Cayoosh Range Mountain goat survey in the Cayoosh area, management unit 3-16, Thompson region, British Columbia, July 2008 Prepared for: Doug Jury British Columbia Ministry of Environment Thompson Region 1259 Dalhousie Drive Kamloops, BC V2C 5Z5 Prepared by: Kim G. Poole Aurora Wildlife Research 2305 Annable Road, Nelson BC V1L 6K4 Tele. (250) 825-4063; e-mail: [email protected] September 2008 Cayoosh mountain goat survey, July 2008 ii ABSTRACT Mountain goats (Oreamnos americanus) are managed as a big game species in British Columbia, and as such aerial surveys are conducted periodically to document population trend and productivity, and to establish hunting quotas. As a result of suspected declines in the population and a 10-year gap since the last survey, a survey was conducted to determine the numbers and distribution of goats in subzones 3- 16B, C, D, E and F in the Pacific and Lillooet ranges of the Coast Mountains southwest of Lillooet, southeastern British Columbia, in July 2008. Standard survey techniques were followed using a Bell 206B helicopter. We used 18.4 hrs of helicopter time, including 15.7 hrs on survey, and surveyed a 675-km2 census zone of potential goat habitat under good survey conditions. Overall survey effort averaged 1.4 min/km2. We observed 210 goats (150 adults, 60 kids) in 56 groups. Kids comprised 29% of total goats (40 kids:100 adults [non-kids]). Groups were distributed from 5,400 to 8,100 feet (1,650–2,470 m) elevation. I applied a sightability correction factor of 60% to derive an estimate of 350 goats for the census zone within the 5 subzones (density of 0.52 goats/km2). Other wildlife observed included 2 black bears (Ursus americanus) and 1 grizzly bear (U. arctos), and a pair of wolves on a ridgetop above Duffy Lake at 7,100 feet (2,160 m) elevation. The last complete survey that covered most of these subzones was conducted in 1998. Comparison with the 1998 data, and considering survey effort and coverage, suggests a 50–60% reduction in goat numbers in all subzones censused with the exception of subzone 3-16C, where the estimate is similar between years. The cause(s) of the population decline in the Cayoosh are unknown. Annual hunter harvest since 2000 within the 5 subzones has averaged 6.25 animals annually, an annual harvest rate of approximately 1.8% of the estimated population size. The proportion of females in the harvest, while high during the 1980s and 1990s (averaging 41% and 36%, respectively), has declined since 2000 (19%). Wolves appear to have been re-established within the region starting in the late 1990s, and wolf predation on goats may have increased over the past 10 years. High kid ratios suggest a productive population not food-supply limited. The estimate for subzone 3-16F was 25 goats; therefore, I suggest that hunting be eliminated or substantially reduced within this subzone until such point as the population is shown to be larger. The other subzones censused (3-16B, C, D, and E) can sustain continued harvest, although some reduction in harvest may be warranted given that it is unclear whether the decline observed from 1998 to 2008 is continuing, has stabilized, or the population has begun to increase. To monitor population status I recommend that the subzones be re-surveyed at 3–5 year intervals. Ministry of Environment should continue to provide hunter education and goat sex identification training for both resident and non- resident hunters/guides. Aurora Wildlife Research Cayoosh mountain goat survey, July 2008 iii TABLE OF CONTENTS ABSTRACT..................................................................................................................................................ii INTRODUCTION ........................................................................................................................................1 STUDY AREA .............................................................................................................................................1 STUDY DESIGN AND METHODOLOGY................................................................................................3 RESULTS .....................................................................................................................................................3 Survey .......................................................................................................................................................3 Harvest data ..............................................................................................................................................5 DISCUSSION...............................................................................................................................................6 Population estimate...................................................................................................................................6 Kid ratios...................................................................................................................................................8 Management recommendations ................................................................................................................8 ACKNOWLEDGEMENTS..........................................................................................................................9 LITERATURE CITED .................................................................................................................................9 Aurora Wildlife Research Cayoosh mountain goat survey, July 2008 1 INTRODUCTION Mountain goats (Oreamnos americanus) are an important species in British Columbia, with over half of the world population occurring in the province. Mountain goats are found in eastern and western sections of the Thompson Region (Region 3) of southern British Columbia (Shackleton 1999), with roughly 6% of the provincial total (Hatter 2005b). All goat hunting within the region is controlled on a Limited Entry Hunting (LEH) permit system, based on estimated population size, with 196 resident goat LEH permits and an average of 16 non-resident permits currently allocated annually. There is a perception of population declines across much of the region (Lemke 2005, D. Jury, Ministry of Environment [MoE], Kamloops, personal communication), but limited surveys have been conducted from the late 1980s to mid 2000s to substantiate this trend (Poole 2007a). Periodic surveys are required to update population estimates to ensure that harvests are sustainable. This survey focussed on a number of subzones within management unit 3-16 on both sides of Cayoosh Creek southwest of Lillooet in southwestern British Columbia (Fig. 1). Considerable research (Lemke 1999) and surveys on mountain goats were conducted in this area in the 1990s, in part because it was used as a source for transplants within the province, and in part because of a ski development proposed for the Melvin Creek area. The last complete survey of this area occurred in September 1998 (Lemke 1998). This current survey covers goat management unit subzones 3-16B, C, D, F and the northwestern half of E (Fig. 1). Eight or 10 resident LEH permits are currently allocated within each subzone (totalling 44 permits for the 5 subzones). Resident hunter effort within the subzone (i.e., whether a permitted hunter actually hunts) is unknown. One guide outfitter territory covers all 5 subzones, with a current annual allocation of 5.4 goats/year over a 4-year allocation period. The impetus for this survey was the 10 years since the last inventory and declining hunter success (D. Jury, MoE, Kamloops, personal communication). Wolves (Canis lupus) were first observed in the areas in the late 1990s, which may have increased predator mortality within the population. The objectives of this survey were to determine the number and distribution of mountain goats within the subzones, and to compare survey results with historic data. Data obtained will be used to support current harvest management strategies. STUDY AREA The Cayoosh study area is located in the Pacific and Lillooet ranges of the Coast Mountains, primarily in the dry climatic moisture regime of the (former) Kamloops Forest Region (Lloyd et al. 1990). Potential goat habitat in the study area primarily is made up of 2 biogeoclimatic zones: the Engelmann Spruce-Subalpine Fir (ESSF) zone and the Alpine Tundra (AT) zone above tree line. Tree line is generally located between 1,800–2,000 m (5,900–6,550 ft) (Lloyd et al. 1990); there is little open alpine in this area. July and January mean temperatures for Lillooet, on the northeastern edge of the study area, are 21.4ºC and –3.6ºC, respectively (Environment Canada climate normals, unpublished data). Lillooet receives an average of 330 mm of precipitation including 32 cm of snowfall annually. Climate varies within the study area, with cooler temperatures and deeper snowfalls at higher elevations and on north and east-facing slopes. High on the valley sides, hybrid white-Engelmann spruce (Picea glauca x engelmannii) and subalpine fir (Abies lasiocarpa) dominate, with scattered stands of lodgepole pine (Pinus contorta) on drier sites (Lloyd et al. 1990, Parish et al. 1996). A census zone of potential goat habitat was surveyed, which generally included steep or cliff habitat above 5,500 feet (1,700 m) elevation in most areas. (Feet are included as the unit of measure because the helicopter’s altimeter was in feet). Aurora Wildlife Research Cayoosh mountain goat survey, July 2008 2 Figure 1. Location