Geology topics

Michael J. Cherry

Publications and source records attributed to Michael J. Cherry.

13 recordsLinked to original sources

USGS2026

Biological and environmental drivers of early life fawn survival in a declining pronghorn population

Pronghorn Antilocapra americana occupy only a portion of their historical range and in Oklahoma occur at the eastern edge of the species' contemporary distribution. Monitoring has suggested pronghorn populations in Oklahoma have declined in recent years. We captured and collared 125 adult females across two winters, monitored them for signs of parturition during each subsequent spring, and then captured and radio-collared 70 fawns ≤ 4 days old. We assessed cause-specific mortality, estimated proportional survival, and visualized survival of fawns through 60 days of life with Kaplan–Meier curves. Nearly 87% of fawn mortalities were attributed to predation, with > 77% of predations attributed to coyotes Canis latrans . Our results indicated that fawn survival was lowest during the first 15 days of life, with 33% of fawns surviving to 15 days and 12% surviving to 60 days. We used known-fate models to evaluate the influence of biological factors (i.e. sex, mass, birth timing), environmental factors (i.e. ambient temperature, precipitation, vegetation), and temporal variation on the probability of early life (i.e. the first 15 days) survival. For each adult female with a collared fawn, we used female space-use patterns for 30 days before and 15 days after parturition to collect environmental covariates. Early life probability of survival was lower for larger fawns, those born earlier in the parturition period (i.e. earlier in the year relative to the range of parturition days), and those with higher pre-parturition temperatures; daily probability of survival decreased with time-since-parturition within the first 15 days of life. Our results indicate poor fawn survival, highlight a potential limitation of population growth, and can inform population management by identifying factors influencing early life fawn survival.

Oklahoma↗

USGS2026

Multiscale resource selection for a reintroduced elk population

Patterns of resource selection are driven by the decision-making processes of animals occurring at multiple scales from where to establish a home range (i.e., second order selection) to which resource patches to use within the home range (i.e., third order selection). Elk ( Cervus canadensis ) were reintroduced to southwestern Virginia, USA, from 2012 to 2014 following successful translocations onto reclaimed surface coal mines in the region. We sought to understand how elk have acclimated following their translocation using location data from GPS-collared adult female elk ( n = 33) collected from 2019 to 2022 along with remotely sensed terrain and land cover data. We utilized continuous-time movement models paired with generalized linear mixed-effects modeling to describe seasonal resource selection at second and third orders. At both scales of selection and throughout the year, female elk selected reclaimed surface mines, conifer forests, ridgetops, and areas with lower terrain roughness, while avoiding mixed hardwood and oak ( Quercus spp.) forests. Unmined open land was only selected at the third order during periods of forage scarcity (i.e., winter) and increased metabolic requirements (i.e., late gestation). Although surface coal mining leaves legacy environmental impacts on the landscape, management of these sites provides benefits to elk and maintains open habitat that is otherwise limited.

Virginia↗

USGS2026

Interacting effects of human presence and landscape modification on birds and mammals

Sustainable human–wildlife coexistence requires a mechanistic understanding of the many ways that humans affect animals. However, progress is hampered by the lack of accessible data measuring the dynamic presence of people. Here, we leverage mobile-device data to disentangle how human presence and landscape modification differentially influence the use of geographic and environmental space for 37 mammal and bird species across the United States. Human presence affected more than 65% of species, with substantial variation across species. For ~60% of species that responded to human activities, the effects were interdependent—animals tended to react more strongly to human presence in less modified habitats. Our results demonstrate that human presence and landscape modification have complex combined effects on wildlife, which need to be considered for effective management.

Science↗

USGS2025

Harmless tags or hazardous ads? Investigating the potential for ear tags to increase predation on neonatal ungulates

Studies involving individually marked animals provide insights predicated on the assumption marked individuals are accurate models of their unmarked counterparts. Taxa-specific and marker-specific examinations are needed to determine if marked animals are suitable models for the parameter(s) being measured. Our objective was to determine if brightly colored ear tags influenced the probability of predation for neonatal ungulates. We captured 94 neonatal pronghorn (Antilocapra americana (Ord, 1815)), fitted each neonate with a tracking collar, and attached a yellow ear tag to 49 (52.1%) of the captured neonates. We monitored the survival of each neonate during 2023–2024 in Oklahoma, USA. Predation was the leading cause of mortality during our monitoring period and accounted for 29 (82.9%) of the 35 mortalities with a known cause. Coyotes (Canis latrans Say, 1823) were the predominant predator of neonatal pronghorn in our study area. Presence of a yellow ear tag seemingly did not influence the probability of predation, even though coyotes can distinguish yellow objects from most natural backgrounds. A larger sample size may be needed to validate our results, but neonatal ungulates with an ear tag appear to be accurate models of neonatal ungulates without an ear tag when examining predation risk.

