2009 Stone s Sheep / Caribou Inventory - MU 7-52

Transcription

1 PEACE REGION TECHNICAL REPORT 2009 Stone s Sheep / Caribou Inventory - MU 7-52 by: Conrad Thiessen Wildlife Biologist Ministry of Environment th Avenue Fort St. John BC V1J 6M7 March 2009 F I S H & W I L D L I F E S E C T I O N

2 TABLE OF CONTENTS Executive Summary... 3 List of Figures Introduction Background Objectives Methods Study Area Census methods Sightability Results Stone s Sheep Northern Mountain Caribou Incidental Species Discussion Acknowledgements References Appendices

3 Executive Summary Between February 25 and March 5, 2009 an aerial classified total count of Stone s sheep was conducted in Management Unit 7-52 of the Peace Region of British Columbia. During the survey a total of 1101 sheep were counted (627 ewe-like sheep, 135 lambs, 60 class I rams, 128 class II rams, 124 class III rams, 30 class IV rams). A sightability correction factor of 79% was applied to the observations based on research conducted in the Sulfur/8 Mile study area bringing the estimated number of Stone s sheep in the inventory area to In 1997 an inventory covering a portion of MU 7-52 was conducted during which 1528 sheep were observed (1037 of which were within the boundaries of the 2009 survey area). In 2007 a wildlife inventory was conducted by ResCan as part of an environmental assessment for mining operations in the Kutcho Lake area of MU During that survey 67 sheep were counted. By combining all the survey observations collected over the last two years in the Peace Region: 1101 sheep from the 2009 MU 7-52 survey, 3137 sheep from the 2007 MoE Stone s sheep inventory, 67 sheep from the Kutcho Creek count and 939 sheep from the Sulfur/8 Mile survey a total of 5244 sheep were observed in the Peace Region. If the 79% sightability correction factor is applied then there are an estimated 6345 Stone s sheep in the Peace Region. As these were primarily total counts it is not possible to put confidence intervals around the estimate. However, results from the Sulfur/8 Mile project showed 95% confidence intervals in the +/ % range. Caribou were the other primary species observed during this survey. We counted 721 caribou in the survey area, of which 492 were adult females, 165 adult males, and 56 calves. ResCan counted 17 caribou in MU 7-52 in the Kutcho Creek area in 2007, bringing the minimum number of caribou in 7-52 to 738 (assuming that no caribou moved from Kutcho west between 2007 and 2009). As this was a total count and not an estimate, no confidence intervals were calculated. The following incidental species were also counted and mapped in the survey area in 2009: 385 mountain goats, 3 mule deer, 94 moose, 57 elk, 6 wolves, 4 coyotes, 1 lynx, 202 ptarmigan, 4 falcons (gyrfalcon or peregrine), and 1 great gray owl. Citation: Thiessen, C Stone s sheep/caribou inventory MU BC Ministry of Environment, Fort St. John, BC. Contact: Conrad Thiessen, Wildlife Biologist Wildlife Branch, BC Ministry of Environment, # Ave. Fort St. John, BC, V1J 6M7. conrad.thiessen@gov.bc.ca 3

