Ungulate Ecology & Management

Contributed Oral Presentations


Contributed paper sessions will be available on-demand for the duration of the conference, then again at the conclusion of the conference.


Quantifying the Importance of Cover in Bighorn Sheep Lambing Habitat Using Unmanned Aerial Vehicles
Marcus Blum; Kelley Stewart; Jonathan Greenberg; Mike Cox; Brian Wakeling
Desert bighorn sheep (Ovis canadensis nelsoni) have evolved to select habitat types in precipitous terrain during certain times of the year. These behavioral adaptations allow individuals to increase their survival, and the likelihood of recruiting young into the population by staying in rugged terrain to evade predators. While terrain ruggedness and slope are commonly associated with bighorn lambing habitat, little is known about the effects of aerial and ground cover on selection of parturition sites or lamb rearing habitat. Recent studies demonstrated the importance of ground cover in the uphill and downhill directions in selection of birth-sites by bighorn sheep, however, measurements collected at these sites do not fully represent sightability or shrub-cover within the immediate area. We captured female bighorn sheep from January 2016 through June 2018 on Lone Mountain, ~ 20 km west of Tonopah, NV. We also captured neonatal young and determined location of birth sites as well as information on survival. Following lambing season, we plotted all birth site locations from captured lambs and conducted unmanned aerial vehicle flights using a Mavic Pro unmanned aerial vehicle. Imagery obtained from the transects were used to generate point clouds and develop view sheds from birth sites and random locations at ~ 2 cm resolution. These viewsheds were used to quantify the relationship between aerial and ground cover with selection of birth sites. These methods offer a new, more accurate representation of vegetative cover in bighorn sheep habitat that inform our understanding of landscape features that contribute to selection of birthing areas for bighorn sheep. Additionally, these methods will be useful in quantifying the habitat utilization of many wildlife species and therefore increase our ability to mange their populations effectively.
Risk-Sensitive Allocation of Fat Reserves and Demographic Consequences in Bighorn Sheep
Rachel A. Smiley; Brittany L. Wagler; Tayler N. LaSharr; Kristin Denryter; Thomas R. Stephenson; Hank Edwards; Gregory Anderson; Alyson Courtemanch; Gary Fralick; Doug McWhirter; Tony W. Mong; Corey Class; Leah Yandow; Patrick Hnilicka; Kevin Monteith
Patterns of food availability and energetic demands in seasonal environments shape how some large herbivores allocate resources, which has downstream consequences for life history. Individuals can accumulate fat reserves in times of resource abundance to ensure that they can meet energetic demands in periods of lower resource availability. The accumulation and allocation of fat reserves often occurs in a risk sensitive manner, wherein resources are preferentially allocated to enhance survival over current reproduction. Bighorn sheep, which inhabit particularly unpredictable environments, are known to preferentially enhance their own mass gain over their offspring’s during the summer. Changes in body mass reflect accumulation and catabolism of both fat and protein reserves, but body fat is the primary energetic currency in ungulates, more sensitive to current conditions, and is therefore more reflective of resource allocation than body mass. Thus, we hypothesize that fat accrual and catabolism in bighorn sheep would be risk-sensitive, in that seasonal changes in nutritional condition would first be a function of their current nutritional state, and second, relative nutritional state would dictate allocation to reproduction. We monitored percent ingesta-free body fat (IFBFat), pregnancy, and recruitment of juveniles in bighorn sheep in Northwest Wyoming between 2015 and 2020 through repeated captures of n = 97 individuals in December and March of each year. Individuals in worse nutritional condition accumulated more body fat over the summer (R2 = 0.78), and were less likely to recruit than those in better condition. Further, animals in worse condition lose less fat during the winter (R2 = 0.57), and are less likely to be pregnant than those in better condition. For this high alpine species, nutritional state underpinned resource allocation to maintenance and reproduction, supporting the notion that the currency of risk-sensitive allocation is body fat and that bighorn sheep are selfish mothers.
