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Seeking Snow and Breathing Hard: Behavioral Tactics in Mountain Goats to Combat Warming Temperatures
No full textThe world glaciers and persistent summer snowpack are being lost due to warming temperatures. For cold-adapted species, habitat features may offer opportunities for cooling during summer heat yet the loss of snow and ice may compromise derived thermoregulatory benefits. Herein we offer insights about habitat selection for snow and the extent to which other behavioral adjustments reduce thermal debt among high elevation mammals. Specifically, we concentrate on mountain goats (Oreamnos americanus), a species whose native distribution is tied areas where large patches of persistent summer snow are declining, and which became extinct during geologically warmer epochs. To examine sensitivity to possible thermal stressors and use of summer snow cover, we tracked marked and unmarked mountain goats in Glacier National Park, Montana, USA, to test hypotheses about selection for cold microclimates including shade and snow during periods of relatively high temperature. To understand functional responses of habitat choices, we measured microhabitat temperatures and a component of goat physiology “breaths per minute” as an index for metabolic expenditure. Individuals 1) selected areas closer to snow on warmer summer days, and 2) on snow had a 15% mean reduction in respiration when accounting for other factors, which suggests remnant snow plays an important role in mediating effects of air temperature. The use of shade was not as an important variable in models explaining respiration. Despite the loss of 85% of glaciers in in Glacier National Park, summer’s remnant snow patches are an important reservoir by which animals reduce heat stress and potential hyperthermia
Nest Attentiveness in North America’s Largest Grouse (Poster)
No full textUnderstanding nest attentiveness (i.e., amount of time spent incubating) of North America’s largest grouse, greater sage-grouse (Centrocercus urophasianus, hereafter “sage-grouse”), can be important for conserving populations, as reproductive costs can reduce survival of parents and nest attentiveness can influence nest success. When nesting, parents must allocate their time between incubating and maintenance activities, such as foraging to meet their nutritional demands. Previous research has shown female sagegrouse sustain long stretches of incubation interrupted by relatively short recesses from their nests, but incubation patterns likely differ among females. We initiated our study in 2018 with two objectives: 1) to evaluate what factors influence nest attentiveness, and 2) how nest attentiveness influences nest success by examining duration, number, and timing of recesses, and time spent incubating for successful and unsuccessful nests. We monitored female sage-grouse with GPS transmitters collecting locations every 5 minutes from 0300-2300 MST in Carbon County, Montana in 2018 and 2019 and in Carbon County, Wyoming in 2019. In Montana, we monitored 40 sage-grouse nests (17 hatched, 23 failed) in 2018, and 46 nests (21 hatched, 25 failed) in 2019. In Wyoming, we monitored 50 nests (12 hatched, 38 failed) in 2019. We measured microhabitat vegetation at 81 nests in Montana and 50 nests in Wyoming to determine habitat influences on nest attentiveness. Understanding factors that influence nest attentiveness throughout the incubation period and therefore nest success will add important and novel information to basic sage-grouse nesting ecology
An Interactive Web Tool for Deciding Between Possible Occupancy Study Designs for Rare and Cryptic Species
No full textOccupancy-based monitoring has become a valuable tool for studying rare and cryptic wildlife species. The growth of popularity of occupancy studies has been accompanied by the development of many adaptations to the original standard occupancy design, aiming to improve efficiency and to address cases where model assumptions cannot be met. For example, removal & conditional designs were developed for efficient distribution of effort between initial site visits versus repeat surveys based on how common a species is. The robust design is another adaptation that accounts for cases where the focal species may leave the study site between survey occasions. Given many options, it is not always clear which survey design will be most effective for the multiple constraints of a specific case. Yet, choosing an effective study design is critical, particularly when seeking to obtain information for rare and cryptic species, for which standard approaches are often less effective. We used case studies of Montana’s non-game Species of Greatest Inventory needs to guide development of an interactive, web-based tool that provides recommendations on occupancy study design based on study objectives and focal species characteristics. These recommendations are based on a synthesis of existing research into occupancy study design and accompanying power analyses. Simple power analyses provide users a visual sense of the effort required to obtain information related to covariates or detect trends when using an occupancy study approach under different circumstances. We will demonstrate the app using Montana Species of Greatest Inventory Need as an example
