576 items found

Led ByKen Logan​

​​Study AreaUncompahgre Plateau

Project StatusCompleted

Research Objectives

• To test biological assumptions used by CPW to manage mountain lion populations with recreational hunting. 
• To examine effects of sport-hunting on lion population dynamics.
• To examine the genetics of a lion population.
• To develop tools wildlife managers can use to estimate lion abundance.
• To study lion diseases.
• To develop strategies for managing lion populations.

Research Description

Colorado Parks and Wildlife managers need reliable information on mountain lions in Colorado in order to develop management strategies that work to address public concerns and maintain healthy lion populations. However, the knowledge and tools needed to do so were limited, promoting this 10-year project.

The purpose of this study is to learn how sport-hunting impacts mountain lion population dynamics, develop tools for estimating lion abundance, and to develop strategies for managing lion populations. This knowledge will be provided to wildlife managers and to the public for application to lion management and conservation.  

This project was designed with two 5-year periods, a reference period and a treatment period. In the reference period (completed 2004-2009), CPW closed the study area to mountain lion hunting. The reference period provided data on lion population dynamics without lion deaths caused by sport-hunting.  During this time, researchers collected data on population abundance, sex and age structure, reproduction, and sources of mortality.

In the treatment period (2009-2014), researchers are manipulating the mountain lion population with sport hunting. The hunting treatment is designed to test assumptions CPW applies to other lion populations managed with sport-hunting in Colorado. The same type of data collected in the reference period is being collected in the treatment period for comparison. 

In both study periods, researchers gathered mountain lion population characteristics by capturing, marking, radio-collaring, and tissue-sampling lions in the study area (e.g., skin, blood, saliva, tongues from dead lions). To date (August 2014), over 220 lions have been captured, marked, and sampled.

Moreover, in collaboration with researchers at Colorado State University and Oklahoma State University, CPW researchers have tested mountain lion tissues for diseases. CPW researchers are also collaborating with geneticists from Arizona State University to examine lion population genetics, relatedness, and reproductive success.

Led By:

Study Areas

• Bear’s Ears elk herd (DAU E-2)
• Trinchera elk herd (DAU E-33)
• Uncompahgre Plateau elk herd (DAU E-20)

Project Status

Research Objectives

• To estimate calf and adult female survival and cause-specific mortality rates
• To quantify pregnancy rates and nutritional condition
• To evaluate factors influencing survival, pregnancy rates, and nutritional condition

Project Description

In 2017, researchers began a 2-year pilot study to investigate factors influencing elk recruitment in two study areas in the state. The initial pilot project was expanded into a 3^rd study area in 2019 and the research continues to better understand elk population dynamics in Colorado and determine how predators, habitat, and weather conditions are impacting elk recruitment in Colorado.

Reports:

Evaluating Factors Influencing Elk Recruitment in Colorado (2019-current)

Publications:

Crews, S., N.D. Rayl, M.W. Alldredge, E.J. Bergman, C.R. Anderson Jr., and G. Bastille-Rousseau. 2025. Drivers of spring migration phenology in Rocky Mountain elk. Scientific Reports 15:7807.

Led ByJake Ivan

Study AreaStatewide

Project StatusOngoing

Research Objectives

• To evaluate options to monitor the long-term success of lynx reintroduction efforts.

Project Description

In 1997, Colorado Parks and Wildlife began a large-scale effort to reintroduce lynx into the state with the goal of establishing a self-sustaining population of lynx. Four years after the last lynx was released into the state in 2006, CPW deemed the initial lynx introduction effort a success. Research focus has now shifted towards determining the long-term success of the reintroduction. 

Researchers cannot use traditional methods to estimate abundance of lynx populations because the animals move extensively, exist at low densities, and can be difficult to capture. Instead, this project aims to monitor lynx population trends by using presence/absence data to estimate the proportion of the landscape occupied by lynx.  This proportion should trend up or down as lynx abundance moves up or down.

From 2009 to 2010, researchers tried various methods of detecting lynx in areas where they were known to be present. This work showed that snowtracking surveys conducted by snowmobile were the most efficient means to detect lynx. However, such surveys can only occur in roaded areas. For surveys in wilderness areas, researchers determined that remotely triggered wildlife cameras were the most efficient method for detecting lynx. 

Based on data collected from field research in 2009-2010, researchers determined that a sample of 50 sample units would need to be surveyed annually in the San Juan and South San Juan Mountains in order to be able to detect meaningful trends in lynx occupancy in the region. 

Work will be completed by CPW in partnership with the U.S. Forest Service. Additionally, other ranges throughout the state will be surveyed on a rotating basis such that when the monitoring effort is at full strength, annual data will be collected in the Southwest to monitor trends in the population, and periodic surveys will be conducted elsewhere to determine the extent of the population in the state.  

Associated Publications

• Ivan, J. S., 2013. Statewide Monitoring of Canada lynx in Colorado: Evaluation of options. Pages 15-27 in Wildlife Research Report, Mammals Research Program, Colorado Division of Parks and Wildlife, Fort Collins, CO. 310 pp.
• Ivan, J. S., 2012. Monitoring Canada Lynx in Colorado Using Occupancy Estimation: Initial Implementation in the Core Lynx Research Area. Pages 26-34 in Wildlife Research Report, Mammals Research Program, Colorado Division of Parks and Wildlife, Fort Collins, CO. 195 pp.
• Ivan, J.S., 2011. Monitoring Canada Lynx in Colorado Using Occupancy Estimation: Initial Implementation in the Core Lynx Research Area. Wildlife Research Report, Mammals Research program, Colorado Division of Parks and Wildlife, Fort Collins, CO.

