A NOTE ABOUT THE EFFECTS OF INTRODUCED WOLVES ON TRE OPERATIONS OF ELK FEEDGROUNDS IN WESTERN WYOMING RON DEAN.' Wyoming Game and Fish Department, P.O. Box 3488, Alpine, WY 83128, USA SCOTT WERBELOW, Wyoming Game and Fish Department, P.O. Box 850, Pinedale, WY 82941, USA BERNARD HOLZ, Wyoming Game and Fish Department, P.O. Box 850, Pinedale, WY 82941, USA Abstract: Wolves (Canis lupus) were released into Yellowstone National Park (YNP) in 1995, and have dispersed throughout western Wyoming since. The first wolves observed on elk (Cewus elaphus nelsoni) feedgrounds operated by the Wyoming Game and Fish Department (WGFD), were documented in the Gros Ventre River valley in 1999. The following winter, wolves began affecting other feedgrounds. Within 5 years of their release, wolves had affected management of 14 of 22 feedgrounds in Wyoming. Wolves have displaced elk fiom feedgrounds resulting in increased operating costs, risks of disease transmission to livestock, and agricultural damage. Wolf activity has also impacted the ability to run sanitary feeding operations and reduced the number of fiee-ranging elk in areas where elk have been chased. Given the present political situation, the WGFD will continue to store extra hay at feedgrounds and respond to situations created by elk displacement fiom feedgrounds. WESTERN STATES AND PROV1IVCES DEER AND ELK WORKSHOP 5:23-29 Key words: Canis lupus, Cewus elaphus nelsoni, elk, feedgrounds, predation, supplemental feeding, wolves. In 1995, wolves were "re-introduced" into YNP, northwestern Wyoming, where they were once part of the ecosystem. However, the socio-economic environment of that region differs markeqy fiom conditions that existed when wolves previously inhabited Wyoming. The elk feeding program generally evolved as a management tool since the 1930s7 after the original wolf populations had disappeared. This paper discusses some effects "introduced" wolves are having on the management of elk feedgrounds. The WGFD operates 22 feedgrounds for elk in western Wyoming. The number elk fed at individual sites ranges fiom 200 to 1,500, collectively totaling about 16,000 annually. Since 1995, wolves have increased and expanded their range to an area encompassing most of the state's elk feedgrounds. STUDY AREA All WGFD feedgrounds are located in 3 counties in western Wyoming, south and southeast of YNP (Fig. 1). The feedgrounds are situated within an area of about 80 by 145 km. Vegetation and proximity of elk escape cover vary considerably among individual feedgrounds. Some feedgrounds are within or adjacent to large blocks of contiguous conifer forest, and others are within areas dominated by big sagebrush (Artemisia tridentata) several miles fiom forested habitat. Snow depths also vary considerably among feedgrounds. Some feedgrounds are within areas where snow depths seldom exceed 0.3-0.5 m, depths at other feeding sites are commonly more than 1.3 m. 1 E-mail: rdean@wgf.state.wy.us
ALKALI PATROL CABIN FISH CREEK SOUTH PARK HORSE CREEK DOG CREEK CAMP CREEK DELL CREEK MCNEEL ALPINE BLACK BUlTE FRANZ GREEN RIVER LAKE FOREST PARK SODA LAKE FALL CREEK SCAB CREEK MUDDY FINNEGAN NORTH PINEY BENCH CORRAL JEWElT Fig. 1. Locations of Wyoming Game and Fish Department feedgrounds. METHODS We observed wolves, elk, and wolf-elk interactions opportunistically when elk were present on feedgrounds during winter. Ow study evaluated effects of wolf predation on WGFD feedgrounds, fiom 1998 to 2003, but excluded wolf-caused mortalities within areas surrounding feedgrounds. Kills were verified based on signs of trauma to elk carcasses, or other evidence such as wolf tracks at the kill site and behavior of associated elk. Wolf-caused kills were classified as surplus when little or none of the carcass had been eaten; wolves did not return to the site to feed; the carcass was not moved at or fiom the kill site by wolves; and minimal human activity had been present in the vicinity. We did not consider surplus killings to include carcasses that were removed fiom the kill site or otherwise handled extensively by persons feeding elk, however these carcasses were included in the tally of wolf-killed elk. Accordingly, we believe ow estimate of surplus killings is conservative. Elk movements were considered wolf-induced if wolf tracks were present at the site or the pattern of elk tracks indicated a response to wolves. Normal movements are characterized by scattered tracks when elk are feeding, and a narrow path when elk move through deep snow between areas. Tracks of elk herds chased by wolves are typically 35-70 meters wide and indicate rapid movement or a "stampede" effect.
