561 items found
Type:
Subjects:
Description:
CPW Lake and Reservoir research scientists devote themselves to understanding and improving fisheries throughout the state.
Their research focuses on food web structures, lake and reservoir characteristics, understanding and managing prey bases, growth and condition of sport fish and how sport fish interact with each other.
Research scientists use a combination of new and long-standing techniques to address issues facing sport fisheries in Colorado.
Lake and Reservoir Ecology Research Projects:
- Evaluating Sterile Predators as a Management Tool
- Post-Stocking Performance of Triploid Walleye
- Evaluating Standard Sampling Protocols for Assessing Sport Fish Populations
- Evaluating the Biological Effectiveness of Angler Harvest Incentive Programs
- Population Assessment of Pelagic Fishes Using Hydroacoustics
- Reservoir Food Webs and Predator-Prey Interactions
- Understanding and Managing Gill Lice Infections in Reservoir Sport Fish
- Understanding and Managing Mercury Bioaccumulation in Sport Fish
Type:
Subjects:
Type: Article
Subjects: Acoustic ecology
<em>Odocoileus hemionus</em>
Vigilance
Mule deer
<em>Odocoileus hemionus</em>
Vigilance
Mule deer
Type:Article
Subject:Acoustic ecology
<em>Odocoileus hemionus</em>
Vigilance
Mule deer
<em>Odocoileus hemionus</em>
Vigilance
Mule deer
Description:While visual forms of vigilance behavior and their relationship with predation risk have been broadly examined, animals also employ other vigilance modalities such as auditory vigilance by listening for the acoustic cues of predators. Similar to the tradeoffs associated with visual vigilance, auditory behavior potentially structures the energy budgets and behavior of animals. The cryptic nature of auditory vigilance makes it difficult to study, but on-animal acoustical monitoring has rapidly advanced our ability to investigate behaviors and conditions related to sound. We utilized this technique to investigate the ways external stimuli in an active natural gas development field affect periodic pausing by mule deer (Odocoileus hemionus) within bouts of rumination-based mastication. To better understand the ecological properties that structure this behavior, we investigate spatial and temporal factors related to these pauses to determine if results are consistent with our hypothesis that pausing is used for auditory vigilance. We found that deer paused more when in forested cover and at night, where visual vigilance was likely to be less effective. Additionally, deer paused more in areas of moderate background sound levels, though responses to anthropogenic features were less clear. Our results suggest that pauses during rumination represent a form of auditory vigilance that is responsive to landscape variables. Further exploration of this behavior can facilitate a more holistic understanding of risk perception and the costs associated with vigilance behavior. [show more]
Type: Article
Subjects: Analysis
Animal behavior
Endangered species
Lynx
Animal behavior
Endangered species
Lynx
Type:Article
Subject:Analysis
Animal behavior
Endangered species
Lynx
Animal behavior
Endangered species
Lynx
Description:Understanding movement behavior and identifying areas of landscape connectivity is critical for the conservation of many species. However, collecting fine-scale movement data can be prohibitively time consuming and costly, especially for rare or endangered species, whereas existing data sets may provide the best available information on animal movement. Contemporary movement models may not be an option for modeling existing data due to low temporal resolution and large or unusual error structures, but inference can still be obtained using a functional movement modeling approach. We use a functional movement model to perform a population-level analysis of telemetry data collected during the reintroduction of Canada lynx to Colorado. Little is known about southern lynx populations compared to those in Canada and Alaska, and inference is often limited to a few individuals due to their low densities. Our analysis of a population of Canada lynx fills significant gaps in the knowledge of Canada lynx behavior at the southern edge of its historical range. We analyzed functions of individual-level movement paths, such as speed, residence time, and tortuosity, and identified a region of connectivity that extended north from the San Juan Mountains, along the continental divide, and terminated in Wyoming at the northern edge of the Southern Rocky Mountains. Individuals were able to traverse large distances across non-boreal habitat, including exploratory movements to the Greater Yellowstone area and beyond. We found evidence for an effect of seasonality and breeding status on many of the movement quantities and documented a potential reintroduction effect. Our findings provide the first analysis of Canada lynx movement in Colorado and substantially augment the information available for conservation and management decisions. The functional movement framework can be extended to other species and demonstrates that information on movement behavior can be obtained using existing data sets. [show more]