Fisher Occupancy Twenty-Five Years After Translocation in The Rocky Mountains of Montana
No full textThe historical distribution of fisher throughout Montana and the northern Rocky Mountains of the United States is uncertain, and most fishers in Montana appear to be descendants from translocated animals originating from the midwestern United States and British Columbia; however, a genotype that is unique and native to the Northern Rockies of Idaho and Montana exists in west-central Montana. Predictions based on Idaho models depict potential suitable habitat for fishers throughout the Cabinet Mountains of northwest Montana, yet distribution, occupancy and population status is currently unknown for these fishers. We conducted the first comprehensive monitoring of fishers in the Cabinet Mountains of Montana using baited camera/DNA stations. We detected fishers at 7 out of 21 cells, which resulted in a 0.43 probability that fishers occupied a grid cell. Detection probability was low, but increased slightly throughout the sampling periods. Genetic analysis revealed a minimum population count of 4-6 individual fishers in the study area, but all individuals successfully identified were males and of midwestern genetic origin. The low number of fisher detections may indeed reflect low abundance of fisher, yet these results also raise questions about our study design and sampling regime. We recommend future monitoring to increase precision of the occupancy estimate and determine the reason for a lack of female detections. We also recommend maintaining a closed trapping season on fisher, until data exists to indicate a population large enough to sustain harves
Grassland Ghosts Keeping an Eye on The Recovering Swift Fox 2018 International Census
No full textSwift Fox (Vulpes velox) were extirpated from Canada in 1938 and in Montana in 1969, largely due to federal eradication campaigns in the 1930’s targeting coyote and wolves. Reintroduction efforts in Canada occurred from 1983 until 1997. By 2001, swift fox were thought to be established in Northern Montana. In Montana, survey efforts began in 2000/2001, then repeated in 2005/2006, 2014/2015, and most recently the summer of 2018. Surveys in the winter of 2014/2015 consisted of two methods, live trapping and camera trapping. The goal was to determine changes in demography and distribution, but also to assess the feasibility of switching exclusively to camera traps for future survey efforts. There was little difference in detection probability between the two methods suggesting camera trapping is an effective alternative to live trapping. This resulted in only camera trapping being used for the 2018 census. Analysis comparing occupancy between 14/15 and 2018 showed that swift fox populations in the sampling area remained stable and relatively unchanged despite the harsh winter of 2017/2018. Through a finer scope, the Montana populations seem to have experienced a slight increase. The swift fox population in Canada and northern Montana is interdependent and continued collaboration for monitoring across jurisdiction and boundaries is important. Management of swift fox in Montana will continue to follow the Swift Fox Conservation Strategy
Microhabitat Selection by Reproductive State in Greater Sage Grouse
No full textGreater sage grouse (Centrocercus urophasianus; hereafter sage-grouse) are the focus of much research and conservation efforts owing to their obligate relationship with sagebrush (Artemisia spp.) and dramatic population declines over the last 50 years. Research suggests female survival and chick survival are two of the most important demographic parameters for sage-grouse. In addition, recent research has shown habitat partitioning occurs between broodless (i.e., females without a brood) and brood-rearing females and that broodless females have lower mortality risk than females with chicks. Thus, habitat used by both reproductive states must be considered in management plans. Our study was initiated in spring 2018 in Carbon County, Montana to identify seasonal habitat use and compare landscape and microhabitat characteristics between brood-rearing and broodless females. Identifying differences in habitat use between reproductive states can inform better management to account for all life stages of sage-grouse. We monitored 39 and 43 females captured at 7 leks in 2018 and 2019, respectively, with the use of GPS transmitters. We monitored 17 broods in 2018 and 21 broods in 2019 until 5 weeks post-hatch. We examined 5-minute locations for females to focus vegetation surveys during different behavior’s day and night roosts and active day locations. We measured vegetation characteristics (e.g., shrub, grass, forb, and ground cover) at 66 early brood-rearing (2 weeks post-hatch), 72 late brood-rearing 5 weeks post-hatch), 75 broodless locations, and 123 random locations. Understanding female sage-grouse habitat use during both reproductive states will better inform wildlife practitioners to manage habitat for all sage-grouse life stages
Sage-Grouse: Fine-Scale Specialist or Shrub-Steppe Generalist?