Oklahoma↗

USGS2025

The influence of human presence and footprint on animal space use in US national parks

Given the importance of protected areas for biodiversity, the growth of visitation to many areas has raised concerns about the effects of humans on wildlife. In 2020, the COVID-19 pandemic led to temporary closure of national parks in the United States, offering a pseudonatural experiment to tease apart the effects of permanent infrastructure and transient human presence on animals. We compiled GPS tracking data from 229 individuals of 10 mammal species in 14 parks and used third-order hierarchical resource selection functions to evaluate the influence of the human footprint on animal space use in 2019 and 2020. Averaged across all parks and species, animals avoided the human footprint, whether the park was open or closed. However, although animals in remote areas showed consistent avoidance, on average those in more developed areas switched from avoidance to selection when protected areas were closed. Findings varied across species: some responded consistently negatively to the footprint (wolves, mountain goats), some positively (mule deer, red fox) and others had a strong exposure-mediated response (elk, mountain lion). Furthermore, some species responded more strongly to the park closure (black bear, moose). This study advances our understanding of complex interactions between recreation and wildlife in protected areas.

western United States↗

USGS2025

Predator-induced injury of a neonatal pronghorn cues abandonment of current reproductive investment

Evolutionary theory predicts that parental care is favored when the fitness benefits outweigh the costs of providing care (Klug et al., 2012 ). In mammals, parental care is generally provided by females, who provide nourishment through lactation, protection from predators, aid in juvenile movement, or otherwise facilitate offspring survival (Balshine, 2012 ; Lent, 1974 ). However, in capital breeding species that rely on stored energy reserves for reproduction, increased investment can reduce the female's body condition and the number of offspring produced in subsequent years (Balme et al., 2017 ; Cook et al., 2013 ; Stephens et al., 2009 ). Unlike income breeders, which produce offspring from concurrent energy uptake, capital breeders deplete energy stores during reproduction, and lactation hinders the recovery of these stores (Clutton-Brock et al., 1983 ; Cook et al., 2013 ; Stephens et al., 2009 ). Consequently, iteroparous mammals face a trade-off between investing in current offspring and investing in maintenance or future offspring (Hamel et al., 2010 ; Stearns, 1989 ; Williams, 1966 ).

Ecology↗

USGS2023

Survival, cause-specific mortality, and population growth of white-tailed deer in western Virginia

Understanding the role of recruitment in population dynamics of white-tailed deer ( Odocoileus virginianus ) is important for management. In the central Appalachian Mountains, deer are part of a largely forested ecosystem that supports 3 carnivore species thought to be capable of influencing white-tailed deer recruitment: black bears ( Urus americanus ), coyotes ( Canis latrans ), and bobcats ( Lynx rufus ). Yet little is known about predation, how other environmental factors influence recruitment, or the importance of neonate survival to white-tailed deer population performance in the region. Our objectives were to identify causes of mortality for neonates, analyze effects of landscape attributes on survival of neonates, estimate survival rates for neonates and adult female white-tailed deer, and to model population growth trends based on current vital rates and hypothetical harvest and neonate survival scenarios. During 2019–2020, we captured 57 neonate deer in Bath County, Virginia, USA, by monitoring 38 pregnant females equipped with global positioning system collars and vaginal implant transmitters and by conducting transect searches for recently born neonates. We observed 37 neonate mortalities and identified cause of death using field and genetic evidence. Mortalities included 28 predation events and 9 deaths from other causes (e.g., abandonment, malnutrition, disease). Black bears accounted for 48.6% of neonate mortalities, and 64.2% of predation events ( n = 18), followed by bobcats ( n = 5) and coyotes ( n = 3). Annual survival for adult female deer was 0.871 and neonate survival to 12 weeks old was 0.310. Elevation was a significant predictor of neonate survival; mortality risk increased 20% for every 100-m increase in elevation. Models of annual population growth using observed vital rates predicted an increasing population (λ = 1.10). A 10% increase in female harvest would still result in a potential population increase of 2% (λ = 1.02), but a 20% increase in harvest rate would result in a potential 7% decline (λ = 0.93). Neonate survival was higher near fertile valley bottoms and lower along forested ridges characterized by shallow, infertile soils and limited edge or early successional forests. While predation, largely influenced by black bears, was the leading cause of neonate mortality and contributed to low neonate survival, we observed little evidence of population decline, and suggest there is opportunity for a modest increase in harvest of female deer.

