Population Dynamics and Predator-Prey Relationships in Migratory Caribou of the Québec-Labrador Peninsula in the Context of Climate and Anthropogenic Changes
Environmental determinants of migratory caribou survival
Ungulate survival rates may vary due to different parameters linked to habitat or demographic components such as sex ratio or recruitment. These fluctuations are related to the relative sensibility of each age and sex classes to environmental determinants such as climate or vegetation productivity. Many populations of Rangifer are currently declining. It is the case of the Rivière-George (RG) and Rivière-aux-Feuilles (RAF) herds in northern Quebec and Labrador. These herds show strong demographic fluctuations. Caribou are a key resource in Arctic ecosystems, ecologically, economically, and socially. To present effective management and conservation measures, we need to identify the survival determinants with which each category of migratory caribou (age, sex) is interacting. For the RG and RAF herds, some studies suggest a positive correlation between the decreasing survival rate of females and the decline phases observed among these populations.
Our objective is to identify environmental determinants (e.g. climate, vegetation productivity) and quantify their effects on the annual survival of migratory caribou from the RG and RAF herds, depending on their age, sex and mass. Annual and seasonal fluctuations in survival will be considered to identify risk periods and refine the impact of various factors on survival. We will test whether: (1) changes observed in survival are indeed correlated to growth and decline phases, independently of environmental factors; (2) a rapid, strong decline in the population is associated mainly with the decline of adult females survival.
We will use data from a satellite survey, initiated in 1991, with more than 600 caribou of known sex. We will test the effects of different environmental and individual variables on the survival of the two sexes. Over 3 years, we will study juvenile survival by fitting radiocollars on adult females with calf. Data such as juvenile mortality, maternal body condition, climate, and vegetation productivity will be linked with juvenile survival rate. Finally we will test the link between calf:adult female ratio during autumn and the following variables : herd size, climate or NDVI (vegetation productivity) indicators. This part refers to a time-series of caribou recruitment started in 1973.
This project will increase our knowledge of the population dynamics of the RG and RAF herds from northern Quebec and Labrador by shedding light on the determinants of survival. It will also allow for more informed wildlife management strategies in which individual survival plays a fundamental role.
biologie, Centre d'études nordiques
Pavillon Alexandre-Vachon, 1045 av. de la Médecine, local 3076
Québec, Quebec G1V 0A6