African elephants occupy less rangelands due to poaching, human pressure
Friday April 09 2021
African elephants occupy just 17 percent of the range of land they could due to human pressure and killing of elephants for ivory, warn researchers.
In a study titled Human footprint and protected areas shape elephant range across Africa and published in the journal Current Biology on April 1, the researchers have uncovered vast areas of historical elephant rangelands and potentially suitable habitat for elephants, that not too long ago held hundreds of thousands of elephants.
For example, the Central African Republic and the DR Congo today only hold about 5,000 to 10,000 forest elephants, while just three decades ago it was estimated that about 172,000 forest elephants lived in the Congo Basin and 70,000 in the CAR.
Between the 1970s and 1980s when the global demand for ivory grew and poachers traded traditional hunting methods for rifles, an estimated 750,000 elephants were killed, leaving just 600,000, and leaving much of Africa, once home to as many as 10 million elephants, an elephant graveyard.
The researchers say African savanna and forest elephants can live in many environments, from semi-deserts to tropical swamp forests.
“We looked at every square kilometre of the continent,” says lead author Jake Wall of the Mara Elephant Project in Kenya. “We found that 62 percent of 29.2 million square kilometres is suitable habitat.”
The findings suggest that, if secure from human pressure, elephants still have potential for recovery in areas where the human footprint is light.
Those 18 million square kilometres include many areas where there is still room for peaceful coexistence between humans and elephants.
To analyse suitability of habitats over the entire continent at a kilometre-level scale, Mr Wall and his colleagues drew on data from GPS-tracking collars fitted on 229 elephants across Africa by Save the Elephants and its partners over the past 15 years.
Using Google Earth Engine, they looked at the vegetation, tree cover, surface temperature, rainfall, water, slope, aggregate human influence, and protected areas in the areas the elephants traversed. This allowed them to determine which habitats can support elephants and the extremes of conditions that they currently can tolerate.
“Combining three powerful tools — GPS telemetry, continent-wide remote sensing at a fine resolution, and a suite of analytical techniques — we see what factors control the movement and lives of these ecologically important species and where, if circumstances change, they could range more widely across their historical home,” said Wildlife Conservation Society’s Samantha Strindberg.
“The major no-go areas include the Sahara, Danakil, and Kalahari deserts, as well as urban centres and high mountaintops,” said founder of Save the Elephants, Iain Douglas-Hamilton.
To secure long-term survival of elephants, the researchers say that habitat protection, protection of elephants from illegal killing, and an ethic of human-elephant coexistence will be essential.