Alien plant coverage shocks Water Affairs

Posted by: Saving Water SA (Cape Town, South Africa) – partnered with Water Rhapsody conservation systems – 28 July 2010

Invasive alien plants now infest 20-million hectares of South Africa – an area twice as large as previously estimated.

Wattles have taken over more than 1.6-million hectares of South Africa

The shock finding comes from an Agricultural Research Council (ARC) report commissioned by Water Affairs.

“The previous figure was 10 million hectares. We knew this was an under-estimate, but we didn’t think it was this big. It’s come as quite a shock,” the department’s natural resource management programme operations head, Christo Marais, told Sapa.

The ARC had briefed the department on the new estimate at a Working for Water (WfW) implementation meeting earlier this month.

Marais said it had long been obvious there was an under-estimation of the scale of the problem, particularly in the Eastern Cape and KwaZulu-Natal.

Invasive alien vegetation, including various species of wattle, pine, poplar, weeping willow, gum trees, hakea and prickly pear, among others, pose a serious threat to South Africa’s water supply, as well as the country’s agricultural potential and biodiversity.

If the 20-million hectares of alien invasive vegetation across the country could be condensed into a single area, it would form a dense, impenetrable thicket about twice the size of the Kruger National Park. Continue reading

Water markets follow trend set by carbon markets

Posted by: Saving Water SA (Cape Town, South Africa) – partnered with Water Rhapsody conservation systems – 11 May 2010

By: Christo Marais – Working for Water: Natural Resource Management Programmes

It has often been said that environmentalists are “underselling the value of their products” with the result that their arguments are not being heard in mainstream economic debates. Historically, we have not been willing to put a value to biodiversity and environmental services. How do we value nature and what is the value of nature, they have argued. During the last few decades though, this has begun to change.

Pezula's rehabilitation programme has cleared over 300ha of alien trees and vegetation

With the advent of global climate change and the need for carbon sequestration and mitigation measures, the global face of natural resource management has changed. Although not as well-developed internationally, water markets are following the trend set by the carbon market.

So often when water resource management is being considered, the management options focus on augmentation and engineering solutions to water quantity and quality rather than the full spectrum of resource management options.

The impact of land management and the management of natural water resources such as wetlands, rivers and catchments is seldom seriously considered. For example, the drying up of our catchments, degradation and transformation of our wetlands, river banks and floodplains impacts on the proper functioning of these water resource systems by decreasing the amount of water absorbed into the systems and increasing the intensity of floods.

Furthermore, when invasive alien trees out-compete natural vegetation in these areas, this results not only in changing the flows, but also causes major water losses due to significantly increased water use.

This has a direct impact on the availability of water in our rivers, aquifers and even on the yield of dams.

A recent study has shown that 4 percent of utilisable water, or registered water use, is being lost due to invasive alien trees in our catchments, wetlands, river banks and floodplains. If left unchecked, this could increase to more than 16 percent within a relatively short period of time. Continue reading