Summary
Project Title: Population dynamics and body condition of caribou in northern Québec/Labrador
More than one million migratory tundra caribou are distributed in Northern Québec and Labrador, ranging over nearly a million square kilometres. Two migratory populations are recognized in this region: the Rivière-aux-Feuilles (Leaf River) herd and the Rivière-George (George River) herd. Population numbers have varied dramatically in the past. Because migratory caribou are at the heart of the culture and the economy of northern regions, we seek to identify the factors influencing variations in caribou abundance and body condition to improve the management and conservation of their populations.
The identification of factors influencing changes in body condition of migratory caribou is essential to our understanding of natural and human-induced variations in the survival and reproductive success of individuals and the demography of herds. Therefore, this project aims to assess the relationship between individual body condition and population dynamics of both herds.
Results
During 2007 and 2008, we have established a monitoring program to assess the body condition and health of caribou of the George River and Leaf River herds. We compared the body condition and parasite loads of female-calf pairs in each herd during June (calving) and October-November (weaning). In both years and seasons, we collected the following measurements and samples on female-calf pairs: total body mass (kg), dressed body mass (kg), total length (cm), chest girth (cm), hind foot length (cm), peroneus muscle mass (g), back fat (cm), kidney fat (%), ear sample (for DNA), muscle and fat samples (for isotope analyses), rumen sample, ovaries, femur (marrow fat), mandible, tissues for Besnoitia analysis, blood strips (for blood parasites), visual evaluation of parasites (i.e. warble flies, lung cysts, liver flukes, tænia cysts in muscles) and protein samples (urine, feces, muscle and hair).
In 2007, calves from the George River herd had greater body mass and hind foot length at birth (6.2 ± 0.2kg and 33.2 ± 0.3cm) and at weaning (52.1 ± 1.3kg and 49.5 ± 0.4cm) than those from the Leaf River herd (birth: 5.2 ± 0.2kg and 31.9 ± 0.3cm and weaning: 41.3 ± 1.2kg and 46.2 ± 0.4cm). Adult females from the George River herd were heavier, both at calving (80.4 ± 1.8kg) and at weaning (98.5 ± 1.9kg), than those from Leaf River herd (calving: 73.0 ± 1.8kg and weaning: 88.7 ± 1.8kg), but they did not differ in skeletal size.
In 2008, calves from both herds were of similar body mass and hind foot length at birth (George: 6.1 ± 0.2kg and 32.7 ± 0.3cm and Leaf : 5.8 ± 0.2kg and 33.1 ± 0.3cm), but George River calves were much heavier and larger at weaning (George: 53.1 ± 1.6kg and 49.0 ± 0.5cm and Leaf : 44.2 ± 1.4kg and 47.9 ± 0.3cm). Adult females from the George River herd were slightly heavier, both at calving (83.1 ± 1.5kg) and at weaning (102.1 ± 2.4kg), than those from the Leaf River herd (calving: 73.0 ± 1.8kg and weaning: 97.0 ± 1.8kg), but they did not differ in skeletal size.
During the fall field season (October-November), we also determine an index of recruitment and the reproductive status of satellite-collared females. In falls of 2007 and 2008, the recruitment was low for both the George River herd (2007 : 29.3 calves per 100 females; 2008 : 24.8 calves per 100 females) and the Leaf River herd (2007 :16.7 calves per 100 females; 2008 : 33.4 calves per 100 females).
In fall 2009, the recruitment was estimated at 35 calves per 100 females for the Rivière George herd and 28 calves per 100 females for the Rivière aux Feuilles herd. Adult females from the Rivière George herd were heavier, both at calving (82.2 ± 1.8 kg) and at weaning (100.1 ± 2.5 kg), than those from the Rivière aux Feuilles herd (calving: 75.4 ± 1.6 kg and weaning: 91.3 ± 1.4 kg). Calves from both herds were of similar body mass (Rivière George: 5.8 ± 0.2 kg; Rivière aux Feuilles: 5.4 ± 0.2 kg), but Rivière George calves were much heavier at weaning (Rivière George: 48.2 ± 1.4 kg; Rivière aux Feuilles: 39.3 ± 1.8 kg). Our results suggest great differences in body condition between caribou of both herds.
Applications
Combining the June and fall datasets, we will compare adult female body condition and calf body condition and early growth in the two herds. The comparison of the fall dataset with data collected at calving will provide us with direct information on the body condition and indirect information on the quality of the summer range use by female-calf pairs of each herd. Differences in body condition of female-calf pairs may be useful indicators of demographic changes. Our results already suggest large differences in body condition between herds, possibly indicating different demographic trends.
Reports
Couturier, S., R. D. Otto, S. D. Côté, G. Luther, and S. P. Mahoney. 2010. Body size variations in caribou ecotypes and relationships with demography. J. Wildl. Management 73(3):395-404. Download (447 kB)
Contacts
Steeve Côté
Department of Biology and Centre for Northern Studies
Pavillon Vachon, 1045 avenue de la Médecine
Université Laval
Sainte-Foy, Quebec
G1V 0A6, CANADA
Telephone: (418) 656-2131 ext. 3490
Fax: (418) 656-2043
E-mail: steeve.cote 'at' bio.ulaval.ca
Joëlle Taillon
PhD student
Department of Biology and Centre for Northern Studies
Pavillon Vachon, 1045 avenue de la Médecine
Université Laval
Sainte-Foy, Quebec
G1V 0A6, CANADA
Telephone : (418) 656-2131 ext. 8152
Fax: (418) 656-2043
E-mail: joelle.taillon 'at' bio.ulaval.ca
Vincent Brodeur
Biologist - Wildlife
Ministere des Ressources naturelles et de la Faune
Direction de l'aménagement de la faune du Nord-du-Quebec
951 boul. Hamel
Chibougamau, Quebec
G8P 2Z3, CANADA
Telephone: (418) 748-7701 ext. 225
Fax: (418) 748-3338
E-mail: vincent.brodeur 'at' mrnf.qc.ca