Type:Fact Sheet

Subject:Tiger trout
Fishing
Research
Fact sheet

Description:Many of Colorado’s coldwater lakes contain fish species, such as suckers and minnows, which provide little value to anglers, compete with managed sport fish, and have the potential to reduce water quality. However, these undesirable fish may be valuable prey items. Sterile fish that have the ability to grow to predatory size quickly and eat the unwanted fish could act as a biological control agent and provide a unique fishing opportunity. Being unable to reproduce, sterile fish can be closely managed through stocking and harvest regulations. Tiger trout, a sterile hybrid between male brook trout and female brown trout, have the potential to fill this role. Tiger trout have already been stocked in some Colorado lakes. Our understanding of what tiger trout eat and how well they grow and survive in lakes with different species of undesirable fish remains limited, and should be fully investigated as a management tool. [show more]

Type:Article

Subject:Vector-pathogen relationships
Puma
Bobcat
Cats, domestic
Infectious diseases

Description:Anthropogenic landscape change can lead to increased opportunities for pathogen transmission between domestic and non-domestic animals. Pumas, bobcats, and domestic cats are sympatric in many areas of North America and share many of the same pathogens, some of which are zoonotic. We analyzed bobcat, puma, and feral domestic cat samples collected from targeted geographic areas. We examined exposure to three pathogens that are taxonomically diverse (bacterial, protozoal, viral), that incorporate multiple transmission strategies (vector-borne, environmental exposure/ingestion, and direct contact), and that vary in species-specificity. Bartonella spp., Feline Immunodeficiency Virus (FIV), and Toxoplasma gondii IgG were detected in all three species with mean respective prevalence as follows: puma 16%, 41% and 75%; bobcat 31%, 22% and 43%; domestic cat 45%, 10% and 1%. Bartonella spp. were highly prevalent among domestic cats in Southern California compared to other cohort groups. Feline Immunodeficiency Virus exposure was primarily associated with species and age, and was not influenced by geographic location. Pumas were more likely to be infected with FIV than bobcats, with domestic cats having the lowest infection rate. Toxoplasma gondii seroprevalence was high in both pumas and bobcats across all sites; in contrast, few domestic cats were seropositive, despite the fact that feral, free ranging domestic cats were targeted in this study. Interestingly, a directly transmitted species-specific disease (FIV) was not associated with geographic location, while exposure to indirectly transmitted diseases – vector-borne for Bartonella spp. and ingestion of oocysts via infected prey or environmental exposure for T. gondii – varied significantly by site. Pathogens transmitted by direct contact may be more dependent upon individual behaviors and intra-specific encounters. Future studies will integrate host density, as well as landscape features, to better understand the mechanisms driving disease exposure and to predict zones of cross-species pathogen transmission among wild and domestic felids. [show more]

Type:Article

Subject:Avian occupancy
Mastication
Piñon–juniper
Pinyon pine
Treatments
Woodland birds

Description:Natural resource managers are increasingly applying tree reduction treatments to piñon–juniper woodlands to meet a range of ecological, social, and economic goals. However, treatment effects on woodland-obligate bird species are not well understood. We measured multiscale avian occupancy on 29 paired (control/treatment) sites in piñon–juniper woodlands in central Colorado, USA. We conducted point counts at 232 stations, 3 times each season in 2014 and 2015. We used hierarchical multiscale modeling to obtain unbiased estimates of landscape and local occupancy (i.e. probability of use) in treated and untreated sites for 31 species. Treatments reduced the occupancy of conifer obligates, including Mountain Chickadee (Poecile gambeli), Clark’s Nutcracker (Nucifraga columbiana), and White-breasted Nuthatch (Sitta carolinensis), and increased occupancy of Lark Sparrow (Chondestes grammacus) and Mountain Bluebird (Sialia currucoides). Occupancy of Virginia’s Warbler (Oreothylpis virginiae) and Gray Flycatcher (Empidonax wrightii), two piñon–juniper specialists, decreased at the landscape scale in treated sites, and Pinyon Jay (Gymnorhinus cyanocephalus) occupancy decreased at the local scale. Tree reduction treatments in piñon–juniper woodlands have the potential to reduce habitat quality for a suite of bird species of conservation concern. We suggest that treatments designed to retain higher tree density and basal area will benefit conifer-obligate and piñon–juniper specialist bird species.Los gestores de los recursos naturales aplican cada vez con mayor frecuencia tratamientos de raleo de árboles a los bosques de piñón y enebro para alcanzar una serie de objetivos ecológicos, sociales y económicos. Sin embargo, no se comprenden claramente los efectos de los tratamientos para las especies de aves que habitan de forma obligada en los bosques. Medimos la ocupación de las aves a múltiples escalas en 29 sitios pareados (control/tratamiento) en bosques de piñón y enebro en el centro de Colorado, EEUU. Realizamos conteos en puntos en 232 lugares, tres veces en cada estación en 2014 y 2015. Usamos modelos jerárquicos a escalas múltiples para obtener estimaciones no sesgadas de ocupación (i.e. probabilidad de uso) a escala de paisaje y local en sitios tratados y no tratados para 31 especies. Los tratamientos redujeron la ocupación de las especies que habitan en forma obligada los bosques de coníferas, incluyendo a Poecile gambeli, Nucifraga columbiana y Sitta carolinensis; y aumentaron la ocupación de Chondestes grammacus y Sialia currucoides. La ocupación de Oreothylpis virginiae y Empidonax wrightii, dos especialistas de los bosques de piñón y enebro, disminuyó a la escala de paisaje en los sitios tratados, y la ocupación de Gymnorhinus cyanocephalus disminuyó a escala local. Tres tratamientos de raleo de los bosques de piñón y enebro tienen el potencial de reducir la calidad de hábitat para un grupo de especies de aves de interés para la conservación. Sugerimos que los tratamientos diseñados para retener mayor diversidad de árboles y área basal beneficiarán a las especies de aves que habitan de forma obligada los bosques de coníferas y a las especialistas de piñón y enebro. [show more]

