Competition for Grass Gets Serious Among Herbivores

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Kenya: Competition for Grass Gets Serious Among Herbivores

The Nation (Nairobi)

28 February 2008Posted to the web 27 February 2008

Michael NjugunaNairobi

A swirling wind sweeps the scorched woodland sending showers of palpable ash and dust towards the salty waters of Lake Nakuru.

At another section of Lake Nakuru National Park, which escaped the fire that destroyed a 50 square kilometres portion, a troop of baboons sits under an acacia tree, watching blue wisps of smoke rising from a burning shrub that only hours earlier was the source of some wild fruits.

 

 

 

 

 

 

 

A young agitated baboon dances on the back of its mother, stealing quick glances at a tourist quenching her thirst with mineral water from the safety of a tourist van.

Lake Nakuru National Park, luscious and beautiful during the wet season, has the country's most successful rhino sanctuary. The sanctuary was started in 1984 to save the rhino from the poachers' gun.

It was a defining year for the rhino indeed because poachers had cut them down to 350 by 1988 from 20,000 in 1973.

Solio Ranch in Laikipia donated the first few rhinos, whose number was boosted by a donation of 10 white rhinos by the Government of South Africa in 1994. The rhinos from Kwa Zulu, Natal, were 20. Ten of them were taken to Olchoro Oirua, where they were wiped out by diseases spread by the tsetse fly.

The 10 white rhinos, donated to Lake Nakuru National Park, survived mainly due to good management by Kenya Wildlife Service.

By the end of last year, the rhinos had multiplied and were more than 100. A few had been translocated to Meru National Park.

The rhino is but only one of the few species of bulk eaters at the park likely to be affected adversely by the fire that destroyed swathes of bush-land and pasture.

Should the prevailing dry spell continue for a few more months, the buffaloes, Rothshchild giraffes, zebras, impalas, warthogs, waterbucks and gazelles will be subjected to stiff competition for available pasture.

The park has more than 3,000 buffaloes and a slightly higher number of impalas, although the sanctuary's carrying capacity for buffaloes is only 500.

In fact, reports indicate that the number of impalas rises to 5,000 when food is abundant.

The park was reputed to have the highest density of waterbucks in Africa in the mid '70s, but their numbers have since dropped significantly due to the stiff competition for pasture.

According to KWS records, the waterbuck population increased from 2,759 in 1986 to 4,979 in 1990 but their number had dropped to only 712 by 2001.

The euphorbia forest, reputed to be the biggest in East and Central Africa, is a popular habitat for the black rhino and the colobus monkey, while the olea is popular with the eland.

Both tree species were affected by the fire and ecologists fear that the impact of the euphorbia loss would be long term due to its long regeneration period.

The euphorbia cover is said to be the remnant of the forest that once extended to the Mau Forest but has since been cleared by farmers.

"It is going to take botanists, zoologists, ecologists and ornithologists time to assess the fire's impact on the entire ecosystem," ecologist Jackson Raini told the Nation.

The park's senior warden, Mr Charles Muthui, said that initial reports indicated that none of the big game perished in the fire. However, reptiles, rodents and other small animals could have been burnt, he added.

KWS records indicate that the woodland is the second largest habit in the park. It is popular with lions, jackals, impalas, giraffes and birds.

Widespread invasive weeds

Even before last week's fire, the park's herbivores were competing for food owing to the widespread invasive weeds such as tarconanthus camphorutus and datura stramonium. The latter is poisonous.

"Tarconanthus camphoratus, which now seems to occupy half the park, has been studied before by range ecologists and has been declared as one of the most troublesome species," the KWS Integrated Management Plan document says.

The document says that the corollary impact of bush encroachment has been severe overgrazing in the park's open grasslands, especially during the dry season. This mainly affects herbivores that are not adapted to feeding in the bushland vegetation.

Prior to 1976, animals in the park had access to the big grazing corridor between Lord Delamere's Soysambu ranch and Suswa in Naivasha.

A report compiled by Lord Delamere's son Tom Cholmondeley a couple of years ago, when he was the chairman of the Nakuru Wildlife Forum, indicated that the ranches had more than 40,000 wild animals, four times the number of animals at the park.

The fencing off of the 188 square kilometres park with a solar powered electric fence in 1986, effectively confined all the herbivores in the sanctuary, leading to the current overgrazing problem.

 

 

 

 

 

 

 

The management of the protected parks is made difficult by the fact that the KWS does not cull wildlife and allows the natural attrition to take its course.

The KWS used to provide ranchers with culling quotas to enable them sell game meat and recover some of their expenses, but this again was withdrawn, leaving the ranch owners to shoulder the burden of maintaining wildlife.

At Soysambu for instance, the Delamere Estate management has to maintain more than 10,000 wild animals alongside a herd of about 6,000 Boran beef cattle.

Left in abeyance

"We spend a lot of money to pump water from boreholes for the benefit of wildlife and livestock which is a very big burden. The wildlife also breaks fences and feeds on food supplements meant for our livestock," the security manager, Mr Jeff Mitto said.

Mr Cholmondeley and the KWS had a few years ago started talks on the possibility of removing the perimeter fence within the Congreve section of Soysambu Ranch to allow herbivores at the park to migrate to the 50,000- acre ranch but the talks were left in abeyance and the overgrazing at the park unresolved.

Although the park has a number of lions, leopards, hyenas and jackals, among other carnivores, the predation rate is low.

A conservationist told the Nation that park could recover the lost pasture if rains come soon. "Grasses will sprout quickly but that is also likely to apply for the invasive weeds," he said, adding that some of the weeds could only be eradicated manually by uprooting which was not easy owing to the large number of dangerous animals and high labour costs.

Lake Nakuru National Park remains the most popular tourist destination among Kenya's protected parks.