New study shows steep declines in populations of giraffes and other animals at Kenya’s Masai Mara reserve

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A 15-year study of the grazing wildlife in Kenya’s famed Masai Mara reserve has revealed a startling drop in the reserve’s giraffe, warthog, impala, hartebeest, topi and waterbuck populations.

The study, published in the May issue of the British Journal of Zoology, is based on researchers’ analysis of data gathered from monthly monitoring of seven ungulate (or hoofed) species between 1989 and 2003. It was carried out by the International Livestock Research Institute (ILRI), which is based in Kenya, and funded by the World Wide Fund for Nature (WWF). The Guardian reports:

Their sample counts were backed by government population estimates that showed actual losses as high as 95% for giraffes, 80% for warthogs and 76% for hartebeest for the period dating back to 1979. ...

The main reason for the population decrease was the rapid expansion of human settlements on the land next to the reserve. The area was traditionally used by wild animals for seasonal grazing but is increasingly being turned over to livestock and crop production.

‘In particular, our analysis found that more and more people in the ranchlands are allowing their livestock to graze in the reserve, an illegal activity the impoverished Masai resort to when faced with prolonged drought and other problems,’ said Joseph Ogutu, lead author of the study and a statistical ecologist with ILRI.

Until recently, the Masai people, historically semi-nomadic herders, were able to coexist with the reserve’s wildlife. But in recent decades, the Masai have increasingly been gravitating to more permanent settlements near the reserve. And, the group found, as the region’s permanent human population boomed, its ungulate population rapidly declined. From the Guardian:

In Koyiaki, one of the ranches next to the reserve, the number of huts increased from 44 to 2,345 between 1950 and 2003. Individual titleholders now own what was once communal land.

Ogutu said this meant wild grazing animals that previously moved freely in and out of the reserve were increasingly competing for habitat with cattle and large-scale crop cultivation. The destruction of trees for firewood was also having a negative effect.

‘The situation we documented paints a bleak picture and requires urgent and decisive action if we want to save this treasure from disaster,’ Ogutu said. ‘Our study offers the best evidence to date that wildlife losses in the reserve are widespread and substantial, and that these trends are likely linked to the steady increase in human settlements on lands adjacent to the reserve.’ And the ungulates aren’t the only ones in danger, according to the BBC:

The loss of grazing animals is already having an impact on lions, cheetahs and other predators, according to researchers.

‘The carnivores which depend on these wildlife are the first casualties,’ said Dr. Ogutu.

‘The numbers of lions are going down. The cheetah numbers are declining. The wild dogs in the Mara system have become extinct.’

The good (if paradoxical) news is that ungulate wildlife can actually benefit from close proximity to humans, if the conditions are right. Robin Reid, a co-author of the study and the director of Colorado State University’s Center for Collaborative Conservation, explained that grazing wildlife often gravitate to pastoral settlements for food during the wet season. Grass near such settlements is both nutritious and short, since it’s used as grazing land for pastoralists’ herds. Short grass means it’s easier to see predators.

Reid explains, ‘There appears to be a ‘tipping point’ of human populations above which former coexistence between Masai and wildlife begins to break down. In the villages on the border of the Mara, this point has been passed, but large areas of the Mara still have populations low enough that compatibility is still possible.

‘These apparently contradictory findings are now being used by local Masai communities to address the loss of wildlife. They see that wildlife are lost when settlements are too numerous, but that moderate numbers of settlements can benefit wildlife.’ Masai landowners are working to create conservancies to establish an ideal balance between settlements and wildlife.

Beyond their concern for the wildlife, there is another consideration at play: tourism revenue. ‘With [the pastoralist peoples’] help and the significant tourism revenue that the Mara wildlife generates, it should be possible to invest in evidence-based approaches that can protect this region’s iconic pastoral peoples as well as its wildlife populations,’ said Carlos Seré, IRLI’s director general.

--Lindsay Barnett

Top photo: Giraffes at the Masai Mara reserve