RESULTS Wolf Distribution Wolves began impacting feedgrounds during late April of 1999 when approximately 700 elk were chased off the Fish Creek Feedground in the Gros Ventre River drainage (Fig. 1). The following year, wolves were observed on all 3 feedgrounds (Fish Creek, Patrol Cabin, and Alkali) in the Gros Ventre drainage. By the winter, 2001, wolves had expanded into the Green River drainage where observations were made on the Black Butte and Soda Lake feedgrounds (about 56 and 80 km, respectively, southeast of the Gros Ventre feedgrounds). During 2001-02, wolves ranged farther down the Green River, appearing at the Scab Creek feedground south of Pinedale (about 1 10 km from the first sighting in the Gros Ventre) and on the Bench Corral feedground near Big Piney (about 120 km south of the Gros Ventre). The same winter, wolves moved into the Greys River drainage to the Forest Park feedground, (about 96 krn southwest of the Gros Ventre) and onto the Horse Creek and Camp Creek feedgrounds in the Hoback River drainage (about 48 km southwest of the Gros Ventre, Fig.1). By the conclusion of the feeding season in 2003, wolves were observed on 14 of 22 feedgrounds (Fig. 2). Based on track evidence, wolves commonly used snowmobile trails to travel between feedgrounds. Fig. 2. Cumulative number of feedgrounds on which wolves have killed elk, 1998-2003. Wolf Kills Wolves have killed at least 137 elk on feedgrounds since 1999. The current mortality rate on feedgrounds is not considered significant at a population level. To date, the largest number of elk killed on feedgrounds in a single winter was 73 in 2002 (Fig. 3).
The composition of elk killed by wolves was 57%, 39%, and 4% calves, cows, and bulls, respectively (Fig. 4). Based on the age composition of documented kills, wolves appear to select calves. Although calves comprised only about 30% of the total elk population, they were taken at a rate nearly double their proportionate availability. We determined 18 (1 3%) of the 137 elk killed by wolves were surplus kills because the carcasses were either not used as food, or only fed upon slightly. 1998 1999 2000 2001 2002 2003 Fig. 3. Number of elk killed by wolves on feedgrounds, 1998-2003. 1998 1999 2000 2001 2002 2003 Total Fig. 4. Sex and age composition of elk killed by wolves on feedgrounds, 1998-2003. Damagemisease Concerns Resulting &om Elk Movement Wolves readily chased elk from feedgrounds. In some cases, elk returned the same or next day, as observed at the Jewett feedground. In winter 2003, elk were chased off this feedground
on 4 occasions, but returned within a day. Similar episodes took place at the Fall Creek, Soda Lake, Green River Lakes, and Bench Corral feedgrounds. In several instances, the elk moved about 5 km from the feedground before returning. In other cases, elk were chased from one feedground to another, as routinely happened in the Gros Ventre River drainage. The 3 feedgrounds located there are about 8 km apart. In 2002, elk were also chased back and forth between the Horse Creek and Camp Creek feedgrounds, about 5 km part. During 2003, elk from Black Butte were displaced 50 km to the Soda Lake feedground and the North Piney elk were displaced 26 km to the Bench Corral feedground. However, movements from North Piney to Bench Corral have happened in the past, before wolves were present. During winter, 2003, wolves displaced elk 3 and 9 krn northwest of Alkali Feedground, onto the Red Rock and Red Hills ranches, respectively, where presence of the elk created conflicts with livestock. Similar movements took place in the New Fork River Valley where elk were chased from Black Butte onto private lands in 2003. Adjusting Hay Storage When elk were chased between feedgrounds, hay shortages developed rapidly as abnormal numbers of elk moved onto individual feedgrounds. Attempting to freight existing hay reserves among the feedgrounds dwing winter proved costly and dangerous (given the large volume of recreational snow machines on roads). To deal with the potential for feeding more elk than normal, extra hay was purchased and stored. The 3 feedgrounds in the Gros Ventre River drainage are normally stocked with hay supplies for 800,600, and 1,000 elk. After wolves chased elk between these feedgrounds, one large herd of 2,000-2,700 elk congregated. We could not predict where the herd would ultimately move, so extra hay was siored at all sites. Before wolf activity was present in the Gros Ventre drainage, an average of 1,210 tons of hay was stored at the beginning of each winter. Storage for the winter of 2004 will be increased to 1,800 tons, representing about $65,000 in extra hay. The extra tonnage exceeds the capacity of storage facilities, and will increase spoilage and waste. Although the amount hay fed has not changed greatly (the decrease in 2003 was the result of a mild winter), the amount purchased and stored has increased steadily since wolves were introduced (Fig. 5). Elk Distribution By scattering feed on clean snow over a large area, managers can reduce the potential for disease transmission, competition among elk, and damage to soil and vegetation. Optimizing this feeding strategy became difficult when large numbers of elk concentrated on 1 feedground. In the Gros Ventre drainage, numbers of elk on the 3 feedgrounds recently averaged 762,424, and 888. After wolves moved into this area, the elk combined into a single herd that included additional free-ranging elk. As a consequence, 2,000-2,700 elk were fed at 1 one site for an extended period. Abnormal concentrations of elk were also noted at Soda Lake, Horse CreekICamp Creek, and Bench Corral feedgrounds.