4 List of Tables Table 1. Classification of sheep observed in MU 7-52 during 2009 inventory. SCF is number of sheep estimated based on the total observed sheep including a sightability correction factor assuming 79% of the population was observed. Table 2. Summary of inventory results for Stone s sheep in the Peace Region from Total SCF is an estimate of the number of animals in the survey areas calculated by applying a 79% sightability correction factor to the total number of animals counted. List of Figures Figure 1. Management Unit 7-52 in relation to other MUs in the Peace Region. The red polygon is the area within MU 7-52 that was surveyed in The green area was surveyed in 2007 by the Sulfur/8 Mile Project and the yellow area was surveyed by Ministry of Environment in Figure 2. Area surveyed (dark black polygon) within MU 7-52 during the 2009 Stone s sheep inventory. Red line represents 1400 meter elevation contour. Figure 3. Biogeoclimatic zones within the survey area (outlined in black) during the 2009 Stone s sheep inventory in MU The red line represents 1400 meters in elevation which was used to approximate alpine areas to narrow the search area. Figure 4. Flight lines (blue) from survey effort during 2009 Stone s sheep/caribou inventory in MU General survey area highlighted in yellow. Figure 5. Distribution of sheep groups within the survey area during the 2009 Stone s Sheep inventory in MU Red lines are the 1400 meter elevation mark. Figure 6. General habitat types within 500 meters of sheep groups observed during 2009 Stone s sheep inventory in MU Figure 7. Distribution of Northern Mountain Caribou in 2009 survey area within MU The northern range or the Frog herd is shown as a green polygon. Figure 8. Distribution of species sighted incidentally during 2009 Stone s Sheep/Caribou survey in MU Figure 9. Map of MU 7-52 Stone s sheep survey areas in 1997 (blue shaded area) and 2009 (cross hatched area). Figure 10. Comparison of lamb:ewe and ram:ewe ratios between 1997 and 2009 surveys for Stone s sheep in MU

5 1.0 Introduction 1.1 Background Stone s sheep (Ovis dalli stonei Allen, 1897) are the most abundant mountain sheep in the Peace Region of British Columbia, and the region contains a large proportion of the global population. The First Nations people of BC highly value mountain sheep, including Stone s sheep (Demarchi and Hartwig 2004). Stone s sheep are highly sought by hunters. Over the last decade an average of 599 residents of BC per year have hunted Stone s sheep. Guided non-resident hunters pay up to USD$35,000 for the opportunity to hunt a male Stone s sheep, and an average of 172 non-residents per year have hunted sheep in the Peace Region over the last 10 years. Two caribou herds are known to inhabit MU 7-52, the Horseranch and the Frog herds. Inventory of these herds has been sporadic, and more up to date information would be beneficial for the management of these herds. The need for the survey arose from conservation concerns for Stone s sheep expressed by resident hunters and guide/outfitters as well as to inform harvest allocation decisions. Additionally, Ungulate Winter Ranges and Wildlife Habitat Areas are being created for Stone s sheep, mountain goats and caribou in the Peace Region and the data from this survey will be used to inform those decisions. 1.2 Objectives The main objective of the inventory was to obtain a total classified count of Stone s sheep within MU The count was designed to allow calculation of lamb : ewe ratios and male : female ratios. The second objective was to gather similar information for caribou in the alpine, with the understanding that caribou also inhabit lower elevation forested areas that would not be covered by this survey. The third goal was to record incidental species observed during the inventory to inform habitat protection measures. 2.0 Methods 2.1 Study Area The area surveyed was encompassed by wildlife Management Unit The eastern boundary is the Kechika River and the western boundary is the height of land along the continental divide (Figure 1). Focus was placed on replicating the search area from 1997, however funding did not allow for the entire area to be resampled, so a portion of the area was sampled from MU 7-52 (Figure 2). 5

6 Figure 1. Management Unit 7-52 in relation to other MUs in the Peace Region. The red polygon is the area within MU 7-52 that was surveyed in The green area was surveyed in 2007 by the Sulfur/8 Mile Project and the yellow area was surveyed by Ministry of Environment in

7 Figure 2. Area surveyed (dark black polygon) within MU 7-52 during the 2009 Stone s sheep inventory. Red line represents 1400 meter elevation contour. 7

8 Three biogeoclimatic zones are represented within MU 7-52, the Boreal White and Black Spruce (BWBS), the Spruce Willow Birch (SWB), and the Boreal Altai Fescue Alpine Zone (BAFA) (Figure 3). Treeline is within the SWB at approximately 1400 meters elevation. Figure 3. Biogeoclimatic zones within the survey area (outlined in black) during the 2009 Stone s sheep inventory in MU The red line represents 1400 meters in elevation which was used to approximate alpine areas to narrow the search area. 8

