561 items found
Type: Article
Subjects: Animal movement
Bayesian hierarchical model
Energy development
Habitat selection
Movement ecology
Mule deer
Natural gas
Resource selection function
Bayesian hierarchical model
Energy development
Habitat selection
Movement ecology
Mule deer
Natural gas
Resource selection function
Type:Article
Subject:Animal movement
Bayesian hierarchical model
Energy development
Habitat selection
Movement ecology
Mule deer
Natural gas
Resource selection function
Bayesian hierarchical model
Energy development
Habitat selection
Movement ecology
Mule deer
Natural gas
Resource selection function
Description:Extraction of oil and natural gas (hydrocarbons) from shale is increasing rapidly in North America, with documented impacts to native species and ecosystems. With shale oil and gas resources on nearly every continent, this development is set to become a major driver of global land-use change. It is increasingly critical to quantify spatial habitat loss driven by this development to implement effective mitigation strategies and develop habitat offsets. Habitat selection is a fundamental ecological process, influencing both individual fitness and population-level distribution on the landscape. Examinations of habitat selection provide a natural means for understanding spatial impacts. We examined the impact of natural gas development on habitat selection patterns of mule deer on their winter range in Colorado. We fit resource selection functions in a Bayesian hierarchical framework, with habitat availability defined using a movement-based modeling approach. Energy development drove considerable alterations to deer habitat selection patterns, with the most substantial impacts manifested as avoidance of well pads with active drilling to a distance of at least 800 m. Deer displayed more nuanced responses to other infrastructure, avoiding pads with active production and roads to a greater degree during the day than night. In aggregate, these responses equate to alteration of behavior by human development in over 50% of the critical winter range in our study area during the day and over 25% at night. Compared to other regions, the topographic and vegetative diversity in the study area appear to provide refugia that allow deer to behaviorally mediate some of the impacts of development. This study, and the methods we employed, provides a template for quantifying spatial take by industrial activities in natural areas and the results offer guidance for policy makers, mangers, and industry when attempting to mitigate habitat loss due to energy development. [show more]
Type: Article
Subjects: Conservation incentive
<em>Dendroica chrysoparia</em>
Dispersal
Fort Hood, Texas
Golden-cheeked Warbler
Metapopulation
Recovery Credit System
Sensitivity analysis
<em>Dendroica chrysoparia</em>
Dispersal
Fort Hood, Texas
Golden-cheeked Warbler
Metapopulation
Recovery Credit System
Sensitivity analysis
Type:Article
Subject:Conservation incentive
<em>Dendroica chrysoparia</em>
Dispersal
Fort Hood, Texas
Golden-cheeked Warbler
Metapopulation
Recovery Credit System
Sensitivity analysis
<em>Dendroica chrysoparia</em>
Dispersal
Fort Hood, Texas
Golden-cheeked Warbler
Metapopulation
Recovery Credit System
Sensitivity analysis
Description:A growing number of programs seek to facilitate species conservation using incentive-based mechanisms. Recently, a market-based incentive program for the federally endangered Golden-cheeked Warbler (Dendroica chrysoparia) was implemented on a trial basis at Fort Hood, an Army training post in Texas, USA. Under this program, recovery credits accumulated by Fort Hood through contracts with private landowners are used to offset unintentional loss of breeding habitat of Golden-cheeked Warblers within the installation. Critical to successful implementation of such programs is the ability to value, in terms of changes to overall species viability, both habitat loss and habitat restoration or protection. In this study, we sought to answer two fundamental questions: Given the same amount of change in breeding habitat, does the change in some patches have a greater effect on metapopulation persistence than others? And if so, can characteristics of a patch (e.g., size or spatial location) be used to predict how the metapopulation will respond to these changes? To answer these questions, we describe an approach for using sensitivity analysis of a metapopulation projection model to predict how changes to specific habitat patches would affect species viability. We used a stochastic, discrete-time projection model based on stage-specific estimates of survival and fecundity, as well as various assumptions about dispersal among populations. To assess a particular patch's leverage, we quantified how much metapopulation viability was expected to change in response to changing the size of that patch. We then related original patch size and distance from the largest patch to each patch's leverage to determine if general patch characteristics could be used to develop guidelines for valuing changes to patches within a metapopulation. We found that both the characteristic that best predicted patch leverage and the magnitude of the relationship changed under different model scenarios. Thus, we were unable to find a consistent set of relationships, and therefore we emphasize the dangers in relying on general guidelines to assess patch value. Instead, we provide an approach that can be used to quantitatively evaluate patch value and identify critical needs for future research. [show more]
Type: Fact Sheet
Subjects: Wildlife diseases
Rabbit calicivirus disease
Cottontail rabbit
Jackrabbit
Rabbit calicivirus disease
Cottontail rabbit
Jackrabbit
Type:Fact Sheet
Subject:Wildlife diseases
Rabbit calicivirus disease
Cottontail rabbit
Jackrabbit
Rabbit calicivirus disease
Cottontail rabbit
Jackrabbit
Description:Fact sheet covering species affected in Colorado, what to look for, cause and transmission, and public health concerns.