2000 c/l 1500 - + Hay storage -A- Fed - - - - --- - --- - - - --- - - Fig. 5. Hay stored and fed to elk on feedgrounds, 1998-2003. Reduction in Free Ranging Elk Fewer free-ranging elk were present in the Gros Ventre drainage after wolves became established. Elk are herd animals that typically respond to threats by banding together. Although speculative, we believe free ranging elk encountered by wolves sought the security of a large herd and this herd tended to remain intact for the duration of the feeding season. Based on observations fiom helicopter flights and a comparison of elk numbers during the 4 years prior to wolf establishment, and 4 years afterward, on average 41 1 more elk were fed after the wolves were present. ly feeding costs subsequently increased $22,605. Benefits of Wolf Presence Some elk movements caused by wolves were beneficial. When elk were chased fiom Black Butte to Soda Lake and fiom North Piney to Bench Corral feedgrounds, they were subsequently fed on feedgrounds with a shorter feeding season. This reduced feedground costs and increased the length of time elk foraged in a fiee-ranging state. DISCUSSION Over the past 60 years, substantial areas of native winter ranges and forage have been impacted by development, land use conversions and decreased tolerance of fiee-ranging elk (due to disease/damage concerns). Feedgrounds have enabled the WGFD to sustain larger elk populations than the available forage base and political tolerance for elk would allow. Feedgrounds attract and hold elk at specific sites, providing a means by which man and elk can co-exist in areas no longer suitable to accommodate the needs of both elk and humans. Because wolves routinely chase elk from feeding sites, they impact the effectiveness of feedgrounds for dealing with damage (both agricultural and residential) and wildlife disease concerns. Wolfinduced movements have created some feedground management problems and have elevated
risks to other public sectors. Movements of feedground elk are comparatively new (5 years of observations) and appear to be random, which causes managers substantial concern. Based on our observations of wolf-elk interactions, we anticipate incidents of elk moving erratically onto and off feedgrounds will continue, costs associated with hay storage will increase, numbers of fiee-ranging elk will decrease, and more elk will move onto private property. Conversely, as time passes and experience is gained, some wolf-induced elk movements may become more predictable and could have a favorable outcome. It is conceivable the management of wolves could benefit some aspects of elk feedground management. The sex and age compositions of wolf-killed elk we documented are consistent with those reported by Jimenez (2003) in the Gros Ventre drainage from 1999 to 2002 (53% calves, 43% cows, and 4% bulls). Our estimate of surplus killings (213% of the total) exceeded the proportion Jimenez (2003) observed in the Gros Ventre drainage (5% of 1 19 wolf-killed). Personnel who feed elk reported wolves commonly did not return to kills after their initial feeding. Wolves may prefer killing another elk rather than returning to a prior kill when they have access to an abundant prey base. The behavior of wolves in response to prey abundance may affect interpretations of what constitutes surplus killing. MANAGEMENT IMPLICATIONS The size and distribution of the wolf population are expanding unchecked by management action. Consequently, wolves will continue to affect elk feedground management and the effects are likely to change over time. It is difficult to predict how wolves and feedground management may evolve until political issues have been resolved and management of wolves can be integrated into overall management of wildlife in western Wyoming. ACKNOWLEDGMENTS We thank the many persons who routinely feed elk, and the WGFD employees who provided documentation of wolf and elk activity. We appreciate the helpful comments and insights of D. Freddy who edited the manuscript. LITERATURE CITED JIMENEZ, M. 2003. Wolflelk interactions on State managed feedgrounds grounds in Wyoming. 2002 Progress Report, Unpublished. U.S. Fish and Wildlife Service, Lander, Wyoming, USA. Reviewer: D.J. Freddy