561 items found
Type: Article
Subjects: Resource dispersion
Wolf
Lion
Spatial organization
Territoriality
Wolf
Lion
Spatial organization
Territoriality
Type:Article
Subject:Resource dispersion
Wolf
Lion
Spatial organization
Territoriality
Wolf
Lion
Spatial organization
Territoriality
Description:
- The spatial organization of a population can influence the spread of information, behaviour and pathogens. Group territory size and territory overlap and components of spatial organization, provide key information as these metrics may be indicators of habitat quality, resource dispersion, contact rates and environmental risk (e.g. indirectly transmitted pathogens). Furthermore, sociality and behaviour can also shape space use, and subsequently, how space use and habitat quality together impact demography.
- Our study aims to identify factors shaping the spatial organization of wildlife populations and assess the impact of epizootics on space use. We further aim to explore the mechanisms by which disease perturbations could cause changes in spatial organization.
- Here we assessed the seasonal spatial organization of Serengeti lions and Yellowstone wolves at the group level. We use network analysis to describe spatial organization and connectivity of social groups. We then examine the factors predicting mean territory size and mean territory overlap for each population using generalized additive models.
- We demonstrate that lions and wolves were similar in that group-level factors, such as number of groups and shaped spatial organization more than population-level factors, such as population density. Factors shaping territory size were slightly different than factors shaping territory overlap; for example, wolf pack size was an important predictor of territory overlap, but not territory size. Lion spatial networks were more highly connected, while wolf spatial networks varied seasonally. We found that resource dispersion may be more important for driving territory size and overlap for wolves than for lions. Additionally, canine distemper epizootics may have altered lion spatial organization, highlighting the importance of including infectious disease epizootics in studies of behavioural and movement ecology.
- We provide insight about when we might expect to observe the impacts of resource dispersion, disease perturbations, and other ecological factors on spatial organization. Our work highlights the importance of monitoring and managing social carnivore populations at the group level. Future research should elucidate the complex relationships between demographics, social and spatial structure, abiotic and biotic conditions and pathogen infections.
Type: Text
Subjects: Gunnison sage-grouse
<em>Centrocercus minimus</em>
Wildlife management
<em>Centrocercus minimus</em>
Wildlife management
Type:Text
Subject:Gunnison sage-grouse
<em>Centrocercus minimus</em>
Wildlife management
<em>Centrocercus minimus</em>
Wildlife management
Description:Gunnison sage-grouse (Centrocercus minimus, hereafter GUSG) is a species of concern in Colorado. Two conservation issues addressed in the Gunnison Sage-grouse Rangewide Plan (RCP) are the population persistence of GUSG (especially the small populations) and the relatively low genetic diversity among GUSG. Augmenting small GUSG populations is a potentially useful management tool to address these conservation concerns. Five alternative techniques to transplanting yearling or adult individuals are discussed in the RCP, including use of captive-reared GUSG. Researchers at the U.S.D.A. National Wildlife Research Center (NWRC) in Fort Collins, CO were able to maintain 18 yearling greater sage-grouse (C. urophasianus, hereafter GRSG) in captivity for 8 months. Recent Colorado Parks and Wildlife (CPW) research on GRSG has evaluated different aspects of captive-rearing techniques. The objectives for this project were to: 1) collect 70 GUSG eggs, 2) artificially incubate and hatch eggs, 3) develop captive breeding techniques for GUSG,4) determine if captive GUSG can initiate incubation and rear a brood in captivity, 5) augment wild surrogate broods with domestically-reared chicks at 1-, 3-, 5-, and 7- weeks of age. Female GUSG were captured using spot-lighting techniques. Females were radio-marked and monitored to assist in locating nesting females. Eggs were collected from laying and incubating females. Eggs were transported from the Gunnison Basin to the CPW Foothills Wildlife Research Facility (FWRF) in Fort Collins and placed in an incubator in a newly constructed building until an external pip was observed (25-26 days) and then they were moved to a hatcher. [show more]
Type: Article
Subjects: Abundance
Colorado
Environmental change
Habitat management
Mark–resight
Mule deer
<em>Odocoileus hemionus</em>
Resighting probabilities
Colorado
Environmental change
Habitat management
Mark–resight
Mule deer
<em>Odocoileus hemionus</em>
Resighting probabilities
Type:Article
Subject:Abundance
Colorado
Environmental change
Habitat management
Mark–resight
Mule deer
<em>Odocoileus hemionus</em>
Resighting probabilities
Colorado
Environmental change
Habitat management
Mark–resight
Mule deer
<em>Odocoileus hemionus</em>
Resighting probabilities
