Informing elephant management through demographic snapshots

Understanding a species' demography is central to its conservation and management. For some species, surveying populations is a costly and labor-intensive endeavor. Here, we present a cost-effective sampling methodology for measuring age structures of savannah elephant populations across southern Africa. We utilize aerial imagery to measure back lengths and generate demographic snapshots that inform management strategies. We test four hypotheses. First, provisioning supplementary water sources results in populations with a higher proportion of young individuals; second, it mitigates the effects of episodic periods of low rainfall. Third, we show density-dependent effects on lower fecundity, with populations at higher densities exhibiting longer calving intervals. Fourth, when applied with sufficient coverage, immunocontraceptives have a strong effect on the proportion of newborns within a population. These four impacts should be monitored closely to achieve the intended outcomes. Regardless of the management strategies employed, conservationists will need rapid, cost-effective approaches to monitoring the demography of savannah elephants across Africa.

Duke Scholars

Author Stuart L. Pimm Environmental Natural Science