199 research outputs found
Follow the Money: The Entertainment Software Association Attack on Video Game Regulation
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Testing the Tools: Highlands Bighorn Sheep Project
No full textMore than a dozen of Montana’s bighorn sheep herds have experienced all-age pneumonia die-offs in the past two decades and most have yet to fully recover. Wildlife managers have employed various strategies to help restore these herds such as natural herd re-establishment (hands off approach), augmentations, identification and subsequent removal of chronic shedders of Mycoplasma ovipneumonia (M. Ovi), and complete herd removal. Using the Highlands bighorn sheep herd in SW Montana, we designed a 5-year study to explore the efficacy of two additional tools for restoring bighorn sheep herds following a pneumonia outbreak: single detection test and removal, and selenium supplementation. Utilizing the metapopulation structure of the Highlands herd, we will collect two years of baseline information on the five sub-herds that comprise the Highlands metapopulation to 1) monitor disease exposure of individuals, 2) monitor lamb survival, and 3) estimate connectivity of sub-herds. We will then implement a single detection and removal strategy in two sub herds, selenium supplementation strategy in two sub herds, and no management intervention in the remaining sub herd. The efficacy of these treatments will be monitored for an additional two years. An increase in lamb survival, population growth and decrease in M. ovi detections in the sub herds receiving a treatment would indicate success of the management tool. Results of this experiment will add to the management toolbox of struggling bighorn sheep herds across Montana and the intermountain west
Effects Of A Rest-Rotation Grazing System On Wintering Elk Distributions On The Wall Creek, Montana Winter Range
No full textUnderstanding livestock grazing effects on wildlife remains an important conservation issue. The purpose of this project was to evaluate the effects of a rest-rotation grazing system on elk resource selection within the Wall Creek winter range in southwest Montana. We collected bi-weekly observations of elk (Cervus elaphus) number and distributions across the winter range from 1988-2007. Using a matched-case control logistic regression model to estimate selection coefficients, we evaluated the effects of annual green-up conditions, winter conditions, landscape features, and grazing treatment on elk resource selection within the grazing system. We found that within the grazing system, elk preferentially selected for rested pastures over pastures that were grazed the previous summer. The strength of selection against the pasture grazed during the growing season was strongest, and pastures grazed during the early and late summer were selected for over the pasture grazed during the growing season. The number of elk utilizing the grazing system increased in the 19 years following implementation of the grazing system; however, total elk herd size also increased during this time. We found no evidence that the proportion of the elk herd utilizing the grazing system changed following implementation of the rest-rotation grazing system. Our results provide support for the principals of rest-rotation grazing systems. Wintering elk preference for rested pastures suggests rested pastures play an important role in rotation grazing systems by conserving forage for wintering elk. We recommend wildlife managers maintain rested pastures within rotation grazing systems existing on ungulate winter range
Changes in Elk Resource Selection and Distributions Associated with the Madison Valley Late-Season Elk Hunt
No full textChanges in resource selection associated with human predation risk may alter elk (Cervus elaphus) distributions and availability for harvest. Using Global Positioning System (GPS) data collected from telemetry-collared cow elk, we evaluated effects of refuges (areas where hunting was prohibited), spatial variation in hunting risk and landscape attributes on resource selection within an established Greater Yellowstone Area wintering range and we evaluated elk distributions during and outside of a late-season hunting period. Refuge areas and landscape attributes such as habitat type and snow water equivalency (SWE) affected resource selection. During the hunting period, selection for refuge areas increased, and we estimated odds of elk occupancy in refuge areas more than doubled. Elk selection for flat grasslands increased as SWE increased likely because these areas are heavily windswept leaving grasses exposed for foraging. Elk distributions differed during hunting and no-hunting periods, and during the hunting period elk distribution shifted to privately owned land where hunting was prohibited. Risk-driven changes in resource selection resulted in distributions that reduced the availability of elk for harvest. Elk selection for areas where hunting is prohibited presents a challenge for resource managers that use hunting as a tool for managing herd sizes
Restoration Potential of Bighorn Sheep in a Prairie Region
No full textThis is the peer reviewed version of the following article: [Restoration Potential of Bighorn Sheep in a Prairie Region. The Journal of Wildlife Management 84, 7 p1256-1267, which has been published in final form at https://doi.org/10.1002/jwmg.21922. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions: https://authorservices.wiley.com/author-resources/Journal-Authors/licensing/self-archiving.html#3. Deposited by shareyourpaper.org and openaccessbutton.org. We've taken reasonable steps to ensure this content doesn't violate copyright. However, if you think it does you can request a takedown by emailing [email protected]
