2008 QUESNEL HIGHLAND (MU 5-15A) WINTER MOOSE INVENTORY

Transcription

1 2008 QUESNEL HIGHLAND (MU 5-15A) WINTER MOOSE INVENTORY PREPARED FOR: MINISTRY OF ENVIRONMENT BORLAND STREET WILLIAMS LAKE, BC, V2G 4T1 PHONE: (250) FAX: (250) PREPARED BY: EDI ENVIRONMENTAL DYNAMICS INC. PO BOX 5, 2011 PG PULPMILL ROAD PRINCE GEORGE, BC V2L 4R9 CATHY MACKAY, R.P.BIO. (250) EDI PROJECT NO.: 07-BC-0156 MARCH 2008 PRINCE GEORGE, BC VANCOUVER, BC WHITEHORSE, YT GRANDE PRAIRIE, AB

2 TABLE OF CONTENTS ABSTRACT... I ACKNOWLEDGEMENTS INTRODUCTION STUDY AREA METHODS RESULTS DISCUSSION CONCLUSIONS RECOMMENDATIONS REFERENCES LIST OF TABLES Table 1. Rating system for the 3 strata system for moose population estimates in MU 5-15A Table 2. Sampling intensity, classification, and population estimates by strata for the 2008 survey area (Management Unit 5-15A)... 8 Table 3. Comparison of observed composition ratios among previous years and average for Cariboo Region Moose surveys conducted between 1994 and Moose density is compared between 2008 survey and Regional average LIST OF FIGURES Figure 1. Snow water equivalent (SWE) on February 7 at Boss Mountain on average for the 15 year record, and for each year there is a record and moose surveys were conducted in the Management Unit 5-15 (River Forecast Center 2008) LIST OF APPENDICES APPENDIX A. MU 5-15A MOOSE SURVEY MAP APPENDIX B. DAILY MOOSE OBSERVATIONS APPENDIX C. SUMMARY OF CARIBOO REGION MOOSE SURVEY RESULTS, EDI Project #: 07-BC-0156 EDI ENVIRONMENTAL DYNAMICS INC i

3 ABSTRACT A random stratified block aerial survey was conducted in the Quesnel Highland Management Unit 5-15A during February 2008 to monitor the density, sex ratio, and recruitment rate within the moose population. This survey was funded by the Ministry of Environment and conducted by Environmental Dynamics Inc. (EDI). The survey method was based on protocols of Gasaway et al. (1986). Data analysis was completed using moosepop (Reed 1989) to calculate population estimates and optimal sampling allocation in the field. Aerial Survey (Unsworth et al. 1998) was used to calculate sightability, and the results from the two programs provided a corrected population estimate. For this survey, the density was 0.29 moose per km 2, the bull/cow ratio was 36.4 bulls per 100 cows, and the calf/cow ratio was 7.7 calves per 100 cows. The moose density was below average for survey areas east of the Fraser River, which was 0.44 moose per km 2 for surveys completed between 1994 and The bull/cow and ratio was higher, and the calf/cow ratios was lower than the average for survey areas east of the Fraser River of 30.7 bulls per 100 cows and 36.8 calves per 100 cows, respectively. This is the first time a stratified random block aerial survey was conducted in this MU. Reconnaissance surveys were conducted in the past to determine composition of the moose population. The composition ratios are compared among years, but a statistical trend analysis is not possible. The technique normally used in stratified random block surveys in the Cariboo Region was adapted for this survey. ESRI s ArcMap software was used to create sample units, to complete real-time navigation and data collection in the field, and for data analysis. The technique was successful to complete stratified random block surveys and was vital to complete the survey type given the mountainous terrain of this MU. It is recommended that the technique is used in future survey and that stratified random block surveys are continued in the MU so that comparison of moose population trends among years is possible. Key words: Aerial survey, Alces alces, British Columbia, Cariboo Region, moose, and stratified random block. EDI Project #: 07-BC-0156 EDI ENVIRONMENTAL DYNAMICS INC 1