Type: Article
Subjects: Snowshoe hare
<em>Lepus americanus</em>
Latitudinal variation
Energy expenditure
Food supply
Winter
Snow depth
Growing season
<em>Lepus americanus</em>
Latitudinal variation
Energy expenditure
Food supply
Winter
Snow depth
Growing season
Type:Article
Subject:Snowshoe hare
<em>Lepus americanus</em>
Latitudinal variation
Energy expenditure
Food supply
Winter
Snow depth
Growing season
<em>Lepus americanus</em>
Latitudinal variation
Energy expenditure
Food supply
Winter
Snow depth
Growing season
Description:The relationship between body size and latitude has 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 Erxleben, 1777) follow Bergmann’s rule by investigating differences in body mass using data from six published studies and from data of 755 individual hares captured from 10 populations across North America covering 26° of north latitude. We also explored alternative hypotheses related to variation in hare body mass, including winter severity, length of growing season, elevation, and snow depth. We found body mass of hares varied throughout their range, but the drivers of body mass differed based on geographic location. In northern populations, females followed Bergmann’s rule, whereas males did not. In northern populations, male mass was related to mean snow depth. In contrast, in southern populations, body mass of both sexes was related to length of the growing season. These differences likely represent variation in the drivers of selection. Specifically, in the north, a large body size is beneficial to conserve heat because of low winter temperatures, whereas in the south, it is likely due to increased food supply associated with longer growing seasons.Le lien entre la taille du corps et la latitude a fait l’objet de dizaines d’études portant sur de nombreuses espèces. Les résultats des études visant à valider la règle de Bergmann, qui stipule que les organismes vivant en climat plus froid ou à plus haute altitude auraient des corps de plus grandes tailles, ne sont pas cohérents d’une étude à l’autre. Nous avons vérifié si les lièvres d’Amérique (Lepus americanus Erxleben, 1777) suivaient la règle de Bergmann en examinant les différences de masse corporelle dans des données de six études publiées et pour 755 lièvres capturés de 10 populations réparties à la grandeur de l’Amérique du Nord, sur un territoire couvrant 26° de latitude nord. Nous avons aussi examiné différentes hypothèses concernant les variations de la masse corporelle de lièvres, touchant notamment à la rigueur de l’hiver, la durée de la période végétative, l’altitude et l’épaisseur de la neige. Nous avons constaté que la masse corporelle des lièvres varie dans toute leur aire de répartition, mais que les facteurs qui l’influencent diffèrent selon l’endroit. Dans les populations nordiques, les femelles suivent la règle de Bergmann, mais non les mâles. Dans les populations nordiques, la masse des mâles est reliée à l’épaisseur moyenne de la neige, alors que dans les populations méridionales, la masse corporelle des deux sexes est reliée à la durée de la période végétative. Ces différences représentent vraisemblablement des variations des facteurs influant sur la sélection. Plus précisément, au nord, une grande taille du corps est utile parce qu’elle facilite la conservation de chaleur pour faire face aux faibles températures hivernales, alors que dans le sud, elle est probablement due à un meilleur approvisionnement en nourriture associé à des périodes végétatives plus longues. [Traduit par la Rédaction] [show more]
Type:Fact Sheet
Subject:Hunting
Fishing
Fact sheet
Fishing
Fact sheet
Description:Fishing and hunting have a total combined economic effect in Colorado of more than $3.2 billion. Fishing and hunting create more than 25,000 jobs, many in rural Colorado communities. Fishing and hunting licenses account for more than 40 percent of Colorado Parks and Wildlife’s (CPW’s) revenue and fund wildlife and fisheries management throughout our state. [show more]
Type: Article
Subjects: Hunter education
Volunteerism
Volunteer process model
Instructor
Recruitment
Retention
Volunteerism
Volunteer process model
Instructor
Recruitment
Retention
Type:Article
Subject:Hunter education
Volunteerism
Volunteer process model
Instructor
Recruitment
Retention
Volunteerism
Volunteer process model
Instructor
Recruitment
Retention
