575 items found
Type: Text
Subjects: Colorado
Mule deer
Management
Habitat
Mule deer
Management
Habitat
Type:Text
Subject:Colorado
Mule deer
Management
Habitat
Mule deer
Management
Habitat
Description:The management and research of mule deer (Odocoileus hemionus) in Colorado and throughout the Rocky Mountain West is an exciting arena for wildlife professionals as the prevailing view among biologists, managers, researchers, hunters, wildlife viewers and general wildlife enthusiasts is that they would like to see more deer on the landscape. This desire, and the subsequent support it generates for mule deer research, has paved the way for research projects to evolve: each project has generated new data, new knowledge and answers to questions, but each projected has also generated new questions. My research has been a part of this evolution; it benefited from and was built on existing information, it adds new knowledge and hopefully, it will help guide future research. [show more]
Type:
Subjects: Demography
Healthy herds
Infectious disease
Matrix model
Prion
Healthy herds
Infectious disease
Matrix model
Prion
Subject:Demography
Healthy herds
Infectious disease
Matrix model
Prion
Healthy herds
Infectious disease
Matrix model
Prion
Description:Abstract
- Predators may create healthier prey populations by selectively removing diseased individuals. Predators typically prefer some ages of prey over others, which may, or may not, align with those prey ages that are most likely to be diseased.
- The interaction of age-specific infection and predation has not been previously explored and likely has sizable effects on disease dynamics. We hypothesize that predator cleansing effects will be greater when the disease and predation occur in the same prey age groups.
- We examine the predator cleansing effect using a model where both vulnerability to predators and pathogen prevalence vary with age. We tailor this model to chronic wasting disease (CWD) in mule deer and elk populations in the Greater Yellowstone Ecosystem, with empirical data from Yellowstone grey wolves and cougars.
- Model results suggest that under moderate, yet realistic, predation pressure from cougars and wolves independently, predators may decrease CWD outbreak size substantially and delay the accumulation of symptomatic deer and elk. The magnitude of this effect is driven by the ability of predators to selectively remove late-stage CWD infections that are likely the most responsible for transmission, but this may not be the age class they typically select. Thus, predators that select for infected young adults over uninfected juveniles have a stronger cleansing effect, and these effects are strengthened when transmission rates increase with increasing prey morbidity. There are also trade-offs from a management perspective—that is, increasing predator kill rates can result in opposing forces on prey abundance and CWD prevalence.
- Our modelling exploration shows that predators have the potential to reduce prevalence in prey populations when prey age and disease severity are considered, yet the strength of this effect is influenced by predators' selection for demography or body condition. Current CWD management focuses on increasing cervid hunting as the primary management tool, and our results suggest predators may also be a useful tool under certain conditions, but not necessarily without additional impacts on host abundance and demography. Protected areas with predator populations will play a large role in informing the debate over predator impacts on disease
ID: Experimental evaluation of population trend and harvest composition in a Wyoming cougar population
Type: Article
Subjects: Adaptive management
Cougar
Exploitation
Population trend
<em>Puma concolor</em>
Sex–age composition
Cougar
Exploitation
Population trend
<em>Puma concolor</em>
Sex–age composition
Type:Article
Subject:Adaptive management
Cougar
Exploitation
Population trend
<em>Puma concolor</em>
Sex–age composition
Cougar
Exploitation
Population trend
<em>Puma concolor</em>
Sex–age composition
Description:Cougar (Puma concolor) management has been hindered by inability to identify population trends. We documented changes in sex and age of harvested cougars during an experimentally induced reduction in population size and subsequent recovery to better understand the relationship between sex-age composition and population trend in exploited populations. The cougar population in the Snowy Range, southeast Wyoming, was reduced by increased harvest (treatment phase) from 58 independent cougars (>1 year old) (90% C***l = 36–81) in the autumn of 1998 to 20 by the spring of 2000 (mean exploitation rate = 43%) and then increased to 46 by spring 2003 following 3 years of reduced harvests (mean exploitation rate = 18%). Pretreatment harvest composition was 63% subadults (1.0–2.5 years old), 23% adult males, and 14% adult females (2 seasons; n = 22). A reduction in subadult harvest, an initial increase followed by a reduction in adult male harvest, and a steady increase in adult female harvest characterized harvest composition trends during the treatment phase. Harvest composition was similar at high and low densities when harvest was light, but proportion of harvested subadult males increased at low density as they replaced adult males removed during the treatment period (high harvest). While sex ratio of harvested cougars alone appears of limited value in identifying population change, when combined with age class the 2 appear to provide an index to population change. Composition of the harvest can be applied to adaptively manage cougar populations where adequate sex and age data are collected from harvested animals. [show more]
Type: Fact Sheet
Subjects: Aquatic animals -- Effect of water pollution on -- Colorado
Metals -- Toxicology -- Colorado
Metals -- Toxicology -- Colorado
Type:Fact Sheet
Subject:Aquatic animals -- Effect of water pollution on -- Colorado
Metals -- Toxicology -- Colorado
Metals -- Toxicology -- Colorado
Description:Experiments conducted by Colorado Parks and Wildlife suggest the current water quality standard for iron (Fe) is two to four times higher than it should be to protect Colorado's aquatic life.