4 ACKNOWLEDGEMENTS We wish to acknowledge the contributions of Matt Swan who was observer on all of the survey flights. Melvin Paul and Chris Wycotte assisted as observers on some of the survey flights. Steve Goodliffe of Interior Helicopters was the pilot and provided excellent navigation skills. Jody Watson of EDI provided Geographic Information System (GIS) support for this project. Mike Stalberg provided advice, and developed many of the protocols and the reporting structure during past surveys in the Cariboo Region. Doug Heard and Kim Poole provided information that supported data analysis. Randy Wright and Mike Stalberg administered the project. Mike Stalberg reviewed and edited this report. EDI Project #: 07-BC-0156 EDI ENVIRONMENTAL DYNAMICS INC 2

5 1 INTRODUCTION A stratified random block aerial survey following RISC Standards (RISC 2002) was conducted within Management Unit (MU) 5-15 A of the Cariboo Region of British Columbia. A survey of this type has not been completed in this MU before. Aerial reconnaissance surveys were completed in previous years with the main objective of observing moose in each survey area to obtain composition ratios (Bowser 2007). Stratified random block surveys as completed in other MU s within the region were not seen as efficient for this MU primarily due to its topography. Given recent use of real-time navigation tools in adjacent regions (Heard et al. 2007, Serrouya and Poole 2007), it was proposed to test this method to conduct a stratified random block survey in MU MU 5-15 coincides with habitat occupied by several populations of Mountain Caribou (Rangifer tarandus caribou), a species designated by the Committee on the Status of Endangered Wildlife In Canada (COSEWIC) as threatened. Predator-prey relationships are known to be a contributing factor in the reduction of Mountain Caribou populations (MCTAC 2002). Although there is generally separation between habitat used by moose and caribou during the winter (Seip 1992, Stotyn et al. 2005), it is recognized that predators can control ungulate populations and that population size of one prey species can affect level of predation on an alternate prey species (Messier 1994, Seip 1992). Serrouya and Poole (2007) suggested that reduction in alternate prey (moose) should be accompanied by a reduction in wolves in order to mitigate predation risk to caribou. In 2001, the Ministry of Environment began a program to reduce wolf population in a project area encompassing MU 5-15 and adjacent MU Managing and monitoring the population of moose in this survey area is complementary to this program as moose population dynamics also have implications for the recovery of Mountain Cariboo through predatorprey dynamics. This is in addition to the primary purpose of this survey to manage game harvest for the management unit. The objectives of the survey are to estimate moose population size, density, sex ratio, and recruitment rate. These results are compared anecdotally with previous composition ratios. A second objective is to present a new technique to complete a stratified random block survey in this MU. Presenting the technique includes providing a critique and recommendations to its future use. EDI Project #: 07-BC-0156 EDI ENVIRONMENTAL DYNAMICS INC 3

6 2 STUDY AREA The project was located within Management Unit (MU) 5-15 A (Appendix A), contained 36 sample units (SUs) and covered 958 km 2. The MU is within the Quesnel Highland physiographic unit of the Cariboo Region and includes biogeoclimatic zones Interior Cedar-Hemlock (ICH), Engelmann Spruce-Subalpine Fir (ESSF), Interior Mountain-heather Alpine (IMA), and a small portion of Interior Douglas-fir (IDF) at the southern boundary near Canim Lake (Steen and Coupe 1997). The majority of the sample units are within ICH, which extends from valley bottom to an elevation of approximately 1250 meters where it borders the ESSF. The ICH is characterized by the highest annual precipitation in the Region of which snowfall accounts for 30-35%. Vegetation is dominated by western redcedar, western hemlock, white spruce, subalpine fir, and Douglas-fir. Common shrub species are black huckleberry, oval-leaved blueberry, devil s club, falsebox, thimbleberry, and black gooseberry. The ESSF is dominated by Engelmann spruce and subalpine fir in multi-stored, all-aged stands. Lodgepole pine is a relatively minor component, and spruce dominates the younger forest. The IMA is a small component of the MU that occurs above 2100 m. EDI Project #: 07-BC-0156 EDI ENVIRONMENTAL DYNAMICS INC 4