Bison and the Transformation of the North American Wildlife System
Perry S. Barboza; Jeffrey M. Martin
The North American system of wildlife management and governance was assembled to save iconic species such as the bison (Bison bison) more than a century ago. However, the system is challenged by persistent and growing conflicts about governance, human land use, and wildlife habitat for populations that range from local overabundance to a high risk of extinction in their native range. Bison are unusual among native species because they can be privately owned as livestock or publicly owned as wildlife, as a result bison are an anomaly for management of terrestrial species in this system. The bison system has public, non-profit NGO, private, and tribal sectors to increase conservation value in ecological, economic, and cultural domains. We use bison to explore avenues for transforming the North American Model of wildlife conservation. The private sector of the bison system expands the economic domain by providing an ecologically sustainable food to not only the rural community but to a wide variety of urban consumers. The public sector of the bison system upholds the sovereign responsibility to sustain bison as a public resource. The public system can also serve as a genetic reserve to maintain the functional diversity of the private herds, which could become a new source of revenue for the public herds. The private system has the potential to expand beyond providing meat and hides to restoring ecosystems; a valuable public service that could transform the social ecological systems of rangelands and wildlife.
A Comprehensive Study of Parasites of the Texas State Bison Herd: Part 1
Sara B. Boggan
Parasites can have a significant effect on the typical growth, weight gain, and milk production of any species. Therefore, infections are often managed with common antihelminthics. The purpose of this study is to provide Texas Parks & Wildlife Department (TPWD) with recommendations for treatment of parasites in the Texas State Bison herd at Caprock Canyons State Park (CCSP), Briscoe County, Texas. TPWD biologists base their management plans on restoring native prairies to preserve the historic herd. To improve their management, we will provide TPWD with data concerning the type of parasites, and prevalence and load of intestinal parasites found in the herd. This is the first part of the study for which we report baseline information prior to treatment of some of the individuals. We observed 4 different parasite types: Coccidia, Moniezia, Strongyloides, and Strongylid-type. For our initial analysis we proceeded to sort individuals by age class. Fewer juveniles were infected with Coccidia (χ2 = 5.7, P = 0.017), but more were infected with Strongylid-type (χ2 = 28.8, P < 0.001) and Moniezia (χ2 = 37.9, P < 0.001), but no different in Strongyloides (χ2 = 2.7, P = 0.10) when compared to adults Following sampling for this portion of the study, TPWD treated half of the sampled bison (n = 50) with Cydectine (moxidectine, de-wormer for parasites) leaving the remaining half untreated. As we move into part 2 of the study we will evaluate environmental influences and examine how age of individuals could be affecting parasite prevalence.
Comparison of Woodland Caribou Calving Areas Determined by Movement Patterns Across Northern Ontario
Philip D. Walker; Arthur R. Rodgers; Jennifer L. Shuter; Ian D. Thompson; John M. Fryxell; John G. Cook; Rachel C. Cook; Evelyn H. Merrill
Two drivers of population dynamics are adult female survival and calf recruitment, the latter of which depends on parturition and neonatal mortality. There is limited information on calving and neonatal mortality of woodland caribou (Rangifer tarandus caribou; hereafter caribou) in Ontario. We identified parturition sites and 4-week neonatal mortality using a movement-based approach across 3 northern Ontario study regions (Pickle Lake, Nakina, and Cochrane) that vary in their capacity to support woodland caribou populations. In comparing footage from 22 video-collared caribou to predictions of the movement-based approach, we found parturition events were 100% correctly classified, date of parturition was within 1.08 ± 0.28 (x̄ ± SE) days, and mortality events up to 4 weeks were 88% correctly classified. Across study regions, 76% of caribou (n = 107) gave birth with median parturition dates a week later in Cochrane (23 May) than in Pickle Lake (17 May) and Nakina (16 May). We compared selection ratios for 3 cover types and presence of linear features within 1 km for caribou with a calf-at-heel (n = 81) during a neonatal (defined by movement rates postpartum) and a post-neonatal period (up to 35 days postpartum). Across study regions, caribou consistently selected for closed-canopied forests, and mostly against areas of early-seral stands (< 20 years old) and areas nearlinear featuresduring both periods, whereas caribou only selected for lowlands during the post-neonatal period. Thirty percent of the caribou that gave live births (n = 81) lost their calf within the first 4 weeks post-parturition with higher risk of neonatal mortality associated with increased use of lowlands, linear features, and higher movement rates in lowlands.
