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.poaching | overharvest | population estimation | extinction | endangered species consumption

Radiocarbon dating of seized ivory confirms rapid decline in African elephant populations and provides insight into illegal trade

“…However, we note that the radiocarbon calibration and related uncertainties have large associated errors and that refined regional radiocarbon calibrations may provide better constraints on regional differences in lag times. where data show population decline due to unsustainable poaching rates, especially in Central and East Africa (3,4). As a result, it may take longer to accumulate enough large tusks to make a large shipment more profitable.…”

“…wildlife | forensics | isotopes | Africa | genetics T he illegal trade in elephant ivory has increased significantly in the past decade (1,2), with studies estimating the current rate of decline of regional African elephant populations to be as high as 8%, primarily due to poaching (3,4). Central African forest elephant populations decreased by ca.…”

“…The savanna elephant population in the Selous Wildlife Reserve in Tanzania saw a 66% decline from 2009 to 2013 (7). The rapid decline in elephants across Africa has been attributed to the high poaching rates and increased amount of ivory seized over the last decade or so (3). Total global seizures in excess of 40 tons of ivory have occurred in several years since 2010 (8), with over 70% of all ivory seizures exceeding 0.5 ton (hereafter termed "large seizures" or "large ivory seizures").…”

Trends in Illegal Killing of African Elephants (Loxodonta africana) in the Luangwa and Zambezi Ecosystems of Zambia

“…For instance, high numbers of fresh and recent carcasses in Table 1 offer evidence of increasing threat of poaching to the Luangwa Valley elephant populations. PIKEs of greater than 0.5-0.54 or 50-54% are precursors of severe poaching threats to elephant populations, resulting in declining populations (Nellemann et al, 2013;Wittemyer et al, 2014). Despite low ranger (scout) Though there were comparatively fewer illegally killed elephants annually in the three sites evaluated than some sites in Africa, they were higher than the average recorded in Southern Africa (CITES et al, 2013;Nellemann et al, 2013).…”

“…Illegal wildlife trade is driving global extirpation of populations of commercially valuable species (Wittemyer, Northrup, Blanc, Douglas-Hamilton, & Omondi, 2014). African elephants are illegally killed for ivory and bushmeat in increasingly unsustainable numbers (Bennett et al, 2007;Lindsey et al, 2013;Maiselset al, 2013;Nellemann, Formo, Blanc, Skinner, Milliken, & De Meulenaer, 2013;Wittemyer, Daballen, & Douglas-Hamilton, 2013).…”