Type:Article

Subject:Hunting
New York State
Recruitment

Description:"New York State is open for hunting!" With this official state proclamation, residents and visitors are invited to enjoy the variety of hunting opportunities that can be found in New York. We have generous hunting seasons for many game species prized for food and recreation. We have an excellent record of hunting safety. We have millions of acres of public land. And we have a centuries-long tradition of hunting, which has cultivated a strong base of hunters in the state. [show more]

Type:Article

Subject:Angling
College students
Conservation policy
Funding
Hunting
Public support
Wildlife management

Description:Insufficient funding is a major impediment to conservation efforts around the world. In the United States, a decline in hunting participation threatens sustainability of the “user-pay, public benefit” model that has supported wildlife conservation for nearly 100 years, forcing wildlife management agencies to contemplate alternative funding strategies. We investigated support for potential funding options among diverse college students, a rapidly expanding and politically active voting bloc with a potentially powerful influence on the future of conservation. From 2018 to 2020, we surveyed 17,203 undergraduate students at public universities across 22 states. Students preferred innovative approaches to conservation funding, with 72% supporting funding derived from industry sources (e.g., natural resource extraction companies), 63% supporting state sources (e.g., general sales tax), and 43% supporting conventional user-based sources such as license fees and excise taxes associated with outdoor recreation activities (e.g., hunting). Findings emphasize the need to broaden the base of support for conservation funding and highlight the importance of considering the preferences and perspectives of young adults and other diverse beneficiaries of wildlife conservation. [show more]

Type:Article

Subject:Bobcat
Detection probability
Exurban landscape
<em>Lynx rufus</em>
Mark–resight
Mountain lion
Occupancy
Population density
<em>Puma concolor</em>
Urbanization
Wildland–urban interface

Description:Urbanization is a primary driver of landscape conversion, with far-reaching effects on landscape pattern and process, particularly related to the population characteristics of animals. Urbanization can alter animal movement and habitat quality, both of which can influence population abundance and persistence. We evaluated three important population characteristics (population density, site occupancy, and species detection probability) of a medium-sized and a large carnivore across varying levels of urbanization. Specifically, we studied bobcat and puma populations across wildland, exurban development, and wildland–urban interface (WUI) sampling grids to test hypotheses evaluating how urbanization affects wild felid populations and their prey. Exurban development appeared to have a greater impact on felid populations than did habitat adjacent to a major urban area (i.e., WUI); estimates of population density for both bobcats and pumas were lower in areas of exurban development compared to wildland areas, whereas population density was similar between WUI and wildland habitat. Bobcats and pumas were less likely to be detected in habitat as the amount of human disturbance associated with residential development increased at a site, which was potentially related to reduced habitat quality resulting from urbanization. However, occupancy of both felids was similar between grids in both study areas, indicating that this population metric was less sensitive than density. At the scale of the sampling grid, detection probability for bobcats in urbanized habitat was greater than in wildland areas, potentially due to restrictive movement corridors and funneling of animal movements in landscapes influenced by urbanization. Occupancy of important felid prey (cottontail rabbits and mule deer) was similar across levels of urbanization, although elk occupancy was lower in urbanized areas. Our study indicates that the conservation of medium- and large-sized felids associated with urbanization likely will be most successful if large areas of wildland habitat are maintained, even in close proximity to urban areas, and wildland habitat is not converted to low-density residential development. [show more]

Type:Article

Subject:Felidae
Virology
Theoretical models
Microbiology
Lynx
Puma
Parasitology
Animal behavior
Colorado

