Intraspecific Drivers of Variation in Bat Responses to White-nose Syndrome and Implications for Population Persistence and Management PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Intraspecific Drivers of Variation in Bat Responses to White-nose Syndrome and Implications for Population Persistence and Management PDF full book. Access full book title Intraspecific Drivers of Variation in Bat Responses to White-nose Syndrome and Implications for Population Persistence and Management by Marianne Gagnon. Download full books in PDF and EPUB format.
Author: Marianne Gagnon Publisher: ISBN: Category : Languages : en Pages : 137
Book Description
Emerging infectious diseases of wildlife are among the greatest threats to biodiversity. Indeed, when pathogens are introduced into naïve host populations, they can impose novel selective pressures that may cause severe host declines or even extinction. However, disease impacts may vary both within and among host species. Thus, one of the key goals for management is to identify factors that drive variation in host susceptibility to infection, as they may improve our understanding of hosts' potential to develop disease resistance and/or tolerance and inform conservation strategies aimed at facilitating host persistence. For instance, Pseudogymnoascus destructans (Pd) - an invasive pathogenic fungus that causes white-nose syndrome (WNS) in hibernating bats - is highly virulent, has killed millions of bats in North America, and continues to spread at an alarming rate. Yet, the continued persistence of bat colonies in contaminated areas despite initial mass mortality events suggests variation in survival among infected individuals. I thus aimed to better understand intraspecific drivers of variation in bat susceptibility to WNS and their implications for population persistence and management in affected areas. Specifically, my objectives were to: 1) evaluate the extent to which variation in hibernaculum microclimate temperature and humidity affects Pd infection severity and disease progression in affected bats during hibernation, 2) compare how bats from colonies that vary in duration of exposure to Pd and from different age classes behaviorally respond to the infection, and examine how these behavioral changes affect host fitness and 3) model the population dynamics of remnant bat populations to assess the likeliness of persistence and the potential effectiveness of management interventions in affected colonies. I addressed these objectives through field research, experimental infection studies, and demographic modeling of the little brown myotis (Myotis lucifugus). In my dissertation, I first provide causal evidence of environmentally-driven variation in pathogen growth and infection severity on bats in the field. Both warmer and more humid microclimates contribute to the severity of the infection by promoting the production of conidia, the erosion of wing tissues, and, therefore, the transmission potential and virulence of Pd. I then document potential mechanistic links between Pd-induced behavioral change and host fitness. Higher infection levels, independent of bats' past exposure to Pd or age class, may cause individuals to groom longer, prolong euthermic arousals, accelerate the depletion of fat reserves, and ultimately increase mortality risk. Finally, I predict that populations will face a high risk of extirpation in the next decade or two if no management action is taken, but that interventions such as environmental control of Pd and hibernaculum microclimate manipulation can prevent short-term population collapse in remnant bat populations. Together, these studies provide key, mechanistic insight into the pathology of WNS and the probability of persistence of affected bat colonies, while highlighting the importance of prioritizing winter habitat preservation and enhancement for the conservation of hibernating bats.
