Overall, GEC researchers estimate the savannah elephant population is 352,271 in the 18 countries surveyed to date, representing at least 93 percent of savannah elephants in these countries. They say the rate of decline increased from 2007 to 2014.

In their surveys, they sighted 84 percent of the elephants in legally protected areas compared to 16 percent in unprotected areas. However, large numbers of carcasses were counted in many protected areas, indicating that elephants are struggling both within and outside of parks. Experts say that poaching and the ivory trade pose serious threats, and if not stopped, savannah elephants could disappear from many parts of Africa.

The survey was led by EWB director Mike Chase. Findings have been published on Sept. 1, in the peer-reviewed open access journal PeerJ.

For this work, EWB worked with dozens of elephant researchers, government wildlife agencies and conservation groups to conduct aerial surveys from small planes and helicopters to count elephant herds across African savannahs. The GEC was launched in late 2013 and the first flights were in February 2014 over the Tsavo National Park in Kenya. These surveys covered 463,000 km, equal to flying to the moon and a quarter of the way home.

The census has completed 18 country surveys with two countries still to be completed, organizers say. South Sudan and the Central African Republic are to be flown by the end of 2016, depending on safety conditions.

Overall, 90 scientists, six non-governmental organization partners and two advisory partners collaborated in the GEC. EWB partnered with park biologists and rangers, game wardens and organizations including the International Union for Conservation of Nature's African Elephant Specialist Group, Wildlife Conservation Society, Save the Elephants, The Nature Conservancy, Frankfurt Zoological Society and African Parks Network.

Wildlife ecologist Curt Griffin at the University of Massachusetts Amherst, with postdoctoral researcher Scott Schlossberg, are members of a research team that compiled the data, conducted statistical analyses and applied new data analysis techniques to help Chase and EWB estimate the abundance and geographic distribution of savannah elephants across Africa using the most accurate, up-to-date statistical methods to analyze the survey data. Results provide a baseline that governments and wildlife conservation organizations can use to coordinate conservation efforts.

The GEC is the first continent-wide aerial survey of African elephants. Griffin, who visits Africa every year to conduct research with Chase and EWB, says, "We at UMass Amherst are very proud to be a key partner in this great elephant count. We continue to advocate and work hard for the conservation of elephants in the face of the slaughter they are caught in."

"An important question we wanted to answer in our research," Griffin adds, "is how many elephants are being missed by observers on aerial surveys. To answer that we did a double observer study to understand the sources of error, so we can develop more accurate estimates of elephant population numbers."