Description:The suite of demands competing for wildlife management funds necessitates direct assessment of management decisions, especially when these decisions have direct costs, as well as tangible opportunity costs. We conducted a mark–resight study that estimated mule deer (Odocoileus hemionus) density across multiple study units in southwest Colorado that had been exposed to different intensities of habitat treatments. Our treatments were comprised of common habitat management techniques including hydro-axe and roller-chopper disturbances as well chemical control of weeds and reseeding with desirable mule deer browse species. Reference study units received no habitat management treatments. Total deer densities varied between 20–84 deer/km2 in southern study units and 4–12 deer/km2 in northern study units. We did not observe a consistent pattern of higher deer density on advanced treatment study units despite it being the primary hypothesis of the study. We observed a wide range of variation in deer density among years. Resighting probabilities (range 0.070–0.567) were best modeled as an interactive function of study unit and year, although sampling method was also influential. We recommend that if population density is to be used as a population response variable, it be used in tandem with other, possibly more sensitive parameters such as overwinter survival or late winter body condition. [show more]
Type: Article
Subjects: Brown trout
Colorado River
Habitat associations
<em>Oncorhynchus mykiss</em>
Rainbow trout
<em>Salmo trutta</em>
Colorado River
Habitat associations
<em>Oncorhynchus mykiss</em>
Rainbow trout
<em>Salmo trutta</em>
Type:Article
Subject:Brown trout
Colorado River
Habitat associations
<em>Oncorhynchus mykiss</em>
Rainbow trout
<em>Salmo trutta</em>
Colorado River
Habitat associations
<em>Oncorhynchus mykiss</em>
Rainbow trout
<em>Salmo trutta</em>
Description:Habitat restoration activities continue to increase in large rivers, but many of these projects focus on improving juvenile or adult habitats. Incorporating the habitat associations of fry into restoration designs will allow for broader successes from restoration for all life stages and may be useful for either multispecies or specific-species management. This study investigated the habitat associations of rainbow trout Oncorhynchus mykiss and brown trout Salmo trutta fry in the upper Colorado River, focusing on the mean substrate size (D50), velocity (m s−1), depth (m) and presence of wood in near-shore habitats. S. trutta and O. mykiss were found in higher numbers in fry sites with a D50 of 151 mm (ranging from 96 to 206 mm), velocities ranging from 0.20 to 0.23 m s−1 and depths ranging from 0.17 to 0.18 m. Although there was considerable overlap in habitat associations between the two species, there may be opportunities for single-species management, if this is a goal of such restoration activities, by adjusting design criteria based on differing habitat associations. In addition, the results suggest that including larger particle sizes in near-shore habitats and upstream of fry sites could decrease Tubifex tubifex habitat and thereby fry infection severity by reducing exposure to Myxobolus cerebralis. Stocking, interspecific competition and/or the presence of pathogens can affect fry habitat associations and cause deviations from demonstrated suitability indices. As such, evaluating system-specific differences in habitat associations may allow future habitat restoration activities to be more effective. [show more]
Type: Article
Subjects: Colorado
Fawn survival
Habitat management
Hydro-axe
mule deer
<em>Odocoileus hemionus</em>
Roller-chop
Fawn survival
Habitat management
Hydro-axe
mule deer
<em>Odocoileus hemionus</em>
Roller-chop
Type:Article
Subject:Colorado
Fawn survival
Habitat management
Hydro-axe
mule deer
<em>Odocoileus hemionus</em>
Roller-chop
Fawn survival
Habitat management
Hydro-axe
mule deer
<em>Odocoileus hemionus</em>
Roller-chop
Description:In the absence of natural or anthropogenic disturbance, many pinyon pine (Pinus edulis)–Utah juniper (Juniperus osteosperma) woodland habitats reach late seral stages that encroach into forest openings. This encroachment typically occurs at the expense of browse species that are preferred by mule deer (Odocoileus hemionus). Wildlife managers often treat habitat management as a tool to bolster mule deer populations, but documented changes in deer vital rates in response to habitat manipulations are lacking. We evaluated the effects of different levels of habitat improvement on pinyon pine–Utah juniper winter ranges in Colorado on mule deer overwinter survival. Mule deer fawns that overwintered on areas that received both a traditional mechanical treatment as well as follow-up chemical treatments experienced increased survival ( = 0.768, SE = 0.0851) over fawns on winter range that had only received traditional mechanical treatments or no habitat treatments ( = 0.675, SE = 0.112). When treatment intensity was partitioned into 3 levels: no treatment, traditional mechanical treatments, and advanced treatments comprised of both mechanical and chemical treatments, mule deer fawns inhabiting winter range subjected to advanced treatments experienced higher survival ( = 0.768, SE = 0.0849) than fawns on units that experienced only traditional mechanical treatments ( = 0.687, SE = 0.108), which in turn experienced higher survival than fawns in areas that had received no habitat treatments ( = 0.669, SE = 0.113). Our study provides evidence that habitat management on winter ranges can positively influence a key vital rate for mule deer in pinyon pine–Utah juniper ecosystems. We recommend that as habitat treatments are planned for benefit of mule deer, those plans include follow-up reseeding and weed control efforts. [show more]