Author: Marianne Gagnon Publisher: ISBN: Category : Languages : en Pages : 137
Book Description
Emerging infectious diseases of wildlife are among the greatest threats to biodiversity. Indeed, when pathogens are introduced into naïve host populations, they can impose novel selective pressures that may cause severe host declines or even extinction. However, disease impacts may vary both within and among host species. Thus, one of the key goals for management is to identify factors that drive variation in host susceptibility to infection, as they may improve our understanding of hosts' potential to develop disease resistance and/or tolerance and inform conservation strategies aimed at facilitating host persistence. For instance, Pseudogymnoascus destructans (Pd) - an invasive pathogenic fungus that causes white-nose syndrome (WNS) in hibernating bats - is highly virulent, has killed millions of bats in North America, and continues to spread at an alarming rate. Yet, the continued persistence of bat colonies in contaminated areas despite initial mass mortality events suggests variation in survival among infected individuals. I thus aimed to better understand intraspecific drivers of variation in bat susceptibility to WNS and their implications for population persistence and management in affected areas. Specifically, my objectives were to: 1) evaluate the extent to which variation in hibernaculum microclimate temperature and humidity affects Pd infection severity and disease progression in affected bats during hibernation, 2) compare how bats from colonies that vary in duration of exposure to Pd and from different age classes behaviorally respond to the infection, and examine how these behavioral changes affect host fitness and 3) model the population dynamics of remnant bat populations to assess the likeliness of persistence and the potential effectiveness of management interventions in affected colonies. I addressed these objectives through field research, experimental infection studies, and demographic modeling of the little brown myotis (Myotis lucifugus). In my dissertation, I first provide causal evidence of environmentally-driven variation in pathogen growth and infection severity on bats in the field. Both warmer and more humid microclimates contribute to the severity of the infection by promoting the production of conidia, the erosion of wing tissues, and, therefore, the transmission potential and virulence of Pd. I then document potential mechanistic links between Pd-induced behavioral change and host fitness. Higher infection levels, independent of bats' past exposure to Pd or age class, may cause individuals to groom longer, prolong euthermic arousals, accelerate the depletion of fat reserves, and ultimately increase mortality risk. Finally, I predict that populations will face a high risk of extirpation in the next decade or two if no management action is taken, but that interventions such as environmental control of Pd and hibernaculum microclimate manipulation can prevent short-term population collapse in remnant bat populations. Together, these studies provide key, mechanistic insight into the pathology of WNS and the probability of persistence of affected bat colonies, while highlighting the importance of prioritizing winter habitat preservation and enhancement for the conservation of hibernating bats.
Author: Tina L. Cheng Publisher: ISBN: 9780355334098 Category : Languages : en Pages : 122
Book Description
Emerging infectious diseases can place severe pressures on wildlife populations, leading to major population declines, local extirpation, and species extinctions. However, variability in disease impacts, existing among species and across a spatial and temporal scale, can help us identify species or populations persisting with disease either via resistance, tolerance, pathogen evasion, or by existing within environmental refugia. Understanding mechanisms leading to host persistence can inform conservation management priorities and strategies. White-nose Syndrome (WNS) is a recently emerged disease caused by the fungal pathogen, Pseudogymnoascus destructans (Pd), that has led to severe declines in hibernating bat populations in North America. This work examines patterns and mechanisms associated with variability in WNS impacts with implications for the conservation of affected species. My first chapter investigates spatial heterogeneity in initial impacts of Pd spread across half of continental North America. We found that WNS-related impacts were lessened in the southwestern regions of North America, suggesting potential spatial refugia from WNS-related impacts but only for Perimyotis subflavus. We found that annual air surface temperatures driving Pd growth explained, in part, this spatial variation in WNS-related impacts. Despite evidence for lessened WNS-related declines in the southwest, impacts to bat populations are severe throughout North America for most bat species. My second chapter examines colonies of M. lucifugus that have experienced variability in declines over time, persisting potentially due to host-specific responses. Specifically, I investigate if differences in early winter fat reserves could explain survivorship and persistence of M. lucifugus colonies with WNS. We found that bats persisting with WNS in 2016 were significantly fatter than bats colonies sampled during WNS arrival in 2008 and 2009 at four out of our six sampled sites. At another two sites, we found that bats were either fatter in 2008 and 2009 compared to 2016. We used hibernation energetic models to estimate the amount of fat afforded to survival and found that increased fat reserves from bats measured in 2016 could reduce mortality by 65%. These data suggest that increased fat reserves can explain, in part, the persistence of M. lucifugus colonies with WNS. Lastly, my third chapter experimentally investigates one possible cause of variability in WNS impacts, variation host susceptibility via protective bacteria in the skin microbiome. In this chapter, I explore the efficacy of using a probiotic bacterium, harvested from the skin of a species experiencing lessened WNS impacts, Eptesicus fuscus , as a conservation tool applied to a more highly affected bat species, M. lucifugus. We found relative increases in survival for probiotic-treated groups compared to our sham control group. We also found evidence for decreased fungal infection and severity in probiotic-treated groups. Our results suggest that probiotic treatment can reduce incidence of White-nose Syndrome in M. lucifugus although timing of treatment is an important factor. Together, this work finds that variability in spatial, species-specific, and temporal impacts from WNS can inform conservation efforts. Namely, this work suggests that bat conservation should involve a multi-pronged approach that protects colonies where bats are persisting with WNS via habitat restoration, and potentially treating bats for threatened populations not persisting with WNS. Given the continued threat of WNS to bats as it spreads throughout North America, using a variety of tools to combat this disease may be critical to prevent disease-induced extinction and the local extirpation of affected bat species.
