Nevada Mule Deer Research Update to the Wildlife Commission

Transcription

1 Nevada Mule Deer Research Update to the Wildlife Commission Cody Schroeder In Collaboration with: Tony Wasley NDOW Caleb McAdoo NDOW Jeremy Lutz NDOW Carl Lackey NDOW Kari Huebner - NDOW Dr. Kelley Stewart UNR Marcus Blum - UNR

2 Brief Overview Introduce topics of mule deer research Migration study Reason for study Research Questions Collaring efforts and status Preliminary findings Fawn survival analysis Mining Related Projects Pequops Bald Mountain Mine Carlin Trend

3 All organisms are constrained by life history traits that limit the allocation of energy to meet three primary goals: Growing Surviving Reproducing Individual Fitness

4 Individual Fitness Demographic Rates Migration Behavior Energy Body Condition Balance Forage Climate Effects

5 Cause for Study

6 Hypothesized reasons for mule deer declines: Habitat quality Land Use Climate Change Effects on Migration??

7 Objectives of Research 1) Provide a quantitative analysis of physiological and fitness related costs of mule deer migrations 2) Determine specific fitness related costs for different sex and age classes -Males vs. Females -Juveniles vs. Adults

8 Research Questions Does migration strategy affect fitness in mule deer? Predict: Resident = Poor strategy in severe winters Migrators = Better strategy Does sex and body condition influence survival in mule deer? Predict: Male survival Female survival Better condition individuals

9 Migration Study Areas A) Carson-Tahoe Basin B) Simpson Park Range C) Ruby Mountains Mining Study Areas D) Carlin Trend E) Pequop Mtns A B D C E

10 Number of Deer Captured since 2011 Capture Year Study Area Age Ruby Mtns Adult Fawn Simpson Parks Adult Fawn Carson Range Adult Fawn Pequop Mtns Adult Carlin Trend Adult Total Captured Grand Total 780 VHF Collars: 465 GPS Collars: 315

11 Collar Design 4 different designs for each age sex class Adult Buck GPS Collar Expandable Buck Fawn Collar

12 Carson Range Summer Ranges Simpson Park Ruby Mtns 10,000 ft. 8,000 ft. Winter Ranges

13 Ruby Mountain Study Area Distinct winter ranges separated by long distances

14 Data Collection Captured 780 mule deer using helicopter and net-gun Weight, body condition, body size metrics, blood Attached either VHF or GPS radio-collars

15 Capture crew catches deer using helicopter and net-gun

16

17 Ben Regan Radio Telemetry Marlette Lake Backcountry

18 Variation in Migration Strategy Resident Strategy Net Displacement = 8 km Long Distance Migration Net Displacement = 120 km 8 km 120 km (75 miles)

19 Preliminary Data Migration Distance A) Ruby Mtns Less Synchronous B) Carson-Tahoe More Synchronous Greater Migration Distance Less Migration Distance

20 Dispersal 4% Ruby Mtn Deer Dispersal 9% Simpson Park Deer Migrants 13% Resident 20% Partial 11% Migrants 65% Resident 58% Partial 20% Sample Size = 284 Sample Size = 152 Dispersal 2% Carson Range Deer Resident 39% Migrants 53% Partial 6% Sample Size = 118

21 Survival Data Analysis Modeling Survival Using Known-Fate Program Mark Individual Covariates Sex Age (Adult, Juveniles) Migration distance (Net Displacement) Body Condition Index (BCI) PCA with 3 size variables (Jaw length, Metatarsus, Chest girth) Winter Severity Index (WSI) WSI = (SSI TSI)/2 Hurley et al. (2011) Wildlife Monograph Previous Summer Precipitation (June-Aug) Standardized across Study Areas

22 PC 1 explained 93.3% variation in body size (Jaw, Leg, Chest) Residuals from linear regression (Weight ~ PC1) = BCI

23 Results Top Model AICc Weight Param. Sex + Age + Sex*Season + Winter Severity juv + Body Cond Index + Migration Distance + Migration Distance Male Male Male Winter Summer Autumn Winter Body Mig Mig Severity Mass Dist Dist 2

