Mountain Goat Population Inventory Thompson Region Management Units 3-43 and August 9-11, 2005

Transcription

1 Mountain Goat Population Inventory Thompson Region Management Units 3-43 and 3-44 August 9-11, 2005 Prepared for: Ministry of Environment Environmental Stewardship Division Fish and Wildlife Science and Allocation Section Thompson Region by: S. L. Lemke, R.P. Bio. November 2005

2 SUMMARY Mountain goat sightings by LEH zone, MUs 3-43 and 3-44, August * Classified Unclassified % Juvenile Average Group Size Female Kid Male Adult Goat 3-43A Clemina/Dominion/Moonbeam B Pyramid/Gum/Upper Bone C Mud/Hellroar A Upper N. Thompson (North) B Upper N. Thompson (South) C Miledge D North Blue s * goats includes yearlings Mountain goat observations and population estimates by LEH zone, MUs 3-43 and 3-44, August Observed Estimated (corrected for sightability) (SCF=1.5) Zone Population Estimate (1994) 3-43A Clemina/Dominion/Moonbeam B Pyramid/Gum/Upper Bone C Mud/Hellroar A Upper N. Thompson (North) B Upper N. Thompson (South) C Miledge D North Blue s Mountain goat densities by LEH zone, MUs 3-43 and 3-44, August 2005, as compared to 1980s surveys Zone Area (km 2 ) Approx. Area searched (km 2 ) Observed 2005 /km 2 Searched (Observed) 1980s /km 2 Searched (Observed) 3-43A Clemina/Dominion/Moonbeam B Pyramid/Gum/Upper Bone C Mud/Hellroar A Upper N. Thompson (North) B Upper N. Thompson (South) C Miledge D North Blue s ii

3 Goat sighting rates by LEH zone, MUs 3-43 and 3-44, August 2005, as compared to 1980s surveys Search time (hrs.) 2005 /hour 1980s /hour 3-43A Clemina/Dominion/Moonbeam B Pyramid/Gum/Upper Bone C Mud/Hellroar A Upper N. Thompson (North) B Upper N. Thompson (South) C Miledge D North Blue s North Thompson mountain goat survey counts, 1983, 1986 and s % of 1980s counts 3-43A Clemina/Dominion/Moonbeam B Pyramid/Gum/Upper Bone C Mud/Hellroar A Upper N. Thompson (North) B Upper N. Thompson (South) C Miledge D North Blue - 3 3* s *Partial survey iii

4 Table of Contents SUMMARY...ii INTRODUCTION... 1 METHODS... 1 RESULTS... 2 Survey Conditions... 2 Observations and Population Estimates... 2 Densities and Sighting Rates... 3 Elevational Range of Observed... 4 Additional Wildlife Sightings... 4 DISCUSSION... 4 Population Inventory... 4 Harvest Management... 6 Management Unit Management Unit Trends in Nanny Harvest RECOMMENDATIONS REFERENCES List of Tables Table 1. Mountain goat sightings by LEH zone, MUs 3-43 and 3-44, August Table 2. Mountain goat observations and population estimates by LEH zone, MUs 3-43 and 3-44, August Table 3. Mountain goat densities by LEH zone, MUs 3-43 and 3-44, August Table 4. Goat sighting rates by LEH zone, MUs 3-43 and 3-44, August Table 5. North Thompson mountain goat survey counts, 1983, 1986 and Table 6. North Thompson minimum observed goat densities, 1983, 1986 and Table 7. Current annual allowable harvests (AAH) and 3-year and 5-year average mountain goat harvests, by LEH zone, MU Table 8. Current annual allowable harvests (AAH) and 3-year and 5-year average mountain goat harvests, by LEH zone, Management Unit List of Figures Figure 1. Estimated hunter-days and goat LEH permits, Management Unit 3-43, Figure 2. Goat LEH permits and harvest, Management Unit 3-43, Figure 3. Mountain goat harvest per unit effort with linear trend, Management Unit 3-43, Figure 4. Estimated hunter-days and LEH permits, Management Unit 3-44, Figure 5. Goat LEH permits and harvest, Management Unit 3-44, Figure 6. Mountain goat harvest per unit effort with linear trend, Management Unit 3-44, iv