Description:Transmission of pathogens among animals is influenced by demographic, social, and environmental factors. Anthropogenic alteration of landscapes can impact patterns of disease dynamics in wildlife populations, increasing the potential for spillover and spread of emerging infectious diseases in wildlife, human, and domestic animal populations. We evaluated the effects of multiple ecological mechanisms on patterns of pathogen exposure in animal populations. Specifically, we evaluated how ecological factors affected the prevalence of Toxoplasma gondii (Toxoplasma), Bartonella spp. (Bartonella), feline immunodeficiency virus (FIV), and feline calicivirus (FCV) in bobcat and puma populations across wildland-urban interface (WUI), low-density exurban development, and wildland habitat on the Western Slope (WS) and Front Range (FR) of Colorado during 2009–2011. Samples were collected from 37 bobcats and 29 pumas on the WS and FR. As predicted, age appeared to be positively related to the exposure to pathogens that are both environmentally transmitted (Toxoplasma) and directly transmitted between animals (FIV). In addition, WS bobcats appeared more likely to be exposed to Toxoplasma with increasing intraspecific space-use overlap. However, counter to our predictions, exposure to directly-transmitted pathogens (FCV and FIV) was more likely with decreasing space-use overlap (FCV: WS bobcats) and potential intraspecific contacts (FIV: FR pumas). Environmental factors, including urbanization and landscape covariates, were generally unsupported in our models. This study is an approximation of how pathogens can be evaluated in relation to demographic, social, and environmental factors to understand pathogen exposure in wild animal populations. [show more]

Type:Article

Subject:Foraging
Human-wildlife conflict
Resource subsidies
Stable isotopes
<em>Ursus americanus</em>

Description:Food subsidies have become a widely available and predictable resource in human-modified landscapes for many  from ScienceDirect's AI-generated Topic Pages" class="topic-link">vertebrate species. Such resources can alter individual foraging behavior of animals, and induce population-wide changes. Yet, little consensus exists about the relative influence of the availabilities of native and human food subsidies to wildlife foraging throughout altered landscapes. We explored this unresolved question by analyzing the effects of landscape factors on American black bear (Ursus americanus) diet across the state of Colorado, USA. We estimated assimilated diet using stable isotope analysis of harvested black bear tissues to determine the contribution of human-derived foods to bear diets throughout Colorado, as well as how increasing reliance on human-derived food subsidies increases the risk of conflict. We found that bears (n = 296) showed strong regional diet variability, but substantial use of human-derived food subsidies in eastern Colorado (> 30% assimilated diet). The age-sex class of the bear and housing density of its harvest location were the most influential predictors of ¹³C enrichment (a tracer of human food subsidies). Furthermore, foraging on subsidies increased risk of conflict; the odds of being a nuisance bear increased by 60% for each ~ 1‰ increase in δ¹³C. Our study confirms the efficacy of δ¹³C as a proxy for human activity, and indicates that while demographic differences play a clear role in the foraging ecology of bears, availability of subsidies coincident with varying levels of human activity appears to be a major driver in predicting black bear diet throughout the western United States. [show more]

Type:Article

Subject:Adaptations
Senescence
Demography
Hibernation
Aging

Bears
Food

Description:Human foods have become a pervasive subsidy in many landscapes, and can dramatically alter wildlife behavior, physiology, and demography. While such subsidies can enhance wildlife condition, they can also result in unintended negative consequences on individuals and populations. Seasonal hibernators possess a remarkable suite of adaptations that increase survival and longevity in the face of resource and energetic limitations. Recent work has suggested hibernation may also slow the process of senescence, or cellular aging. We investigated how use of human foods influences hibernation, and subsequently cellular aging, in a large-bodied hibernator, black bears (Ursus americanus). We quantified relative telomere length, a molecular marker for cellular age, and compared lengths in adult female bears longitudinally sampled over multiple seasons. We found that bears that foraged more on human foods hibernated for shorter periods of time. Furthermore, bears that hibernated for shorter periods of time experienced accelerated telomere attrition. Together these results suggest that although hibernation may ameliorate cellular aging, foraging on human food subsidies could counteract this process by shortening hibernation. Our findings highlight how human food subsidies can indirectly influence changes in aging at the molecular level. [show more]

Type:Article

Subject:Animal movement
Kullback–Leibler
Telemetry data

Description:A common population characteristic of interest in animal ecology studies pertains to the selection of resources. That is, given the resources available to animals, what do they ultimately choose to use? A variety of statistical approaches have been employed to examine this question and each has advantages and disadvantages with respect to the form of available data and the properties of estimators given model assumptions. A wealth of high resolution telemetry data are now being collected to study animal population movement and space use and these data present both challenges and opportunities for statistical inference. We summarize traditional methods for resource selection and then describe several extensions to deal with measurement uncertainty and an explicit movement process that exists in studies involving high-resolution telemetry data. Our approach uses a correlated random walk movement model to obtain temporally varying use and availability distributions that are employed in a weighted distribution context to estimate selection coefficients. The temporally varying coefficients are then weighted by their contribution to selection and combined to provide inference at the population level. The result is an intuitive and accessible statistical procedure that uses readily available software and is computationally feasible for large datasets. These methods are demonstrated using data collected as part of a large-scale mountain lion monitoring study in Colorado, USA. [show more]