9 2.2 Census methods The inventory generally followed the guidelines for a total count as described by the BC Resource Inventory Committee (Resources Inventory Committee 2002). Counts were conducted with three observers and one pilot in a Bell 206B Jet Ranger helicopter. The forward observer also acted as navigator and recorded flight lines on a Garmin GPSmap 60Cx hand held GPS unit. Topographic maps were viewed digitally on a laptop computer during the flights with the tracks plotted in OziExplorer in real time. One observer in the rear acted as data recorder (example of data sheets included in Appendix A). All observers including the pilot scanned for sheep, however the classifications were done by the more experienced observers. When a group was being classified one observer was responsible for counting ewes and yearlings, another observer counted and classified rams, and the third observer counted the total group size. Primary observers were Alicia Goddard, Mike Koloff (pilot), Rob Woods and Conrad Thiessen. A UTM coordinate was recorded for each group and behavioural and habitat data collected (see Appendix 2). Habitat data consisted of snow cover and snow depth, slope, and habitat type within 50 meters of the group and within 500 meters of the group when they were first sighted. Activity when first sighted was also recorded. Classification of sheep followed Geist (1971; Appendix 1). We were unable to differentiate between male yearlings and ewes in the field, so combined the two classes while counting into ewe-like sheep. The current definition of a legal thinhorn ram for harvest is any male thinhorn mountain sheep whose horn tip extends upwards beyond the forehead-nose bridge when viewed squarely from the side or which has attained the age of 8 years as evidenced by yearly horn growth annuli ( Hunting and Trapping Regulations, BC Ministry of Environment). During the survey we were not able to classify rams based on horn annuli, therefore only rams with horns extending beyond the bridge of the nose were classified as Class IV. We classified caribou as adult male, adult female, or calf. Males and females were distinguished by black vulval patch in females. Males were not classified by antler architecture, as many had already lost their antlers. Incidental species were recorded while searching for sheep, however the helicopter did not vary from the search path to allow for classification of incidentals due to time and money restrictions. The point locations recorded for incidentals did not necessarily fall above the actual location of the group, rather points were recorded from the helicopters location when animals were spotted. 2.3 Sightability A total count following similar methods as those used for this inventory was conducted on the Stone s sheep in Management Unit 7-54 in 2007 as part of the Sulfur/8 Mile (S8M) Stone s sheep project. The project maintained approximately 100 VHF and/or GPS collars on ewes throughout the period of the count, and a sightability correction 9

10 factor (SCF) was calculated based on the number of collared animals sighted. During the December S8M survey, 83% of the collared ewes were sighted and in the March survey in the same area 75% of collared ewes were sighted (Cubberley 2008). Snow conditions during the majority of our survey were more similar to the December S8M survey, however behavioural changes between surveys may have influenced sightability, hence the two sightability figures were averaged to arrive at a SCF of 79% for the purposes of the MU 7-52 survey. 3.0 Results The survey was flown between February 25 to March 5, 2009 for a total cost of $44,282 including helicopter charter, accommodations while in the field, and miscellaneous equipment. Weather conditions were favourable throughout the majority of the survey period, with only 2 survey days cancelled due to inclement weather (wind and snow). Fresh snow covered 50-75% of alpine areas surveyed. Temperatures ranged from -6 to - 15 C during the survey. The majority of area above 1400 meters elevation was flown during the survey (Figure 4). The length of the flight path while searching was 2947 km and time spent searching was hours during the survey. The average search rate was 107 km/h. Total flight time including ferry trips to and from Fort St. John was 38.6 hours. 10

11 Figure 4. Flight lines (blue) from survey effort during 2009 Stone s sheep/caribou inventory in MU General survey area highlighted in yellow. 11

