Friday, 29 August 2008 03:00

Land use and climate changes in Mara-Serengeti to blame for decline of animal species

Written by Duncan Mboyah

Scientists say human population growth and land transformations, including the fast development of numerous tourism camps, are causing destruction and loss of wildlife habitats in the Mara region of Kenya and the subsequent decline of animals.

A 15-year study by scientists at the International Livestock Research Institute (ILRI) in Nairobi covering the period 1989 to 2003 states that the increasing number of settlements and people in the pastoral ranches has led to the decline of ungulate (hoofed mammals) species.

The study estimates that 40 percent of wildlife that includes all the elephants and most carnivores in the area will be lost if the on going land privatization continues hence leading to a reduction in foreign money earned from tourism in the country.

“Establishment of permanent settlements near the main entrances into the wildlife reserve from the late 1980s and 1990s to date coincided with increased use of the reserve by livestock owners causing the accentuated the effects of drought on wild herbivores due to elevated competition for forage and water,” ILRI’s Research Scientist Dr. Joseph Ogutu says.

Hartebeest, warthog, topi, impala, giraffe and waterbuck, decreased substantially during the monitoring period.

“The effects of progressive habitat deterioration was accelerated by illegal tree logging, competition with livestock and elevated predation,” adds Dr. Ogutu.

Dr. Ogutu says that the number of settlements outnumbered the number of buffalos, once abundant in the area.

“Abundance of all the species except for waterbuck and zebra decreased significantly as the number of homes and houses increased,” he adds.

The study, carried out on a monthly basis within the period also notes the influence of rainfall, as hoofed mammals populations declined more markedly in sections of the reserve that are experiencing greater livestock incursions and poaching.

Dr. Ogutu says that the transformations are associated with habitat alteration that includes declining woodland cover, increasing competition between wildlife and livestock, harassment and displacement of wildlife and illicit harvest resulting in marked decline in wildlife numbers.

He says that although it was illegal, heavy livestock grazing occurred in the wildlife reserves, implying intensifying competition between wildlife and the large number of livestock in the reserves.

The study also blames economic diversification from livestock herding to trade, tourism development, conservation, cultivation and return to capital investment as the major threats to wildlife conservation in the Mara ranches.

It also identifies rapid changes in customary perceptions, values and aspirations of young Maasai as undermining the traditional symbolic attributes and social institutions that historically protected wildlife and their environments in the pastoral lands of the Mara.

These changes particularly individualization of land ownership, land sub-division and the proliferation of permanent settlements, fences and cultivation are occurring at an alarming rate hence threatening the future of wildlife conservation.

“The rate of land cultivation has increased tremendously in the Mara ranches since 1975 advancing right up to the boundary of the Mara reserve in Ololaimutia,” Dr. Ogutu observes.

He adds that development of major trading centers and settlements near the main gates of the reserve and in parts of the ranches further restrict wildlife movements, hence worsening the situation.

The study reveals that due to the increase in human population, the number of homes increased exponentially from four in 1950 to 368 in 2003 as did the number of houses from 44 in 1950 to 2,735 in 2003.

Severe decline in wildlife populations in the reserves and adjoining pastoral ranches during the period is also attributed to land use and cover changes, most notably the expansion of mechanical large scale wheat farming in the Loita plains.

Group of zebra grazing in Mara
Group of zebra grazing in Mara

 

Livestock grazing in the hills and ridges of the reserve where there are less open grass plains increased strikingly from 1980 to 2003.

The study also blames rising temperatures, recurrent severe drought and floods as contributors to the decline in the number of wildlife.

It states that reduced flexibility and mobility due to progressive habitat loss in the ranches amplifies the vulnerability of wildlife to recurrent climatic extremes that exacerbates their population decline.

All the species except zebra decreased substantially in abundance during the 1993 and 1997 droughts during the monitoring period.

The migratory zebra became more numerous in the reserves during the rainy years of 1995 to 1996 and during the prolonged drought of 1999 to 2000.

It also notes the increasing threat of disease transmission between livestock and wildlife due to an increasing number of domestic dogs and adoption of exotic breeds of livestock by some pastoralists.

Due to the habitat fragmentation, the study however warns of the imminent outbreak of transmission of infectious diseases like the one that led to the extinction of the wild dog packs due to the exposure of wildlife to domestic dogs which acts as a disease reservoir for many zoonotic diseases

Poaching too is blamed for the reduction of the wildlife as most poachers in the Mara-Serengeti ecosystem are poor subsistence farmers dependent on bush meat for protein and incomes.

They have contributed greatly to the population reduction of residential herbivores and have specifically contributed a 90 percent decline in the buffalo population in northern and western Serengeti.

Dr. Ogutu reveals that poachers use wire snares widely and are responsible for the extinction of the roan antelope and greater kudu in the Mara reserve in the 1970s.

The study found that about 160,000 resident and migratory herbivores including about 40,000 wildebeest are illegally harvested annually in the Mara-Serengeti.

During the study, the scientists used prevalence of poaching, illegal livestock grazing in the reserve, range contraction and human population growth in the ranches as indices of anthropogenic impacts.

Currently the killing of wildlife in retaliation for destruction of fences, degradation of water quality, crop damage, livestock depredation, human injuries and fatalities is common and increasing.

“This could portend grave consequences for the future of wildlife conservation, since most wildlife in the Mara live on the ranches or move seasonally between the ranches and the reserve,” Dr. Ogutu notes.

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