Aerial Abundance Estimates, Seasonal Range Use, and Spatial Affiliations of the Barren-Ground Caribou (Rangifer tarandus groenlandicus) on Baffin Island – March 2014 Government of Nunavut Department of Environment Technical Report Series – No: 01-2015 Mitch Campbell Department of Environment, Nunavut Wildlife Research Division, Arviat, NU Jaylene Goorts Department of Environment, Nunavut Wildlife Research Division, Pond Inlet, NU David S. Lee Department of Wildlife and Environment, Nunavut Tunngavik Inc., Rankin Inlet, NU John Boulanger Integrated Ecological Research, Nelson, BC & Troy Pretzlaw Department of Environment, Nunavut Wildlife Research Division, Pond Inlet, NU 1st November 2015 1 Department of Environment Campbell et al., 2015 Baffin Island Caribou Distribution and Abundance Survey February/March 2014 ABSTRACT In late February and March 2014, we estimated the abundance of barren-ground caribou on Baffin Island and ancillary islands, and northern Melville Peninsula using double observer pair and distance sampling methods. The survey was enhanced through the guidance of local knowledge and inclusion of Inuit Qaujimjatuqangit (IQ) from ten Baffin Island communities. With the noted exception of areas on Baffin Island where local Inuit knowledge indicated that no caribou could be found, all of Baffin Island and the northern third of Melville Peninsula were surveyed. In addition, ground surveys were completed in areas around communities where caribou presence was largely unknown but suspected to be very low. We observed 1,130 individuals across all Baffin Island and ancillary islands and northern Melville Peninsula representing an estimated 571,369 km2. Caribou observed included 63 within the North Baffin grouping survey strata, and 824 within the South Baffin grouping survey strata, and 26 on northern Melville Peninsula. We estimated between 315 caribou (95% CI=159-622 SE=109; CV=0.35) caribou (adults, calves and yearlings) within the north Baffin survey stratum, and 4,337 caribou adults, yearlings and calves (95%CI=3,169-5,935; SE=691.05; CV=0.16) within the south Baffin survey stratum. Over all Baffin Island including the northern Melville Peninsula, we estimated 4,872 caribou (95%CI=3,462-6,484; SE=712.23; CV=0.15) adult, yearling and calf caribou. The estimate for Baffin Island and ancillary islands is 4,652 caribou (95%CI=3,462- 6,250; SE=702.79; CV=0.15) adult, yearling and calf caribou. We re-analyzed a north Baffin survey flown in April 2009 and a South Baffin survey flown in April/May 2012. Neither of these survey estimates displayed a statistically significant change in abundance from the March 2014 survey results. The abundance of caribou on Prince Charles Island displayed a significant 2 increase (P(t)=0.002) from 709 caribou (95%CI=525-956;SE=104;CV=0.15) in 2012 to 1,603 (95%CI=1158-2220;SE=25;CV=0.16) in 2014. A review of telemetry data has revealed potential subpopulation structure on Baffin Island within each of the North Baffin survey stratum, South Central Baffin survey stratum, and South East Baffin survey stratum. Daily, seasonal and annual movement rates differed between each of the potential subpopulations. Due to lack of quantitiative data and long-term spatial analysis, the subpopulation structure of caribou on Baffin Island Island remains uncertain. Instead, we use the term “grouping” to describe spatial affiliations until sufficient evidence to support population structure is available. Further studies are required to delineate subpopulation structure and seasonal range fidelity. Generally, South Central caribou displayed much higher movement rates than the South East or North Baffin groupings. North Baffin caribou were the least migratory of all identified groupings showing little differentiation between seasonal movement rates. Key words: Caribou, Barren-Ground Caribou, Baffin Island, Melville Peninsula, North Baffin Island, South Baffin Island, Aerial Survey, Ground Survey, Late Winter, Visual Survey, Baffin Region, Double Observer Pair Method, Distribution, Movements, Seasonal Range Use, Distance Sampling, Spatial Affiliations, Population Structure, Nunavut, Rangifer tarandus groenlandicus, Population Survey, Caribou Late Winter Distribution. 3 Department of Environment Campbell et al., 2015 Baffin Island Caribou Distribution and Abundance Survey February/March 2014 Table of Contents 1.0 INTRODUCTION ................................................................................... 14 2.0 STUDY AREA ....................................................................................... 18 2.1 Arctic Cordillera Ecozone ............................................................................................................. 18 2.2 Northern Arctic Ecozone ............................................................................................................... 21 3.0 METHODS ............................................................................................ 30 3.1 Survey Area and Stratification ..................................................................................................... 30 3.2 Aerial Abundance Survey ............................................................................................................. 37 3.3 Double Observer Pair Visual Method .......................................................................................... 43 3.4 2012 South Baffin Survey Re-Analysis ......................................................................................... 49 3.5 2009 North Baffin Reconnaissance Survey Analysis ................................................................... 52 3.6 Subpopulation Delineation and Distribution ............................................................................... 53 3.6.1 Utilization Distribution ........................................................................................................... 53 3.6.2 Spatial Analysis ...................................................................................................................... 54 3.6.3 Grouping Delineation ............................................................................................................. 55 4.0 RESULTS ............................................................................................. 56 4.1 2014 Abundance Estimates ........................................................................................................... 56 4.2 Mark-recapture estimation of detection ...................................................................................... 58 4.3 Distance sampling estimation of detection function .................................................................... 63 4.4 Combined Distance and Mark-Recapture Model ....................................................................... 68 4.5 Abundance Estimates from the MRDS Models ........................................................................... 73 4 4.6 March 2014 HTO Led Ground Surveys ....................................................................................... 77 4.6.1 Qikiqtarjuaq HTO Led Ground Survey............................................................................. 80 4.6.2 Clyde River HTO Led Ground Survey ............................................................................... 80 4.6.3 Arctic Bay HTO Led Ground Survey ................................................................................. 80 4.7 2012 South Baffin Survey Re-Analysis ......................................................................................... 86 4.7.1 Right Truncation of Data ........................................................................................................ 88 4.7.2 Left Truncation of Data .......................................................................................................... 88 4.7.3 Distance Analysis – Left Truncation ...................................................................................... 92 4.7.4 Differential Sightability .......................................................................................................... 92 4.7.5 Sensitivity to Left Truncation ................................................................................................. 92 4.7.6 Distance Analysis – No Left Truncation ................................................................................ 97 4.8 2009 North Baffin Survey Distance Re-Analysis ....................................................................... 101 4.8.1 Distance Analysis ................................................................................................................. 101 4.9 Spatial Affiliations .................................................................................................................. - 105 - 4.10 Seasonal Distribution .............................................................................................................. 110 5.0 DISCUSSION ...................................................................................... 120 5.1 Baffin Island Populations/Subpopulations................................................................................. 121 5.2 Subpopulation Delineation ..................................................................................................... - 126 - 5.2.1 Spatial Affiliations Summary .......................................................................................... - 128 - 5.3 Distribution and Movements 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