title: Illegal killing for ivory drives global decline in African elephants.
abstract: Illegal wildlife trade has reached alarming levels globally, extirpating populations of commercially valuable species. As a driver of biodiversity loss, quantifying illegal harvest is essential for conservation and sociopolitical affairs but notoriously difficult. Here we combine field-based carcass monitoring with fine-scale demographic data from an intensively studied wild African elephant population in Samburu, Kenya, to partition mortality into natural and illegal causes. We then expand our analytical framework to model illegal killing rates and population trends of elephants at regional and continental scales using carcass data collected by a Convention on International Trade in Endangered Species program. At the intensively monitored site, illegal killing increased markedly after 2008 and was correlated strongly with the local black market ivory price and increased seizures of ivory destined for China. More broadly, results from application to continental data indicated illegal killing levels were unsustainable for the species between 2010 and 2012, peaking to ∼ 8% in 2011 which extrapolates to ∼ 40,000 elephants illegally killed and a probable species reduction of ∼ 3% that year. Preliminary data from 2013 indicate overharvesting continued. In contrast to the rest of Africa, our analysis corroborates that Central African forest elephants experienced decline throughout the last decade. These results provide the most comprehensive assessment of illegal ivory harvest to date and confirm that current ivory consumption is not sustainable. Further, our approach provides a powerful basis to determine cryptic mortality and gain understanding of the demography of at-risk species.
authors.affiliation: Department of Fish, Wildlife, and Conservation Biology and Save the Elephants, Nairobi, Kenya 00200; Graduate Degree Program in Ecology, Colorado State University, Ft. Collins, CO 80523-1474; g.wittemyer@colostate.edu.
authors.forename: George
authors.initials: G
authors.lastname: Wittemyer
authors.affiliation: Department of Fish, Wildlife, and Conservation Biology and.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Northrup
authors.affiliation: Monitoring the Illegal Killing of Elephants, Secretariat of the Convention on International Trade in Endangered Species of Wild Fauna and Flora, Nairobi, Kenya 00100;
authors.forename: Julian
authors.identifier: http://orcid.org/0000-0003-4331-5339
authors.initials: J
authors.lastname: Blanc
authors.affiliation: Save the Elephants, Nairobi, Kenya 00200; Department of Zoology, University of Oxford, Oxford OX1 3PS, United Kingdom; and.
authors.forename: Iain
authors.initials: I
authors.lastname: Douglas-Hamilton
authors.affiliation: Kenya Wildlife Service, Nairobi, Kenya 00200.
authors.forename: Patrick
authors.initials: P
authors.lastname: Omondi
authors.affiliation: Department of Fish, Wildlife, and Conservation Biology and.
authors.forename: Kenneth P
authors.initials: KP
authors.lastname: Burnham
mesh_terms: D000349:Africa; D000818:Animals; D016001:Confidence Intervals; D004606:Elephants / Q000033:anatomy & histology*; D056727:Endangered Species; D006708:Homicide; D038622:Internationality; D011157:Population Dynamics
keywords: endangered species consumption; extinction; overharvest; poaching; population estimation