Botswana's wildebeest populations have dropped by nearly 90 percent due to multiple causes including land use, habitat fragmentation, vegetation changes, drought, veterinary fences, fires and poaching.

Wildebeest, Botswana [File?photo]

A recent study conducted by Elephants Without Borders (EWB), a charitable organization dedicated to conserving wildlife and natural resources, showed Botswana's wildebeest is on the brink of extinction and will be difficult to rejuvenate. The wildebeest populations, especially in the northern districts Ngamiland and Chobe, have dropped by nearly 90 percent over the last 15 years.

EWB founder Michael Chase was quoted by local daily Mmegi on Tuesday as saying other animals whose declining numbers were of grave concern included giraffe, kudu, lechwe, ostrich, roan, tsessebe and warthog.

"Particularly troubling is the almost 90 percent drop in the numbers of wildebeest sighted by the survey," Chase said. "For example, in Chobe, we sighted only 500 wildebeest."

According to the survey, the decline in the animals' populations largely due to land use, habitat fragmentation, vegetation changes, drought, veterinary fences, fires and poaching.

"Bush fires tend to kill tens of animals at a go," Chase said. "For example, in a national park, we saw 43 carcasses of zebra which had obviously been killed by wildfires."

He said increasing rate in poaching further exacerbates the situation. "In one case, poachers killed a lactating lion that had six cubs." While the population of elephant in northern Botswana remained stable at about 130,000 individuals.

The survey, which was commissioned by the Department of Wildlife and National Parks, took nearly 250 hours of flying time and flight lines totalling 25,598 km over 73,478 square km in the country's most national parks. It analyzed comparative data from nine similar surveys that were conducted between 1993 and 2004.