The decline of the Knysna elephants: Pattern and hypotheses
Moolman L, Ferreira SM, Gaylard A, Zimmerman D, Kerley GIH. The decline of the Knysna elephants: Pattern and hypotheses. S Afr J Sci. 2019;115(3/4), Art. #4805, 7 pages.
https://doi.org/10.17159/sajs.2019/4805
Abstract:
Understanding and identifying drivers of local population declines are important in mitigating future risks
and optimising conservation efforts. The Knysna elephants have, after being afforded protection since the
early 1900s, declined to near extinction today. We propose three hypotheses as to why the Knysna elephant
population declined. The refugee hypothesis suggests that anthropogenic activities forced the elephants
to take refuge in the forest and that the low-quality food acted as the primary driver of decline. The illegal
killing hypothesis suggests that the elephants adapted to the forest and its immediate fynbos habitat, with
the decline being a consequence of illegal kills. The stochastic founder population hypothesis postulates
that the population size and structure left it vulnerable to demographic stochasticity. We critically reviewed
available evidence for these hypotheses and found that, although the historical elephant range decline
most likely resulted through the refugee hypothesis, the weak demographic and life-history information
limits elimination of either of the other hypotheses. We touch on the implications for decision-makers and
draw attention to information requirements.