Continent-wide survey reveals massive decline in African savannah elephants - PubMed (original) (raw)

doi: 10.7717/peerj.2354. eCollection 2016.

Scott Schlossberg 1, Curtice R Griffin 2, Philippe J C Bouché 3, Sintayehu W Djene 4, Paul W Elkan 5, Sam Ferreira 6, Falk Grossman 7, Edward Mtarima Kohi 8, Kelly Landen 1, Patrick Omondi 9, Alexis Peltier 10, S A Jeanetta Selier 11, Robert Sutcliffe 1

Affiliations

Continent-wide survey reveals massive decline in African savannah elephants

Michael J Chase et al. PeerJ. 2016.

Abstract

African elephants (Loxodonta africana) are imperiled by poaching and habitat loss. Despite global attention to the plight of elephants, their population sizes and trends are uncertain or unknown over much of Africa. To conserve this iconic species, conservationists need timely, accurate data on elephant populations. Here, we report the results of the Great Elephant Census (GEC), the first continent-wide, standardized survey of African savannah elephants. We also provide the first quantitative model of elephant population trends across Africa. We estimated a population of 352,271 savannah elephants on study sites in 18 countries, representing approximately 93% of all savannah elephants in those countries. Elephant populations in survey areas with historical data decreased by an estimated 144,000 from 2007 to 2014, and populations are currently shrinking by 8% per year continent-wide, primarily due to poaching. Though 84% of elephants occurred in protected areas, many protected areas had carcass ratios that indicated high levels of elephant mortality. Results of the GEC show the necessity of action to end the African elephants' downward trajectory by preventing poaching and protecting habitat.

Keywords: Aerial survey; African elephant; Carcass ratio; Conservation; Loxodonta africana; Population decline; Population trend; Protected areas.

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Conflict of interest statement

Michael J. Chase is the Founder of Elephants Without Borders, and Elephants Without Borders managed the Great Elephant Census which generated the data in this article. Michael J. Chase, Scott Schlossberg, Paul W. Elkan, Falk Grossman, Kelly Landen, and Robert Sutcliffe either currently work for or, while conducting this research, were supported by nongovernmental organizations that sometimes engage in advocacy for wildlife conservation. Alexis Peltier is an employee of Air Adventures, Nairobi, Kenya.

Figures

Figure 1

Figure 1. Estimated density of elephants by stratum on GEC survey areas, 2014–2015.

Densities are in elephants per km2, and estimates are presented by stratum, as defined by survey teams.

Figure 2

Figure 2. Estimated trends in elephant populations for GEC study areas with historical data available, 1995–2014.

Results are based on 1,000 Monte Carlo replicates. Dark shaded area indicates ±1 SD; light shaded area indicates 95% confidence interval. Tick marks on _x_-axis indicate dates of data points used in model; dates are perturbed slightly to prevent overlap.

Figure 3

Figure 3. Estimated population trends in GEC study areas by country for sites with historical data available.

Results are based on 1,000 Monte Carlo replicates for each country. Dark shaded area indicates ±1 SD; light shaded area indicates 95% confidence interval. Tick marks on _x_-axis indicate dates of data points used in model; dates may be perturbed slightly to prevent overlap. “W. Africa” refers to the WAP ecosystem in Benin, Burkina Faso, and Niger.

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Grants and funding

The Great Elephant Census was funded by Paul G. Allen. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

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