Virginia↗

USGS2023

Estimating elk abundance using the Lincoln-Petersen method

Achieving a target population size is often the first goal of species restorations. From 2012 to 2014, the Virginia Department of Wildlife Resources released 75 elk ( Cervus canadensis ) originating from Kentucky into Buchanan County in southwestern Virginia. These individuals were ear tagged with unique numbers upon release with an additional 33 elk tagged within the Virginia Elk Management Zone (VEMZ) from 2019 through early 2022. To assess post-release population size, we conducted visual driving surveys throughout Buchanan County from January through mid-April, 2021 and January through March, 2022, counting elk and noting sex, age class, and tagged individuals when observed. We conducted four surveys annually, each consisting of pooled elk counts from eight driving routes, and calculated a Lincoln-Petersen population estimate with Chapman’s bias correction for each survey, then averaged estimates for each year. The population estimate in Buchanan County was 250 (95% CI: 100–400) elk in 2021 and 303 (155–452) in 2022. Our elk population estimates indicate Virginia is on the trajectory of meeting the first goal in their 2019–2028 elk management plan of achieving a viable elk population.

Virginia↗

USGS2022

Drivers of habitat quality for a reintroduced elk herd

Understanding spatiotemporal variation in habitat quality is essential for guiding wildlife reintroduction and restoration programs. The habitat productivity hypothesis posits that home range size is inversely related to habitat quality. Thus, home range size may be used as a proxy for habitat quality and can identify important land cover features for a recovering species. We sought to quantify variation in home range size across the biological cycle (seasons) for a reintroduced elk ( Cervus canadensis ) population in southwestern Virginia, USA and quantify habitat quality by linking home range sizes to the land cover types they contain using linear mixed-effects models. We found mean home range size was largest during late gestation for female elk. Additionally, throughout the year, smaller home ranges were associated with larger proportions of non-forested habitats whereas forested habitats were generally the opposite. However, both presumed poor- and high-quality habitats influenced female elk space use. Our approach revealed spatial variation in habitat quality for a recovering elk herd, demonstrated the importance of non-forested habitats to elk, can guide decisions regarding the location of future elk reintroduction programs, and serve as a model for evaluating habitat quality associated with wildlife reintroductions.

Virginia↗

USGS2022

Survival of white-tailed deer fawns on Marine Corps Base Quantico

Some jurisdictions in the eastern United States have reduced harvest of white-tailed deer ( Odocoileus virginianus ) because of perceived declines in recruitment and population size over the last decade. Although the restoration of American black bears ( Ursus americanus ) and the colonization of coyotes ( Canis latrans ) have increased fawn predation in some areas, limited information exists on how temporally dynamic resources and weather influence fawn survival. Therefore, we evaluated fawn survival probability, cause specific mortality, and if factors such as oak ( Quercus spp.) mast abundance, winter severity, precipitation, and landscape composition influenced mortality risk on Marine Corps Base Quantico in northern Virginia, USA, from 2008 to 2019. We tracked 248 fawns outfitted with very high frequency radio-collars and predation was the leading cause of mortality ( n = 42; 45%). We estimated survival to 133 days and survival pooling all years (2008–2019) was 0.50 (95% CI = 0.42–0.60). Increased annual red oak ( Quercus spp.) mast abundance from the previous fall reduced mortality hazard for fawns. The longevity of our study revealed a link between fawn survival and a specific maternal resource (red oak mast) only available during gestation. Our results highlight the importance of oak mast in eastern deciduous forests and, more broadly, overwinter maternal condition on white-tailed deer recruitment.