12 3.1 Stone s Sheep Due to funding restrictions not all of the sheep range within MU 7-52 was surveyed. During the survey a total of 1101 sheep were sighted (Table 1). The total population in the surveyed area was estimated to be 1332 after applying the sightability correction factor. The majority of sheep were observed above 1400 meters elevation (Figure 5). Table 1. Classification of sheep observed in MU 7-52 during 2009 inventory. SCF is number of sheep estimated based on the total observed sheep including a sightability correction factor assuming 79% of the population was observed. Rams Class I Class II Class III Class IV Ewe-like sheep Lambs Total Total SCF From the survey sample we calculated 21.5 lambs : 100 ewe-like sheep, 54.5 rams : 100 ewe-like sheep, and 4.8 Class IV rams : ewe-like sheep. Figure 5. Distribution of sheep groups within the survey area during the 2009 Stone s Sheep inventory in MU Red lines are the 1400 meter elevation mark. 12

13 The majority of sheep observed were in alpine habitats (83%), with other habitat types accounting for less than 17% of observations (Figure 6). 250 Sheep Groups Observed Alpine Burn Coniferous Deciduous Mixed wood Rock/Cliff Sub Alpine Habitat Type Figure 6. General habitat types within 500 meters of sheep groups observed during 2009 Stone s sheep inventory in MU

14 3.2 Northern Mountain Caribou A total of 721 caribou were observed (Figure 7). Of those 547 were adult female, 56 calves, and 165 adult males. From the total sample we observed 11.4 calves : 100 adult females and 33.5 adult males : 100 adult females. Within the boundaries of the Frog herd 82 caribou were sighted. From the Frog sample we observed 10.2 calves : 100 cows and 28.8 bulls : 100 cows. Only the far north portion of the Frog herd range was flown, so this does not represent a complete survey of the herd. Figure 7. Distribution of Northern Mountain Caribou in 2009 survey area within MU The northern range or the Frog herd is shown as a green polygon. 14

15 3.3 Incidental Species Incidental species observed (Figure 8) included 57 elk (Cervaus elaphus), 94 moose (Alces alces), 385 mountain goat (Oreamnos americanus), 3 mule deer (Odocoileus hemionus), 6 wolf (Canis lupus), 4 coyote (Canis latrans), 4 falcons (likely gyrfalcons or peregrine), 202 ptarmigan, and 1 great gray owl. Figure 8. Distribution of species sighted incidentally during 2009 Stone s Sheep/Caribou survey in MU

16 4.0 Discussion Results of the 2009 survey were compared to a survey done with similar methodology in MU 7-52 in The area surveyed in 1997 was larger than 2009 due to additional funding. The total count from the 1997 survey was 1528 sheep, however within the boundaries of the area surveyed in 2009 (cross hatched area in Figure 9) 1037 sheep were counted. For the 2009 survey area, both the ratio of lambs and rams per 100 ewes were higher in 2009 than 1997 (Figure 10), while the total number of sheep observed did not differ much between years. Figure 9. Map of MU 7-52 Stone s sheep survey areas in 1997 (blue shaded area) and 2009 (cross hatched area). During the 1997 survey three observers were in the helicopter compared to four observers during the 2009 survey. It s possible that more sheep were missed in 1997 due to fewer 16

