PRELIMINARY ANALYSIS OF WOLF-UNGULATE INTERACTIONS WITH SPECIFIC REFERENCE TO MOOSE IN RIDING MOUNTAIN NATIONAL PARK, MANITOBA

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1 PRELIMINARY ANALYSIS OF WOLF-UNGULATE INTERACTIONS WITH SPECIFIC REFERENCE TO MOOSE IN RIDING MOUNTAIN NATIONAL PARK, MANITOBA L. N. CARBYN, Canadian Wildlife Service, Jasper Avenue, Edmonton, Alberta Ab6~~a~~: Research on the wolf-prey interactions in Riding Mountain National Park (RMNP), Manitoba was initiated in July Ungulate surveys consisted of fixed-wing aircraft surveys at 1.6-km intervals covering 25 percent of the area. Radio transmitters were attached to 6 wolves (Cani6 fupu6) running in 5 contiguous packs. Their movements were monitored during the winter (242 radio fixes). Data on predation (prey selection) were collected from scat samples (490 summer samples, 484 winter samples to May 1977) and from ground examination of 35 kills. Wolf densities were considered high at 1/23 km 2 during the 1st year of the study but declined to about 1 wolf/46 km 2 in the 2nd year. Ungulate numbers were relatively stable at about 1 elk (Ce~vu6 ~anaden6i6)/1.8 km 2 and 1 moose (Af~e6 af~e6)/1.0 km 2. Moose were not an important prey species, as determined from both scat collections and wolf kills. Wolf and ungulate population studies in RMNP were initiated in September This research was part of a large mammal systems study (Carbyn 1976) which is being carried out for Parks Canada as part of their management and interpretation programs. Data analyses for the 1st 2 years of fieldwork are incomplete, and this paper presents only the results obtained from the study in the 1st year and some preliminary data from the 2nd year. Elk and moose are indigenous to the park. Their historical fluctuations have been documented (Rounds 1977). White-tailed deer (Odo~oifeu6 vi~gi"ianu6) is a more recent invader which has replaced mule deer (0. hemionu6) over the last several decades. \'701ves were once indigenous but became extinct. In more recent years wolves have repopulated the park (Carbyn et al., Unpublished data). I would like to express my thanks to the contributions in this field by C. Allan, D. Patriquin, and J. Tutt; to B. Briscoe for his liaison work with Parks Canada; and to superintendent G. Rochester and staff of illlnp for their involvement in all phases of the project. The work is being financed by Parks Canada Prairie Region. 283

2 STUDY AREA AND METHODS Riding Mountain National Park is in effect an island ecosystem of ha that is completely surrounded by agricultural land. Animal movements across park boundaries are common, but there is probably 110 contact with other ungulate populations. Wolf movements are more extensive. The park is largely covered by coniferous and deciduous forests with extensive interspersions of grasslands, sedge meadows, and black spruce (Pieea ma~iana) bogs. The climate is typified by cold winters and cool summers. The winters of and were considered mild for the area (Table 1). The 1st permanent snow begins to accumulate in mid November and is almost completely melted by the 1st week in April. Aerial ungulate surveys were carried out February 4-7, 1976 by Parks Canada and Canadian Wildlife Service (CWS). Flight lines were 1.6 km apart and flown at an altitude of 122 m. A navigator and 2 observers carried out the survey and used topographical maps to plot all ungulates in 200 m transect strips. This provided for 25 percent coverage. Total estimates were obtained by multiplying total animals seen by 4. Such surveys have been carried out at RMNP, with some modifications, on a fairly regular basis since 1950 (Rounds 1977). Therefore, trend information on moose and elk is available for over a 20-year period. Population figures probably reflect trends, although they have to be viewed with some reservations as conditions, methods, and personnel varied, particularly during the earlier surveys. Information on trends in wolf abundance since the mid 1920's is available from park records. More detailed population data became available in 1975 when radio-telemetric studies were initiated. Methods were adapted from the techniques reported by Carbyn (1975) and Mech (1975). Traps (No. 14 jump or No.4 double spring) were set along trails during September to October in 1975 and Radio transmitters were attached to the wolves and subsequently monitored from fixedwing aircraft. Kills were examined on the ground whenever it was possible to reach the kill sites. Scat collections were obtained in July-August 1975 (113 samples), 284

3 Table I. Snow conditions and temperature for the first 2 winter seasons of study ( ) as collected by the Resource Conservation staff of Riding Mountain National Park. Snow conditions (mid, northern section of the Park) Month Height of new snow in em Total accumulated de~th in em Tem~eratures (Dau~hin Ai rport) / / /77 MinoC MaxoC M i noc MaxoC September co '" '" Octobe r November December January Feb ruary March Apri I N. D N. D. N.D l No data available.