5 Figure 7. Female mountain goat harvest as a proportion of total harvest, Management Units 3-43, Figure 8. Female mountain goat harvest as a proportion of total harvest, Management Units 3-44, v

6 INTRODUCTION Recent increases in both the level of use and the geographic range of backcountry recreational activities in the North Thompson watershed, specifically heli-skiing and snowmobiling, have raised concerns about the potential impacts on mountain goat habitat use patterns and population productivity. Also, a strong declining trend in the kill per unit effort for mountain goats in the province since 1991 (I. Hatter, pers. comm.) and a lack of recent, reliable inventory data, particularly for Region 3 populations (most of which have not been formally surveyed since the mid-1980s) challenge wildlife managers to formulate science-based, sustainable harvest objectives and regulations. The purpose of this survey was to obtain precise population inventory data, i.e. total count and indices of productivity, for mountain goats in management units (MUs) 3-43 and 3-44 in the North Thompson River watershed. These much-needed data will provide a stronger basis for reliably estimating mountain goat populations, evaluating population trends and preparing sustainable annual allowable harvests. METHODS Survey flights were conducted using a Bell 206B JetRanger helicopter, piloted by Doug Smallman of Cariboo Chilcotin Helicopters Ltd. The aircraft was equipped with bubble windows in the rear and wedge windows in the front for increased visibility. Doug Jury (BC Ministry of Environment, Kamloops) navigated from the front left seat, classifying goats and recording flight lines and incidental wildlife sightings on 1:50,000 scale topographic maps. Susan Lemke (Ursus Ecological Consulting, Kamloops) observed from a rear seat, recording classifications, habitat characteristics and entering animal locations into a hand-held Garmin GPSmap 76C unit. Kurt Kier (BC Ministry of Environment, Kamloops) observed from the second rear seat and assisted in animal classification. Surveys were flown between 0600h and 1200h to avoid the heat of midday, when goats may be less visible while bedding, and to minimize observer fatigue. Drainages were systematically flown at contours ranging between 1700 and 2600 m ( ft). Depending on terrain and timberline, a lower contour was flown initially, usually between the 1900 and 2100 m level. Upper contours were flown between 2100 and 2300 m, again, depending on terrain. Some areas required only one contour flight due to the narrow elevational range of suitable habitat, while the majority required two passes, and occasionally, three. In those areas requiring only a single pass, the flight contour varied with the terrain to optimize coverage of goat habitat. Air speed during searches was maintained between 80 and 100 kph. Depending on local topography, height above ground varied between 30 and 60 m. Consecutive contour flights were flown with a minimum time interval between (<30 minutes) to reduce the incidence of recounting animals moving upslope. were classified as adult or kid based on body size, horn growth and facial structure. In many cases, classification of adult females was assumed based on close association of 1

7 a juvenile. As the intent of the survey was to obtain a total count and calculate an adult/ juvenile ratio, and, considering the disturbance resulting from the increased time and proximity necessary for accurate sex classification, limited efforts were made. The identification of yearling animals was noted, although these were not included in the classification summary; these animals were grouped in the adult classes. RESULTS Survey Conditions Survey flights were initiated on the morning of 9 August, under ideal flying conditions cloudless sky and very little wind. Air temperature was 6 C at 1850 m. Glare and shadows, resulting from the lack of cloud cover, reduced sightability somewhat during the early hours of the survey. The morning of 10 August brought high cumulus clouds with light winds (~15 kph). Air temperature was 0 C at 2150 m. Clear skies and light winds again provided excellent survey conditions on 11 August with a morning air temperature of 6 C at 2050 m. Observations and Population Estimates A total of 83 goats were seen during the survey (Table 1). Of goats sighted, 63 (82%) were adults, and 11 (13%) were kids. Three animals were described as yearlings; these were included in the total count as unclassified goats. Fifty-five animals (66%) were unclassified as to sex, including 51 adults. Of classified adults, 13 (68%) were nannies and 4 (23%) billies. Twenty-four percent of goat sightings (20 animals) were recorded in Zone A of MU 3-44, with 23% (19) in Zone 3-43C, 22% (18) in 3-44B, 14% (12) in 3-43B, 12% (10) in 3-43A, 4% (3) in 3-44D and 1% (1 goat) in 3-44C. Based on 37 unique sightings, the average group size was 2.2 animals, with groups ranging from single animals to the largest group (18 animals), reported in the upper reaches of Adolph Creek. Table 1. Mountain goat sightings by LEH zone, MUs 3-43 and 3-44, August Classified Unclassified % Juvenile Average Group Size Female Kid Male Adult Goat 3-43A Clemina/Dominion/Moonbeam B Pyramid/Gum/Upper Bone C Mud/Hellroar A Upper N. Thompson (North) B Upper N. Thompson (South) C Miledge D North Blue s

