Exotic plants invade parks

Menace. Invasive plants drive wildlife such as elephants away from parks and into human settlements in search of pastures. PHOTO BY DOMINIC BUKENYA.

What you need to know:

  • Under threat. Invasive alien plant species have taken over at least two of Uganda’s national parks, reducing pasture for wildlife and threatening tourism income.

Uganda Wildlife Authority (UWA) has launched a Shs500m multi–pronged pilot project to fight Invasive Alien Species (IAS) that are threatening to take over two of Uganda’s most popular National Parks. The affected parks are Queen Elizabeth and Lake Mburo.
“Sixty five percent of the area in Queen Elizabeth rotected area has been colonised by the Invasive Alien Species while about 85 per cent of Lake Mburo National Park is also affected,” says Dr Peter Beine, the national project coordinator, National Agricultural Research Organisation (NARO).
That means 1,256 square kilometres of Queen Elizabeth National Park is under the Invasive Alien Species leaving only 722 square kilometres of unaffected area for animals. The park measures 1978 square kilometres. Bad as this sounds, Lake Mburo is in a worse situation with only 39 km² out of 260 square kilometres unaffected by the invasive species.
The project to get rid of the alien species is implemented by Uganda Wildlife Authority together with the National Invasive Species Coordination Unit (NISCU), a branch of NARO with technical support from the Inter-Ministerial Working Committee (IMWC-IAS) composed of representatives from the various IAS-affected countries, ministries, departments and agencies.
The International Union for Conservation of Nature (IUCN) defines Invasive plants as non-indigenous or non-native plants that adversely affect the habitats they invade economically, environmentally or ecologically.
Threat to wildlife
A recent analysis of IUCN red list data highlighted invasive alien species as the third most severe threat to birds and mammals.
“These invasive species are a result of global warming. They are a threat to tourism and are one of the main causes of human – wildlife conflict. They eat up the pasture for wild animals forcing the wildlife to community lands. They close up areas for game viewing making it difficult for tourists to see the animals,” the Former UWA Executive Director Dr Andrew Seguya said while launching the exercise along with State Minister for Tourism Godfrey Kiwanda in Queen Elizabeth National Park on March 22.
Tour operators have long complained about lack of animals in the park. “It is hard to come by animals in Queen Elizabeth National Park. Let us hope that this exercise will bring back the animals so that tourists get value for their money,” says Samuel Mugisha, the Proprietor of BIC Tours.
To combat the menace, UWA contracted the services of National Invasive Species Coordination Unit to pilot an integrated management project for selected Invasive Alien Species.
The fight against the weeds is multi-pronged and involves the application and use of mechanical, cultural and classical biological control approaches.
The mechanical approach involves a team of trained casual laborers using, axes, pangas and hoes to get rid of the unwanted vegetation. In Queen Elizabeth National Park an excavator is being used to uproot sickle bush which is then burnt.
In Lake Mburo National Park, war has been declared on Acacia hockii and an extermination campaign launched against Sickle bush Dichrostachys cinerea and Famine or Congress weed Parthenium hysterophorous in Queen Elizabeth National Park respectively.
“All parts of the uprooted invasive plants will be burnt and those that sprout gain will be uprooted to meet the same fate,” says Dr Beine.
The cultural fight involves the recruitment of community members to work as casual labourers in a bid to keep them away from engaging in illegal activities.
Weevils to eradicate weeds
Classical biological control will involve the importation, multiplication and release of weevils to eat up the sickle bush in Queen Elizabeth National Park. The selected bio-control agents will be tested for host specificity and multiplied in rearing facilities at the National Invasive Species Coordination Unit (NISCU) bio- control research facilities at Namulonge.
The classical biological control approach will involve the release of multiplied weevils to eat up the target plant. He revealed that the water hyacinth in Lake Victoria was contained using the biological control method where weevils were deployed that eat up the weed.
“The weevils are very specific feeders. They feed on the weed and nothing else,” he says.
African countries where invasive species have been successfully controlled using similar methods include; Ethiopia, Ghana, Zambia and South Africa.
“The Pilot Project is expected to cost about Shs559m but most of it will go to procurement.” Beine says.
The objectives of the project are to restore wildlife habitat and reduce the exodus of animals to the neighbouring community farms, plant palatable pastures in the cleaned up areas of the parks to increase availability of wildlife feeds and suppress the regeneration of unpalatable plant species.
The fight against these IAS will also spread to monitoring the impact of wildlife habitat rehabilitation, rangeland utilisation and changes on key wildlife populations. UWA also hopes to develop Invasive Species Management Strategy and make policy recommendations that enhance sustained Invasive Species management at local and national levels.
The acacia cleared in Lake Mburo will be sold to schools as firewood and to those who want to make charcoal. Where the acacia is removed, pasture will be planted to provide soil cover and animal feeds.
For sustainability of the project, a team of botanists will be constituted from Makerere University to survey and document the existing flora and fauna in the project target areas of both parks to generate information which will form the baseline data sets for future monitoring of impacts and effectiveness of the programme.