Slow intrinsic growth rate in forest elephants indicates recovery from poaching will require decades

Authors


Summary

  1. African forest elephants Loxodonta cyclotis are experiencing persistent declines driven by illegal killing and range loss. Despite the importance for policy debates regarding elephant trade managed through the Convention on International Trade in Endangered Species (CITES), little is known about forest elephant demography and, consequently, the impacts of offtake and subsequent population recovery potential.
  2. Using 23 years of individually based demographic data from Dzanga, Central African Republic, we found low reproductive potential resulting from annual birth rates averaging 4·3% (SD: 1·4%), a median inter-birth interval of 68 months and a median primiparous age of 23 years. Average mortality was 3·1% per year (SD: 1·0%) during the study, with approximately 1·4% of that attributed to human killing.
  3. This population of forest elephants demonstrated concerningly slow growth rates, with a doubling time of nearly 60 years under current conditions (41 years excluding human impacts), amounting to three times that reported for savanna elephants. As such, forest elephants appear to be significantly more sensitive to human-induced mortality than their congeneric species.
  4. Such slow intrinsic growth challenges current perceptions of historic and contemporary ivory trade impacts on forest elephants, highlighting the urgent need to stem poaching and institute long-term protective measures.
  5. Policy implications. Debates regarding the sustainability of the ivory trade for the species appear to have overestimated growth rates of forest elephants. The information presented here indicates that sustainable offtake models for forest elephants need reassessment.

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