Type: Fact Sheet
Subjects: Rainbow trout
Spawning
Fry
Population management
Spawning
Fry
Population management
Type:Fact Sheet
Subject:Rainbow trout
Spawning
Fry
Population management
Spawning
Fry
Population management
Description:Rainbow Trout are spring spawners, and deposit their eggs in gravel at sites known as redds. The eggs hatch in 4-7 weeks depending on water temperature. After hatching, fish spend up to two weeks as sac fry, remaining in the gravel and absorbing their yolk sac. Once the yolk sac is absorbed, the fry emerge from the gravel to begin feeding. Fry spend the first several months of their life in shallow areas found along the river margins, using vegetation and interstitial spaces between rocks as cover from predators. During this time, they are also easily sampled to estimate population size. Changes in the fry population over time can indicate whether factors such as water quality, flow, temperature, or presence of parasites are affecting survival. Additionally, fry estimates conducted later in the year can be indicative of the number of fish that will recruit to the juvenile and adult populations. Finding ways to increase fry survival in rivers has been the focus of many CPW aquatic research projects. [show more]
Type:
Subjects:
Type: Article
Subjects: Gill lice
Intensity
Invasion
Maturity
Prevalence
Intensity
Invasion
Maturity
Prevalence
Type:Article
Subject:Gill lice
Intensity
Invasion
Maturity
Prevalence
Intensity
Invasion
Maturity
Prevalence
Description:Ecologically and economically valuable Pacific salmon and trout (Oncorhynchus spp.) are widespread and susceptible to the ectoparasite Salmincola californiensis (Dana). The range of this freshwater copepod has expanded, and in 2015, S. californiensis was observed in Blue Mesa Reservoir, Colorado, USA, an important kokanee salmon (O. nerka, Walbaum) egg source for sustaining fisheries. Few S. californiensis were detected on kokanee salmon in 2016 (<10% prevalence; 2 adult S. californiensis maximum). By 2020, age-3 kokanee salmon had 100% S. californiensis prevalence and mean intensity exceeding 50 adult copepods. Year and kokanee salmon age/maturity (older/mature) were consistently identified as significant predictors of S. californiensis prevalence/intensity. There was evidence that S. californiensis spread rapidly, but their population growth was maximized at the initiation (the first 2–3 years) of the invasion. Gills and heads of kokanee salmon carried the highest S. californiensis loads. S. californiensis population growth appears to be slowing, but S. californiensis expansion occurred concomitant with myriad environmental/biological factors. These factors and inherent variance in S. californiensis count data may have obscured patterns that continued monitoring of parasite–host dynamics, when S. californiensis abundance is more stable, might reveal. The rapid proliferation of S. californiensis indicates that in 5 years a system can go from a light infestation to supporting hosts carrying hundreds of parasites, and concern remains about the sustainability of this kokanee salmon population. [show more]