Type:
Subjects:
Description:
Led By
Study Area
Four Colorado Reservoirs (Blue Mesa, Granby, Shadow Mountain, Williams Fork)
Project Status
Completed
Research Objectives
- To explore less time-consuming and more reliable methods for determining fish age.
Project Description
Understanding lake and reservoir food web structure plays a crucial role in determining how best to manage a sport fishery. In order to inform management decisions, managers use a variety of techniques to characterize important aspects of lake and reservoir fisheries.
For example, managers can use otoliths, calcified structures in a fish's inner ear that grow like tree rings, to determine the age of the fish. This information helps managers understand things like fish growth rates, the age structure of a fish population and if certain age classes of fish are missing from the population. This information can help managers identify and potentially address problems in a fish population like disease, poor spawning or recruitment, and overpopulation
Currently, researchers use thin sections of the otoliths to determine the age of the sample fish. However, this method is labor-intensive, requires extensive training and is a subjective classification. Therefore, CPW initiated a research project to determine if otolith mass can be used as a reliable indicator of age. Such a method would require less training, would be faster and would be relatively objective.
During the kokanee salmon spawning runs, researchers collected kokanee salmon from four reservoirs in Colorado. Researchers noted kokanee salmon length and whether the fish was male or female. Otoliths were also extracted from each fish and weighed. A small subset (~30) of otolith sections was used to determine kokanee salmon age and "calibrate" a computer model. All the length and gender data from each fish (hundreds) was then input into the model to estimate ages for all the fish collected. With a relatively low error rate, researchers determined that using otolith mass is a promising addition to traditional age-classification methods.
Results from this study provide managers with a faster and more reliable manner in which to determine fish age in Colorado's lakes and reservoirs. This information will inform future management decisions, streamline methods required to determine fish age and will be applied to the valuable kokanee salmon fishery in Blue Mesa Reservoir.
Associated Publications
Lepak, J.M., Cathcart, C.N., and Hooten, M.B. 2012. Otolith weight as a predictor of age in kokanee salmon (Oncorhynchus nerka) from four Colorado reservoirs. Canadian Journal of Fisheries and Aquatic Sciences. 69(10):1569-1575.