Habitat Loss Accelerates for An Iconic Endangered Species
Mariana Nagy-Reis; Anna Calvert; Mark Hebblewhite; Dale Seip; Sophie Gilbert; Oscar Venter; Dave Hervieux; Michael Burwash; Stan Boutin; Robert Serrouya
Habitat loss is the ultimate cause of population decline for most species at risk of extinction, including the iconic woodland caribou (Rangifer tarandus caribou). Here we evaluate patterns of habitat change within 70 woodland caribou ranges in western Canada to help the development of recovery actions that target habitat protection and restoration. Our results are alarming: with increasing trend over time, habitat loss exceeds habitat gain in most caribou ranges. We had low support for our hypothesis that Federal and/or Provincial recovery plans improve habitat change patterns within caribou ranges. Moreover, despite protection under the Species-at-Risk Act (SARA) and recent effort to achieve “No Net Loss” in Alberta and British Columbia, habitat change within caribou ranges is far from meeting critical habitat protection requirements or offsetting goals, particularly in Alberta. Boreal and Northern Mountain caribou are under higher wildfire rates whereas Southern Mountain caribou suffer higher timber harvest pressures. These results highlight the importance of elaborating ecotype-specific strategies and accounting for cumulative effects when setting thresholds for human-related disturbances and defining offsetting goals for caribou recovery under SARA. Our results support the idea that unless the rate of new disturbances is addressed, shorter-term recovery actions such as predator reductions merely delay caribou extinction. Given the magnitude of ongoing habitat change, it is clear that long-term choices regarding land-use planning need to be made and unless we address this elephant in the room, we will fail to protect and recover caribou populations in Canada.
Disturbance-Recruitment Relationships of Boreal Caribou in Boreal Shield and Hudson Bay Lowland Ecozones
Arthur R. Rodgers; Jennifer Shuter; Jennifer A. Rodgers; Robert S. Rempel; Kevin Green; Dennis Brannen; Daniel Fortin; Phil McLoughlin
Based on a 2011 meta-analysis of disturbance-recruitment data from 24 ranges, Environment Canada recommends a minimum threshold of 65% undisturbed habitat to provide a 60% probability of caribou persistence over a 20-year period. We added new Ontario data to the EC analyses and found almost half of Ontario ranges were outside the 90% PI of the original relationship. We attributed the poor fit to the quality of disturbance data used in the original analysis and differences in disturbance regimes between northern caribou ranges, dominated by natural disturbance, and more southerly ranges, dominated by anthropogenic disturbance. Subsequently, we undertook a reanalysis of disturbance-vital rate relationships in Ontario following the EC methodology but incorporating Ontario-specific disturbance data. We found weak relationships between recruitment and total or natural disturbance in Ontario ranges but a strong negative relationship between recruitment and anthropogenic disturbance in ranges where anthropogenic (primarily forestry) exceeded natural disturbance. However, these analyses were limited to a maximum of 7-13 ranges, and there were few ranges with moderate or high levels of anthropogenic disturbance. Hence, we combined our data with data from other Boreal Shield ranges in Saskatchewan, Manitoba and Quebec to undertake a reanalysis of disturbance-vital rate relationships. With the increase in sample size (n=21), we found a strong quadratic relationship between recruitment and anthropogenic disturbance and weak relationships between recruitment and total or natural disturbance. When we limited our analyses to ranges dominated by anthropogenic disturbance (n=13), there were strong negative relationships between recruitment and both total and anthropogenic disturbance.
Connectivity Across Impermeable Barriers: Predicting Pronghorn Migration Corridors along Interstate 80 in Wyoming
Benjamin Robb; Tristan Nuñez; Jerod Merkle; Hall Sawyer; Jeffrey Beck; Matthew Kauffman
Migrations allow many species to thrive in dynamic environments where resources vary. Pronghorn (Antilocapra americana) migrations in Southern Wyoming have been severed by the construction of Interstate 80 (I-80) five decades ago. Managers are interested in building crossing structures over I-80 to lessen the effects of this barrier on pronghorn movements; however, our ability to identify crossing locations is hindered because pronghorn rarely cross the interstate. We used least cost corridor modeling combined with existing GPS data near I-80 to predict the most effective locations for crossing structures. We used a collaborative GPS-collar dataset for pronghorn from 10 populations along I-80, which included n = 246 migrations and n = 134 dispersals. To identify landscape features that promote connectivity, we used a novel method that directly fits cost-distance models to migration data, then used the resulting least cost corridors to identify potential migration corridors across I-80. We applied seasonal resource selection functions to map high-quality pronghorn habitat on either side of I-80. We then mapped least cost corridors between patches of high-quality habitat on either side of I-80 through a maximum likelihood and optimization routine to identify the environmental covariates and cost-distance models best supported by the GPS data on n = 6 individual spring pronghorn migrations. We found that 45% (191 km2) of habitat severed by I-80 is high-quality pronghorn winter range (upper 75th percentile). Of 8 sites where pronghorn have crossed I-80, the relative probability of those sites from our least cost corridor prediction were on average within the 63rd percentile compared to a distribution of randomly generated crossings. This method allowed us to predict optimal crossing structure locations and test competing hypothesis of the landscape attributes most important to pronghorn connectivity. Our methods and results will have value to managers interested in restoring movement across impermeable barriers.
