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Browsing by Author "Crooks, Kevin, committee member"

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    Bats, elephants, and their food: a conservation perspective on trophic interactions in the Namib Desert
    (Colorado State University. Libraries, 2019) Laverty, Theresa Marie, author; Berger, Joel, advisor; Crooks, Kevin, committee member; Wittemyer, George, committee member; Teel, Tara, committee member
    To view the abstract, please see the full text of the document.
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    Conserving tigers beyond protected area boundaries: the spatial ecology of tigers and their prey in farmlands in north India
    (Colorado State University. Libraries, 2019) Warrier, Rekha, author; Noon, Barry, advisor; Bailey, Larissa, committee member; Crooks, Kevin, committee member; Teel, Tara, committee member
    To view the abstract, please see the full text of the document.
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    Evaluation of a novel wildlife telemetry device with data transfer capabilities
    (Colorado State University. Libraries, 2012) Davis, Melanie, author; Hobbs, N. Thompson, advisor; Miller, Michael W., committee member; Crooks, Kevin, committee member; Massey, Daniel, committee member
    The construction of low-cost, advanced Global Positioning System (GPS) telemetry systems for wildlife tracking is growing in popularity, especially systems that can communicate with each other to track contacts and, more recently, transfer data. This novel function represents a step forward from current technology because it allows researchers to retrieve data from collars that have been damaged or lost. It also elucidates broad networks of interactions between individuals to monitor disease spread and social preference. I tested the communication and data transfer capabilities of a low-cost, custom-built GPS telemetry collar with an on-board wireless sensor network. I performed several trials using captive bighorn sheep to measure how data transfer reliability is impacted by the bodily obstruction of an animal, and to determine the accuracy of logged contacts. I present the results of these trials, which show that data transfer is adversely affected by the placement of the collar around the sheeps' necks, but that the contact accuracy remains uncompromised. Once refined, this technology could represent a significant improvement over currently-available telemetry devices, and may offer novel insight into previously unobserved ecological phenomena.
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    Extrinsic and intrinsic drivers of feline immunodeficiency virus evolution in the mountain lion
    (Colorado State University. Libraries, 2018) Malmberg, Jennifer L., author; VandeWoude, Sue, advisor; Crooks, Kevin, committee member; Quackenbush, Sandra, committee member; Perera, Rushika, committee member
    Viruses are among the most rapidly evolving entities in biology and are so intricately associated with their obligate hosts that the boundary between host and pathogen, and thus the study of one versus the other, is blurred by intimate interactions at scales ranging from proteins to populations. Viral genetic variation is both ecologically and molecularly determined, and thus viruses serve as measurably evolving populations that provide a window into adaptations and behaviors of their vertebrate hosts. Of all viral families, the biology of retroviruses is coupled especially tightly to that of the host due to permanent integration of viral DNA into eukaryotic chromosomes, producing an inherently dynamic infection that persists for life. Feline immunodeficiency virus (FIV) is among the oldest of viruses in the Lentivirus genus and puma (Puma concolor) are the most extensively ranging New World terrestrial mammal. We used molecular analyses to investigate the host-pathogen interactions between pumas and FIV across geographic and temporal space, within and across populations, and among FIV subtypes. In Chapter One, we investigate cross-species transmission of FIV from bobcats to pumas and compare the outcome of spillover infections in two populations separated by vast geographic space. Our findings reveal that the puma is typically a dead-end host of bobcat FIV infection, although altered population dynamics can promote stuttering chains of infection following spillover events. In Chapter Two, we employed a novel next generation sequencing technique to investigate the impact of management interactions such as population supplementation on FIV dynamics in the endangered Florida panther. Results from this chapter show evidence for cointroduction of one subtype of FIV with translocated pumas from Texas, followed by local extinction of the previously circulating, 'less fit' subtype in the puma host. Chapter Three describes an important intrinsic driver of viral evolution through characterization of the APOBEC3 protein A3Z3 in the puma, a primary cellular restriction factor against FIV. We show evidence that at least one geographically associated genotype of puma FIV is able to evade lethal hypermutation typical of A3Z3 activity despite a deficiency in the viral counter protein Vif. The collective findings of this work explore the ancient relationship between a vastly ranging apex predator and a chronic lentiviral infection by applying both novel and conventional methodologies to a unique, naturally occurring host-pathogen system. Although our questions were specific to FIV in pumas, the methodologies described here can be applied to other systems and models to address inherent limitations of opportunistic field studies including DNA degradation and sequencing of low copy number templates from archival biological samples. Ancient viral infections have the potential to elucidate the life history of mammalian hosts, which is particularly useful in the study of elusive and broadly ranging carnivores threatened by urbanization and habitat fragmentation. Future objectives of this work will expand analyses to incorporate additional populations, such as the modern Texas puma, and more thoroughly investigate genotype variation in Vif-A3Z3 interactions. Collectively, our results will inform additional studies that seek to elucidate determinants of host-pathogen interactions in naturally-occurring systems across diverse ecosystems and broad spatiotemporal scales.