Type: Article
Subjects: Anthropogenic disturbances
Behavior
Colorado
Intermountain West
Mule deer
Natural-gas development
<em>Odocoileus hemionus</em>
Resource selection
Spring migration
Behavior
Colorado
Intermountain West
Mule deer
Natural-gas development
<em>Odocoileus hemionus</em>
Resource selection
Spring migration
Type:Article
Subject:Anthropogenic disturbances
Behavior
Colorado
Intermountain West
Mule deer
Natural-gas development
<em>Odocoileus hemionus</em>
Resource selection
Spring migration
Behavior
Colorado
Intermountain West
Mule deer
Natural-gas development
<em>Odocoileus hemionus</em>
Resource selection
Spring migration
Description:The disruption of traditional migratory routes by anthropogenic disturbances has shifted patterns of resource selection by many species, and in some instances has caused populations to decline. Moreover, in recent decades populations of mule deer (Odocoileus hemionus) have declined throughout much of their historic range in the western United States. We used resource-selection functions to determine if the presence of natural-gas development altered patterns of resource selection by migrating mule deer. We compared spring migration routes of adult female mule deer fitted with GPS collars (n = 167) among four study areas that had varying degrees of natural-gas development from 2008 to 2010 in the Piceance Basin of northwest Colorado, USA. Mule deer migrating through the most developed area had longer step lengths (straight-line distance between successive GPS locations) compared with deer in less-developed areas. Additionally, deer migrating through the most developed study areas tended to select for habitat types that provided greater amounts of concealment cover, whereas deer from the least developed areas tended to select habitats that increased access to forage and cover. Deer selected habitats closer to well pads and avoided roads in all instances except along the most highly developed migratory routes, where road densities may have been too high for deer to avoid roads without deviating substantially from established migration routes. These results indicate that behavioral tendencies toward avoidance of anthropogenic disturbance can be overridden during migration by the strong fidelity ungulates demonstrate towards migration routes. If avoidance is feasible, then deer may select areas further from development, whereas in highly developed areas, deer may simply increase their rate of travel along established migration routes. [show more]
Type: Fact Sheet
Subjects: Wildlife diseases
Hemorrhagic disease
Hemorrhagic disease
Type:Fact Sheet
Subject:Wildlife diseases
Hemorrhagic disease
Hemorrhagic disease
Description:Fact sheet covering species affected in Colorado, what to look for, cause and transmission, and public health considerations.
Type: Article
Subjects: Mule deer
Habitat management
Habitat management
Type:Article
Subject:Mule deer
Habitat management
Habitat management
Description:The relationships between habitat, body condition, life history characteristics, and fitness components of ungulates are interwoven and of interest to researchers as they strive to understand the impacts of a changing environment. With the increased availability of portable ultrasound machines and the refinement of hormonal assays, assessment of ungulate body condition has become an accessible monitoring strategy. We employed body condition scoring, estimation of % ingesta-free body fat (%IFBF), assessment of free thyroid hormones (FT4 and FT3), and assessment of pregnancy, as metrics to determine if landscape-level habitat treatments affected body condition of adult (≥1.5 years old) female mule deer (Odocoileus hemionus). All body condition related metrics were measured on 2 neighboring study areas — a reference area that had received no habitat treatments and a treatment study area that had received mechanical removal of pinyon pine (Pinyus edulis) - Utah juniper (Juniperus osteosperma) forest, chemical control of weeds, and reseeding with preferred mule deer browse species. A consistent trend of higher %IFBF was observed in the treatment study area than in the reference study area , although variation of estimates was larger than hypothesized. A similar pattern was observed with higher thyroid hormones concentrations being observed in the treatment study area, but large amounts of variation within concentration estimates were also observed. The consistent pattern of higher body condition related estimates in our treatment study area provides evidence that large mammalian species are sensitive to landscape change, although variation within estimates underlie the challenge in detecting population level impacts stemming from environmental change. [show more]