Description:Hunter education (HE) is offered in all 50 states, with oversight provided by state wildlife agencies (SWAs). The vast majority of HE courses are taught by volunteers. Recruiting and retaining volunteers to meet the demand for HE courses are growing concerns among SWAs. Insufficient information exists about volunteer instructors’ motivations, experiences, and satisfactions – all of which may affect recruitment and retention. Using the volunteer process model as the theoretical framework for a mixed-methods study, 38 semi-structured telephone interviews were conducted with current and former instructors in New York, followed by a mail survey administered to active instructors (n = 2,126). Findings indicated that volunteers are motivated to teach HE to sustain the tradition of hunting and create safe hunters. Those motivations, coupled with positive experiences teaching in teams, corresponded with instructor recruitment and long-term retention. Unclear roles, limited programmatic influence, and strained relationships were negatively associated with volunteer retention. [show more]
Type: Article
Subjects: Abundance
Auditory
Cougar
Mark–resight
Noninvasive
Predator calls
<em>Puma concolor</em>
Auditory
Cougar
Mark–resight
Noninvasive
Predator calls
<em>Puma concolor</em>
Type:Article
Subject:Abundance
Auditory
Cougar
Mark–resight
Noninvasive
Predator calls
<em>Puma concolor</em>
Auditory
Cougar
Mark–resight
Noninvasive
Predator calls
<em>Puma concolor</em>
Description:From 2014 to 2016, in the Front Range of Colorado, USA, we assessed noninvasive approaches to sampling cougar (Puma concolor) populations in an attempt to provide a new method that would be less field intensive, less expensive, and could be applied over large spatial extents compared with current methods. We assessed the use of predator calls to lure cougars to a site with remote camera traps for detection and also evaluated hair snags at sites to noninvasively identify individual animals. Predator calls effectively attracted cougars to specific sites with an average of 82 unique photographic detections of cougars per survey year (0.03 detections/trap-night). However, obtaining hair samples from these animals was less effective because animals did not always pass through hair snags and ability to uniquely identify individuals by genotype was poor. We evaluated different approaches to estimating cougar density and found mark–resight to be a viable option in our study system. Mark–resight density estimate after correcting for partial use of the sampling area by cougars was 4.1 cougars/100 km2 (95% CI = 2.4, 5.8). Our results indicate that combining methods of noninvasive genetic sampling and auditory calls to monitor cougar populations can provide reliable density estimates over large geographic areas and areas with significant amounts of inaccessible private lands. [show more]
Type: Article
Subjects: Swift fox
Conservation translocations
Demographics
Habitat fragmentation
Reintroductions
<em>Vulpes velox</em>
Conservation translocations
Demographics
Habitat fragmentation
Reintroductions
<em>Vulpes velox</em>
Type:Article
Subject:Swift fox
Conservation translocations
Demographics
Habitat fragmentation
Reintroductions
<em>Vulpes velox</em>
Conservation translocations
Demographics
Habitat fragmentation
Reintroductions
<em>Vulpes velox</em>
Description:The successful recovery of imperiled species is dependent on knowledge of how demographic drivers mediate population growth and expansion. One of the largest species restoration projects has been the reintroduction of swift foxes Vulpes velox to southern Canada, where 947 foxes were released between 1983 and 1997. Swift foxes have since increased and expanded their range into northern Montana (USA), but have experienced a population decline and stall in recolonization over the past 10 years. The objective of this study was to estimate the survival and reproductive rates of swift foxes in northern Montana, which constitutes the southern edge of this population. In addition, we evaluated support for two different hypotheses of how environmental factors and several demographic factors influence survival. Although our length of monitoring was relatively short, we found that adult and juvenile annual survival rates were 54% and 74%, respectively, and fecundity was 0.85. We found the most support for the hypothesis that the percentage of native grassland at the 1-km scale influenced survival and found that survival increased, on average, 2.1% for every 5% increase in grassland. Compared to previous estimates of swift fox population growth immediately following the release, our data suggest the population is currently stable. The long-term successful recolonization and connectivity of swift fox populations in this region will likely be dependent on maintaining large tracts of contiguous grassland. Comparing the estimates of demographic rates among different points in space and time should help managers better understand the population dynamics and inform restoration strategies for recovering populations. [show more]
Type:
Subjects:
Description:The Colorado Division of Wildlife established a conservation order for light geese in 1999. Annual reports detail the conservation order period, participation estimates, and harvest estimates.