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    Group-level social influences for carnivore restoration and management
    (Colorado State University. Libraries, 2023) Gonzalez, Mireille N., author; Niemiec, Rebecca, advisor; Crooks, Kevin, committee member; Teel, Tara, committee member; Quartuch, Mike, committee member; Jacobson, Cynthia, committee member
    In this dissertation, I conducted research on how perceptions of the group level of the social system influence individuals' perspectives and behaviors related to carnivore restoration and management (CRM) in the U.S. American West. Using the case study of gray wolf (Canis lupus) reintroduction in Colorado, I explored three aspects of the group level of the social system. After nearly 80 years since their extirpation, environmental organizations advocating for wolf recovery introduced a ballot initiative (Proposition 114) that mandates Colorado Parks and Wildlife, the state wildlife agency, reintroduce wolves into Colorado by December 31st, 2023. In November 2020 Proposition 114 passed with about 51% of the votes (Colorado Election Results, 2020), marking the first ever U.S. reintroduction of an endangered species via a ballot initiative. In my first chapter, I used public survey data to explore how intragroup perceptions, or how perceptions of a group one identifies as belonging to, influenced individual and collective civic actions related to wolf reintroduction. I found that social norms influenced intended voting for Proposition 114 and plans for those individuals that opposed reintroduction to engage in collective action against reintroduction. In my second chapter, I used stakeholder interview data to examine perspectives of what would make a stakeholder engagement process, that brings together conflicting stakeholders to collaboratively build recommendations for wolf restoration and management, successful. Stakeholders expected that the process should be representative, transparent, and actively inclusive and that it should foster two-way dialogue. Additionally, to be considered successful, they believed it should achieve the social outcomes of conflict reduction, social learning, increased trust in agency, and increased support for the management plan. Lastly, in my third chapter, I used stakeholder interview data to examine how perspectives of the outgroup, or a group one does not identify as belonging to, influence social conflict about wolf reintroduction. I found that conflict was fueled by perceptions that the outgroup is unjust, misinformed, homogenous, and unmalleable. Overall, my dissertation expands our collective understanding of the multi-scalar influencers to human behavior that affect carnivore restoration and management. Based on these findings, I recommend how to develop interventions and stakeholder engagement that can help achieve desired social outcomes related to CRM objectives.
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    Ivory poaching, sociality, and the role of behavior in conservation
    (Colorado State University. Libraries, 2016) Goldenberg, Shifra Z., author; Wittemyer, George, advisor; Archie, Elizabeth, committee member; Crooks, Kevin, committee member; Naug, Dhruba, committee member
    The potential of animal behavior to contribute to conservation biology has been acknowledged for decades, but empirical work to realize this potential has been surprisingly slow (Sutherland 1998; Caro 2007; Angeloni et al. 2008; Berger-Tal et al. 2015). Behavior that reliably conveys the response of populations to human threats may be particularly useful in assessing population status and recovery potential as it can be measured over relatively short time periods. African elephants (Loxodonta africana) rely heavily on behavioral decisions and are highly dependent on complex social processes that revolve around older animals (Douglas-Hamilton 1972; Moss 1988; Wittemyer et al. 2005b). Within the last decade poaching of elephants for their ivory has increased to meet rising demand on international markets (Maisels et al. 2013; Wittemyer et al. 2014), which has disproportionately been targeted toward older elephants for their larger tusks (Wittemyer et al. 2013; Chiyo et al. 2015). In this dissertation I analyze behavior in the context of a well-studied population of African elephants in northern Kenya under illegal killing pressure, with emphasis on social behavior. I describe baseline levels of sociality among adult male elephants prior to the intensification of poaching, compare hierarchical social network structure of female elephants before and during poaching, investigate fine-scale social strategies among young females following family mortalities, assess the utility of a flight metric as a behavioral indicator of harvest pressure, and examine the overlap in area use of two adjacent subpopulations. This work contributes to the growing literature on conservation behavioral methods and advances understanding of sociality in this threatened species.