Winter Elk Distribution and the Risk Of Brucellosis Transmission from Elk to Livestock in the Northern Greater Yellowstone Ecosystem
No full textPredicting spatio-temporal variations in elk (Cervus elaphus) distributions is necessary to forecast the risk of brucellosis transmission from elk to livestock within the Greater Yellowstone Ecosystem (GYE). Using Global Positioning System (GPS) data collected from 49 telemetry-collared female elk during 2005-2006, we developed predictive resource selection function models for the brucellosis transmission risk period. To determine applicability of predictive models across the larger GYE landscape, we validated predictive models internally, as well as externally at two additional elk ranges within the GYE using 63 telemetry-collared cow elk during 2002-2009. Finally, we integrated extrapolated resource selection function maps and domestic livestock distributions to forecast elk to domestic livestock brucellosis transmission risk. We found elk distributions varied spatially and temporally during the risk period and predictive accuracy was highest in the study area where the model was developed. Predictive accuracy of extrapolated resource selection function maps was lower in other study areas indicating that risk models developed in one portion of the GYE are not as accurate in other portions of the GYE. Relative to the other areas included in this study, the Madison Valley and northern Paradise Valley areas were predicted to have the highest risk of elk to livestock transmission risk. Predictions regarding spatio-temporal variations in transmission risk may be used to prioritize management actions aimed at reducing the potential for brucellosis transmission risk, for example hazing to reduce elk-livestock commingling or producer management of livestock distribution
Wildfire extends the shelf life of elk nutritional resources regardless of fire severity
No full textAbstract Large‐scale, high‐severity wildfires are increasingly frequent across the western United States. Fire severity affects the amount of vegetation removed and helps dictate what, where, and how many plants regenerate postfire, potentially altering the available habitat and nutritional landscape for wildlife. To evaluate the effects of fire severity on summer nutritional resources for elk (Cervus canadensis), we collected field data and remotely sensed information in Years 2 and 3 after a large‐scale wildfire to compare forage quality and quantity across forest types and fire severities within the summer range of one elk population in west‐central Montana. To understand the landscape‐level effects of fire severity on nutritional resources, we developed predictive forage quality and quantity models. We used these models to predict nutritional resources across the landscape for four landscape scenarios representing different fire severity patterns (i.e., an unburned landscape, a landscape burned only at low severity, a landscape burned only at high severity, and the observed landscape burned at mixed severity). Shortly after the wildfire, summer forage quality and herbaceous forage quantity increased in both burned mesic and dry mixed‐conifer forests regardless of fire severity. Summer shrub forage quantity was greater in unburned mesic and dry forests, and there was no difference between fire severities in dry forests. Low‐severity burned mesic forests had significantly greater shrub forage quantity compared with high‐severity burned mesic forests. The three predicted burned landscape scenarios had the highest percentage of the summer range with adequate forage quality, which increased throughout the summer. By contrast, the predicted unburned landscape had the lowest percentage of summer range with adequate forage quality, which decreased throughout the summer. Wildfire extended the duration in which elk can access high‐quality forage in the summer in Years 2 and 3 postfire. Therefore, shortly after a large‐scale wildfire, elk may be better able to meet their nutritional requirements, which may positively impact elk body condition, reproductive performance, and survival
Linking Landscape-Scale Differences in Forage to Ungulate Nutritional Ecology
No full textUnderstanding how habitat and nutritional condition affect ungulate populations is necessary for informing management, particularly in areas experiencing carnivore recovery and declining ungulate population trends. Variations in forage species availability, plant phenological stage, and the abundance of forage make it challenging to understand landscape-level effects of nutrition on ungulates. We developed an integrated spatial modeling approach to estimate landscape-level elk (Cervus elaphus) forage quality in two adjacent study areas that differed in coarse measures of habitat quality and related the consequences of differences in forage quality to elk body condition and pregnancy rates. We found no support for differences in dry matter digestibility between plant samples or in phenological stage based on ground sampling plots in the two study areas. Forage quality, measured as digestible forage biomass, varied among land cover types and between study areas. We found that altered plant composition following fires was the biggest driver of forage quality differences, suggesting that maintaining a mosaic of fire history and distribution will likely benefit ungulate populations. Study area, lactation status and year affected fall body fat of adult female elk. Elk in the study area exposed to lower quality summer range forage had lower nutritional condition entering winter. These differences in nutritional condition resulted in differences in pregnancy rate, with average pregnancy rates of 89% for elk exposed to higher quality forage and 72% for elk exposed to lower quality forage. Summer range forage quality has the potential to limit elk pregnancy rate and calf production, and these nutritional limitations may predispose elk to be more sensitive to the effects of harvest or predation. Wildlife managers should identify ungulate populations that are nutritionally limited and recognize that these populations may be more impacted by recovering carnivores or harvest than populations inhabiting more productive summer habitats
