The Montana Cooperative Wildlife Research Unit
The University of Montana
The Montana Cooperative Wildlife Research Unit
The University of Montana
Natural Science Building - Room 312A
|Dave and his son, Sam, and B490 shortly after being radiocollared and released in central Idaho|
Wolf population monitoring
Idaho wolf population monitoring
Gray wolf (Canis lupus) populations can be difficult to monitor due to logistical and budgetary challenges. We devised a wolf population monitoring program rooted in patch occupancy modeling, a statistical technique that can integrate data from multiple sampling methods, allowing managers to monitor wolf populations using a suite of methods best suited for their management needs and available resources. To populate a patch occupancy model, we tested a variety of survey methods and showed strong relationships to wolf abundance and distribution. The survey methods we tested in Idaho were hunter surveys, rendezvous site surveys, howlboxes, and rub stations. Each of the survey methods we designed can provide the data needed to populate a patch occupancy model; further, some of the methods can yield highly detailed information on wolves in focal areas, providing biologists with unprecedented tools for understanding wolves in areas where management interest is high. We suggest a monitoring framework based on patch occupancy modeling, using observations available from a variety of sampling techniques, can provide reliable statewide estimates of wolf population size.
In Idaho we conducted a statewide survey of 13,000 hunters in 2010 and again in 2011. We surveyed close to 700 predicted rendezvous sites between 2009 and 2010 where we detected at least 2 adult wolves or ≥ 1 pup at 7.8% and 6.4% of the sites, respectively. We worked with The University of Montana’s Computer Sciences Department to improve the howlbox and tested its efficacy under field conditions in 2011. We deployed rub stations in 2010 to provide occupancy data using 2,300 collected hair samples. We found the estimates of abundance and distribution of wolf packs from our patch occupancy model compared favorably to the 2009 and 2010 counts reported by the state of Idaho.
Southwest Alberta wolf population monitoring
Our study area ranges from the international border north to Highway 1 and is bordered on the east by Highways 6 and 22, except for the Porcupine Hills which are included in our study area. No wolf packs are currently radiomarked in this area. We surveyed Alberta big game hunters for wolf sightings after the 2012 hunting season. We received 2,227 completed surveys and 161 hunters reported seeing >2 live wolves in our study area during the 2012 big game hunting season. To target wolf survey efforts and increase our ability to find and sample wolf packs in the field we developed a habitat model that predicts suitable wolf pack rendezvous site habitat. In summer 2012, we surveyed 420 potential wolf rendezvous sites between the international border and the Highwood River (including Porcupine Hills) and collected 439 genetic samples that yielded 45 individual wolf genotypes. This represents a minimum count of wolves in that area at that time and should not be interpreted as a population estimate. We resumed surveying in summer 2013 at 301 predicted rendezvous sites across the entire study area from the international border to Highway 1 and detected 4 litters of pups. DNA analysis of the 415 genetic samples collected during these surveys is currently underway at the University of Idaho.
As a response to community feedback we sent letters to >300 grazing leaseholders and included refrigerator magnets with our contact information in an attempt to gain more public input and sightings of wolves in the study area. We gave multiple public outreach presentations in January and July throughout the study area and contacted members of the South Country Trappers Association to gain information about wolf activity in the study area. We also conducted multiple interviews about our project with media in the region over the last 12 months.
Immediately after the 2013 big game hunting season, we will survey hunters in our study area for observations of live wolves once again. The resulting data, coupled with the 2012 hunter surveys and rendezvous site survey data from summers 2012 and 2013, will feed an occupancy model and provide preliminary estimates of wolf pack abundance and distribution in the study area. We plan to continue rendezvous site, DNA, and hunter surveys in 2014. Our goal by early 2015 is to have developed and tested a monitoring framework based on patch occupancy modeling that uses data from a variety of sampling techniques to provide reliable estimates of wolf population size in southwest Alberta annually.
Biofence and wolves
Gray wolves (Canis lupus) can conflict with livestock production throughout Idaho, Montana, and Wyoming. Generally, wolves that prey on domestic livestock are killed by management agencies or private landowners. These actions typically stop depredations for producers in the short-term but are not a lasting solution because wolf packs generally fill the recently vacated territory within 1 year and livestock predation often continues. Most tools currently available for non-lethal control of wolves are short-lived in their effectiveness or require constant human presence. Wolves, like most canids worldwide, use scent-marking (deposits of urine, scat, and scratches at conspicuous locations) to establish territories on the landscape and avoid intraspecific conflict. We tested human-deployed scent-marks consisting of scat and urine (i.e., “biofence”) to manipulate wolf pack movements in Idaho.
We deployed 64.7 km and 64.8 km of biofence within 3 wolf pack territories in central Idaho during summers 2010 and 2011, respectively. In 2010, location data provided by satellite collared wolves in 2 of the packs showed little to no trespassing of the biofence. Sign survey at predicted rendezvous sites in areas excluded by the biofence yielded little to no recent wolf use of those areas. We also opportunistically deployed a biofence between a resident wolf pack’s rendezvous site and a nearby (1.6 km) active sheep grazing allotment totaling 2,400 animals. This pack was not implicated in any depredations in 2010. In 2011, however, location data indicated some individuals showed little aversion to trespassing the biofence. Our study provides evidence that wolf movements can be manipulated by human-distributed scent-marks but not all individuals respond strongly to the biofence. Importantly, it appears that wolves’ response to biofencing diminished between years of our study suggesting that one would need to maintain a biofence continuously to ensure effectiveness. We believe more frequent refreshing of the biofence, year-round presence once the biofence is established, an adequate buffer distance from the area to be excluded, and the use of howlboxes may fortify biofenceing, but further study is needed to test this.
Human caused mortality and wolves
Wolves (Canis lupus) live in family groups comprising a breeding pair, their offspring, and several related helper wolves. Mortality, however, can affect this family group structure and result in smaller packs with adopted, unrelated individuals. Little is known about how characteristics of groups (i.e. size, composition, tenure) affect population growth, individual behavior, group stability, or reproduction. States in the Rockies recently initiated public hunting and trapping seasons for gray wolves and our study is well-positioned to answer important questions about how that new source of mortality might affect gray wolf pack composition and reproduction. Additionally, population modeling of vital rates based on groups can give us insight into how differences in group size and composition affect population growth in this cooperatively breeding canid.
Our three focal study areas (southwest Alberta, central Idaho, and Yellowstone National Park, WY) represent a range of human-caused mortality from heavily harvested and agency-controlled (SW Alberta and central Idaho) to fully protected (YNP). We intensively sampled 8-10 wolf packs in central Idaho since 2007 and recently began sampling 6-8 wolf packs in YNP and 3-8 wolf packs in SW Alberta in summer 2012. We will begin assessing the impacts of human caused mortality on wolf packs by examining pack pedigrees generated via genetic samples collected from surveyed rendezvous sites in the three focal study areas. DNA analysis of collected samples is underway. We are also examining homesite attendance of satellite collared wolves from the three study areas to explore facets of helping behavior. We plan to continue field sampling through 2014 and complete analyses in 2015.
Natural Sciences Room 205
Missoula, MT 59812