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    Population ecology of black-footed ferrets (Mustela nigripes) in relation to sylvatic plague
    (Colorado State University. Libraries, 2023) Livieri, Travis M., author; Angeloni, Lisa, advisor; Antolin, Michael, committee member; Biggins, Dean, committee member; Crooks, Kevin, committee member
    Infectious diseases can have significant impacts, both direct and indirect, on the conservation of endangered species. A full understanding of these impacts is hindered by the difficulty of teasing apart disease effects from other factors that led to endangerment, the scarcity of population data from before and after disease detection, and the inherent challenge of studying rare species, which are often difficult to detect. Ideally, a disease and population monitoring strategy will detect outbreaks so effective management and mitigation strategies can be implemented. Disease mitigation strategies, such as vaccination or removal of infected individuals, can be effective but costly to implement and rigorous evaluations of such efforts are rare. Here we present a case study and evaluation of a multi-faceted effort to manage multiple impacts of sylvatic plague (plague hereafter), an invasive disease, in a reintroduced population of endangered black-footed ferrets (Mustela nigripes) and their prey, black-tailed prairie dogs (Cynomys ludovicianus), in Conata Basin/Badlands National Park, South Dakota. Since reintroduction in 1994-1999, this is the largest free-ranging ferret population. Chapter One provides a broad introduction to black-footed ferret natural history, ecology, and conservation efforts. We briefly described the life history of black-footed ferrets, their reliance upon prairie dogs (Cynomys spp.) as prey and habitat engineers, and the conflicts between prairie dogs and agricultural interests that motivated human efforts to eradicate prairie dogs and inadvertently drove ferrets towards extinction. Ensuing captive breeding and reintroduction efforts averted extinction of the species, but plague, caused by Yersinia pestis bacteria, led to high mortality in both black-footed ferrets and prairie dogs, was a second factor in ferret decline, and continues to threaten reintroduced populations. Plague management, through flea vector control and vaccination, is a high priority for the black-footed ferret recovery program, along with maintaining genetic diversity and securing habitat. We concluded that black-footed ferret recovery to date has been partially successful, but challenges remain, and plague represents the largest biological threat. In Chapter Two, we evaluated the efforts to manage plague for black-footed ferrets and prairie dogs at Conata Basin/Badlands National Park. We effectively monitored plague using carnivore serology, prairie dog testing, and visual surveys to detect the invasion of plague and inform our mitigation efforts. Both prairie dog colonies and black-footed ferret populations declined precipitously with the plague epizootic. We applied deltamethrin dust into prairie dog burrows to kill fleas and vaccinated black-footed ferrets against plague during annual monitoring efforts. Our results suggested that dusting was effective in maintaining prairie dog colonies compared to non-dusted colonies and significantly increasing survival of black-footed ferrets. Additionally, our vaccination of black-footed ferrets added incremental gains in ferret survival. These combined efforts of plague surveillance, dusting prairie dog burrows, and vaccinating black-footed ferrets likely prevented extirpation of this population. In Chapter Three, we used stable isotope analysis to understand the effects of plague on the proportion of prairie dogs in black-footed ferret diets. Previous studies on black-footed ferrets found up to one-third of ferret diet is comprised of non-prairie dog rodents. Plague causes high mortality in prairie dogs and other small mammals found on prairie dog colonies, potentially increasing variability in prey available for black-footed ferrets. We sampled black-footed ferrets and two prey items, prairie dogs and deer mice (Peromyscus sonoriensis), before and during a plague epizootic and used stable isotope analysis to estimate the diet proportions in relation to plague and dusting. We found that prior to plague black-footed ferret diets in Conata Basin/Badlands National Park were similar to previous studies, but during a plague epizootic ferrets shifted their diet almost completely to prairie dogs. Dusting prairie dog burrows prior to the invasion of plague had a similar effect in shifting black-footed ferret diets. We concluded that despite observed foraging plasticity, black-footed ferrets can be considered prairie dog colony specialists, and any diet effects following deltamethrin dust treatment are likely less severe than the impacts of plague on unprotected ferret populations.