Author: Publisher: ISBN: 9781321933178 Category : Languages : en Pages : 60
Book Description
Emerging infectious diseases pose a key threat to wildlife, and the number of disease emergence events is increasing. Despite the importance of disease in wildlife conservation, understanding the drivers of population and species extinction from disease has not been tested in an empirical framework. My research incorporates empirical and theoretical approaches to understand factors that influence pathogen transmission and disease impacts. Here, we focus on the emerging fungal disease of bats, white-nose syndrome, which has caused widespread declines in bat populations across Eastern North America. Our findings highlight the importance of social behavior, microclimate conditions, and seasonality in driving impacts from this disease. We find that while seasonal transmission is broadly similar across species, winter differences in pathogen growth drive variation in species impacts from disease. Species appear to have different transmission mechanism which influences the likelihood they will persist in the face of white-nose syndrome. We also identify a species, the Northern long-eared bat, which is likely to go extinct if rapid management action is not taken. These data provide critical information needed to manage wildlife disease epidemics, enabling management action prior to species extinction.
Author: Riley Fehr Bernard Publisher: ISBN: Category : Bats Languages : en Pages : 107
Book Description
This dissertation investigates regional differences in the behavior and activity of bats in eastern North America during the white-nose syndrome epizootic, specifically in the understudied region of the Southeastern United States. An introductory section provides a brief review of the history of whitenose syndrome, an emerging infectious disease in bats, and its introduction into North America. Chapter one provides the first documented evidence of bat activity outside of hibernacula throughout winter. The research presented in chapter two attempts to explain the variation in load and prevalence of P. destructans among species, sites and between years. Finally, chapter three examines the differences in the species affected by white-nose syndrome in the Southeast, as well as the regional variation in the timing and severity of decline in bat communities during summer. A conclusion section at the end of this dissertation summarizes the main findings and provides directions for future research.
Author: United States. Congress. House. Committee on Natural Resources. Subcommittee on Fisheries, Wildlife, Oceans, and Insular Affairs Publisher: ISBN: Category : Medical Languages : en Pages : 64
Author: United States. Congress. House. Committee on Natural Resources. Subcommittee on Insular Affairs, Oceans, and Wildlife Publisher: ISBN: Category : Nature Languages : en Pages : 80
Author: Keslie Naffa Publisher: ISBN: Category : Bats Languages : en Pages : 88
Book Description
White-nose syndrome (WNS) has had a large negative impact on bat populations across eastern North America since its arrival in 2006. Bats affected by WNS appear to die of starvation, possibly due to the increased arousals during hibernation when there is no food present to replace the energy used to arouse. During hibernation, the bat’s immune system should be suppressed. However, once a bat of a susceptible species is exposed to the fungus that causes WNS, Psuedogymnoascus destructans (Pd), the immune system seems to respond, potentially causing an elevation in metabolic rate, which may cause the bat to arouse more often. I hypothesize that resistant bats do not mount an immune response; however, if they do mount an immune response, I hypothesize that bats inoculated with Pd and treated with an anti-inflammatory treatment will not respond to the infection, ultimately preserving fat reserves and lowering metabolic expenditures during hibernation. I tested these hypotheses by inoculating a species that does not suffer from high WNS mortality (big brown bats: Eptesicus fuscus), with Pd. Meloxicam was given to one of the three treatment groups in order to suppress the immune system. Metabolic rate during torpor, via oxygen consumption, was measured in addition to arousal/torpor bout patterns, the latter utilizing temperature-sensitive dataloggers. To quantify expression of four immune-function genes (NLRP10, CD200, ICAM5, and TNFRSF21), gene activity was measured via RT-qPCR on tissue and blood samples taken from each bat pre- and post-hibernation. These genes were chosen based on a prior study that showed differences in these genes between susceptible and resistant species. There were no significant differences found across treatment groups for gene expression, nor energetic data; however, hibernation did suppress NLRP10 expression, and blood samples consistently had higher gene expression than tissue samples, thus indicating these genes may be expressed at low levels in some tissues. It is imperative that we continue investigating the differences between susceptible and resistant bat species as WNS is advancing westward throughout the country.
