Moose Stratified Block Census, Management Unit 8-5, Okanagan Region, February 2005

Transcription

1 Moose Stratified Block Census, Management Unit 8-5, Okanagan Region, February 2005 by Les W. Gyug, R.P.Bio. Okanagan Wildlife Consulting 3130 Ensign Way Westbank, B.C. V4T 1T9 Prepared for B.C. Ministry of Water, Land and Air Protection, Okanagan Region Penticton, B.C. February 13, 2005

2 TABLE OF CONTENTS INTRODUCTION...3 METHODS...3 RESULTS...4 DISCUSSION...5 LITERATURE CITED...6 APPENDIX 1. Raw Data for IDFG Moose Sightability Program...7 APPENDIX 2. Maps...8 Map 1. Management Unit 8-5. Final winter moose range stratification. Map 2. Management Unit 8-5. Helicopter survey routes, February 8-9, Map 3. Management Unit 8-5. Ungulates seen on helicopter surveys, February 8-9, List of Tables Table 1. Moose-density strata, blocks, areas, population estimates, density estimates and confidence intervals for Management Unit 8-5, February Table 2. Cow, calf and bull numbers counted and estimated, population proportion estimates and ratios in Management Unit 8-5, February 2005, using simple unstratified block model. 5 Acknowledgements This project and report was completed under contract to the British Columbia Ministry of Water, Land and Air Protection (WLAP), Okanagan Region. Brian Harris, WLAP, served as contract monitor. I would like to thank Conservation Officers Alan Lay and Chris Walder who participated in the aerial counts. Additional assistance as observers was provided by Bruce Ryder. Helicopter services were provided Kokanee Helicopters, Kelowna, and pilot, Wayne Finn. MOOSE CENSUS 8-5, FEB

3 INTRODUCTION A previous moose stratified block census had been undertaken in MU 8-5 in 2001 (Gyug 2001). The objectives of this project were to provide a population estimate of moose through a stratified block census of Management Unit (MU) 8-5 of the Okanagan Region of the Ministry of Water, Land and Air Protection (WLAP) provide classified counts of cows, calves and bulls for the same areas note any other ungulates observed during the moose surveys. MU 8-5 is to the west of Highway 5A from Manning Park north to the Voght valley near Aspen Grove. Total area of MU 8-5 is 2345 km 2. METHODS A stratified block census method was used to estimate the moose population of each MU within the total overall flight cost budget of 12 hours helicopter time. MU 8-5 was stratified into blocks of relatively homogeneous moose winter densities with the target block size of approximately km 2. A pre-survey stratification was undertaken based on the census results and stratification of Changes were made to the block boundaries based on dispersion and areas occupied by moose in February A pre-census fixed-wing stratification flight was attempted on February 6, 2005, but cancelled after 1 hour due to deteriorating weather conditions. All stratified block censuses were done with a Bell Jet Ranger helicopter on February 8 and 9, 2005, using a total of 12.1 hours flight time, including daily ferry time to and from Kelowna (about ½ hour each way). Blocks chosen for survey were selected randomly from within each stratum. I acted as navigator and recorder in the left front helicopter seat. Block census boundaries had been entered into a mapping GPS unit that also recorded the track of the helicopter every 5 seconds, and into which all observations of moose or other ungulates were marked. The locations as marked in the data and GIS files reflect the position of the helicopter when the point was marked on the GPS unit, and not the exact position of the animal. Many times the position as marked could be up to 100 m from the actual position depending on whether I marked the position when the animal was first seen, or marked when circling over the exact spot. Therefore general precision of the data points should not be considered more accurate than 100 m. Searches were made along straight lines m apart flown at km/h at a height of m. I sat in the front seat beside the pilot and acted as navigator and recorder of all data. Two people in the back seats acted as observers viewing through bubble windows. When the pilot or any passenger observed moose, the helicopter was turned to circle the location to provide a more accurate count and to classify the moose as cow, calf or bull. Data were recorded on modified Resources Inventory Committee (1997) data forms. Where possible the age of the bull was noted based on relative size, shape of bell or size of antlers for any bulls that still had antlers. Also recorded for each moose observation was the percentage of canopy cover where the location was made, the number of animals in the group, the general habitat type and the activity of the animals (bedded, standing, walking, running). All other ungulate observations were also recorded but MOOSE CENSUS 8-5, FEB