4 September 1975-May 1976 (279 samples), June-August 1976 (377 samples), and September 1976-May 1977 (205 samples).a Methodology in scat identification was tested (Carbyn, Unpublished data). Hair impression techniques were used in scale impression and whole mount identifications. Park Warden Service kept weather records at the warden stations. Records of rr.onthly new snowfall totals and accumulated snowfall at the end of each month were taken from Northgate Warden Station. Mean monthly maximum and minimum temperature data were obtained from official Ministry of Transport records from Dauphin, Manitoba. RESULTS During the 1st year of study mid-winter elk and moose densities were /km 2 and 1.0/km 2 respectively, and 1.6 and 1.05 respectively for the 2nd winter (park files). In the fall and early winter wolf density for the west half of the park (prime elk range) was 1 wolf/23 km 2 These data apply to fall and mid-winter wolf densities in which territory sizes were plotted from 242 radio fixes representing the movement of 54 wolves in 5 packs. b Similar data on wolf densities were not obtained from the east half of the park where no wolves were caught. Data collected from kills found 2 out of 31 kills were moose, and scats analyzed (Table 2) indicated that moose were not an important prey item for wolves in the park. This was substantiated by results obtained about parasites of wolves (W. Samuel, personal communication) where an examin~tion of 12 wolf carcasses obtained from trappers adjacent to the park yielded no adult forms of the tapeworm Ta~nia k~abbei. a Periods were chosen to conform to biological cycle of wolves: June-August (rearing of pups) and September-May (pack movements to denning and early rendezvous site formation). b six animals were caught and equipped with transmitters. Invasion of a pack with collared wolves by a pack without coll.'red wolves oomplicated matters regarding calculation of territory sizes. Another complicating factor was that not all packs were monitored over the same length of time. Generally, the longer a radio was functional the more exact was the definition of territory size. 286

5 Table 2. Resul ts of wolf scat analysis during 2 summer-ta-spring periods (numbers refer to food item). Species SUJMle r (June-August) Win ter (Septembe r-may) Total Total Total N % N % N % N % N % N % % E Ik(adu Its) Elk(calves) Moose(adul ts) Moose(calves) T 0 T 5 T Whi te-tai led deer Whi te-tai led deer (fawns) T 0 T 14 Cattle T T Beaver Muskrat Red squirrel T 2 9 T Snowshoe hare T Porcup i ne T 5 23 Microtine Grouse Other llncludes wolf ha i r (probably ingested through groomi ng) ; egg shells and feathers; insects. 2Represen ts 974 scat samples. 287

6 Moose accounted for only 4 percent of the food items found in the scat samples. Less than 1 percent of the food items was of moose calves. Elk and beaver together accounted for 60 percent of the food items, and white-tailed deer, which appeared to exist at much lower densities, accounted for 10 percent \ \ I of the food items. There were variations in results from the 2 years. Moose remained low (7 percent summer, 5 percent fall to spring in the 1st year versus 2 percent and 8 percent respectively in the 2nd year). Elk remained around 45 percent, whereas beaver increased from 4 percent and 2 percent in the 1st year to 21 percent and 23 percent in the 2nd year. The increase was statistically significant (P~O.l; chi-square). The number of deer remains in scat samples declined from 18 percent and 24 percent to 5 percent and 6 percent respectively (P<O.l; chi-square test). DISCUSSION It is too early to reliably report on the relationship of wolf predation to the population dynamics of moose. However, some trends are emerging. Despite the high wolf densities (estimated at I wolf/23 km 2 for the whole park), moose are not an important prey species in RMNP. Predation pressures are largely absorbed by elk, beaver, and deer. The wolf population declined during the 2nd year (estimated density at 1 wolf/45 km 2 based On a capture of 8 wolves in 3 different packs). Predation on moose calves is light which probably reflects the difficulty of wolves getting at the calves in face of anti predator behavioral responses of cows. Results to date are based on small sample sizes, therefore data on the relative importance of buffer prey species are inconclusive. The picture is further complicated by the difficulty of distinguishing between elk and deer hair in wolf scat samples. Another important component that will have to be considered in future analyses of trends is the effect of plant succession on the 2 species. One can speculate that a loss of grasslands is a disadvantage to elk. Furthermore, the cyclical phenomenon of snowshoe hare (Lepu~ ame~icanu~) may be important; that is, when hare are numerous they may be competing with ungulates for food. The last peak in hare numbers was in

7 Wolves prey extensively on moose when it is the most available prey species (Peterson 1976). This predation pressure is largely directed toward calves and older animals (Wolff 1977). On Isle Royale, "belly-deep" snow rendered calves particularly vulnerable (25-30 percent of all wolf kills were of moose), but this increased when snow depth exceeded 75 m (Peterson and Allen 1974). The and winters were mild and accumulated snow depths in RMNP were well below 75 cm. Therefore, snow conditions did not seem to greatly affect the vulnerability of moose to predators in the park. With an abundance of prey species, wolves can be expected to kill those species which have the least highly evolved antipredator mechanisms. In the absence of elk, beaver, and deer in the park, the predation on moose (and possibly cattle that graze outside the park) undoubtedly would increase. The wolf-moose relationship at present in RMNP differs from those in Alaska and Isle Royale, Ontario (R. Peterson, personal communication). In recent years, wolf predation and winter conditions are significant factors contributing to moose declines. In Alaska, this had led to lively debates on the role and relative importance of wolves (the predator) and man (the hunter). The Isle Royale situation is of particular interest since, as in the case with RMNP, Isle Royale is an island ecosystem and there is no harvest by man. Riding Mountain National Park differs from Isle Royale in that in the former there is a constant "bridge II with the "mainland" and constant resource utilization takes place outside the park boundary. Isle Royale is only periodically (in severe winters) continuous with the mainland. 289