Title
Understanding the drivers of mortality in African savannah elephants
Author(s)
Schlossberg, S.;Gobush, K. S.;Chase, M. J.;Elkan, P. W.;Grossmann, F.;Kohi, E. M.
Published
2020
Publisher
Ecological Applications
Published Version DOI
https://doi.org/10.1002/eap.2131
Abstract
Populations of African savannah elephants (Loxodonta africana) have been declining due to poaching, human‐elephant conflict, and habitat loss. Understanding the causes of these declines could aid in stabilizing elephant populations. We used data from the Great Elephant Census, a 19‐country aerial survey of savannah elephants conducted in 2014 and 2015, to examine effects of a suite of variables on elephant mortality. Independent variables included spatially explicit measures of natural processes and human presence as well as country‐level socioeconomic measures. Our dependent variable was the carcass ratio, the ratio of dead elephants to live plus dead elephants, which is an index of recent elephant mortality. Carcass ratios are inversely proportional to population growth rates of elephants over the four years prior to a survey. At the scale of survey strata (n = 275, median area = 1,222 km2), we found strong negative associations for carcass ratios with vegetation greenness at the time of the survey, overseas development aid to the country, and distance to the nearest international border. At the scale of ecosystems (n = 42, median area = 12,085 km2), carcass ratios increased with drought frequency and decreased with human density and overseas development aid to the country. Both stratum‐ and ecosystem‐scale models explained well under half of the variance in carcass ratios. The differences in results between scales suggest that the drivers of mortality may be scale‐specific and that the corresponding solutions may vary by scale as well.
Keywords
African elephant;carcass ratio;great elephant census;savannah elephant;Loxodonta-africana;mortality;drought;fire;aerial survey

Access Full Text

A full-text copy of this article may be available. Please email the WCS Library to request.



Back

PUB26194