Progress Report
Sustainable Development and Strategic Science
December 2009
Mahoney, S. P., and Weir, J. N.

With the striking exception of insular Newfoundland, woodland caribou are listed as Threatened or Endangered throughout North America. In the last decade, however, insular Newfoundland has experienced a dramatic downturn in its caribou population. The Caribou Data Synthesis was initiated in 1996 in an effort to describe and understand the dynamics of caribou in insular Newfoundland. This systematic compilation, analysis and interpretation of all available data has revealed that caribou numbers are declining rapidly in association with changes in population sex and age structure and body size. In particular, calf survivorship has decreased dramatically over the past decade. The Caribou Data Synthesis is an ongoing project which continues to explore existing data and incorporate new information to enrich our understanding of the dynamics of caribou on the island of Newfoundland.

The Synthesis provides several significant conclusions:

  1. Caribou herd distribution and fidelity to calving ranges changed significantly by the mid-1990s.
  2. Population size has declined rapidly—overall a 60% decline in the past decade. Modeling indicates that this decline is likely to continue in the next five years, with or without harvesting.
  3. Recruitment - the addition of young animals to the population - declined from 25-30% in the 1980s to less than 10% in most herds in recent years. Since 2003, over 80% of radio-collared calves died during the first six months of life and predation was the primary cause of death.
  4. Calf production (birth rate) has declined marginally for some herds since the 1980s and requires continued monitoring.
  5. The proportion of adult males has declined significantly since the late 1980s, likely exacerbated by our male-biased harvest regulations.
  6. The population has aged as a result of very few young animals being recruited to the population.
  7. Antler size in males, birth weight of calves, and adult jawbone size has declined, and in many cases significantly.
  8. Hunter success rate has decreased from 80–85% in the late 1980s to less than 60% in 2005 and has resulted in harvest restrictions. Since 2005, success rate has improved slightly.
  9. Both recreational human disturbance and industrial development have been intensively studied and confirm caribou avoidance responses believed sufficient to negatively affect caribou survival.
  10. Island-wide compilations of historical weather data as well as long term climatic changes are indicating that climate may be contributing to changes in caribou body size.

Collectively, these demographic and morphological trends indicate that we are facing a serious situation. The current body of evidence clearly indicates that if declining trends in calf survivorship are not arrested or reversed, caribou of insular Newfoundland will fall through a predictable series of declines and designations, ultimately leading these populations to join those of the rest of the continent in being classified under federal and provincial statutes as Threatened or Endangered. The consequences for the sustainable development of resource-based economies of forestry, mining, outfitting, energy development, and adventure tourism are unknown but significant in magnitude to both the province as a whole and to rural Newfoundland especially.