7 3 METHODS The survey is based on stratifying sample units within the MU based on expected moose density, and completing an aerial survey of randomly selected sample units to estimate population of moose. As the first step, all winter moose habitat within the MU was selected based on historical data of winter moose locations available from previous surveys. Surveys were conducted in three past years within MU 5-15A: 2001, 2003, and However, data from seven past years of surveys conducted in the entire MU 5-15 were used to establish an elevation criterion. The majority of moose observations in these data were located below 1300 meters. Three of 201 moose locations were above 1300 m, with the exception of the 2003 survey, where 23 of 157 observations above 1300 meters. The year 2003 coincided with the lowest snow depth on record between 1994 and 2008 (Figure 1). With a relative high snow depth in 2008, 124 % of normal on February 7, 2008 (River Forecast Center 2008), 1300 meters was considered a conservative elevation criterion expected to capture all winter moose habitat in MU SWE (mm) Figure 1. Snow water equivalent (SWE) on February 7 at Boss Mountain on average for the 15 year record, and for each year there is a record and moose surveys were conducted in the Management Unit 5-15A (River Forecast Center 2008). A series of 1:100,000 scale maps were plotted for the study area with features such as past winter moose locations, topography, cutblocks, transportation, and water. Sample units were first delineated on these maps, then digitized using ArcView. Boundaries were determined based on protocol in Gasaway et al. (1986) as follows. Target size of km 2, and absolute range of 23 km 2-39 km 2. Shapes should be conducive to aerial survey; avoid protruding narrow extensions. Avoid using high value moose habitat features as boundaries. EDI Project #: 07-BC-0156 EDI ENVIRONMENTAL DYNAMICS INC 5

8 The sample units were then stratified by conducting fixed-wing flights assisted by a real-time navigation system. Flight lines were determined prior to flight and were followed in-flight using a laptop with ArcView (ESRI ArcMap 9.2) and the DNR Garmin extension (Version , Minnesota Department of Natural Resources), paired with a Garmin 60Cx GPS. A Cessna 205 made either one or two passes per sample unit for a transect width of 1 km. One observer sat on each side in the rear of the aircraft, and the navigator sat in the front recording the habitat category determined by each observer for each SU pass. Flights were approximately m above ground, at speeds of km/hour. Sample units were stratified into low, moderate, or high based on the number of moose and moose tracks observed during flight. The 10 strata system used for other moose surveys in the Cariboo Region was modified into a three strata system (Table 1). Sample unit polygons and the associated attribute table containing strata category and area are provided with this report as a shapefile. Table 1. Stratification using the three strata system for moose population estimates in MU 5-15A. Strata Low Mod High Symbol L M H Tracks Moose Seen (-15 o C) Moose Seen (+1 o C) Average moose expected per block A rotary-wing aircraft (Bell 206 Jetranger) was used for survey flights with real-time navigation on each flight. The navigator pre-determined flight lines through each randomly selected sample unit. Transects were spaced at 500 meters, and were at times modified in-flight if case topography caused insufficient coverage by blocking the observers view. This occurred for a small number of transects, for example when the transect fell close to the crest of a ridge an additional transect was flown. Moose locations and classifications were entered by the navigator directly using ArcView on the laptop, and this file was subsequently used for data analysis. Survey flights were conducted at meters above ground, at speeds of km/hour. When moose were located, the helicopter was positioned to allow accurate classification of moose into: bull, cow, cow/calf or lone calf designations based on criteria outlined in Oswald (1982), primarily by the presence or absence of the vulva patch. The activity of the moose and the percentage and type of vegetative cover surrounding a 10 meter radius of the moose s position when it was first seen was recorded (Anderson 1994). Diagrams of vegetation cover were used as a reference (Unsworth et al. 1998). The helicopter resumed flying the transect as soon as classification was determined. Moose population estimates were calculated using the moosepop program (Reed 1998). Population estimates included: total moose, cow, bull and calf totals, as well as bull/cow and calf/cow ratios. For every estimate a 90% confidence interval (CI) was established. Quayle et al. (2001) determined through multivariate statistical analysis that the most important variable influencing sightability was vegetation cover. Given the vegetation cover for each moose group observation, a model developed for moose sightability in EDI Project #: 07-BC-0156 EDI ENVIRONMENTAL DYNAMICS INC 6

9 BC modified with data from the Prince George area (Quayle et al. 2001) was used to determine sightability correction factors within the Aerial Survey program (Unsworth et al. 1998). Aerial Survey was not used to calculate population estimates because the program assumes equally sized sample units. The spreadsheet Heardpop was used to calculate corrected moose population statistics. EDI Project #: 07-BC-0156 EDI ENVIRONMENTAL DYNAMICS INC 7

