Isotopic analysis of arctic ground squirrel tissues and potential food sources

Given limited knowledge of the food sources of Arctic ground squirrels, an important arctic prey species, it is difficult to predict the implications of changes in food source availability that could result from climate change. I hypothesized that Arctic ground squirrels at two colonies, Atigun and Toolik, would have similar feeding habits and mushrooms would contribute to their diet The Arctic ground squirrels at Toolik had significantly higher del15N (3.7 per mill difference) and del13C values (1.3 per mill difference) than those at Atigun. Mixing models indicated that the signatures observed in the Atigun hair could result from a combination of several foods. The relatively high isotope values of the Toolik hair indicated that squirrels there are feeding on a food source with higher isotope values than most of the sampled vegetation. Mushrooms could provide a proportional contribution between 0.09 and 0.60 to the diet of Toolik squirrels

Effects Of A Rest-Rotation Grazing System On Wintering Elk Distributions On The Wall Creek, Montana Winter Range

Understanding 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

Elk Movements and Brucellosis Transmission Risk in Southwest Montana

The presence of Brucella abortus within free-ranging elk populations is an important conservation and management issue because of the risk of brucellosis transmission to livestock. Understanding elk distributions is necessary to forecast elk and livestock spatial overlap and the potential for brucellosis transmission. As part of a 5-yr brucellosis surveillance project, 30 adult female elk were captured and fitted with GPS collars in each of the winters of 2010, 2011 and 2012 in three southwest Montana study areas. We used elk location information to assess elk movements, and spatial overlap with livestock and adjacent elk herds. The elk movement results were further augmented with data from Wyoming and Idaho elk herds. The elk movement data shows interchange of females between elk herds during the transmission risk period. Resource selection models predicting elk distribution and spatial overlap with livestock during the transmission risk period were developed and extrapolated across the designated brucellosis surveillance area of Montana. We used the elk location data collected in this study to validate and refine models predicting elk distributions and spatial overlap with livestock during the risk period. Predictive models may be used as a tool for focusing management actions aimed at minimizing elk and livestock spatial overlap during the transmission risk period

Preliminary Findings of an Elk Brucellosis Surveillance and Epidemiology Project in Southwestern Montana

Brucellosis is a bacterial disease that causes abortions in cattle, bison (Bison bison) and elk (Cervus elaphus). Transmission of the disease from wildlife to cattle has serious financial implications to producers and the livestock industry in Montana. Brucellosis in elk populations of southwestern Montana results in reduced tolerance for elk on private property and can influence management of elk populations. In the winter of 2010/2011, Montana Fish, Wildlife and Parks initiated a five-year project with the goals of delineating the geographical distribution of brucellosis in elk populations, enhancing our understanding of how brucellosis functions in elk populations, and evaluating factors that may influence the spread and prevalence of brucellosis in elk. One-hundred adult female elk were captured in hunting districts (HD) 324 and 326 in the winter of 2010/2011 with eight testing positive on blood tests(seropositive) in the field for exposure to Brucella. Ninety-three adult female elk were captured in HD 325 in the winter of 2011/2012, five of which were seropositive. Elk testing positive in the field were fitted with a GPS collar and, if pregnant, implanted with a vaginal implant transmitter (VIT). Seropositive pregnant elk were tracked from the ground and air 2-3 times/week in order to locate birth or abortion sites. B. abortus was not cultured from VITs or samples collected at birth sites in the first year of the project. B. abortus was cultured from tissues or VITs associated with two aborted calves in 2012. The known distribution of brucellosis in elk has expanded based on information obtained in this study

Brucellosis in Montana Elk: Factors that Influence Disease Prevalence and the Social And Political Influences and Issues Associated with Managing a Disease of Concern for Livestock in a Free-Ranging Elk Population

