Tuesday, 14 November 2017

Kafue Flats: A threatened wetland

Moonga (left) is worried about the spread of the Mimosa plant. (Main picture) A small herd of the Kafue Red Lechwe with a flock of water birds.

Kafue Flats: A threatened wetland

BACK in April, while flying from Mongu, I beheld its breathtaking beauty – like a huge canvas painting spread for miles on end.

Even from a thousand metres above, the eyes could only frame in so much of the shades of green broken by shimmering patches of silver, turning to gold as the afternoon sun waned. Such is the beauty of the Kafue Flats.
After coursing for several hundred kilometres from its source at Kipushi on the border with the Democratic Republic of Congo, the Kafue River seems to just dissipate, breaking up into oxbows, lagoons, tributaries and ponds. The result is this expanse of grassy plains covering an area of 6,500sq km.
Six months later, here I was again crossing the flats, except this time I was not flying over it, but driving through it.
And sadly, the picture-perfect image of the Kafue Flats that I had seen from the skies is not as perfect from the ground.
This grassy wilderness, which is home to the Kafue Red Lechwe, an endemic antelope species, is under threat from human activities and an invasive plant called Giant Sensitive Tree or Mimosa Pigra, a native of Central America. The “sensitive” in its name probably refers to its reaction to touch – the Mimosa’s leaves retract when touched.
The plant is believed to have been introduced by European farmers in the pre-independence period who had settled in the Lochinvar area.
According to Griffin Shanungu, a leading ecologist working for the Department of Wildlife and National Parks, the increase in the area covered by woody and shrub species in Lochinvar National Park on the Kafue Flats has impacted mammal habitats by reducing the area of grassland.
And here, the Mimosa has no natural enemy, and is armed with sharp spikes to defend itself. The Mimosa has already claimed over 20 percent of the parkland in Lonchinvar, blocking access routes for the Lechwe, while in some instances it has pushed the animal closer to human habitations in the game management area.
Mr Shanungu says studies show that in 1980, the plant only covered about two hactares.
“By 1986, that shrub had covered about 100ha, and now, the cover of Mimosa Pigra is about 3,000ha,” he says.
There is now an ambitious plan to physically remove the plant, although other means such as biological and chemical methods are still being studied.
Mr Shanungu says the spread of the Mimosa is a big conservation issue on the Kafue Flats.
“If it is left unchecked, we face a risk of the entire wetland area within the Kafue Flats being occupied by this plant. It is not eaten by anything, the local people don’t use it for firewood, so if nothing controls it, it will just continue growing. We will wake up one day to find that the huge swath of grassland has been overtaken by Mimosa Pigra and all the animals displaced. And we will lose an animal that is not found anywhere else but here in Zambia, and that will be a disaster,” says Mr Shanungu.
There may be various reasons for the spread of the Mimosa Pigra, but one of them, according to Mr Shanungu, could be the changing hydrology of the Kafue Flats.
The Kafue Flats sit between two dams – the Itezhi-tezhi Dam and the Kafue Gorge – and that in itself has created problems for the wetland. In many ways, the natural hydrology of this landscape has been altered.
While the two dams answer to the country’s ever increasing energy needs, and account for about 50 percent of the hydroelectricity produced, their existence may have huge negative impact on this ecological area.
“We never used to have this lagoon before. The water used to start from there,” says Wilfred Moonga, the area warden as we stand at the edge of a pool of water.
Because of unnatural flooding, areas that never used to get flooded are now under metre-high water while others have become drier.
According to a 2017 status report of the Kafue River by the World Wide Fund for Nature (WWF), the impact of human influences and socio-economic development on the Kafue Flats wetland ecology has largely been negative.
“While the details of the causal linkages require further investigation before conclusions can be drawn, it is clear that the change in the flow regime due to the construction of the Itezhi-tezhi and Kafue Gorge dams for hydropower production has been one of the key drivers of change. Changes in floodplain habitat availability and vegetation community structure, mainly the reduction of the area of grassland which constitutes the original floodplain vegetation and breeding habitat for waterbirds and fish, have had the most direct impact,” the report says.
Mr Moonga says there is need to find a way of regulating the water flow to mimic the natural flooding of the area in order to restore the integrity of the wetland and the animals that depend on it.
Kafue Flats is one of the most important ecological zones in Zambia with unequalled biodiversity, with over 400 bird species. It also supports about one million people and the country’s largest cattle population in Namwala.
The disturbance of the Kafue Flats also spells doom for the Kafue Lechwe.
About a century ago, the Kafue Lechwe roamed these plains in their hundreds of thousand, but now only a few thousand remain to fight a seeming unwinnable battle against poachers who have found a ready market in the capital, and an invasive plant that is claiming more and more of its habitat by the day.
The first documented count of Kafue Lechwe in 1931 revealed an estimated 250,000 animals on the flats. By the 1970s, the six-digit figure had fallen to about 93,000. By the early 1980s, the population had decreased by more than half, and was restricted to the areas protected by Lochinvar and Blue Lagoon National Parks and the surrounding Game Management Area.
In the most recent aerial survey conducted by the Department of National Parks, Kafue Lechwe numbered about 28,000.
According to the department, approximately 1,000 Kafue Lechwe are lost to poaching on the Kafue flats annually.
The Kafue Lechwe is now fighting extinction, and is listed as vulnerable by the International Union for Conservation of Nature in 2008.
The Kafue Lechwe may not be as iconic as other endangered species such as the rhino, but it is considered as a keystone species of the Kafue Flats, meaning the existence of this ecosystem is hinged on its survival.
“It is easy for us to reverse the negative trends. If we put our resources together and empower the government departments that are working there, we can completely conserve that animal. It only takes protecting it from massive poaching, it only takes us investing resources to remove that invasive plant and the population will start increasing again,” Mr Moonga says.
Without any deliberate action, the lechwe could become extinct in just a few years. The only Kafue Lechwe future generations may be able to see is the life-size sculpture of the antelope in the lobby of the Kenneth Kaunda International Airport.

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