8 Gonzalez-Voyer et al. (2001) compared the number of mountain goats seen during aerial surveys to the actual number of goats in a marked population in Alberta. On average, 69.5% of the goats were seen during aerial surveys. Cichowski et al. (1994) reported similar results, suggesting that this figure may apply widely to mountain goat helicopter surveys. Therefore, using as an approximate sightability correction factor (SCF), the corrected population estimate for the survey area as a whole is 126 goats, with 62 and 64 animals estimated in MUs 3-43 and 3-44, respectively (Table 2). Densities and Sighting Rates Overall observed goat density was 0.12 goats/km 2 (Table 3). Observed goat densities were highest in 3-44B, with 0.34 goats/km 2, lowest in 3-44 C and D (0.02 goats/km 2 ). Goat sighting rates were highest in 3-44A, where 20 goats were observed in 0.5 hours of search time (40 goats/hour). However, one of the three sightings in this zone was a group of 18 animals (the largest group by far sighted during the whole survey), making the sighting rate calculation of little value. The lowest sighting rate was in 3-44C at 1.3 goats/hour (Table 4). The overall sighting rate for the survey was 9.4 goats/hour. Table 2. Mountain goat observations and population estimates by LEH zone, MUs 3-43 and 3-44, August Observed Estimated (corrected for sightability; SCF=1.5) Zone Population Estimate (1994) 3-43A Clemina/Dominion/Moonbeam B Pyramid/Gum/Upper Bone C Mud/Hellroar A Upper N. Thompson (North) B Upper N. Thompson (South) C Miledge D North Blue s Table 3. Mountain goat densities by LEH zone, MUs 3-43 and 3-44, August 2005 Zone Area (km 2 ) Area searched (km 2 ) Observed 2005 /km 2 Searched (Observed) 3-43A Clemina/Dominion/Moonbeam B Pyramid/Gum/Upper Bone C Mud/Hellroar A Upper N. Thompson (North) B Upper N. Thompson (South) C Miledge D North Blue s

9 Table 4. Goat sighting rates by LEH zone, MUs 3-43 and 3-44, August 2005 Search 2005 time (hrs.) /hour 3-43A Clemina/Dominion/Moonbeam B Pyramid/Gum/Upper Bone C Mud/Hellroar A Upper N. Thompson (North) B Upper N. Thompson (South) C Miledge D North Blue s Elevational Range of Observed The average elevation of goat sightings was approximately 2100 m (6900 ft), with the lowest elevation sighting at 1200 m (4000 ft), and the highest at 2375 m (7800 ft). More than fifty percent of goats sighted were at or above 2150 m (7000 ft). Additional Wildlife Sightings Seven caribou (1 male, 4 cows and 2 calves) were sighted at approximately 1041h on 9 August in the upper reaches of Allan Creek (MU 3-44A). A lone bull was observed at 1150h the same day in Pleasant Creek (also 3-44A) at approximately 2150 m in elevation. DISCUSSION Population Inventory The Thompson regional wildlife management plan estimated a 1994 fall mountain goat population of approximately 500 animals in LEH goat zones in MUs 3-43 and With the lack of formal inventory work over the past two decades, a reliable update of these estimates has not been possible. The August 2005 survey indicates that a minimum of 83 goats inhabit these zones, with 126 animals estimated when observations are corrected for sightability bias. Efforts were made to search all high quality mountain goat range within the survey area; however, due to time and budgetary constraints, some good quality habitats were certainly left out. Survey coverage in MU 3-44 was similar to that in 1986; the 2005 survey encompassed 28% of the land area; the 1986 effort covered 27%. All major drainages of MU 3-43 surveyed in 1983 were again covered in The August 2005 population inventory suggests that the mountain goat population in the North Thompson has declined significantly in the past two decades, with the current population estimate 43% of the 1980s estimate (using the same sightability correction factor). Notably, goat numbers and densities in zones 3-44C (Miledge Creek), 3-43B (Pyramid/Gum/Bone Creeks), and, to a lesser extent, 3-43C (Mud/Hellroar) appear to 4