Fence types influence pronghorn movement responses
No full textAbstract Impediments that constrain animal movements across spatiotemporally heterogeneous landscapes can result in reduced or complete loss of access to critical resources. Across their range in North America, pronghorn (Antilocapra americana) are exposed to fences that can affect their ability to permeate the landscape, access critical resources, and respond to climatic variations. Understanding pronghorn movement responses to fences is essential for improving landscape permeability; however, prior studies provide only limited insight due to lack of information on fence characteristics and small sample sizes. Our study used hourly collar locations from adult female pronghorn in six herds in Montana, USA, and identified encounters with mapped fences to evaluate three movement responses (i.e., probability of an unaltered initial response, probability of crossing following an altered initial response, and passage time following an altered initial response) as a function of fence and landscape attributes. Based on 5581 encounters identified from movement pathways of 265 collared pronghorn and 979 km of mapped fences, we found that variability in pronghorn fence response was correlated with fence type. Woven wire fences substantially reduced unaltered initial and crossing responses and increased passage times as compared with low (i.e., average lowest wire height <41 cm) or high (i.e., average lowest wire height ≥41 cm) strand fences. Both low and high strand fences elicited similar responses of being relatively permeable at the initial encounter with reduced permeability thereafter. Fence crossing probabilities following altered initial responses increased through time modestly for strand fences but only negligibly for woven wire fences, with passage times averaging approximately 14 h. Pronghorn knowledge of and fidelity to specific permeable locations along fences, which may be due to inconsistent fence and landscape characteristics along the fence stretch, likely allow some woven wire fences and most strand fences, regardless of the average lowest wire height, to be permeable. Improving landscape permeability for pronghorn should focus on removing woven wire fences, replacing woven wire fences with strand fences, and incorporating variation in the lowest wire heights into new fence designs or modifications of existing fences
Effects of Hunter Access on Hunting Season Elk Distributions in the Missouri River Breaks
No full textIncreasing harvest of adult female elk (Cervus elaphus nelsoni) is the primary management tool for curtailing elk population growth and reducing elk populations. However, this tool is not effective when elk are located on private properties that restrict hunter access to elk during the hunting season. The purpose of this project was to evaluate the effects of hunter access and other landscape factors on elk resource selection during the archery and rifle hunting seasons in the Missouri River Breaks area. We sampled 46 adult female elk for 2-years in 2 adjacent populations: the Missouri River Breaks (MRB) population and the Larb Hills population. The MRB archery and rifle season elk population ranges were 97% accessible to hunters. Several large properties in the center of the Larb Hills range restricted or did not allow hunter access, and the archery and rifle season elk population ranges were 79% accessible to hunters. To quantify the effects of hunter access and other factors on elk selection of home ranges and elk selection of locations within their home range, we conducted a resource selection modeling exercise. Second-order population-level selection coefficients showed that elk in both MRB and Larb Hills selected home ranges in areas with no hunter access, and hunter access was the strongest predictor of second-order selection. Similarly, third-order population-level selection coefficients showed elk in both populations selected locations within their seasonal home range with no hunter access, and the strength of selection for locations with no hunter access was stronger in the archery season than the rifle season. However, individual models revealed that although third-order population-level selection for no hunter access was strong, only 43% of MRB elk selected for no hunter access during the archery season and 18% of elk selected for no hunter access during the rifle season. Additionally, the majority of all MRB elk locations (i.e., 68% of archery locations and 91% of rifle locations) occurred in areas accessible to hunters. In Larb Hills, individual models confirmed results of the population-level analysis, and 76% and 60% of elk selected for locations with no hunter access during the archery and rifle seasons. Even if hunter access is restricted or in a relatively small geographic area within an elk population range, elk refuge situations may have a disproportionate affect on elk distributions and prevent effective harvest of female elk to maintain elk populations at objective levels. Working cooperatively with stakeholders to minimize these situations is necessary for curtailing further elk population increases and maintaining a distribution of elk across public and private lands. If elk refuge situations cannot be resolved, stakeholders may need to choose between allowing some level of hunter access to harvest female elk or accepting higher numbers of elk, and associated property damage issues
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