CONSERVATORS within the Ngorongoro Conservation Area (NCA) in Tanzania are worried about the pace at which Gutenbergia cordifolia, a killer invasive weed that has now found its way inside the crater, is spreading.
The conservators say almost 40 per cent of the crater has been infested by the invasive species, much to the worry of wildlife experts.
In his interview with The Guardian yesterday, a Wildlife and Range Management Manager with the Ngorongoro Conservation Area Authority, Hillary Mushi, described the invasion of Gutenbergia cordifolia as a serious threat that suppressed the growth of plants mostly preferred by herbivores inside the crater.
“We still consider the invasion and spread of Gutenbergia a serious threat to the NCA’s ecosystem because we have not controlled it at 90 per cent,” explained the wildlife expert.
He, however, pointed out that the NCAA had slashed 1000 acres of land as a way of controlling the weed’s further spread.
Mushi observed that they were only limited to using mechanical methods of controlling the invasive weed as opposed to biological methods due to environmental reasons.
“We do it through mechanical mowing, using tractors before the seeds have fully germinated to control its further spread,” he revealed.
Mushi also revealed that NCAA spent Sh141million in the 2016/17 financial year in controlling invasive plants and other weeds inside the crater.
According to the wildlife expert, Gutenbergia Cordifolia was an Indigenous species which flourished and blossomed during rainy seasons.
He added that such plants dominated places synonymous with environmental disturbance.
Wildlife experts say the Gutenbergia cordifolia invasive weed species has been known to suppress native plants and to dominate more than half of the entire crater floor (250 km2) in the NCA.
The NCA, together with the Serengeti, Lake Manyara and the Masai Mara National Parks form an ecologically and economically important area and hosts a vast variety of larger mammalian species.
However, invasive plants, both native and exotic, have been identified as among the main known threats to the biological diversity of these areas.
In and around NCA alone, for instance, a total of 139 exotic invasive plants have been reported, including Acacia mearnsii, Datura stramonium, Lantana camara, Leucaena leucocephala, Lonicera japonica and Tagetes minuta.
Meanwhile, the NCAA has said it is keeping tabs on the spread of Parthenium hysterophorus, another invasive plant, so that it doesn’t find its way inside the crater.
According to Mushi, wildlife experts had already included Parthenium hysterophorus, locally known as ‘gugu karoti,’ among invasive plants with a potential of causing harm to animals inside the crater.
The invasive weed is said to have originated from Mexico before spreading to central and Southern America.
Studies also show that the killer plant arrived in Ethiopia in the 1980s, and despite the best efforts of scientists throughout East Africa, it still spread to Somalia and Kenya.
In 2010, the Parthenium weed was first identified in Arusha Region before spreading to Kyerwa District at the Ugandan border three years ago.