10 have declined dramatically (Table 5). Observed goat densities in these units were significantly reduced from previous surveys (Table 6). Comparison of the 1980s and 2005 data suggest that other areas, i.e. the upper North Thompson River, Clemina, Dominion and Moonbeam Creeks and North Blue River, are supporting stable goat populations (Table 5). However, the complete lack of formal inventory data in the intervening years (precluding population trend analyses) leaves the productivity and status of these herds in question. Interestingly, the observed kid component is very similar between surveys; 10%, 13% and 13% for the 1983, 1986 and 2005 surveys, respectively. These productivity values are low compared to the 25-30% juvenile components seen in historically productive goat habitats in the region, for example in MUs west of the Fraser River. The billy ratio of 31 per 100 nannies observed here is considered low for lightly hunted populations; however, the small sample (17 animals) and the tendency for the largely solitary males to inhabit sub-optimal, very rugged habitats where observability is reduced, limits the value of the parameter. Similarly, the observed kid:nanny ratio (85:100) is of no value due to the small sample size and the high number of unclassified animals observed. The complete lack of reliable inventory data for these populations for the past two decades and the limited sample size obtained on the 2005 preclude definitive estimates of population size and productivity in these MUs. The provincial Wildlife Harvest Strategy (1996), Harper et al. (2001) and Morgan (2005) recommend population monitoring for mountain goats every three to five years, and standardized inventories were recently identified as a priority for funding in BC (Ayotte 2005). Considering the above factors, and the apparent sensitivity of goats to aerial disturbance, goat population inventories in the North Thompson MUs (particularly in historic high density areas, i.e. 3-44B, perhaps an indicator of goat population health in the North Thompson) are strongly recommended every 2 to 3 years. At the barest minimum, the 2005 survey should be replicated in 2006 to verify (or refute) zone counts and obtain classification data to evaluate the adult sex ratio and productivity indices, i.e. kid:nanny ratio and juvenile component. Table 5. North Thompson mountain goat survey counts, 1983, 1986 and s % of 1980s counts 3-43A Clemina/Dominion/Moonbeam B Pyramid/Gum/Upper Bone C Mud/Hellroar A Upper N. Thompson (North) B Upper N. Thompson (South) C Miledge D North Blue - 3 3* s *Partial survey 5

11 Table 6. North Thompson minimum observed goat densities, 1983, 1986 and s 2005 /km 2 * /km 2 /km 2 /km A Clemina/Dominion/Moonbeam B Pyramid/Gum/Upper Bone C Mud/Hellroar A Upper N. Thompson (North) B Upper N. Thompson (South) C Miledge D North Blue s *1983 densities from Jury, The small average group size (2.2 animals) observed for this survey is unusual; generally, large nanny/kid maternity groups have formed or are forming at this time of year, to feed in relative safety on abundant alpine forage. The significance of this finding is currently unknown, but concerning; a regular series of comprehensive surveys (as recommended above) should be revealing. Mountain goats are sensitive to disturbance, particularly that associated with human activities, including vehicles and aircraft. Disturbance can increase stress, alter movement patterns, reduce foraging efficiency, increase susceptibility to disease and predation, affect reproduction, increases accidents and falls and may ultimately lead to range abandonment by mountain goats (Vogel, Ables and Scott, 1995). Winter backcountry recreational activities in the North Thompson, notably heli-skiing and snowmobiling, have increased in popularity in recent years, resulting in an increase in not only the volume of users but also an extension of the land base under use. High performance snowmobiles have allowed riders access to more remote and more challenging terrain than ever before, including areas adjacent to important goat winter range. While the more rugged habitats used by billies may insulate them somewhat from disturbance, nannies with kids are obligated to use sites of higher quality to ensure proper nutrition for their young. These winter habitats have become subjected to increased human activities and vehicular disturbance during this critical period, which may displace nannies and kids to more marginal habitat, reducing the chances of kid survival. The immediate effect of this scenario would be reduced recruitment, with the cumulative effect being population decline. Harvest Management Management Unit 3-43 On average, hunter-days have remained relatively consistent over the past decade (Figure 1). The spike in hunter-days in 1999 is most likely due to sampling error, and not indicative of a tripling in hunter effort, particularly when considering the number of LEH permits was reduced significantly in 1999 (see below). Harvest has been highly variable, with the average increasing slightly (Figure 2). Resident LEH authorizations were reduced by more than 30% in 1999 and then by an additional 50% in 2000 in response to 6