17 observers, but the difference cannot be quantified. As well, there is no record of effort spent searching from the 1997 survey, so it is not possible to compare effort between years lambs:100 ewe-like sheep rams:100 ewe-like sheep Figure 10. Comparison of lamb:ewe-like sheep and ram:ewe-like sheep ratios between 1997 and 2009 surveys for Stone s sheep in MU In addition to the 1997 count, a wildlife survey was conducted in 2007 by the consulting company Rescan in the area of Kutcho Creek as part of an impact assessment (Rescan 2007). Observations from within MU 7-52 were extracted from their overall survey. They observed 67 Stone s sheep and 17 caribou in MU The sightability correction factor from the Sulfur/8 Mile study was based on collared ewes, however we made the assumption for the purposes of the population estimate that the entire population, including rams, were equally observable. Over the past two years almost the entire Peace Region has been surveyed for Stone s sheep. The following is a summary of those surveys, including the minimum number of sheep observed in each survey and an estimate based on a sightability correction factor (Table 2). In 2007 Ministry of Environment conducted a Stone s sheep inventory in MUs 7-35, 7-36, 7-42, 7-43, 7-50, 7-51, and 7-57 and observed 3137 sheep (Thiessen 2009). Also in 2007 MU 7-54 was surveyed by the Sulfur/8 Mile project during which they observed 939 sheep in their December survey (Cubberley 2008). Rescan surveyed wildlife in the upper Turnagain/Kutcho Creek area of MU 7-52 in 2007 and counted 67 sheep (Rescan 2007). During the survey conducted by Ministry of Environment in 2009, and reported here, 1101 sheep were observed. With all of these observations combined a minimum of 5244 Stone s sheep were observed in the Peace Region between 2007 and 17

18 2009. With a 79% sightability correction factor applied to the number of sheep observed, we estimate there to be 6345 Stone s sheep in the Peace Region. No confidence intervals can be applied to this estimate as the counts were primarily total counts. However, results from the Sulfur/8 Mile project showed 95% confidence intervals in the +/- 13 to 25% range (Cubberley 2008). Table 2. Summary of inventory results for Stone s sheep in the Peace Region from Total SCF is an estimate of the number of animals in the survey areas calculated by applying a 79% sightability correction factor to the total number of animals counted. Year Total Count Area Reference MU 7-35, 7-36, 7-42, 7-43, 7-50, 7-51, 7-57 Thiessen MU 7-54 Clubberley western part of MU 7-52 Rescan eastern part of MU 7-52 reported here Total 5244 Peace Region Total SCF 6345 Peace Region A large portion of MU 7-52 between the Horseranch herd and the Frog herd is shown as having low caribou densities on provincial maps. Within this low density area we counted 629 caribou. The majority of these caribou were in the northern part of the survey area adjacent to the Horseranch herd boundary suggesting that the boundary of the Horseranch herd should potentially be expanded south to encompass these caribou. 5.0 Acknowledgements Funding for this inventory was provided by the BC Ministry of Environment and the Wild Sheep Society of BC. Mike Koloff from Qwest helicopters provided safe and skilled flying for the duration of the survey. Andy Knox filled in as an observer for one afternoon and provided logistical support. Joann Knox kept us fed and watered with hearty meals. Lodging was provided by Folding Mountain Outfitters. 18

19 6.0 References Cubberley, J.C Stone s sheep demographics and distribution in the Sulphur / 8 Mile Project area, northern British Columbia, winter Synergy Applied Ecology, Mackenzie, BC. 20 pp plus appendices. Demarchi, R. A. and Hartwig, C. L. Status of Thinhorn Sheep in British Columbia. December Victoria, B.C., B.C. Ministry of Water, Land and Air Protection, Biodiversity Branch. Rescan Kutcho Project Mounain Ungulate Studies Baseline Report. Prepared for Western Keltic Mines Inc. by Rescan Environmental Services Ltd. August Resources Inventory Committee. Aerial-based Inventory Methods for Selected Ungulates: Bison, Mountain Goat, Mountain Sheep, Moose, Elk, Deer, and Caribou. Version Victoria, BC, British Columbia Ministry of Sustainable Resource Management: Terrestrial Information Branch. Thiessen, C March 2007 Stone s sheep inventory - Peace Region. BC Ministry of Environment. Fort St. John, BC. 19

20 7.0 Appendices Appendix 1. Data protocols and codes for 2009 Stone s sheep inventory. 20

21 Appendix 2. Data sheet used during 2009 Stone s sheep inventory in MU Appendix 3. Photos showing typical snow conditions and terrain. 21

22 Stone s sheep herd in alpine habitat. Eskona Mountain from the south. 22