Caribou Nutrition Study

Nutritional Ecology of Caribou in Northwestern Ontario

Funding: National Council for Air and Stream Improvement

A collaborative research project is being undertaken to better understand how well different habitats in the boreal forests of Northwestern Ontario provide for the nutritional needs of female caribou and their calves during summer when nutritional needs of caribou are highest.  This project will identify summer diet and habitat characteristics such as nutrient content of forage, amount of forage, and types of forage that may strongly influence nutrition of caribou, and how disturbances such as wildfires and logging affect these habitat characteristics.  The research will be led by the National Council for Air and Stream Improvement (NCASI), the University of Alberta, and the University of Northern British Columbia, in collaboration with the Ontario Ministry of Natural Resources and Forestry (MNRF).


Caribou (boreal population) are listed as threatened or endangered across their Canadian range, including Ontario. The extent and severity of the declines is considered to be the most widespread wildlife conservation issue currently facing Canada.  Much research has already been conducted and has largely focused on the effects of industrial development, predation by wolves, bears, and other carnivores, and habitat suitability of caribou ranges.

However, caribou population trends are also a function of performance and productivity, including: vigor and health of newborn calves, juvenile growth, body condition (such as body fat levels and weight), and timing and probability of breeding.

Other studies have found that summer nutrition is a link between productivity of large ungulates such as caribou and the habitat on which they depend.  Key life processes—gestation during late pregnancy, juvenile growth, recovery of body fat after winter, and breeding—occur late spring through mid-autumn, and these impose large nutritional demands that, if unsatisfied, reduce reproductive performance, health and body condition, and increase susceptibility to winter weather and predation.  Specific relationships among summer habitat conditions, summer nutrition, and productivity of caribou populations in boreal forests of Canada have been infrequently studied.  Understanding if, or how, summer nutrition is limiting to caribou may help inform caribou conservation and recovery efforts.

Beginning in 2008, NCASI’s Canadian Operations initiated a large-scale 12-year research effort to evaluate summer nutritional influences on caribou productivity, initially with researchers at the University of Alaska-Fairbanks and University of Northern British Columbia.  Four years of intensive research has been conducted in northeastern British Columbia and, to some extent, in southern Northwest Territories.  This project will carry out similar research in Northwestern Ontario.

Research Objectives

  1. Identify the potential role of nutrition in limiting productivity of caribou.
  2. Evaluate relationships between fine scale vegetation characteristics and nutritional performance of caribou.
  3. Link caribou nutrition to ecological conditions, disturbance regimes, and forest successional patterns in a framework useful for describing current and future spatial distributions of nutritional resources as a function of natural and anthropogenic disturbance.

Research Methods

Fifteen captive caribou, highly habituated to humans and trained for the study, will be placed in different forested habitats and closely monitored for the different forage types they eat, the nutrient content of this forage, and the amount of forage they consume each day.

Considerable planning will be conducted during winter and spring 2017 to identify key habitats and study area boundaries for conducting the work.  Foraging data will be collected in summers of 2017 and 2018.  Analysis of data to complete final reports will require approximately two years after the second field season ends.