12 continued high female harvests province-wide and to the lack of recent reliable inventory information on which to base population estimates (and thus the annual allowable harvest). Despite this, hunter effort increased through 2002, although now appears to be falling off. Hunter success has been highly variable through this period, likely the result of difficulties in accessing extremely rugged, steep goat habitats in this area and pure luck (Figure 3). Sampling error in the estimation of hunter-days is likely the cause of an extremely high success rate (1.0) calculated for 2004 (not graphed) Resident Hunter-Days Resident Permits Estimated hunter-days Permits available Figure 1. Estimated hunter-days and goat LEH permits, Management Unit 3-43, Resident Harvest Resident Permits goat harvest Permits available Figure 2. Goat LEH permits and harvest, Management Unit 3-43,

13 14 12 harvested per 100 hunter days Figure 3. Mountain goat harvest per unit effort with linear trend, Management Unit 3-43, Average goat harvests in all three zones of MU 3-43 have consistently been below the annual allowable harvest (AAH), which was reduced from 5% to 3% of the estimated population in 2003 (Table 7). Table 7. Current annual allowable harvests (AAH) and 3-year and 5-year average mountain goat harvests, by LEH zone, MU Population Estimate (1994) AAH (3% of 1994 population estimate) 3-Year Average Harvest ( ) 5-Year Average Harvest ( ) 3-43A Clemina/Dominion/Moonbeam B Pyramid/Gum/Upper Bone C Mud/Hellroar Management Unit 3-44 Hunter-days and harvests in MU 3-44, in general, have been slowly decreasing since the late 1990s as permit numbers have been reduced (Figures 4 and 5). Hunter success, as in MU 3-43, has been variable, though on average, is decreasing (Figure 6). This suggests that goat numbers have declined. Average harvests in all goat LEH zones of MU 3-44 are well below the respective AAHs (Table 8). There have been no harvests in 3-44C or 3-44D for many years (the last goats were taken in 1994 and 1993, for Zones C and D, respectively). Zone D was closed in 2003 due to concern for the local population. Significantly, 3-44D reported the most 8

14 dramatic decline in observed goat numbers compared to 1986 survey. Whether due to actual population decline or range abandonment in favour of previously unidentified habitats within the drainage or elsewhere is unclear. Further inventory work will, hopefully, clarify the situation Estimated hunter-days Resident Hunter-Days Resident Permits Permits available Figure 4. Estimated hunter-days and LEH permits, Management Unit 3-44, Resident Harvest Resident Permits 120 goat harvest Permits available Figure 5. Goat LEH permits and harvest, Management Unit 3-44,

