Ecology of Wildlife Disease

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Some of the biggest challenges facing wildlife today are changes to their environment from both natural and anthropogenic causes. Natural resource managers, planners, policy makers, industry and private landowners must make informed decisions and policies regarding management, conservation, and restoration of species, habitats, and ecosystem function in response to these changes.

The United States is undergoing ecological change that is increasing the interface between wildlife, humans, and disease. Such changes are resulting in unpredictable shifts in the balances of disease cycles in natural hosts and humans, with consequences to many imperiled species. In addition to population declines, the loss of wildlife from disease contributes to a corresponding decline in ecosystem services that benefit human health and economies. TSH scientists collaborate with researchers and resource managers around the world to gain better scientifi c understanding of the ecological factors involved in the transmission and epidemiology of infectious diseases in wildlife, as well as contributing to the development of tools and techniques to help understand and manage disease in wildlife populations.

 

Image: Black-Footed Ferret
The USGS National Wildlife Health Center is working to develop an oral vaccine to protect the endangered black-footed ferret from plague. Public domain.

Ecology of PlaguePrincipal Investigator - Dean Biggins

In North America, the flea transmitted plague bacterium (Yersinia pestis) has colonized and altered native animal communities and ecosystems since its invasion a little more than a century ago. Many species have suffered adverse consequences from plague, perhaps none more than the endangered black-footed ferret. Plague has established within the ranges of all North American prairie dog species, which collectively serve as the sole habitat and predominant prey base for the endangered black-footed ferret. This disease causes periodic and sometimes dramatic die-offs of both prairie dogs and ferrets. 

The initial objectives of this study are to assess efficacy, longevity, and cost of flea control using deltamethrin delivered as dust within burrows and measure population responses of prairie dogs and associated mammals. Research, development, and field trials of vaccines against sylvatic plague in prairie dogs and black-footed ferrets are also underway.

 

A little brown bat displaying white nose syndrome. FWS photo.
A little brown bat displaying white nose syndrome. FWS photo.

Ecological Investigations of White-Nose Syndrome in Bats - Principal Investigator - Paul Cryan

White-Nose Syndrome (WNS) is a devastating disease that threatens the survival of hibernating bats in North America. Since first documented in the winter of 2005/2006, WNS has spread from a very small area of New York across at least two thousand kilometers in 25 states and 4 Canadian provinces. Over five million bats are estimated to have died during the past 7 winters after contact with WNS, and all four federally listed endangered species and subspecies of hibernating cave bats are in harm’s way.

There are three primary objectives to this project as follows: continue to help coordinate research efforts directed toward white-nose syndrome at a national level and provide technical support on aspects of bat ecology to USGS researchers and others in the scientific and resource management community; assess the possible behavioral mechanisms by which skin infection from the causative fungus specifically acts to cause bat mortality; and assess the possible physiological mechanisms by which skin infection from the causative fungus specifically acts to cause bat mortality.

 

 

 

Image: Tagged Prairie Dog
This wild prairie dog has been tagged by scientists in an effort to study the efficacy of a USGS-developed oral sylvatic plague vaccine (SPV) to help immunize prairie dogs against plague. Public domain.

 

Effects of Soil and Colony Age on Flea Densities Principal Investigator - Dean Biggins

Abundance of fleas is thought to drive rates of plague transmission in the wild. In the complex process of plague maintenance and transmission, fleas as vectors are a potentially weak link in the system that can be exploited. To date, exploiting this link has provided the only stand-alone tools that are operationally effective for managing plague in the black-footed ferret and prairie dog communites (e.g., use of various insecticides for flea control). FORT scientists are addressing the question of how to most efficiently use these tools by conducting studies of flea ecology that examine the influences of colony age, soil characteristics, microclimates in burrows, weather patterns, and differences among flea species. 

 

 

A non-invasive monitoring camera for bat research.
USGS has, for the first time, non-invasively monitored the hibernation behaviors of bats over entire winters. Here are weatherproof thermal-infrared and near-infrared video surveillance cameras deployed near hibernating bats in a Virginia cave.

 

Non-invasive Surveillance of Bat Hibernacula to Investigate Potential Behavioral Causes of Mortality Associated with White Nose Syndrome - Principal Investigator - Paul Cryan

WNS is named for the ubiquitous presence of a newly identified species of cold-loving fungus (Pseudogynmnoascus destructans) that is capable of penetrating and infecting the skin and wing membranes of bats during hibernation. It is critical that research efforts directed toward WNS incorporate the expertise of scientists familiar with the ecology of bats and hibernation physiology.

The objectives of this project are to better understand bat hibernation and to assess the possible behavioral mechanisms by which skin infection from the associated fungus (Pseudogymnoascus destructans) may act to cause bat mortality. We are using new methods for observing natural behaviors of hibernating bats by building and deploying remote video surveillance systems inside caves and mines where bats hibernate. After successfully monitoring the in situ behaviors of hibernating bats over as many as six winters, we are now in the process of interpreting these new observations. 

 

Image: Black-Footed Ferret
The USGS National Wildlife Health Center is working to develop an oral vaccine to protect the endangered black-footed ferret from plague. Public domain.

Grassland Ecology and Conservation - Principal Investigator - Dean Biggins

Grasslands are arguably one of the most anthropogenically stressed ecosystems of the western United States. The highly endangered black-footed ferret and prairie dogs epitomize grassland mammals of high conservation concern. The Utah prairie dog is a federally listed species, while black-tailed prairie dogs, white-tailed prairie dogs, and Gunnison's prairie dogs all have received attention in the form of listing proposals. Research conducted within this project will focus on these imperiled prairie dog communities and their vertebrate and invertebrate associates, but will not necessarily be limited to those communities. Studies will be driven by the need to better understand ecological relationships among grassland animals, interactions of these animals with their environments, and anthropogenic influences affecting these systems.

 

 

WNS Data Management Coordination - Principal Investigator - Patty Stevens

As White Nose Syndrome (WNS) spreads, the challenges for understanding and managing the disease continue to increase. In June 2008, an effort to formalize a coordinated approach for addressing WNS was initiated among the Department of the Interior, Department of Agriculture, Department of Defense, and State wildlife management agencies. A national plan for assisting states, Federal agencies, and tribes in managing WNS in bats was developed. This plan provides a framework that outlines the actions necessary to coordinate Federal and State efforts and identifies actions in support of State, Federal, tribal, and partner WNS management efforts. Each of seven elements identified in the plan would be administered by a working group responsible for the coordination of activities within that element.

 

 

 

North American Bat Data Integration - Principal Investigator - Patty Stevens

Image: Bat with White-nose Syndrome
Hibernating little brown bat with white muzzle typical of White-nose syndrome. Public domain.

Bats are essential to the health of our natural world. They help control pests and are vital pollinators and seed-dispersers for countless plants. Bat populations are in trouble, however. Since 2006, more than 5 million bats have died due to a fungal disease called White-nose Syndrome (WNS). At the same time, several migratory tree-dwelling species are being killed in unprecedented numbers by wind turbines. In light of these emerging threats, the scientific community has expressed great interest in improving access to historical information and WNS data to better inform bat conservation efforts. To address this need, this project is integrating two important datasets into the USGS Bat Population Database, an enterprise data management system for bat researchers.

Bat Banding Clearinghouse - Principal Investigator - Patty Stevens

The need to mark bats individually in order to assess life history parameters and movements is especially important as threats from white-nose syndrome (WNS) and wind energy development continue to negatively affect bats. Although disparate bat banding efforts are ongoing, no coherent strategy, official clearinghouse or coordination program exists in North America, despite the recognized need. A major recommendation made in 2008 in “Summary and Analysis of the U.S. Government Bat Banding Program” was to develop a national clearinghouse for banded bats in order to optimize information obtained from marked bats. The U.S. Geological Survey, Fort Collins Science Center (FORT) and the U.S. Fish and Wildlife Service, Great Lakes-Big Rivers Region are developing a clearinghouse for banded bats beginning with the endangered Indiana bat (Myotis sodalis).

 

Image: White-tailed Prairie Dog (Cynomys leucurus)
Cynomys leucurus resting on its haunches next to a burrow. Public domain.

Transmission of Plague by Small Mammals at Badlands National Park - Principal Investigator - Dean Biggins

Plague was first detected in the southwest corner of Badlands National Park (BADL), and spread northeastward, reaching the northeast corner in 2011. Plague is now common throughout BADL (NPS and USFS, unpublished data), and threatens efforts to preserve and manage the federally endangered black-footed ferret in BADL, which were reintroduced into the park in 1994.

This study will serve as an exploratory effort to gain insight into which species of small mammals and their fleas are primary participants in the plague cycle; which are secondary participants, and which are bystanders. We will conduct a field experiment based on a randomized complete block design to investigate whether small mammals are chronically affected by enzootic levels of plague and which are potential hosts that may function as short-term reservoirs in the flea-borne transmission of plague in black-tailed prairie dog colonies and surrounding environments in BADL.

 

Cryan taking a female hoary bat out of a net. This bat was intercepted during its spring migration through New Mexico.
USGS Research Biologist Paul Cryan taking a female hoary bat out of a net. This bat was intercepted during its spring migration through New Mexico. Photo by Leslie Cryan.

Bat Species of Concern: An Ecological Synthesis for Resource Managers - Principal Investigator - Paul Cryan

A large number of bat species are considered “species of concern” in the United States and its Territories, and resource managers are increasingly interested in learning more about their distribution, status, and potential management. This project involves developing a synthesis report on 25 of these species, including detailed species accounts, an updated distribution GIS database, and a review of the scientific basis for bat management and conservation measures. With this report, resource managers will have a “handbook” detailing available information on bat species in their areas as well as management practices that can enhance bat conservation. Publication is expected in early 2017.

 

 

North American Bat Monitoring Program (NABat) - Principal Investigator - Patty Stevens

Photograph of bats
Bats are an example of a migratory species for which the social and economic values of bat habitat provision, an ecosystem service, can vary along the migration route.

Despite their importance and the many threats facing their populations [e.g., white-nose syndrome (WNS), climate change, wind energy development, habitat loss and fragmentation, there are currently no national programs to monitor and track bat populations in North America. 

A statistically rigorous and nationally coordinated bat monitoring program is critical for determining the impacts of the many stressors on bat populations, as well as for determining the efficacy of management actions taken to conserve bat populations. The objectives of the North American Bat Monitoring Program (or NABat) are to provide the architecture for coordinated bat monitoring to support local, regional and range-wide inferences about trends in bat populations and abundances in response to WNS, climate, wind energy, and habitat loss, and provide managers and policy makers with the information they need on bat population trends to effectively manage bat populations, detect early warning signs of population declines, and estimate extinction risk. Additional Information: Bat Population Database, https://my.usgs.gov/bpd/

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