4 no time was spent circling them to confirm sex and age. In areas where very few moose were seen, the locations of fresh moose tracks were noted. A major snowfall (5-15 cm) occurred on the evening of February 6 th so that fresh tracks of moose could be discerned. In areas where no fresh moose tracks were seen, surveys were done with more widely spaced transect lines, and at faster rates of speed to avoid coverage of large areas at high survey intensity when, in fact, no moose were currently present. Also recorded was the beginning and ending time for each survey block, along with weather data for each flight including percent cloud cover, precipitation, wind, temperature, and percent snow cover for the area. The Idaho Department of Fish and Game moose population estimation software (Leban and Garton 2000) based on the Wyoming moose sightability model of Anderson and Lindzey (1996) was applied to the data to provide population estimates and classified count ratios for the areas. RESULTS Based on the 2001 census, only Low and Very Low density units (based on provincial benchmarks) were used in the study area. Because there was very little density difference between Low (2-5 moose seen per block) and Very Low units (<2 moose seen per block), I defaulted to a simple block census. Even if they area had been pre-stratified with a fixed-wing survey, it is generally not possible to distinguish between such low densities of moose based on track counts alone. Before the survey, it was not always predictable which stratum a survey block would be in so the simple block census was deemed to be more valid. Maps showing the blocks, the survey routes and ungulates seen are contained at the end of the report. In MU 8-5, 24 blocks (nominally 7 Low and 14 Very Low) were designated. Six of the Low and 4 of the Very Low blocks were censused. The total number of moose counted in the census blocks was 28, with one additional cow moose counted in an unsurveyed block while in transit between survey blocks. Two of the moose were unclassified adults (Table 1). The estimated number of moose in MU 8-5 is 75 with a 90 Confidence Interval (C.I.) of 26 (Table 1). The cow-calf ratio was 52 calves per 100 cows (Table 2). The bull-cow ratio was 92 bulls per 100 cows. Confidence intervals on ratios were very large generally because of the low numbers of moose counted. Running the analysis using the nominally designated blocks in the Low and Very Low strata did not improve the confidence intervals. Of the total observations of 23 groups of moose, 14 were in the IDFdk2 BEC variant, 4 in the IDFdk1, 4 in the MSdm2 and 1 in the MSxk, using the updated (2004) BEC coverage for the Kamloops Forest Region. This BEC coverage has only minor adjustments from the the previous BEC boundaries in the MU 8-5 area. Moose were seen between at all elevations, and relatively evenly dispersed between 1060 and 1380 m, with one observation at 1570 m elevation. Elevations were derived from a 10-m contour interval coverage of the area derived from TRIM mapping of the GPS d locations. They were not derived from the GPS elevations directly, which were frequently up to 100-m above the animal s location. MOOSE CENSUS 8-5, FEB

5 Table 1. Moose-density strata, blocks, areas, population estimates, density estimates and confidence intervals for Management Unit 8-5, February Moose Strata No. Blocks Total Stratum Area (km 2 ) Mean Block Area (km 2 ) No. Blocks Sampled Search Intensity (min/km 2 ) Moose Counted Est. No. Moose 90 C. I. Estimated Moose Density (/km 2 ) 90 C. I. Simple Model Table 2. Cow, calf and bull numbers counted and estimated, population proportion estimates and ratios in Management Unit 8-5, February 2005, using simple unstratified block model. Cows Bulls Calves Unclassified Ratios (±90 C.I.) Total Counted Total Estimated Calves (±29) per 100 Cows 90 C.I Bulls (±64) per 100 Cows of Population C.I DISCUSSION The moose densities in MU 8-5 are generally low. In addition, the winter of was a low snow year, and moose appeared to be very dispersed, with some moose being found as high as 1570 m on Shovelnose Mountain and other tracks seen as high as 1450 m on Pike Mountain, where no sign had been seen during the surveys in Given the overall low densities, and difficulty in predicting which blocks were actually low or very low in density, higher precision than the approximately 33 range in the population estimate (75±26) would be difficult to achieve without censusing almost all blocks. Estimated calf (52±29)and bull (92±64) ratios were even less precise with 90 confidence intervals of of the estimated ratios. The previous estimate of moose numbers in 2001 in MU 8-5 was 128±65 (Gyug 2001) with a calf ratio of 75±67 and bull ratio of 50±32 per 100 cows. The population estimate from 2005 I believe to be considerably more accurate, and based on increased coverage of the MU. The principal reason for the decrease in the estimate from 2001 to 2005 is that fewer census blocks were delineated in 2005, but I believe the 2005 census more accurately reflected the actual distribution of moose in MU 8-5 at the survey time, and the 2001 census probably delineated many areas where there were virtually no moose at the time, but which could not be accurately determined because of a lack of fresh snow in MOOSE CENSUS 8-5, FEB