[show more]Type: Article
Subjects: Constraints
Motivations
Nontraditional path hunter
Recruitment
Socialization
Motivations
Nontraditional path hunter
Recruitment
Socialization
Type:Article
Subject:Constraints
Motivations
Nontraditional path hunter
Recruitment
Socialization
Motivations
Nontraditional path hunter
Recruitment
Socialization
Description:Anecdotal evidence suggests that adults lacking previous hunting experience and family support for hunting comprise a growing proportion of new hunters. Empirical evidence of such a trend is lacking. Furthermore, hunting motivations and constraints for these “nontraditional path hunters” (NTPHs) have not been well documented. We articulate a strategy for identifying potential NTPHs in New York, describe socialization mechanisms initiating NTPHs into hunting, and explore motivations and constraints of these hunters. Data were collected using a Web-based survey of 3,605 NTPHs identified among 2014 Sportsman Education course graduates in New York. We found that many NTPHs were initiated by friends and co-workers, and their motivations and constraints were similar to traditional hunters. These findings suggest that NTPHs are not a panacea to the trend of declining numbers of hunters in New York. [show more]
Type: Article
Subjects: Feline foamy virus
Epidemiology
Retrovirus
<em>Spumaretrovirus</em>
Mountain lion
<em>Puma concolor</em>
ELISA
Epidemiology
Retrovirus
<em>Spumaretrovirus</em>
Mountain lion
<em>Puma concolor</em>
ELISA
Type:Article
Subject:Feline foamy virus
Epidemiology
Retrovirus
<em>Spumaretrovirus</em>
Mountain lion
<em>Puma concolor</em>
ELISA
Epidemiology
Retrovirus
<em>Spumaretrovirus</em>
Mountain lion
<em>Puma concolor</em>
ELISA
Description:Feline foamy virus (FFV) is a retrovirus that has been detected in multiple feline species, including domestic cats (Felis catus) and pumas (Puma concolor). FFV results in persistent infection but is generally thought to be apathogenic. Sero-prevalence in domestic cat populations has been documented in several countries, but the extent of viral infections in nondomestic felids has not been reported. In this study, we screened sera from 348 individual pumas from Colorado, Southern California and Florida for FFV exposure by assessing sero-reactivity using an FFV anti-Gag ELISA. We documented a sero-prevalence of 78.6% across all sampled subpopulations, representing 69.1% in Southern California, 77.3% in Colorado, and 83.5% in Florida. Age was a significant risk factor for FFV infection when analyzing the combined populations. This high prevalence in geographically distinct populations reveals widespread exposure of puma to FFV and suggests efficient shedding and transmission in wild populations. [show more]
Type:Fact Sheet
Subject:Wildlife diseases
Soft tissue tumors
Soft tissue tumors
Description:Fact sheet covering species affected in Colorado, what to look for, causes and transmission, and public health considerations.
Type: Article
Subjects: Genetic differentiation
Heterozygosity fitness correlation
Migration
Mule deer
Multilocus heterozygosity
<em>Odocoileus hemionus</em>
Single-locus heterozygosity
Wildlife
Heterozygosity fitness correlation
Migration
Mule deer
Multilocus heterozygosity
<em>Odocoileus hemionus</em>
Single-locus heterozygosity
Wildlife
Type:Article
Subject:Genetic differentiation
Heterozygosity fitness correlation
Migration
Mule deer
Multilocus heterozygosity
<em>Odocoileus hemionus</em>
Single-locus heterozygosity
Wildlife
Heterozygosity fitness correlation
Migration
Mule deer
Multilocus heterozygosity
<em>Odocoileus hemionus</em>
Single-locus heterozygosity
Wildlife
Description:The relationship between genetic variation and phenotypic traits is fundamental to the study and management of natural populations. Such relationships often are investigated by assessing correlations between phenotypic traits and heterozygosity or genetic differentiation. Using an extensive data set compiled from free-ranging mule deer (Odocoileus hemionus), we combined genetic and ecological data to (i) examine correlations between genetic differentiation and migration timing, (ii) screen for mitochondrial haplotypes associated with migration timing, and (iii) test whether nuclear heterozygosity was associated with condition. Migration was related to genetic differentiation (more closely related individuals migrated closer in time) and mitochondrial haplogroup. Body fat was related to heterozygosity at two nuclear loci (with antagonistic patterns), one of which is situated near a known fat metabolism gene in mammals. Despite being focused on a widespread panmictic species, these findings revealed a link between genetic variation and important phenotypes at a fine scale. We hypothesize that these correlations are either the result of mixing refugial lineages or differential mitochondrial haplotypes influencing energetics. The maintenance of phenotypic diversity will be critical to enable the potential tracking of changing climatic conditions, and these correlates highlight the need to consider evolutionary mechanisms in management, even in widely distributed panmictic species. [show more]
