Monitoring the Population Status of the Leaf River Herd

Transcription

1 Monitoring the Population Status of the Leaf River Herd By Julien Mainguy, Government of Québec Vincent Brodeur, Government of Québec Declining Caribou: Shared Concerns, Shared Solutions Workshop organized by the Hunting, Fishing and Trapping Coordinating Committee, the Nunatsiavut government and the Torngat Wildlife and plants co-management board September 13,

2 Monitoring in Partnership Long term monitoring of the Leaf River herd has been managed by the Québec Government and the HFTCC Research efforts were often in collaboration with academic partners, as it is done with the Caribou Ungava research group and partners for the past 5 years Financial support from Hydro-Québec and Makivik Corporation has also been significant 2

3 Satellite Telemetry All monitoring efforts rely on a significant number of active collars Sampling plans have to be representative of the population 3

4 Satellite Telemetry The number and distribution of active collars is representative of the population 4

5 Fall Classification Sampling of the population structure in the fall is essential to monitor caribou demography: Proportion of calves in the population Proportion of adult males and females Key elements of population monitoring are estimates of the proportion of calves and of adult female survival 5

6 Population Monitoring The adult survival is currently estimated from: Trend between population surveys Survival of collared animals Defining the cause of any mortality is a complex task: Natural mortality Disease events Predation Harvests Crippling loss Poaching 6

7 Population Monitoring Adult Survival + Calves = Population Trend 7

8 Aerial Surveys The 2011 was the first reliable survey in the past 20 years The interval between surveys should be proportional to the size and trend of the population 8

9 Aerial Surveys Long term monitoring of the recruitment and survival estimates are used to understand population trends Calculated Survey The population would have stayed below caribou Rasiulis et al. unpublished data 9

10 Population size variations Proportion of calves Adult survival Body condition 10

11 Variation of recruitment - Number of calves per 100 adult females - LRH: has been higher in mid-1990 s - Since 2000 s: 32 calves/100 adult females + Fall recruitment Fair recruitment in the population 11

12 Variation of adult survival Stable or increasing herd Adult females Over 85% 83% 82% Adult males Over 80% 66% 88% Average to good adult survival may ensure stability 12

13 Proportion of large males Proportion of large males has declined since

14 Population size variations Proportion of calves Adult survival Recently on LRH: Fair recruitment Recently on LRH: Average to good adult survival Low proportion of large males 14

15 Body condition: calves Calf birth mass -From 2007 to 2011: 5.6kg + Birth mass (kg) Low to average body condition of calves at birth 15

16 Body condition : calves Calf body mass at weaning (late October) -From 2007 to 2009: 41.6 kg + Calf body mass (kg) Low body condition of calves at weaning _ Year 16 Couturier et al. 2009, Taillon et al. 2012

17 Body condition : adult females + Female body mass in late October - Slightly higher than in From 2007 to 2009: 92.3 kg Body mass (kg) Average body condition of females in the fall _ Couturier et al. 2010; Taillon et al Year 17

18 Reproduction: gestation rates Changes in gestation rates % 81% 84% Good recent gestation rates 18 Couturier et al ; Qc gov

19 Population size variations Proportion of calves Adult survival Recently on LRH: Fair recruitment Good gestation rate Recently on LRH: Average to good adult survival Low proportion of large males But Calves are in low and adult females in average body condition 19

20 Population size variations Body condition of females and calves suggests: low summer and fall range quality and availability and impact of large scale migration movements Need to identify factors impacting: 1) range quality and availability 2) pattern of space use 20

21 Factors influencing recruitment, survival and gestation Diseases and parasites - Besnoitia: potentially had a significant impact and still present - Other parasites: normal prevalence Habitat quality and availability Climate change Predation Harvest 21

22 Seasonal ranges and habitats All seasonal ranges are identified and delineated annually Winter and summer ranges: incomplete information on habitat quality Spring and fall migration: accurate knowledge on the timing and location of migration routes Calving grounds: critical habitats Winter Summer Calving grounds Fall migration Spring migration 22

23 Changes in location of calving grounds Shift of more than 300km North since

24 Calving grounds : critical habitats Currently in Québec: Wildlife Habitat protects about 16% of LRH annual calving ground Wildlife Habitat Future need: protection of calving grounds must consider the dynamic use of space by adult females 24

25 Seasonal ranges and habitats Main factors known to habitat quality and availability: Caribou itself: browsing and trampling Environmental changes: plant growth and migration conditions (snow) Human activities: modifications and perturbations Winter Summer Calving grounds Fall migration Spring migration 25

26 The impact of caribou itself on its habitat Limited resource (ex. Lichens) Browsing + trampling = habitat degradation Natural decline in population size 26

27 Possible effects of climate change Kangiqsualujjuaq Lévesque et al. Effects on seasonal habitats: vegetation growth, snow depth and melting patterns Effects on body condition (insect harassment) Consequences on movement patterns (migration, predation) 27

28 Human activities and industrial development Low resilience of northern environments Known effects of human activities on caribou behaviors: Disturbance Desertion of key areas Interference with migratory routes Current industrial development in Québec (mining, hydro-electricity, roads, railways ) Caribou and its habitat should be considered in the planification of human activities and industrial development 28

29 Factors influencing recruitment, survival and gestation Diseases and parasites - Besnoitia: potentially had a significant impact and still present - Other parasites: normal prevalence Habitat quality and availability Climate change Predation Harvest 29

30 Role of predation Current efforts to evaluate the role of predation in the population dynamics of caribou: Satellite collars were fitted on wolves and black bears in June 2012 close to calving grounds Future research efforts will focus on predator monitoring to evaluate: movement rate, range use and overlap with caribou seasonal range use 30

31 Caribou harvest Harvest Rate = Harvest / Population Size Long-term monitoring of sport hunters in Québec Partial registration of the Cree harvest The importance of harvest monitoring is recognized by Makivik Reliable harvest monitoring is essential to manage a sustainable harvest 31

32 Caribou harvest A sustainable harvest rate allows to maintain a healthy population: stability increase or decrease The population trend is as important as the population size when defining a sustainable harvest rate Aboriginal and sport harvests most likely do not remove animals that are more susceptible to die 32

33 Caribou harvest The Leaf River caribou sport hunt was reduced of 25%* for outfitters and of 75% in zone 22A in 2011 Hunting zone 23 West A B Total Harvest The Inuit harvest has been estimated at caribou for many years. * Outfitters were limited to 75% of the licenses sold in 2009 and reduction of 75% permits alloted to the draw for zone 22A. The presented aboriginal hunt is a guestimate 33

34 Caribou harvest The estimated harvest rate* would have been high in recent years but recently down to a sustainable level sport harvest Population size Harvest Rate (%) Population Harvest Rate * Total harvest = registered sport harvest + estimated aboriginal annual harvest fixed at 9000 caribou + estimate of crippling, poaching and wasting (20% of total harvest) 34

35 Population Trend Calculated The population has recently declined Adult survival and recruitment are fair Rasiulis et al. unpublished data Biological indicators suggest that the population is stabilizing The population is vulnerable to decline due to poor body condition and extensive migration pattern 35

36 Based on what we know Need a better monitoring of harvest to allocate a sustainable harvest rate Estimated harvest rate of 4% would be sustainable considering the population size and trend Close monitoring of the population trend and harvest rate is recommended Updated management plan with stakeholders 36