Author: Briana Anderson Publisher: ISBN: Category : Bats Languages : en Pages : 180
Book Description
White-nose syndrome (WNS) causes substantial mortality in certain species of hibernating North American bats. The responsible agent is Pseudogymnoascus destructans (Pd), a fungus which causes physiological complications such as increased arousals and energy depletion during the hibernation season. Tricolored bats (Perimyotis subflavus) and northern long-eared bats (Myotis septentrionalis) suffer extensive WNS mortality, while gray bats (Myotis grisescens) and big brown bats (Eptesicus fuscus) are infected, but mortality is rarely observed. It is hypothesized that there is a difference in immune responses and/or hibernation metabolism between these bat species, resulting in this interspecific variation in disease severity. To test these hypotheses, experiments were conducted at both the cellular and whole-bat level. Tricolored bats were infected with Pd and half were treated with an anti-inflammatory to mute any immune response. Data from measurements of torpor energetics did not support the hypothesis, but an immune response was observed in mid-hibernation, based on white blood cell counts. Also, wing tissue fibroblasts from the four species listed above were infected with Pd, and RNA-seq analysis revealed interspecific differences in gene expression in response to Pd. This study could aid in establishing treatment and conservation strategies for North American bats. In addition, a cell culture method has been pioneered that will allow researchers to address a myriad of immunological questions, such as which western bat species might be most susceptible to WNS as it spreads westward.
Author: Publisher: ISBN: Category : Bats Languages : en Pages : 16
Book Description
“White-nose syndrome” (WNS) is an emerging fungal disease of hibernating North American bat species. To date, WNS has likely killed between 5.7 and 6.7 million hibernating bats in caves and inactive mines in the eastern USA, and has contributed to the imperilment of some bat populations and species. The WNS fungus (Geomyces destructans) has the potential to kill individuals of many of the 18 bat species native to Colorado. Bats are ecologically and economically important, and measures to prevent the spread of WNS and minimize its impacts on native bat species are clearly warranted.
Author: Publisher: ISBN: Category : Bats Languages : en Pages : 15
Book Description
“White-nose syndrome” (WNS) is an emerging fungal disease of hibernating North American bat species. To date, WNS has likely killed between 5.7 and 6.7 million hibernating bats in caves and inactive mines in the eastern USA, and has contributed to the imperilment of some bat populations and species. The WNS fungus (Geomyces destructans) has the potential to kill individuals of many of the 18 bat species native to Colorado. Bats are ecologically and economically important, and measures to prevent the spread of WNS and minimize its impacts on native bat species are clearly warranted.
Author: Marianne Gagnon
Author: Marianne Gagnon
Author: Tina L. Cheng
Author: 
Author: Riley Fehr Bernard
Author: United States. Congress. House. Committee on Natural Resources. Subcommittee on Fisheries, Wildlife, Oceans, and Insular Affairs
Author: United States. Congress. House. Committee on Natural Resources. Subcommittee on Insular Affairs, Oceans, and Wildlife
Author: Keslie Naffa
Author: Briana Anderson
Author: 
Author: