Field Trials to Determine the Efficacy of an Oral Plague Vaccine for Prairie Dogs

North American prairie dogs (Cynomys spp.) and black-footed ferrets (Mustela nigripes) have been severely affected by plague, an exotic zoonotic disease caused by the bacterium Yersinia pestis during the last 100 years.  Plague has contributed to population declines of prairie dogs, near extinction of black-footed ferrets, and has caused human illness and fatalities.  An oral sylvatic plague vaccine (SPV) developed and tested jointly by the U.S. Geological Survey, National Wildlife Health Center and University of Wisconsin (Madison, WI) shows great promise as an effective, pre-emptive method for controlling plague in prairie dogs.  Field trials to evaluate the efficacy of SPV were initiated in 2013 and include 4 species of prairie dogs on study areas in 7 states, including Montana.  This presentation is a status report after the second year of a planned 4 year study.  The primary objectives are to measure vaccine/bait uptake and to assess prairie dog survival rates at paired study sites, with and without vaccine application.  At the north-central Montana study site, about 8,000 baits, half with SPV and half placebos, were distributed across 5 pairs of study sites (totaling 81 ha) in 2013 and over 13,000 in 2014 on the same 5 pairs of study sites (totaling 107 ha).  In addition to ear tagging and microchip-marking each individual, flea, hair, whisker and blood samples were collected each year.  A total of 584 individual prairie dogs were marked during 929 capture events in 2013 and 814 individuals during 1,293 capture events in 2014

Conserving Endangered Black-Footed Ferrets: Biological Threats, Political Challenges, and Lessons Learned

There may be few stories in the annals of wildlife management that are as dramatic as the near demise and comeback of the black-footed ferret (Mustela nigripes). Endemic only to North America, this charming little carnivore found only in the continent’s central grasslands was hardly known to science until the mid-20th century. By then, vast colonies of the prey it depended on for food and shelter, the prairie dog (Cynomys spp.), had been wiped out through disease (sylvatic plague) and an agricultural industry with little tolerance for burrowing and grazing rodents. At its low point, the species’ fate would come down to 18 remaining ferrets and a scientific gamble that humans could intervene to save a species on the very brink of extinction. With heroic efforts by federal, state, and private scientists, immediate extinction was forestalled, and a comeback effort mounted. Like so many endangered species stories, the ferret’s tale is a story of tragedy, luck, science, and the acts of people that will determine its ultimate fate. Understanding the challenges going forward for the ferret requires an understanding of the natural history and ecology of black-footed ferrets and prairie dogs, diseases and disease management, and the political landscape, which we present here. The future for black-footed ferrets remains unclear. Ultimately we will need to summon the efforts of conservation biologists, policy makers, and the agricultural industry to determine if ferrets will continue to exist as a valued and unique part of North America’s natural heritage

HABITAT SELECTION BY MOOSE IN THE YAAK RIVER DRAINAGE, NORTHWESTERN MONTANA

Logging began during the 1950s and is now the primary land use in the Yaak River drainage. The relationships between timber management and moose habitat were evaluated using 669 locations of 12 radio marked moose (Alces alces shirasi) collected between January 1982 and September 1983. Harmonic mean home ranges were used as a tool to delineate available habitat for selection analyses. On a yearlong basis, moose use was greater than expected in: clearcuts, logged areas less than 12 ha in size, areas logged 15-30 years ago, or within 100 m of a cutting unit. Moose selected elevations below 1067 m in winter and above 1524 m in summer. Moose used logged areas more in early winter than during mid and late winter when densely timbered sites were selected. Thirty percent of spring and summer locations were in clearcuts. Cows used thicker vegetation than bulls, but bulls were found more often in timbered areas. Cows with calves and bedded moose used security type habitats more than cows without calves and active moose. Maintaining a mosaic of small, 15-30 year-old logged areas intermixed with mature, closed canopy, timbered stands will provide productive moose habitat in the Yaak valley

Efficacy of Electronet Fencing for Excluding Coyotes: A Case Study for Enhancing Production of Black-Footed Ferrets

Reducing coyote (Canis latrans) predation can be an important management objective. Here, we evaluated the efficacy of electronet fencing for excluding coyotes from focal areas on black tailed prairie dog (Cynomys ludovicianus) colonies, measured the effect of fencing on wild-born black-footed ferret (Mustela nigripes) kit survival, and modeled costs and benefits of fencing. From 27 July to 2 October 2010 in northcentral Montana, USA, we erected and maintained 7.7 km of electronet that enclosed 108 ha on portions of 2 prairie dog colonies. We monitored 2 female ferrets and 6 kits inside exclosures and 3 females and 12 kits outside of exclosures. Percent of coyote sightings in the protected areas was 6 times less than expected during the exclosure period (42% pre-exclosure, 7% exclosure, 47% post-exclosure). We conclude that the electronet fencing was effective for dramatically decreasing coyote activity in focal areas where black-footed ferret litters were being raised.We found evidence that survival of kits living primarily in protected areas was 22% higher, but we qualify this finding because of low sample sizes and because our monitoring activity on the study site may have influenced coyote activity. We estimated one-time costs for fencing to be US$4,464/km and operation and/or maintenance costs for the 68 days of fence operation to be US$641/km. If fencing increased survival by 20–30%, then total cost per ferret kit not lost to coyote predation would range between US$5,400 and$3,600, or US$2,550 and$1,700 if fence set-up–take-down labor and use of an all-terrain vehicle were donated. Published 2013. This article is a U.S. Government work and is in the public domain in the USA

Efficacy of Translocations for Restoring Populations of Black-Tailed Prairie Dogs

We evaluated translocation as a method to promote recovery of black-tailed prairie dogs (Cynomys ludovicianus) after plague-induced population declines in colonies at the Charles M. Russell National Wildlife Refuge, Montana. We translocated prairie dogs in June of 1999 and evaluated the effects of translocation on colony area 1 year and 4 years later. We also assessed effects of release group size and estimated rates of population growth and survival. Initial size of experimental colonies was categorized as inactive (0 ha), small (0.1-2.0 ha), or large (2.0-6.6 ha); numbers of prairie dogs translocated to each colony size class were 0 (control), 60, and 120. Among inactive colonies, the control remained inactive and the colony receiving 60 prairie dogs grew to 1.5 ha by 2000 and after a second release in 2002 was 1.9 ha in 2003. The colony receiving 120 grew to 3.3 ha by 2000 and decreased to 2.6 ha by 2003. Patterns on small and large colonies after 1 year were less dramatic, but in each case the proportional increase in colony area was lowest on the control and high- est on the colony receiving 120 prairie dogs. Patterns were more difficult to discern 4 years after translocations. It appears that as large colonies approach historic size, area growth decreases and is slower than on small colonies. Experimental colonies grew 24.6 ha (315%) by 2000 and 72.1 ha (924%) in 4 years compared to non-experimental colonies of similar size that grew 6.5 ha (23%) in 1 year and 26.5 ha (93%) by 2003. Monthly survival rates of prairie dogs during the first 3 months following translocation were higher on large colonies (0.79, 95% Cl=0.75-0.82) than on small (0.67, 95% CI=0.62-0.72) or inactive colonies, (0.63, 95% Cl=0.57-0.68). Monthly survival rates were relatively high (0.88-1.0) during subsequent intervals and did not vary among initial colony size classes. Recapture rates for all colonies were higher during the fall trapping session (0.83, 95% Cl=0.76-0.90) than in the winter (0.59, 95% CI=0.49-0.69). Translocation was effective for restoration of prairie dog populations, particularly on inactive colonies

Efficacy of Electronet Fencing for Excluding Coyotes: A Case Study for Enhancing Production of Black-Footed Ferrets

ABSTRACT Reducing coyote (Canis latrans) predation can be an important management objective. Here, we evaluated the efficacy of electronet fencing for excluding coyotes from focal areas on black tailed prairie dog (Cynomys ludovicianus) colonies, measured the effect of fencing on wild-born black-footed ferret (Mustela nigripes) kit survival, and modeled costs and benefits of fencing. From 27 July to 2 October 2010 in northcentral Montana, USA, we erected and maintained 7.7 km of electronet that enclosed 108 ha on portions of 2 prairie dog colonies. We monitored 2 female ferrets and 6 kits inside exclosures and 3 females and 12 kits outside of exclosures. Percent of coyote sightings in the protected areas was 6 times less than expected during the exclosure period (42% pre-exclosure, 7% exclosure, 47% post-exclosure). We conclude that the electronet fencing was effective for dramatically decreasing coyote activity in focal areas where black-footed ferret litters were being raised. We found evidence that survival of kits living primarily in protected areas was 22% higher, but we qualify this finding because of low sample sizes and because our monitoring activity on the study site may have influenced coyote activity. We estimated one-time costs for fencing to be US$4,464/km and operation and/or maintenance costs for the 68 days of fence operation to be US$641/km. If fencing increased survival by 20-30%, then total cost per ferret kit not lost to coyote predation would range between US$5,400 and$3,600, or US$2,550 and$1,700 if fence set-up-take-down labor and use of an all-terrain vehicle were donated. Published 2013. This article is a U.S. Government work and is in the public domain in the USA

Spatiotemporal dynamics of black-tailed prairie dog colonies affected by plague

Black-tailed prairie dogs (Cynomys ludovicianus) are a key component of the disturbance regime in semi-arid grasslands of central North America. Many studies have compared community and ecosystem characteristics on prairie dog colonies to grasslands without prairie dogs, but little is known about landscape-scale patterns of disturbance that prairie dog colony complexes may impose on grasslands over long time periods. We examined spatiotemporal dynamics in two prairie dog colony complexes in southeastern Colorado (Comanche) and northcentral Montana (Phillips County) that have been strongly influenced by plague, and compared them to a complex unaffected by plague in northwestern Nebraska (Oglala). Both plague-affected complexes exhibited substantial spatiotemporal variability in the area occupied during a decade, in contrast to the stability of colonies in the Oglala complex. However, the plague-affected complexes differed in spatial patterns of colony movement. Colonies in the Comanche complex in shortgrass steppe shifted locations over a decade. Only 10% of the area occupied in 1995 was still occupied by prairie dogs in 2006. In 2005 and 2006 respectively, 74 and 83% of the total area of the Comanche complex occurred in locations that were not occupied in 1995, and only 1% of the complex was occupied continuously over a decade. In contrast, prairie dogs in the Phillips County complex in mixed-grass prairie and sagebrush steppe primarily recolonized previously occupied areas after plague-induced colony declines. In Phillips County, 62% of the area occupied in 1993 was also occupied by prairie dogs in 2004, and 12% of the complex was occupied continuously over a decade. Our results indicate that plague accelerates spatiotemporal movement of prairie dog colonies, and have significant implications for landscape-scale effects of prairie dog disturbance on grassland composition and productivity. These findings highlight the need to combine landscape-scale measures of habitat suitability with long-term measures of colony locations to understand the role of plague-affected prairie dogs as a grassland disturbance process