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    Spatial ecology and conservation of tigers and their prey in the Central Terai Landscape, India
    (Colorado State University. Libraries, 2016) Chanchani, Pranav, author; Noon, Barry, advisor; Bailey, Larissa, committee member; Crooks, Kevin, committee member; Hobbs, N. Thompson, committee member
    Remnant populations of the world’s ~3800 wild tigers (Panthera tigris) are generally small (< 20 adult individuals), subject to high rates of poaching, and confined to fragmented habitats with high levels of human disturbance. The species persistence requires an in-depth understanding of the suite of exogenous and endogenous factors that drive spatial heterogeneity in its occurrence and abundance. We intensively sampled tiger habitats in the populous 4500 km2 Central Terai Landscape along the India-Nepal border and investigated the following questions: (a) what is the relative influence of protection designation (protected area or multiple use forests), prey availability, patch connectivity, human presence and habitat quality on landscape and local-scale tiger occurrence; (b) how do these and other factors drive spatial heterogeneity in tiger density at broad and fine spatial scales; and (c) what are the relationships between landscape fragmentation, adult sex ratios, and inter-specific interactions? We found that tiger occupancy and abundance were similar or higher in multiple use forests with high human use, than in several protected areas. Further, the distribution and abundance of prey and key habitats such as tall grasslands, –rather than protection designation, were the best predictors of spatial heterogeneity in tiger occupancy and density. The co-occurrence of tigers and humans in areas with high human use may be facilitated by refugia habitats such as tall grasslands and temporal partitioning of use. Habitat connectivity promoted high occupancy only when all habitats connected by corridors were effectively protected. Finally, we documented exacerbated potential for inter- and intra-sex competition and reduced population fitness in small, isolated tiger populations with male-biased adult sex ratios. Overall, our study reveals that the establishment of protected areas alone may be an inadequate strategy to secure the future of wild tigers. We identified key ecological and anthropogenic factors that cumulatively enable the species persistence in populous human dominated landscapes.
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    Statistical methods for modeling the movement and space-use of carnivores
    (Colorado State University. Libraries, 2017) Buderman, Frances E., author; Hooten, Mevin, advisor; Boone, Randall, committee member; Crooks, Kevin, committee member; Ivan, Jacob, committee member
    Recent advancements in the ability to monitor animal locations through time has led to a rapidly expanding field focused on statistical models for animal movement. However, many of the existing methods are computationally time-consuming to fit, restricting their application to a few individuals, and inaccessible to wildlife management practitioners. In addition, existing movement models were developed for contemporary animal location data. Many previously collected telemetry data sets may provide important information on animal movement, but there may be additional challenges that are not present in data collected explicitly for movement modeling. For example, telemetry data collected for survival studies may have large temporal gaps, and long-term studies may have used multiple data collection methods, resulting in data points with different error structures. My goal is to develop and expand on methods for modeling individual- and population-level animal movement in a flexible and computationally accessible framework. In Chapter 1, I discuss the role of carnivores in natural resource management and the habitat associations and movement ecology of two carnivores native to Colorado, Canada lynx and cougars. I describe the existing data sets, collected by Colorado Parks and Wildlife, that are available for analyzing Canada lynx and cougar movement ecology. I also discuss contemporary statistical methods for analyzing animal telemetry data. Finally, I conclude with my research objectives. Chapter 2 presents a new framework for modeling the unobserved paths of telemetered individuals while accounting for measurement error. Many available telemetry data sets were not collected for the purposes of movement modeling, making the use of existing methods challenging due to large temporal gaps and varying monitoring protocols. In contrast to the more traditional mechanistic movement models that appear in the literature, I propose a phenomenological functional model for animal movement. The movement process is approximated with basis functions (e.g., splines), which