Invasive aliens threaten stressed water supply

Posted by: Saving Water SA (Cape Town, South Africa) – partnered with Water Rhapsody conservation systems – 08 October 2010

Climate change is likely to increase the threat invasive alien Acacia plants, including wattles, rooikrans and Port Jackson, pose to South Africa’s already highly stressed water supply.

It will cost R34 billion to rid South Africa of invasive alien plants

In a written reply to a parliamentary question, tabled on Friday, Water and Environmental Affairs Minister Buyelwa Sonjica said recent studies showed some Acacia species could respond to warmer conditions by developing stronger, deeper root systems, which sucked up more water.

“The research on the impacts of climate change on the ability of invasive alien plants species to out-compete indigenous vegetation is being led by the SA National Biodiversity Institute.

“So far, one of the most significant findings was that the root and shoot systems of some Acacia species could become stronger, which means that they will be able to access water deeper below the soil surface.

“This could make them more aggressive and increase the potential for invasions, leading to an even bigger threat to our natural resources and biodiversity.”

Research on this was ongoing, but “very expensive” and dependent on the availability of funding, Sonjica said.

Earlier this year, an Agricultural Research Council (ARC) report, commissioned by the department of water affairs, found invasive alien plants now infest 20-million hectares of South Africa — an area twice as large as previously estimated.

Among the ARC’s findings were that invasive black, green and silver wattles alone have taken over more than 1.6-million hectares of the country.

The two most badly affected provinces in this regard are the Eastern Cape and KwaZulu-Natal, where an estimated 600,000 and 300,000 hectares (condensed areas) respectively have been overrun by alien wattles.

In her written reply, Sonjica said recent research — by the Water Research Commission — in KwaZulu-Natal showed stream flow increased by 75,000 cubic metres a year after 65.4 hectares of invasive black wattles were cleared from one study area.

She said the research had also shown that reduction in stream run-off per hectare was twice as great in wattle-infested areas adjacent to streams compared to water losses in infested areas further away from them.

Earlier this year, a senior water affairs official told Sapa that a “conservative” estimate of what it would cost to rid South Africa of invasive alien plants was R34 billion, spent over the next 25 years.

Related Article: Alien plant coverage shocks Water Affairs

2010 – The International Year of Biodiversity

Posted by: Saving Water SA (Cape Town, South Africa) – partnered with Water Rhapsody conservation systems – 20 September 2010

South Africa is considered among the top five most mega-diverse countries in the world, boasting almost 10% of the world’s known bird, fish and plant species and over 6% of the world’s mammal and reptile species contained on a land surface of only 1,1 million square kilometres (1% of the Earth’s total land area).

To highlight the crucial role nature’s rich diversity plays in our lives, the United Nations (UN) has declared 2010 the International Year of Biodiversity (IYB-2010).

Tswaing Crater,about 40 km north of Pretoria, is extraordinarily rich in fauna and flora.

According to the UN Secretariat of the Convention on Biological Diversity, biodiversity (the variety of life on Earth), is essential to sustaining the living networks and systems that provide us with health, wealth, food, fuel and the vital services our lives depend upon.

The Convention, of which South Africa is a signatory, covers all ecosystems, species and genetic resources, linking traditional conservation efforts to economic goal of using biological resources sustainably, setting principles for the fair and equitable sharing of the benefits from use of genetic resources, notably for commercial use and covering rapidly expanding field of biotechnology, and addressing technology development and transfer, benefit- sharing and biosafety.

Unfortunately, South Africa’s increased population growth, habitat destruction, overexploitation, pollution and the introduction of invasive alien species are all placing increasing pressure on our natural systems.

This holds particularly true for South Africa’s freshwater ecosystems, with the 2006 South Africa Environment Outlook indicating that 82% of the country’s main river ecosystems are threatened. Continue reading

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