Virginia↗

USGS2021

Fire, land cover, and temperature drivers of bat activity in winter

Background Understanding the effects of disturbance events, land cover, and weather on wildlife activity is fundamental to wildlife management. Currently, in North America, bats are of high conservation concern due to white-nose syndrome and wind-energy development impact, but the role of fire as a potential additional stressor has received less focus. Although limited, the vast majority of research on bats and fire in the southeastern United States has been conducted during the growing season, thereby creating data gaps for bats in the region relative to overwintering conditions, particularly for non-hibernating species. The longleaf pine ( Pinus palustris Mill.) ecosystem is an archetypal fire-mediated ecosystem that has been the focus of landscape-level restoration in the Southeast. Although historically fires predominately occurred during the growing season in these systems, dormant-season fire is more widely utilized for easier application and control as a means of habitat management in the region. To assess the impacts of fire and environmental factors on bat activity on Camp Blanding Joint Training Center (CB) in northern Florida, USA, we deployed 34 acoustic detectors across CB and recorded data from 26 February to 3 April 2019, and from 10 December 2019 to 14 January 2020. Results We identified eight bat species native to the region as present at CB. Bat activity was related to the proximity of mesic habitats as well as the presence of pine or deciduous forest types, depending on species morphology ( i.e., body size, wing-loading, and echolocation call frequency). Activity for all bat species was influenced positively by either time since fire or mean fire return interval. Conclusion Overall, our results suggested that fire use provides a diverse landscape pattern at CB that maintains mesic, deciduous habitat within the larger pine forest matrix, thereby supporting the diverse bat community at CB during the dormant season and early spring.

Florida↗

USGS2021

Winter roost selection of Lasiurine tree bats in a pyric landscape

Day-roost selection by Lasiurine tree bats during winter and their response to dormant season fires is unknown in the southeastern United States where dormant season burning is widely applied. Although fires historically were predominantly growing season, they now occur in the dormant season in this part of the Coastal Plain to support a myriad of stewardship activities, including habitat management for game species. To examine the response of bats to landscape condition and the application of prescribed fire, in the winter of 2019, we mist-netted and affixed radio-transmitters to 16 Lasiurine bats, primarily Seminole bats ( Lasiurus seminolus ) at Camp Blanding Joint Training Center in northern Florida. We then located day-roost sites to describe roost attributes. For five Seminole bats, one eastern red bat ( Lasiurus borealis ), and one hoary bat ( Lasiurus cinereus ), we applied prescribed burns in the roost area to observe bat response in real-time. Generally, Seminole bats selected day-roosts in mesic forest stands with high mean fire return intervals. At the roost tree scale, Seminole day-roosts tended to be larger, taller and in higher canopy dominance classes than surrounding trees. Seminole bats roosted in longleaf ( Pinus palustris) , slash ( Pinus elliotii ) and loblolly pine ( Pinus taeda ) more than expected based on availability, whereas sweetbay ( Magnolia virginiana ), water oak ( Quercus nigra ) and turkey oak ( Quercus laevis ), were roosted in less than expected based on availability. Of the seven roosts subjected to prescribed burns, only one male Seminole bat and one male eastern red bat evacuated during or immediately following burning. In both cases, these bats had day-roosted at heights lower than the majority of other day-roosts observed during our study. Our results suggest Seminole bats choose winter day-roosts that both maximize solar exposure and minimize risks associated with fire. Nonetheless, because selected day-roosts largely were fire-dependent or tolerant tree species, application of fire does need to periodically occur to promote recruitment and retention of suitable roost sites.

Florida↗

USGS2019

Activity patterns and temporal predator avoidance of white-tailed deer (Odocoileus virginianus) during the fawning season

In the presence of a predator, prey may alter their temporal activity patterns to reduce the risk of an encounter that may induce injury or death. Prey perception of predation risk and antipredator responses may increase in the presence of dependent offspring. We conducted a camera trap study during summer 2015 in North Carolina and Tennessee, USA to evaluate temporal avoidance of a predator (coyote Canis latrans ) by white-tailed deer ( Odocoileus virginianus ). We analyzed activity patterns of bucks, does, and nursery groups (i.e., groups that included fawns) relative to those of coyotes to determine the coefficient of overlap (Δ) using a kernel density estimator. We found that bucks and does had similar Δ with coyotes [Δ 1 = 0.729 (0.629–0.890) and Δ 1 = 0.686 (0.558–0.816, respectively] and exhibited crepuscular activity patterns comparable to those of coyotes. However, nursery groups displayed a dramatically different activity pattern: unimodal activity was concentrated in the middle of the day with little overlap with coyote activity [Δ 1 = 0.362 (0.176–0.491)]. Because adult deer are rarely prey for coyotes, whereas fawns are common prey during summer, the shift in activity patterns of nursery groups demonstrates a behavioral shift likely aimed at avoiding coyote predation on fawns.

North Carolina, Tennessee↗