24 Covariate Effects Net Displacement (Proxy for Migration Distance) Survival N = 438 Annual Survival % C.I Net Displacment (km)

25 Fawn Survival Estimates Jan 2011 to June 2013 SURVIVAL A) Ruby Mtn Fawns % 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Survey Period Jan Feb Mar Apr May Jun MONTH

26

27 Survival Winter Survival of Juveniles n = 220 *Error Bars are 95% C.I. Female Male Ruby Mtns Simpson Parks Carson Range High Population Density Low

28 Covariate Effects Body Mass Index 1.10 A) Adult Survival 1.10 B) Juvenile Survival Survival n = Body Mass Index Male Female n = 220 Male Female Body Mass Index Poor Condition Good Condition Poor Condition Good Condition Body Mass Index = Body Mass corrected for body size

29 Cause specific mortality sources All Study Areas Combined Unknown 48% Predation 30% Source Capture 3% Misc Injury Malnourish 2% 2% Legal Harvest # Morts Predation 100 Capture 6 Misc Injury 5 Malnourish 8 Legal Harvest 36 Illegal Harvest 4 Roadkill 12 Unknown 161 Total 332 Roadkill 4% Illegal Harvest 1% 11%

30

31 Mining Related Projects Bald Mountain Mine Pequop Mtns Long Canyon Mine Carlin Trend

32 Bald Mtn Mine Deer Research Mule deer use of migration corridor impeded by large-scale gold mine Barrick Gold Inc. has proposal to expand production areas by 30% Barrick, NDOW, and UNR teamed up to study effects of mining on migration behavior of mule deer Collared 42 deer between Collars obtaining high frequency GPS fixes (once every hour) during migratory periods

33 Daily Activity of Mule Deer within Bald Mtn Mine Complex (Movements > 100 meters) 24 hr Diurnal Activity of 36 GPS radio-collared Mule Deer within a 10-km buffer of Bald Mtn Mine LOM boundary :00 AM to 8:00 AM 3:00 PM to 6:00 PM Frequency Time of Day (24hr)

34 Marcus Blum s M.S. Thesis Results from Resource Selection Function (RSF) High Disturbance Medium Disturbance Low Disturbance

35 Bald Mtn Mine Research Contract work WEST Inc. Hall Sawyer Provided analysis of migration corridors Calculated Brownian Bridge Movement Model for each radio-collared deer Produced a populationlevel corridor map by averaging all individuals to one final model *Data from 31 GPS collared deer used for analysis

36 Data from ~40 Collared individuals over 4 migration periods Long Cn. Mine Model and analysis provided by Marcus Blum UNR Thesis work

37 Pequop Summit Overpass Silverzone Overpass Completed 2014

38 Pequop Summit Wildlife Safety Crossings Proposed Locations

39 Carlin Trend Deer Collaring Project

40 Conclusions Highly variable migration strategies across Nevada Dependent on weather and climate variables Dependent on study area Survival highly variable for fawns Influenced by winter severity Body Condition Migratory strategy Sex differences in survival 15-20% lower survival for juvenile males 10% for adult males outside of autumn season Mechanism? cost of breeding (Rut), dispersal (yearlings) Mining projects continue to pose challenges for maintaining healthy and viable mule deer migration corridors Important to be proactive in NEPA processes and other coordination with federal land management agencies

41 Acknowledgements Funding Sources: NDOW Biologists Jeremey Lutz Caleb McAdoo Carl Lackey Kari Huebner Field Technicians Travis Allen Ben Regan Marcus Blum Tyler Johnson Larry Johnson Wildlife Heritage Trust Account

42 Questions?

43 Cause Specific Mortality of Collared Mule Deer Ruby Mountains Simpson Parks Unknown 51% Predation 28% Legal Harvest 11% Roadkill 1% Capture 3% Misc Injury 1% Malnourish Illegal 3% Harvest 2% Carson Range Unknown 50% Legal Harvest 12% Predation 34% Misc Injury 1% Malnourish 3% Unknown 42% Predation 30% Capture 1% Misc Roadkill 14% Malnouris Illegal h Legal Harvest 1% Harvest 0% 9% Injury 3%

44