Brucellosis is a bacterial disease that affects elk (Cervus elaphus), bison (Bison bison) and domestic cattle. Transmitted primarily through contact with birth tissues, the disease is a significant livestock disease resulting in significant costs to producers and is a USDA eradication program disease. Brucellosis was first documented in wildlife in the Greater Yellowstone Area (GYA) in the early 1900s and was brought into the region by livestock producers. The disease has since been eradicated in livestock, but persists in elk and bison populations of the GYA. Recently the seroprevalence of brucellosis in free-ranging elk populations of Montana has increased and its range has likely expanded resulting in increased pressure on Montana Fish, Wildlife and Parks (MFWP) to manage the disease in elk. We evaluated factors that potentially influence elk aggregation behaviors and the consequences of these factors on seroprevalence. We used a Bayesian spatial model to estimate seroprevalence across the designated surveillance area. This research approach allowed seroprevalence to be estimated for the first time in areas with limited surveillance data. The socio-political influences associated with managing wildlife potentially infected with a disease that threatens the cattle industry of Montana, the available tools for managing the disease in elk, and MFWP’s current strategy for managing brucellosis in one of Montana greatest public trusts is discussed

Elk Movements and Harvest Across Public and Private Lands in the Sapphire Mountains

Hunting access issues have become increasingly contentious as changes in land ownership and use have influenced elk distributions in some areas. In the Sapphire Mountains of western Montana, hunters have voiced concerns regarding elk aggregations on privately-owned lands that restrict hunter access.   To address these concerns, we initiated a survey of landowners and hunters to determine satisfaction with elk management.  We also radiocollared 65 elk (45 cows, 20 bulls) to better understand elk distributions across public and private lands.  In all seasons, bull elk locations were more likely to occur in publicly accessible areas than cow elk locations. During archery season, 61% of bull locations and 41% of cow locations occurred in publicly accessible areas.  These numbers dropped to 48% of bull locations and 14% of cow locations in publicly accessible areas during rifle season.  During archery and rifle seasons combined, 1 of 39 radiocollared cows (2.4%) was harvested on private land, and 5 of 19 radiocollared bulls (26.3%) were harvested: 3 on publicly accessible land and 2 on private land. Although hunters reported a lack of elk on public lands as a concern, our radiocollar and harvest data confirm that at least a segment of the bull population was accessible to public hunters, but female elk were aggregated in areas that restricted hunter access.  A lack of hunter access to female elk during the hunting season may result in management challenges, including game damage issues, and increases in the population beyond objective levels

Fire and Forage: Variability in Elk Forage on a Landscape of Wildfire and Changing Fire Management

Forest management practices can modify ungulate nutritional resources through landscape-scale processes such as prescribed fire and wildfire. The resulting availability and distribution of nutritional resources can affect ungulate survival, reproduction, and distribution. Our primary goals were to evaluate how landscapes with varying post-fire successional stages influence elk summer nutritional resources and to quantify the variability of nutritional resources associated with varying fire histories and management practices during 1900–2015. Within 3 elk population ranges located in the Bitterroot Valley, Montana, we measured elk forage quality across a range of land cover types and fire histories and developed a landscape-scale forage quality model. Based on historical wildfire and prescribed fire data, we reconstructed decadal land cover models and used our forage models to predict fire-related variations in forage quality each decade within the elk summer ranges. Forage quality was predicted to decrease with successional stage. The area burned by wildfire increased 242–1,772% during 1990–2015 as compared to 1900–1990, resulting in firerelated variations of predicted nutritional resources. The area of highest forage quality varied, increasing 31.3–48.5% in 2 ranges and decreasing 2.4% in 1 range, from 1900–1990 to 1990–2015. These results highlight the important effect of wildfire on the distribution of ungulate nutritional resources and demonstrate that ungulate nutritional resources likely vary over time with variation in fire history and management practices

Effects of a Rest-Rotation Grazing System on Wintering Elk Distributions at Wall Creek, Montana

