Govt moves to control killer plant

BABOKI KAYAWE
Staff Writer | Wednesday May 15, 2013 00:00

The Ministry of Environment, Wildlife and Tourism deputy permanent secretary Rapelang Mojaphoko said prosopis' potential threat to biodiversity and the entire ecosystem has prompted her department to control, eradicate or prevent its spread to new areas.

'We have decided therefore that the development of a National Mesquite (prosopis) Management Strategy is required to guide the department and stakeholders in the best acceptable ways of reducing damage and spread,' she said. 

Although the latest rate of the spread of prosopis is not known, an estimated 5,109 hectares was recorded in 2009. Its coverage was largely endemic in the Kgalagadi area, followed by Gantsi and Central district. Officials at Department of Forestry and Range Resources (DFRR) say there is a likelihood that it has increased significantly and infested new areas, which they say calls for an urgent need for reassessment. The biggest negative impact of prosopis relates to its invasive characteristics that allow it to steadily cover areas previously covered by native plants (with many uses for people) and grassland pastures (used by livestock and wild herbivores). 

By this process, it can dominate and destroy all other native and domestic plants.  An environmental expert with the International Union for Conservation of Nature (IUCN) Dr Geoffrey Howard told a DFRR National Stakeholder on Mesquite (Prosopis Species) Management in Botswana meeting in Gaborone yesterday that the species  sends roots down to deep subsurface water and denies this water to native woody and non-woody plants while continuing to grow and stay green.  

Among its worst impacts, according to Dr Howard, is worsening water shortage in water strained areas. The national forum discussed threats and impacts of prosopis on people's livelihoods and the environment. Howard advised that economic ways of tackling prosopis, which has become problematic, especially in south western Botswana, are short-lived. 

He said when such ways are employed, the plant remains a threat to the environment and becomes of slight benefit to people. Although he mentioned many economical ways communities residing in prosopis or mesquite (popularly known as sexanana) infested areas can enjoy, the benefits are more costly - both to humans and the environment, compared to when other means of controlling or managing the plant are used.

He said the prosopis shrub can be used as a shade to reduce the impact of dust-storms, as well as for enhanced honey production, fire wood and charcoal. 'Pods are eaten by livestock and can be eaten by people in small quantities and are made into cookable flour in some places.

Round up pods can be turned into commercial stockfeed,' he said. In instances where it grows very tall, the tree can be used in timber manufacturing. Moreover, gum exudates are collected from prosopis trees in some places for the food and pharmaceutical industries.

Fredrick Titus is chairperson of the BORAVAST Community Trust, which covers the villages of Bokspits,Rappelspan, Vaalhoek and Struizandam. He said given the positives that communities can enjoy from prosopis, he is against the eradication of the plant. Titus mentioned that prosopis originates from South America.