10 4 RESULTS Stratification was completed on February 2, 2008 in 4.0 hours of fixed-wing flight time. The temperature was -9 o Celsius, and snow coverage was complete. The helicopter survey was completed in 4 days between February 4 and 7, 2008 in a total of 25.5 hours flight time (Appendix B). The survey effort was approximately 1.5 minutes/km 2. Temperatures ranged from -1 to -6 o Celsius for most sample units. A total of 25 of 36 sample units were surveyed for a sampling intensity of 69% (Table 2). In total, 191 moose were observed and the corrected population estimate was to moose (90 % CI). The mean corrected density was 0.29 moose/km 2. The moosepop calculated bull/cow ratio was 36.4 bulls per 100 cows and the calf/cow ratio was 7.7 calves per 100 cows. Table 2. Sampling intensity, classification, and population estimates by strata for the 2008 survey area (Management Unit 5-15A) Year 2008 Cariboo Mountains Moose Survey (5-15A) Statistic Stratum Survey Cateogory LOW MOD HIGH Total Area (km 2 ) No. Sus (% of total) 14 (39%) 13 (36%) 9 (25%) 36 No Sus surveyed Area Surveyed (km 2 ) % of stratum surveyed Observed # Bulls Seen # Cows Seen # Calves Seen Total Moose Seen Observed Bulls / 100 Cows 34.6 Observed Calves/100 Cows 7.7 Estimated Bulls Cows Calves Population Bulls/100 Cows (90% CI) / % ( ) Calves/100 Cows (90% CI) 7.7 +/ % ( ) Corrected Sightability Correction Factor Corrected Population Estimate Pop. Size (90% CI Range) /- 8.0 % ( ) Density (moose/km 2 ) Notes. 1. Estimated bull, cow, and calf figures do not always total the estimated population figure because of unclassified moose. 2. Confidence interval for corrected population estimate is taken from moosepop. EDI Project #: 07-BC-0156 EDI ENVIRONMENTAL DYNAMICS INC 8

11 Reconnaissance surveys were completed in 2001, 2003, and 2007 in 5-15A. Although statistical analysis is not possible, a comparison of observed bull/cow and calf/cow ratios is possible among years (Table 3). Observed bull/cow ratios and calf/cow ratios are lower than ratios of all previous surveys. Compared to the regional average, the 2008 bull cow ratio is similar, and the calf/cow ratio is appreciably lower at 7.7 compared with 42.3 calves/100 cows for the region. A full summary of moose survey results in the Cariboo Region is provided in Appendix C. Table 3. Comparison of observed composition ratios among previous years and average for Cariboo Region Moose surveys conducted between 1994 and Moose density is compared between 2008 survey and Regional average. Observed Estimated Survey Year Density per/km 2 Bulls/100 Cows Calves/100 Cows Bulls/100 Cows Calves/100 Cows Quesenel Highland 5-15A MU 5-15A R 2007 n/a n/a n/a Crooked Lake R 2003 n/a n/a n/a Crooked Lake R 2001 n/a n/a n/a Cariboo Region Average R = Reconnaissance survey EDI Project #: 07-BC-0156 EDI ENVIRONMENTAL DYNAMICS INC 9

12 5 DISCUSSION This was the first stratified random block survey conducted within the Quesnel Highland (5-15A) survey area so it is not possible to compare results with previous surveys. There appears to be a very low calf/cow ratio compared to the regional average and to previous reconnaissance surveys in this management unit. This can be a sign of high predation. It appeared that moose were in healthy condition during the survey without noticeable infestation by ticks, which is another possible factor leading to a low calf/cow ratio. Category 2, or low stratum was limited in its number of moose observations. One moose was seen under 80% cover and the sightability correction factor for the low stratum is based on this one observation. Based on the fresh tracks observed it was felt by observers that moose were being missed in the high crown closure slopes that were interspersed with early seral avalanche tracks. However, the sightability correction factor of 10.6 likely overestimates the corrected population estimate for that stratum. Sampling additional sample units in the low stratum would partly minimize this source of error; however, even twice or three times the number of observations is a statistically low sample size. This is a trade-off in analyzing sightability separately for each stratum. Low number of observations in the low stratum resulted in a very large confidence interval output from Aerial Survey that seemed unrepresentative of the 191 observations in this survey. Therefore, the moosepop confidence interval was reported in the results. Between 2001 and 2004 wolf density in the larger study area of the Quesnel Highland wolf project declined (Roorda and Wright 2007). Removal, sterilization and monitoring of the wolf population continues. An additional management consideration that may help to mitigate predation on Mountain Caribou is to limit the population of moose, and thereby limit sustenance for wolves. Monitoring the population of moose in a repeatable, scientific method such as the stratified random block survey will allow comparison of population estimates among years to determine if management efforts are effective. EDI Project #: 07-BC-0156 EDI ENVIRONMENTAL DYNAMICS INC 10