15 harvested per 100 hunter days Figure 6. Mountain goat harvest per unit effort with linear trend, Management Unit 3-44, Table 8. Current annual allowable harvests (AAH) and 3-year and 5-year average mountain goat harvests, by LEH zone, Management Unit Population Estimate (1994) AAH (3% of 1994 population estimate) 3-Year Average Harvest ( ) 5-Year Average Harvest ( ) 3-44A Upper N. Thompson (North) B Upper N. Thompson (South) C Miledge D* North Blue *Zone closed in Trends in Nanny Harvest The female portion of the harvest in MU 3-43, though highly variable, has averaged 30% over the past decade (Figure 7). In MU 3-44, variable rates of nanny harvest through the late 1990s and early 2000s averaged 23% (Figure 8). There have been no females killed in this MU since Population modelling suggests that the long-term viability of hunted mountain goat populations is threatened under female harvests of more than 30% (I. Hatter, pers. comm.). Despite recent efforts province-wide to better educate goat hunters in the sexing of animals in the field (through print and video media available at no charge), nanny harvests are still too high, although four years of no female harvest, in MU 3-44 at least, is a positive sign. Consideration is being given to a system whereby penalties would be applied for the harvest of female goats, i.e. reduction or loss of future 10

16 hunting opportunities. Hunter education resources should be expanded and made more widely available. 100% 90% Female percentage of total goat harvest 80% 70% 60% 50% 40% 30% 20% 5-year average nanny harvest 10% 0% Figure 7. Female mountain goat harvest as a proportion of total harvest, Management Units 3-43, % 90% Female percentage of total goat harvest 80% 70% 60% 50% 40% 30% 20% 10% 5-year average nanny 0% Figure 8. Female mountain goat harvest as a proportion of total harvest, Management Units 3-44,

17 RECOMMENDATIONS Conduct replicate survey in July/August 2006 Repeat surveys every 2-3 years Survey Management Units 3-35, 3-36 and 3-42, in conjunction with Kootenay Region. 12

18 REFERENCES Ayotte, J st BC Mountain Goat Workshop, March 1 & 2, 2005, Prince George: Summary of current issues, management practices and research needs. PWFWCP Report No pp. BC Ministry of Environment, Lands and Parks Wildlife Program Wildlife Harvest Strategy: Improving British Columbia s Wildlife Harvest Regulations. Victoria, BC. 78 pp. Cichowski, D. B., D. Haas and G. Schultze A method used to estimating mountain goat numbers in the Babine Mountain Recreation Area, British Columbia. Proceedings of the Biennial Symposium of the Northern Wild Sheep and Goat Council 6: Gonzalez-Voyer, A., M. Festa-Bianchet and K. G. Smith Efficiency of aerial surveys of mountain goats. Wildlife Society Bulletin 2001, 29(1):140:144. Harper, F. E A wildlife inventory strategy for ungulate game species within the southern interior region. Unpublished report submitted to Ministry of Environment, Lands and Parks, Kamloops, BC. Jury, D. N Mountain goat survey, MU 3-44, July 23, 24, Unpublished report. Ministry of Environment. 16 pp. Morgan, J A Population Assessment Strategy for Ungulates in the Thompson Region. Unpublished report. Ministry of Water, Land and Air Protection. Ritchey, R., D. Jury & K. Kier Mountain goat inventory covering MU 3-43 and part of MU 3-42 August 25, 26, 1983 (with notes on harvest management). Unpublished report. Ministry of Environment. 7 pp. Vogel, C.A.; Ables, E.D.; Scott, M.J Review and analysis of North American mountain goat (Oreamnos americanus) literature with emphasis on population dynamics. 46 pp. 13

19 APPENDIX A North Thompson mountain goat surveys, 1983, 1986 and North Thompson mountain goat survey effort, 1983, 1986 and goats/hr goats/hr goats/hour 3-43A Clemina/Dominion/Moonbeam B Pyramid/Gum/Upper Bone C Mud/Hellroar A Upper N. Thompson (North) B Upper N. Thompson (South) C Miledge D North Blue s North Thompson mountain goat population estimates, 1983, 1986 and Observed 1986 Observed 1980s Estimated (SCF=1.5) 2005 Observed 2005 Estimated (SCF=1.5) 3-43A Clemina/Dominion/Moonbeam B Pyramid/Gum/Upper Bone C Mud/Hellroar A Upper N. Thompson (North) B Upper N. Thompson (South) C Miledge D North Blue s

20 APPENDIX B Survey area and general animal sighting locations: August 2005 mountain goat population inventory, Management Units 3-43 and

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