are an extremely flexible statistical tool that allows for complex, non-linear movement patterns at different temporal scales. In addition, the observed data contains complicated error structures that vary across telemetry type. I then apply this model to a case-study of two Canada lynx that were reintroduced to Colorado and show that inference about spatio-temporal movement behaviors can be obtained from the unobserved paths. For Chapter 3, I apply a population-level version of the functional movement model, developed in Chapter 1, to 153 Canada lynx that were released in Colorado as part of a state reintroduction program. Twelve offspring of the reintroduced individuals were also included in the analysis. I perform a post hoc analysis of movement paths using spatial visualizations and linear mixed models, allowing the different movement behaviors to vary as a function of season, sex, reproductive status, and reintroduction timeline. This chapter represents one of the most comprehensive analyses of Canada lynx movement in the continental United States. In Chapter 4, I discuss the fine-scale movement of cougars in the Colorado Front Range using a continuous-time discrete-space (CTDS) framework. The CTDS framework is computationally fast, flexible, and easily implemented in standard statistical programs. This chapter focuses on a population-level extension of the CTDS framework that can be used to model the population- and individual-level effect of landscape variables on movement rates and directionality. I use this model to determine potential drivers of cougar movement in the Colorado Front Range, a rapidly urbanizing area in the foothills of the Rocky Mountains. This work also uses the functional model I developed in Chapter 1, but with an error structure more appropriate for small-error GPS data. I conclude with a summary of findings, overarching themes, and potential future research directions in Chapter 5.
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    The physiological condition of orphaned African elephants (Loxodonta africana)
    (Colorado State University. Libraries, 2021) Parker, Jenna Marie, author; Wittemyer, George, advisor; Crooks, Kevin, committee member; Hobbs, Tom, committee member; Pejchar, Liba, committee member
    To view the abstract, please see the full text of the document.
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    The use of acoustic collars for studying landscape effects on animal behavior
    (Colorado State University. Libraries, 2013) Lynch, Emma, author; Angeloni, Lisa, advisor; Wittemyer, George, advisor; Crooks, Kevin, committee member; Fristrup, Kurt, committee member
    Audio recordings made from free-ranging animals can be used to investigate aspects of physiology, behavior, and ecology through acoustic signal processing. On-animal acoustical monitoring applications allow continuous remote data collection, and can serve to address questions across temporal and spatial scales. We report on the design of an inexpensive collar-mounted recording device and present data on the activity budget of wild mule deer (Odocoileus hemionus) derived from these devices, which were applied for a two-week period. Over 3,300 hours of acoustical recordings were collected from 10 deer on their winter range in a natural gas extraction field in northwestern Colorado. Results demonstrated that acoustical monitoring is a viable and accurate method for characterizing individual time budgets and behaviors of ungulates. This acoustical monitoring technique also provides a new approach to investigate the ways external forces affect wildlife behavior. One particularly salient activity revealed by our acoustical monitoring was periodic pausing by mule deer within bouts of mastication, which appear to be adopted for listening for environmental cues of interest. While visual forms of vigilance, such as scanning or alert behavior, have been well documented across a wide range of animal taxa, animals also employ other vigilance modalities such as auditory vigilance, by listening for the acoustic cues of predators. To better understand the ecological properties that structure this behavior, we examined how natural and anthropogenic landscape variables influenced the amount of time that mule deer paused during mastication bouts. We found that deer paused more where concealment cover abounded, and where visual vigilance was likely to be less effective. Additionally, deer paused more often at night than they did during the day, and in areas of moderate background sound levels. Our results support the idea that pauses during mastication represent a form auditory vigilance that is responsive to landscape variables. Furthermore, these results suggest that exploring this behavior is critical to understanding an animal's perception of risk and the costs associated with vigilance behavior.