Led By

​Dr. George J. Schisler​

Study Area

Parvin Lake, Red Feather Lakes, CO​

Project Status

Led ByHeather Johnson, Matt Hammond, Patt Dorsey, Kurt VerCauteren (USDA National Wildlife Research Center), Justin Fischer (USDA National Wildlife Research Center), W. David Walter (USDA National Wildlife Research Center), and Charles Anderson (USDA National Wildlife Research Center).

Study AreaVicinity of Dove Creek, Colorado 

Project StatusCompleted

Research Objectives

• To test various non-lethal techniques to reduce elk and deer crop depredation.
• To examine elk and mule deer distribution and migration patterns around agricultural areas to design public hunting opportunities to reduce crop damage.
• To map and model landscape characteristics associated with elk and deer damage to identify site-specific management strategies to minimize crop depredation.

Project Description

Elk and mule deer provide important recreational, ecological, and economic benefits, but they can also cause substantial damage to crops in rural areas. Crop damage caused by elk and deer accounts for a majority of the state's wildlife damage claims, which Colorado Parks and Wildlife is obligated to pay.

In particular, the sunflower fields around Dove Creek have experienced high rates of damage from elk and deer. Between 2007 and 2009, CPW paid farmers in the region roughly a quarter of a million dollars annually and routinely allocated kill permits, distribution hunts and private land only doe/cow hunts to eliminate animals causing damage. Pressure from local growers over crop damage and frustration from the general public over kill permits prompted CPW to evaluate other management options for reducing crop damage caused by elk and deer. 

As a result, CPW partnered with wildlife damage researchers from the USDA National Wildlife Research Center to test various non-lethal solutions to reduce crop damage. Such techniques include polyrope electric fencing, winged fencing, and an organic repellent. In addition, researchers are tracking deer and elk movement patterns using GPS collars. The data will be used to identify distribution and migration patterns so that public hunts can be designed that target those elk and deer causing conflicts with farmers. In addition, deer and elk location data will be used to model damage potential in relation to field locations, surrounding habitat types, human development, and topography. Information about the location of a crop field in the context of the overall landscape will allow CPW to work with local growers to identify appropriate management strategies to reduce game damage.

Results from this study should enable CPW and local growers to reduce deer and elk crop depredation, leading to a decrease in compensation payments, a decrease in kill permits/distribution hunts, and an increase in public hunting opportunities.ReportsEvaluating solutions to reduce elk and mule deer damage on agricultural reources (2010-2013)

Associated Publications

Led By: Lake and Reservoir Researchers

Study Area: Select reservoirs

Project Status: Ongoing

Research Objectives:Examine the suitability of specialized gill netting protocols for assessing sport fish populations in key Colorado reservoirs.

Project Description

Gill nets are commonly used to monitor fish populations. They are lightweight, easy to use, catch multiple sizes and species of fish simultaneously, and provide information (i.e., numbers and sizes) that can be compared through time. Observed trends in catch information from annual gill net surveys are used to inform fisheries management decisions.

The Lake and Reservoir Research group has been investigating the appropriateness of specialized gill netting protocols developed by the Ontario Ministry of Natural Resources that enable biologists to estimate the total number of fish in a lake or reservoir (i.e., “abundance”). Specifically, lake trout and walleye, which are two highly sought sport fish in Colorado.

Researchers have examined two protocols: Summer Profundal Index Netting (SPIN) for lake trout, and Fall Walleye Index Netting (FWIN) for walleye. Both protocols use gill nets set for a defined duration at multiple depths across all regions of a reservoir, resulting in a rapid, comprehensive survey typically completed over 2-4 days.

Other methods for estimating the abundance of a fish population (like tagging and then recapturing tagged fish) in a lake or reservoir are resource intensive, and can be cost prohibitive. Thus, techniques such as SPIN and FWIN can be valuable when in-depth population assessments are needed to help inform complex management decisions. For example, changes to harvest regulations, how to balance top predators with their prey fish populations, or other challenges managers face.

Associated Publications

Beauchamp, D.A., A.G. Hansen, and D.L. Parrish. 2024. Chapter 7: Coldwater fish in large standing waters. In Standard methods for sampling North American freshwater fishes (2^nd edition). Edited by S.A. Bonar, W.A. Hubert, and D.W. Willis. American Fisheries Society, Bethesda, Maryland.

Hansen, A.G. 2019. Size-dependent retention of pelagic-oriented kokanee in multimesh gill nets. North American Journal of Fisheries Management 39:921-932.

Hansen, A.G., M.W. Miller, E.T. Cristan, C.J. Farrell, P. Winkle, M.M. Brandt, K.D. Battige, and J.M. Lepak. 2023. Gill net catchability of walleye (Sander vitreus): are provincial standards suitable for estimating adult density outside the region? Fisheries Research 266:106800.

Pate, W.M., B.M. Johnson, J.M. Lepak, and D. Brauch. 2014. Managing for coexistence of kokanee and trophy lake trout in a montane reservoir. North American Journal of Fisheries Management 34:908-922.