13 6 CONCLUSIONS Moose density (0.29 moose/km 2 ) for the Quesnel Highland (MU 5-15A) survey area was lower than the Cariboo average (0.41) and lower than the average of all surveys conducted east of the Fraser River (0.44). The bull/cow ratio was lower than the average of all survey conducted east of the Fraser River and was greater than the regional and provincial minimum target of 30 bulls per 100 cows. The calf/cow ratio was lower than the average of all survey conducted east of the Fraser River and lower than the regional and provincial minimum target of 40 calves per 100 cows. 7 RECOMMENDATIONS The technique of using a laptop interfaced with GPS in-flight was successful and it is recommended to continue this method. Pre-determining flight lines allowed covering the irregularly shaped sample units efficiently and was an important step. Attempting to fly these sample units without a real-time navigation system that displays the sample unit boundaries would not be feasible. The tracking system was also invaluable when moose were observed on borders between sample units. Several improvements to this method are recommended: Provide a map with the flight lines and sample unit boundaries to observers during stratification. Due to irregular shape of blocks, this will assist the observers in assessing the sample units. Increase survey intensity from 1.5 min/km 2 to 2.0 min/km 2. The transect width used for the helicopter survey was 500 meters. Given the heavy canopy that can occur in this area a 300 meter transect width would be more appropriate. Determine if stratification flight is required based on snow depth. If snow depths are quite different from 2008 conditions, re-stratify the sample units and verify that the 1300 meter delineation is appropriate. There is an advantage to using the same elevation criterion in that future so that density estimates will be directly comparable. If snow depths are in a similar range, use the same stratification assignments for each sample unit. However, it is recommended to split some of the larger high category sample units. This may allow sampling less total area by sampling only a portion of sample units in the high stratum. EDI Project #: 07-BC-0156 EDI ENVIRONMENTAL DYNAMICS INC 11

14 8 REFERENCES Anderson, Charles R. Jr A Sightability Model For Moose Developed From Helicopter Surveys In Western Wyoming. M.S. Thesis. University of Wyoming. Wyoming Cooperative Fish & Wildlife Research Unit. Bowser, A Reconnaissance Moose Inventory Report Region 5 (2007). Ministry of Environment, Williams Lake, British Columbia. Gasaway, W.C., S.D. DuBois, D.J. Reed, and S.J. Harbo Estimating Moose Population Parameters from Aerial Surveys. No. 22, Biol. Pap. Univ. Alaska, Fairbanks, Alaska. 108pp. Heard, D.C., A.B.D. Walker, J.B. Ayotte, and G.S. Watts Using GIS to modify a stratified random block survey design. In Prep. Unpubl. Ministry of Environment. Prince George, BC. Heard, D.C., Watts, G.S., Smith, R Moose density and composition in the Lower McGregor River and Herrick Creek watersheds, British Columbia, January Final report for Common Land Information Base. Project No Messier, F Ungulate population models with predation: a case study with the North American Moose. Ecology 75: MCTAC (Mountain Caribou Technical Advisory Committee A strategy for the recovery of Mountain Caribou in British Columbia. Version 1.0. BC Ministry of Water Land and Air Protection, Victoria, BC. 73pp + x. Oswald, Klan A Manual For Aerial Observers of Moose. Ontario Ministry of Natural Resources. 103pp. Quayle, J.F., MacHutchon, A.G., and Jury, D.N Modeling moose sightability in south-central British Columbia. Alces 37: Reed, D.J Moosepop- program documentation and instructions. Alaska Dept. of Fish and Game, Fairbanks, Alaska. 15pp. RISC (Resources Information Standards Committee) Aerial-based inventory methods for selected ungulates: bison, mountain goat, mountain sheep, moose, elk, deer and caribou. Standards for components of British Columbia s Biodiversity No. 32. Version 2.0. BC Ministry of Sustainable Resource Management, Victoria, BC, Canada. River Forecast Center Available World Wide Web. (20 March 2008). Ministry of Environment. Roorda, Lara and Randy Wright Quesnel Highland Wolf Project Progress Report July 1, 2001 March 31, Ministry of Water, Land, and Air Protection. Williams Lake, British Columbia. Roorda, Lara and Randy Wright Quesnel Highland Wolf Project Progress Report December March 31, Ministry of Water, Land, and Air Protection. Williams Lake, British Columbia. Seip, D.R Factors limiting woodland caribou populations and their interrelationships with wolves and moose in southeastern British Columbia. Canadian Journal of Zoology 70: EDI Project #: 07-BC-0156 EDI ENVIRONMENTAL DYNAMICS INC 12