6 During the Okanagan Connector Freeway moose telemetry studies (Simpson et al. 1995), seven of the eleven cow moose that were radio-collared in MU 3-12 from Aspen Grove to Paradise Lake spent the summers and/or fall in MU 8-6, migrating up to 50 km from winter to summer ranges. Consequently, overall management of the moose population in this area must consider this seasonal migration across MU boundaries. The moose population present in the hunting season is most likely not entirely the same moose population present in 8-5 in the winter. Given that hunting success for moose in MU 8-5 is generally fairly good (Al Lay, Conservation Officer, WLAP), then some of the moose present in MU 8-5 in the hunting season may migrate northwards into MU 3-12 in the Aspen Grove area (where moose densities are higher than in 8-5, Jury 1985, Simpson et al. 1995) and not be present in MU 8-5 in the winter. The search intensity used in this study was lower than in similar studies. I allowed search intensity to drop particularly in the Low and Very Low strata (meaning every block in this census) where no fresh moose tracks were being seen by increasing the distance between flight lines, and/or the speed traveled. Given the 1-2 days since a fresh snowfall, and that moose were only seen in areas where tracks were also seen, this appeared to be a reasonable way to increase the numbers of blocks searched without compromising the validity of the model used for population estimation. The search intensity was 1.8 min/km 2 in the nominally Low blocks and 1.4 min/km 2 in the nominally Very Low blocks. This was lower than the search intensity for helicopter counts of 3.7 min/km 2 (Jury 1986), 4.6 min/km 2 (Jury 1985) and min/km 2 (Poole et al. 1999) and the rate used to develop the population estimation model of 4.7 min/km 2 (Anderson and Lindzey 1996). The high intensity search rate used by Anderson and Lindzey (1996) was primarily because they flew at slower speeds of km/h rather than the km/h used in this project, but also because search lines were spaced m apart rather than m apart. LITERATURE CITED Anderson, C.R. Jr., and F.G. Lindzey Moose sightability model developed from helicopter surveys. Wildlife Society Bulletin 24(2): Gyug, L.W Moose Stratified Block Census, Management Units 8-5, 8-6 and 8-14, Okanagan Sub-region, February B.C. Ministry of Environment, Lands and Parks, Penticton, B.C. Jury, D.N A random stratified block moose survey of Management Unit 3-12, January Unpublished report, Wildlife Branch, Ministry of Environment, Kamloops, B.C. Leban, F., and O. Garton Aerial Survey for Windows, Verson 1.00 Beta (12 Feb 2000). Available as freeware from Poole, K.G., D.A. Fear, G. Mowat and C.D. Shurgot Moose inventory in the Central Okanagan, January-February Report prepared for Ministry of Environment, Lands and Parks, Penticton, B.C. Resources Inventory Committee Standardized inventory methodologies for components of British Columbia's biodiversity: aerial based inventory techniques for selected ungulates bison, mountain goat, mountain sheep, moose, elk, deer and caribou. Version 1.1. Ministry of Environment, Lands and Parks, Wildlife Branch, Victoria, British Columbia. Simpson, K., Les W. Gyug, and J. Kelsall. Revised The effect of a new freeway on mule deer and moose. IN A Compendium of Wildlife Studies: Okanagan Connector Freeway 1987 to Highway Environment Branch, Min, of Transportation and Highways, Victoria, B.C. MOOSE CENSUS 8-5, FEB

7 APPENDIX 1. Raw Data for IDFG Moose Sightability Program SUBUNIT STRATUM TOTAL COWS CALVES YRLNGBUL ADBULLS UNCLASS ACT SNOW VEG TERRAIN 8_05_ _05_ _05_ _05_ _05_ _05_ _05_ _05_ _05_ _05_ _05_ _05_ _05_ _05_ _05_ _05_ _05_ _05_ _05_ _05_ _05_ _05_ _05_ Note: When actually running the IDFG Aerial Survey program, the Strata were converted all to 1 to make the program only count blocks as all being in one stratum, and the single yearling bull seen was added to the adult bull class so that adult bulls would really be counting all bulls. Activity, snow cover and terrain are not included in the IDFG model, although the model does account for differing sightability by canopy closure ( vegetation). MOOSE CENSUS 8-5, FEB

8 APPENDIX 2. Maps. Map 1. Management Unit 8-5. Final winter moose range stratification, MU8-5, February Aspen Grove Brookmere Tulameen MU 8-5 Boundaries MU 8-5 Blocks 2005 L VL Princeton Kilometers N 21 MOOSE CENSUS 8-5, FEB

9 Map 2. Management Unit 8-5. Helicopter survey routes, February 8-9, Aspen Grove Brookmere Tulameen Aerial Survey Route February 8, Morning February 8, Afternoon February 9, Morning February 9, Afternoon Princeton Kilometers N 21 MOOSE CENSUS 8-5, FEB

10 Map 3. Management Unit 8-5. Ungulates seen on helicopter surveys, February 8-9, Aspen Grove Brookmere Tulameen Ungulates Observed on Aerial Surveys Moose # Elk Mule Deer Princeton Kilometers N 21 # # # MOOSE CENSUS 8-5, FEB