East Africa: Drying Mara River threatens wildlife migration

by May 22, 2011Habitat News, Wildlife News

Human activities within the Mara River basin have reached such proportions that they are now putting the world’s greatest annual wildlife migration across East African plains under threat.

The annual loop of two million wildebeests and other wildlife across Tanzania’s legendary Serengeti National Park and Kenya’s renowned Maasai Mara is a key tourist lure, generating millions of dollars annually.

Mara River Basin extends to over 13,750 square kilometres of which 70 percent and 30 percent is within Kenya and Tanzania respectively.

It traverses within protected areas for 75 kilometres of which 60 kilometres within Serengeti and the remainder in Maasai.

Tanzania National Parks Authority (TANAPA) ecologist Dr James Wakibara said that large scale irrigation and industrial activity such as mining along the sprawling basin has led to higher rates of water extraction.

Increased forest clearance and cultivation in the upper catchments of Mau escarpments in Kenya have progressively led to excessive sediment loads and altered hydrograph of the Mara River, the only source of drinking water for Serengeti-Mara ecosystem wildlife during the dry months of August and September.

Consequently, both seasonal floods and droughts have become more and more frequent and extreme, leading to Mara River water flow becoming unpredictable in the past few years, a scientific study seen by The Guardian on Sunday shows.

Mau forest

Mara River originates on the nearly 3000m above sea level Mau Escarpment in Kenya, among the swamps and remnants of a once expansive forest that receives on average 1400 mm of rainfall annually.

Its two major tributaries, the Nyangores and Amala Rivers exit the source and descends over 1000m on the southern slope of the escarpment, supporting farmers, pastoralists, and a growing urban population in both Tanzania and Kenya.

These rivers also carry headwater rains to the more arid lands further downstream. Nyangores and Amala meet at the base of the escarpment to form the upper Mara River, which flows on a gentler gradient through wooded grasslands used primarily for livestock grazing but increasingly for small-scale agriculture as well.

Due to 40 percent of Mau Forest destruction annual rainfall in this region has dropped over time to well below 1,000 mm, and the main channel of the river provides the only permanent source of surface water for people and animals.

As the Mara River continues into the protected areas of Maasai Mara Game Reserve and across the Tanzanian border into the Serengeti National Park, it is joined by the Talek and Sand Rivers.

Great spectacle

The Mara River sustains one of the greatest spectacles of the natural world – the annual migration of millions of wildebeests, zebras and antelopes arriving in the Mara Basin during the dry season in search of water and forage.

Since Mara River is not a large river, ever increasing activity will eventually severely degrade the riverine ecosystem and even impinge upon the most basic needs of people, livestock, wildlife and the overall basin’s economy. “If the irregular flow of Mara River becomes more and more extreme, it could, for example, cause a collapse in the wildebeest populations, thus hampering the entire migration cycle that sustains the Maasai Mara – Serengeti ecosystem,” Dr Wakibara said.

The annual migration – which has occurred without interruption for thousands of years – is one of the most extraordinary movements of animals on earth. Millions of these huge creatures trudge across Kenya and Tanzania in a vast area. This globally unbeaten spectacle has led Serengeti to be named the 7th Wonder of the World in the year 2008.

En route, the animals eat 7,000 tonnes of grass a day and drink enough water in Mara River to fill five swimming pools.

And around this time of year the migrating animals reach the southern Serengeti Plains where they calve, triggering the biggest baby boom ever known. In three weeks, half a million wildebeests will be born.

“…The implications of Mara River disruption could be far reaching, including not only devastating the tourism industry that supports so much of Kenya and Tanzania economies, but also a change in the entire structure of the Serengeti-Mara savannah ecosystem,” Dr Wakibara noted.

Other threat

Other reports show that the annual rate of human population increase in the sprawling basin stands at three percent accompanied by a 55 percent increase in agricultural activities in the last 16 years.

As if that is not enough, Dr Wakibara says during this span, nearly a quarter of the basin’s forests and grasslands have been destroyed.

On top of this, global warming has been linked to a drought that is gripping much of Africa – ‘the strongest rainfall anomaly on the planet,’ according to Dr Douglas Parker of Leeds University.

Both local and international scientists have raised a red flag against the current rate of growth of human population, coupled with excessive exploitation of natural resources within the core areas of Mara River basin.

“Although the use of the Mara River Basin resources by humans is inevitable, its current nature and scale of utilisation is currently considered unsustainable,” Dr Wakibara explained. He warned that if Mara River stops flowing, the millions of animals, including antelopes, zebras and gazelles which join the wildebeest in this spectacular trek across the expansive Serengeti savannah will die massively as a result of thirst.

Amidst this worrisome situation, many local and international stakeholders spearheaded by the Wordwide Fund for Nature have been actively involved in various conservation initiatives within the basin.

For instance, WWF has facilitated the formation of 14 community based Water User’s Associations, in line with Tanzania’s National Water Policy of 2009 in a bid to devolve the grassroots management of the basin resources to the local people.