No full textSage-grouse (Centrocercus spp.) are driving rapidly-evolving land management policy in the western United States. Management objectives for fine-scale vegetation characteristics have been widely adopted by land management agencies based on resource selection or relationships with fitness proxies reported among numerous habitat studies. However, some managers have questioned the appropriateness of these objectives. Moreover, it remains untested whether habitat-fitness relationships documented at fine scales (i.e., among individual nests within a study area) also apply at scales of management units (e.g., pastures or grazing allotments), which are many orders of magnitude larger. We employ meta-analyses to help resolve the role of fine-scale vegetation structure in nest site selection and nest success across the geographic range of greater sage-grouse (C. urophasianus) and evaluate the validity of established habitat management objectives. Importantly, our approach tests habitat relationships at a range-wide extent and a grain size closely matching scales at which agencies make management decisions. We found moderate, but context-dependent, effects of shrub characteristics and weak effects of herbaceous vegetation on nest site selection. None of the tested vegetation characteristics were related to variation in nest success, suggesting nesting habitat-fitness relationships have been inappropriately extrapolated in developing range-wide habitat management objectives. Our findings reveal surprising flexibility in fine-scale habitat use for a species often depicted as having very particular fine-scale habitat requirements and cast doubt on the practice of adopting precise management objectives for vegetation structure based on findings of individual smallscale field studies
Stress Hormones Mediate Tradeoffs Between Survival and Growth for Amphibians Exposed to Increased Salinity
No full textSalinity has increased in many freshwater ecosystems in the last century. Despite this, limited information exists on its effects on freshwater vertebrates. Amphibians are sensitive to salinity because of their porous skin and primarily-aquatic lifecycle. Wildlife managers often seek biomarkers to gauge the influence of contaminants on population health; one marker maybe changes in stress hormones (e.g., corticosterone; CORT). We investigated the influence of increased salinity on growth, CORT, and survival of larval leopard frogs (Rana pipiens) in a controlled experiment. We exposed larvae to one of three environmentally-relevant saltconcentrations, and compared them against controls. For half of the larvae, we also blocked actions of CORT (using RU486) to determine if it mediates effects of salinity. We used novel, noninvasive techniques to collect waterborne CORT samples from larvae every 4 d for 24 d (baseline and stress-induced). Larval size, development, and survival decreased with exposure to increasing salinity. Survival decreased faster when CORT was also blocked. However, size and development did not decrease compared to controls when CORT was blocked. Baseline and stress-induced CORT were positively related to survival. Our results demonstrate that CORT may mediate life history tradeoffs of larvae exposed to increased salinity by diverting energy from growth and development towards survival. However, by blocking CORT, the opposite occurred. We detected some differences in CORT among treatments during the experiment, but CORT responses were not different after 3 weeks of exposure. Therefore, CORT may not be a suitable biomarker for monitoring influences of salinity on amphibians
Assessment of Sympatric Turtle Populations and Movements in Relation to an Irrigation Barrier on Pryor Creek
No full textHabitat loss and fragmentation due to dams is one of the most significant threats to turtles worldwide. Barriers can isolate populations and reduce gene flow, increasing vulnerability to extinction-level events. Pryor Creek (Huntley, Montana) features a sympatric population of spiny softshell turtles (Apalone spinifera) and snapping turtles (Chelydra serpentina), and a 3-meter tall irrigation barrier. Populations of both species live on either side of the barrier, but connectivity between these populations is unknown. We hypothesized that movements of both species would be restricted by the barrier. We also expected possible differences in population demographic structures of each species above and below the barrier due to habitat differences and population isolation. Mark-recapture and radio-telemetry techniques were used to gather movement data on 150 individual turtles over four years. To date no snapping turtles have been documented bypassing the barrier, but four spiny softshell turtles have passed the barrier. Demographics of both species were found to be significantly different above and below the barrier. No female snapping turtles were caught below the barrier, and no juvenile spiny softshell turtles were caught above the barrier. Mean weight of spiny softshell turtles above and below the dam were significantly different. These differences may indicate differences in survival, reproduction, and possibly food availability. This is the first study looking at the ability of turtles to navigate around an aquatic barrier, which has significant long-term implications for population health and management effort
By Thinking Outside the Box, Mitigation Conserves Working Private Lands Intermingled with Public Lands in Key Sagebrush-Grassland Areas
No full textHabitat treatments such as prescribed burning and mechanical thinning are commonly conducted across the United States for many reasons including reducing fuel loads, increasing habitat quality for wildlife, and modifying forest structural diversity. The Rocky Mountain Elk Foundation has implemented numerous habitat treatments in the Western US to increase habitat quality for elk and other species. Understanding how habitat treatments impact bird communities is important in conserving their habitat and preserving ecosystem services and recreational opportunities that they provide. The objectives of this study are to 1) determine how prescribed burning and mechanical thinning impact occupancy and species richness of birds and 2) determine how these impacts change over time since treatment and in different landscape contexts. To determine these impacts, we sampled the bird community at paired treated-control sites across eastern Oregon, northern Idaho, and western Montana. We sampled sites 1-30 years post treatment. We visited sites three times between May and August, 2018-2019. We conducted point counts and sampled forest and vegetation characteristics along randomly located points within all site pairs. We measured treatment effects on bird communities using changes in occupancy of our focal species (Western Bluebird (Sialia mexicana), Dark-eyed Junco (Junco hyemalis), Mountain Chickadee (Poecile gambeli), and Woodpeckers), and species richness. Our results indicate that there is no significant treatment effect on species richness or occupancy of our focal species