Validations, Degradations, and Determination of Pregnancy in Pronghorn Antelope Using Fecal Steroid Metabolites
Cole A. Bleke; Susannah S. French; Eric M. Gese
Pregnancy status is a key parameter used to assess reproductive performance as it represents a starting point for vital rate measurements. Vital rates allow managers to determine trends in populations such as neonate survival and recruitment; two important factors in pronghorn antelope (Antilocapra americana) population growth. Techniques to determine pregnancy have generally involved capture and restraint of the animal. Non-invasive pregnancy assessment eliminates any hazards between handler and animal and removes handling-induced physiological bias. Using fecal sampling, we conducted hormone validations, investigated pregnancy rates, and determined hormone degradation rates across five pronghorn antelope populations. Samples were collected during April and May of 2018 and 2019 from adult pronghorn of known sex and age class. Levels of testosterone, cortisol, 17β-estradiol, and progesterone were validated in fecal samples, and concentrations of estradiol and progesterone were used for pregnancy determination. Fecal progesterone metabolites (FPM) were significantly different between pregnant and non-pregnant females while levels fecal estrogen metabolites were not different. The greatest difference between pregnant and nonpregnant FPM measurements occurred late in gestation. Results from pregnancy determination sampling showed FPM averages for all five populations significantly different than non-pregnant female validation group. Cortisol, or fecal glucocorticoid metabolites (FGM), were not significant between pregnant female and non-pregnant females, but were different between pregnant and male pronghorn. Degradation rates showed concentrations of FPM and FGM were statistically different across days. Values from Day 1 were significantly different from all subsequent days for FPM, and after Day 9 for FGM, demonstrating the need for fresh samples to accurately measure hormone concentrations. Overall, across populations, average concentrations of FPM indicated pregnancy rates were high. Results of the validations demonstrated that diagnosis of pregnancy is possible in pronghorn via progesterone metabolites if fresh samples are collected during late gestation.
Mycoplasma bovis Results in Fatal Pneumonia in Free Ranging Pronghorn in Northeastern Wyoming
Marguerite D. Johnson; Erika Peckham; Hally Killion; Terry Creekmore; Samantha E. Allen; Hank Edwards; Madison Vance; Rebecca Ashley; Christopher Anderson; Marce Vasquez; Jim Mildenberger; Noah Hull; Karen B. Register; Kerry S. Sondgeroth; Jennifer L. Mal
Mycoplasma bovis is an economically important bacterial pathogen of cattle that contributes to polymicrobial bovine respiratory disease. Historically limited to cattle, the host range of M. bovis has more recently expanded to include North American bison, in which the bacterium is highly pathogenic. In 2019, we documented a fatal M. bovis outbreak involving over 60 pronghorn antelope (Antilocapra americana) in northeastern Wyoming. The bacterium had not previously been reported in pronghorn. In spring of 2020, we documented a second outbreak of M. bovis was documented with an estimated 500 pronghorn deaths in the same area of Wyoming. The reemergence of M. bovis in the pronghorn population suggests either a repeat spillover event from cattle, or infection of naïve pronghorn by animals that survived the 2019 outbreak and served as chronic M. bovis carriers in the recent epizootic. We characterized the pathology and genetics of M. bovis in pronghorn and found that isolates from pronghorn are most similar to those from North American cattle, and more distantly related to isolates from bison and deer. We report that pronghorn are at risk of highly virulent respiratory disease following M. bovis infection, which could have population-level impacts on this sensitive and unique species.


Location: Virtual Date: Time: -