. 2016. Temperature effects on hatching and viability of juvenile gill lice, Salmincola californiensis. Journal of Fish Diseases 39:899–905.
Hargis, L.N., Lepak, J.M., Vigil, E.M., and Gunn, C. 2014. Prevalence and intensity of the parasitic copepod (Salmincola californiensis) on kokanee salmon (Oncorhynchus nerka) in a Colorado reservoir. Southwestern Naturalist 59(1):126-129. 2014. Fact SheetGill Lice in Colorado
[show more]
Led By
Lake and Reservoir Researchers
Study Area
Select reservoirs
Project Status
Ongoing
Research Objectives
- Monitor gill lice infection prevalence and intensity on kokanee salmon and rainbow trout populations in key reservoirs in relation to environmental conditions to identify factors contributing to high parasite burdens and potential mitigation strategies.
Project Description
Gill lice, parasitic copepods (group of small crustaceans), can infect cutthroat trout, kokanee salmon and rainbow trout, which are ecologically and economically important fish species in Colorado. Gill lice are very host-specific, and thus far, only one species of gill lice (Salmincola californiensis) has been identified in Colorado.
Gill lice attach to and damage the gills of host fish, interfering with oxygen exchange. As a result, infections can negatively affect fish behavior, immune system function, growth, warm water tolerance and survival.
Fisheries managers are concerned about gill lice in Colorado because the parasite is resistant to chemical treatments and very difficult to control. Further, very little research has been conducted on gill lice, making management challenging.
Lake and Reservoir Researchers have been monitoring gill lice infestations within kokanee and rainbow trout populations in select reservoirs to better understand how different factors such as the density of vulnerable fish, environmental conditions, and water level fluctuations interact to influence parasite burdens.
With a greater understanding of gill lice dynamics, we may be able to identify management strategies that effectively limit infection prevalence and intensity.
Associated Publications
Hargis, L.N., J.M. Lepak, E.M. Vigil, and C. Gunn. 2014. Prevalence and intensity of the parasitic copepod (Salmincola californiensis) on kokanee salmon (Oncorhynchus nerka) in a Colorado reservoir. Southwestern Naturalist 59:126-129.
Lepak, J.M., A.G. Hansen, M.B. Hooten, D. Brauch, and E.M. Vigil. 2022. Rapid proliferation of the parasitic copepod Salmincola californiensis (Dana) on kokanee salmon, Oncorhynchus nerka (Walbaum), in a large Colorado reservoir. Journal of Fish Diseases 45:89-98 (Cover image and story for journal issue).
Vigil, E.M., K.R. Christianson, J.M. Lepak, and P.J. Williams. 2016. Temperature effects on hatching and viability of juvenile gill lice, Salmincola californiensis. Journal of Fish Diseases 39:899-905.
[show more]Human-bear conflict
Black bear
Human-bear conflict
Black bear