The large-scale influence of livestock grazing in the western United States generates a need to integrate landscape management to incorporate both wildlife and livestock. The purpose of this project was to evaluate the effects of four different grazing cells (spring grazing, summer growing-season grazing, fall grazing, and resting) on wintering elk resource selection within the Wall Creek range in southwest Montana. We collected biweekly observations of elk (Cervus elaphus) numbers and distributions across the winter range from 1988 to 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 group resource selection within the grazing system. We found that within the grazing system, elk groups preferentially selected for rested pastures over pastures that were grazed during the previous spring (1 May-1 June), summer (1 June-15 July), and fall (15 September-30 September). The strength of selection against the pasture grazed during the summer growing season was strongest, and pastures grazed during the spring and fall were selected for over the pasture grazed during the summer. The number of elk utilizing the grazing system increased in the 19 yr 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. Wintering elk group preference for rested pastures suggests rested pastures play an important role in rotation grazing systems by conserving forage for wintering elk. Additionally, rested pastures provide important cover for a host of other wildlife species. We recommend wildlife managers maintain rested pastures within rotation grazing systems existing on ungulate winter range./La influencia a gran escala del ganado en pastoreo en el oeste de los Estados Unidos genera una necesidad de integrar el manejo del paisaje e incorporar tanto fauna y ganado. El propósito de este proyecto fue evaluar los efectos de cuatro células diferentes de pastoreo (pastoreo en primavera, pastoreo durante la época de crecimiento en el verano, pastoreo en el otoño y descanso) en la selección de recursos de los elks en el pastizal de Wall Creek en el Suroeste de Montana. Se colectaron observaciones cada dos semanas del numero y distribución de los elks (Cervus elaphus) en el pastizal durante el invierno desde 1988-2007. Se utilizaron modelos de casos regresión de pares para estimar los coeficientes de selección, evaluamos los efectos de las condiciones decrecimiento anual, condiciones del invierno, características del paisaje, y los tratamientos de pastoreo en la selección de los recursos del grupo de elks dentro de los sistemas de pastoreo. Encontramos que dentro de los sistemas de pastoreo, el grupo de elks seleccionan preferencialmente potreros descansados sobre los potreros que fueron pastoreados previamente en primavera (1 Mayo-1 Junio), verano (1 Junio -15 Julio), y otoño (15 de Septiembre- al 30 de Septiembre). La fuerza de la selección contra los potreros pastoreados durante la condiciones de crecimiento en el verano fue la más fuerte, y los potreros pastoreados durante la primavera y otoño fueron seleccionaron sobre los potreros pastoreados durante el verano. El número de elks que utilizaron el sistema de pastoreo se incrementó en 19 años después de la implementación de los sistemas de pastoreo; sin embargo, el tamaño total del hato de elks también se incrementó durante este tiempo. No se encontró ninguna evidencia que la proporción del hato de elks que utilizaron los sistemas de pastoreo cambio después de la implementación del sistema de rotación del descanso. La preferencia del grupo de elks durante el invierno de los potreros descansados, sugiere que los potreros descansados tienen un papel importante en los sistemas de rotación por medio de la conservación de forraje para los elks durante el invierno. Además, los potreros descansados, proporcionan la cubierta importante para otro tipo de especies silvestres. Recomendamos a los manejadores de fauna silvestre que mantengan potreros en descanso dentro de los sistemas de rotación que existen en el invierno para el uso de ungulados.The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

elk_data

This file contains the fall elk body fat (IFBF) and pregnancy data used in analyses. For fall measurements, lactation status is included; in late-winter/spring measurements lactation status could not be determined. Age was estimated from tooth eruption and wear patterns. Pregnancy was estimated from PSPB levels in the blood. IFBF was estimated following the revised methods of Cook et al. (2010) that included an allometrically scaled MAXFAT index

Data from: Linking landscape-scale differences in forage to ungulate nutritional ecology

Understanding 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) nutritional resources in two adjacent study areas that differed in coarse measures of habitat quality and related the consequences of differences in nutritional resources 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. Our index of nutritional resources, measured as digestible forage biomass, varied among landcover types and between study areas. We found that altered plant composition following fires was the biggest driver of differences in nutritional resources, 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 summer range nutritional resources 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 nutritional resources and 72% for elk exposed to lower nutritional resources. Summer range nutritional resources have 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