15 Serrouya, R., and Poole, K Moose population monitoring in the Lake Revelstoke (Management Units 4-38 and 4-39) and North Thompson (MUs 3-43 and 3-44) valleys, January 2006 and Unpubl. Steen, O.A. and Coupe, R.A A field guide to forest site identification and interpretation for the Cariboo Forest Region. BC Ministry of Forests Research Program, Victoria, BC, Canada. Stotyn, S., Serrouya, R. and McLellan, B The predator-prey dynamics of wolves and moose in the northern Columbia Mountains: spatial and functional patterns in relation to mountain caribou decline. Annual Progress Report. The BC Forest Science Program, Downie Street Sawmills Ltd., Parks Canada, and the Columbia Basin Fish and Wildlife Compensation Program. 22pp. Unsworth, J.W., Leboan, F.A., Garton, E.O., Leptich, D.J., and Zager, P Aerial survey: user s manual. Electronic edition. Idaho Department of Fish and Game, Boise, Idaho. EDI Project #: 07-BC-0156 EDI ENVIRONMENTAL DYNAMICS INC 13

16 Appendix A. MU 5-15A Moose Survey Map EDI Project #: 07-BC-0156 EDI ENVIRONMENTAL DYNAMICS INC

17 Appendix B. Daily Moose Observations EDI Project #: 07-BC-0156 EDI ENVIRONMENTAL DYNAMICS INC

18 Daily Moose observations from the 2008 Quesnel Highland (5-15A) moose survey. Flight Information Moose Obervations Date Blocks Area Time Total (km 2 Bulls Cows Calves Unclassified ) (hours) Moose February 4, February 5, February 6, February 7, Total EDI Project #: 07-BC-0156 EDI ENVIRONMENTAL DYNAMICS INC

19 Appendix C. Summary of Cariboo Region Moose Survey Results, EDI Project #: 07-BC-0156 EDI ENVIRONMENTAL DYNAMICS INC

20 Survey Managemnt Unit Year Area (km2) Density per/km 2 Moose Survey Results Observed Estimated Bulls/100 Cows Calves/100 Cows Bulls/100 Cows Calves/100 Cows Quesnel Highland 5-15A Cariboo Mountains 5-15B Cariboo Mountains 5-15C Horsefly River 5-02B , Big Creek , Barkerville 5-15D , Alexis Creek 5-13A , Anahim East , Alkali Lake 5-02A , Rose Lake 5-02C , Mackin Creek , Mile House , Horsefly River 5-02B , Quesnel River 5-02D , Baker Creek 5-13B , Alkali Lake 5-02A , Big Creek , Alexis Creek 5-13A , McIntosh 5-02C Gaspard , Anahim East , Dean River Kluskus 5-13C , Mile House , Alkali Lake 5-02A , Horsefly River 5-02B , Big Creek , Anahim West Tweedsmuir , Anahim East , Dean River Alexis Creek 5-13A , Horsefly River 5-02B McIntosh 5-02C Quesnel River 5-02D , Upper Big Creek Mackin Creek SCF Blocks Total Blocks Surveyed % Surveyed CI ± % Cariboo Average EDI Project #: 07-BC-0156 EDI ENVIRONMENTAL DYNAMICS INC