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Posted by Enviroadmin
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Monday, 24 May 2010 18:43 |
Cape Town – The government‘s key Working for Water (WfW) programme, aimed at eradicating invasive alien plants that cause billions of rands‘ damage to the economy each year, appears set to fall further behind in its efforts to contain the problem.
According to figures tabled at a meeting of Parliament‘s water affairs and forestry committee yesterday, the rate at which WfW plans to clear the plants over the next three years is considerably slower than the rate at which they are spreading. Water affairs department chief financial officer Onesmus Ayaya said projections were 120 000 hectares would undergo “initial” clearing in the 2008/09 financial year.
Another 120 000ha would be cleared of invasive alien plants the next year, and a further 150 000ha in 2010/11.
According to the most recent South Africa Yearbook, alien plants have so far invaded more than 10 million hectares, about eight per cent of the country. Their numbers are projected to double over the next 15 years.
At this rate, the WfW will be “chasing the target all the time”, ANC MP Jonathan Arendse suggested. “If we continue at this rate, will we ever catch up?” he asked.
He questioned if enough money was being allocated to deal with the problem.
Ayaya said the programme – which started in 1995 – is to receive R472,3-million next year, R521,2-million in 2009/10, and R665,9-million in 2010/11. – Sapa
Source: http://www.theherald.co.za/herald/news/n20_01112007.htm
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Posted by Enviroadmin
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Monday, 24 May 2010 18:43 |
CHICAGO, Illinois, October 11, 2007 (ENS) - Sleeping Bear Dunes National Lakeshore on Lake Michigan is in danger of being loved to death. High numbers of visitors are trampling down vegetation and erosion is occurring in high traffic areas. Water quality and the ecological integrity of Lake Michigan at the Dunes is in poor condition due to invasive species such as quagga and zebra mussels, which have taken over most of the lakebed.
At Sleeping Bear Dunes, the toxic chemicals most present in the air are toluene, xylene-iso, benzyne, formaldehyde, and trichloroethylene, xylene-m, and perchloroethylene. The sources of these pollutants have not been determined. Both sulfates and nitrates are found in concentrations higher than national averages.
Deferred maintenance costs at Sleeping Bear Dunes are about $11.2 million, while the cost of needed rehabilitation tops $8.8 million.
The plight of this national park and that of five other Great Lakes parks are detailed in a new report by the National Parks Conservation Association, NPCA. The parks studied include all four of the U.S. national lakeshores.
"The parks support a variety of wildlife, provide abundant recreational opportunities, and help support regional economies, so it is crucial that we ensure they are well protected and get the funding that they need and deserve," said Lynn McClure, NPCA Midwest regional director.
According to NPCA's Center for State of the Parks report, the six Great Lakes parks face threats from air and water pollution, non-native species that are damaging ecosystems, adjacent development, and funding shortfalls that are threatening every aspect of the parks.
Researchers used established, peer-reviewed methodologies to systemically rate conditions of both natural and cultural resources at five of these six parks; only cultural resources were assessed at Keweenaw National Historical Park.
* At Apostle Islands, there are only two permanent environmental staff responsible for protecting 21 islands spread over 265,000 acres; sandscapes and beach grasses are at risk from trampling and invasive plant species. Rare plant communities are threatened by rapidly increasing white tailed deer populations. Historic buildings at six historic lighthouses, some of which are major visitor attractions, need new roofs, painting, and other maintenance that is beyond the park staff's ability to keep pace with.
* At Indiana Dunes, pollution from ozone, sulphur dioxide, sulfate, and mercury from surrounding industrial facilities harms the air quality of the park. Indiana Dunes National Lakeshore is downwind of Gary, Indiana, and Chicago, Illinois, a region of heavy industry. Contamination from runoff, industrial pollution, and sewage systems degrades park waters, including Lake Michigan. The park's dunes are retreating due to adjacent shoreline development that prevents the natural deposit of sand that replenishes the dunes.
* At Isle Royale, airborne mercury and sulphur dioxide that are deposited in park waters and on park lands are of grave concern to park managers; non-native species found in Lake Superior, such as the spiny water flea and sea lamprey, are threatening native fish species in park waters.
* At Keweenaw, development on private lands within and adjacent to the park, and an incomplete knowledge of those resources not owned by the park, threatens historic structures and archaeological sites. The park also lacks a visitor center, which would make information on the park available year-round and provide a place to display museum objects that are currently in storage.
* At Pictured Rocks, non-native species competing for resources with native plants and animals have contributed to a decline in species including fresh water clams and native coaster brook trout. Sensitive dune habitats are threatened by inappropriate visitor use and some critical historic structures such as Coast Guard stations and lighthouses are in poor condition. The park's museum collection, which features artifacts from shipwrecks, local logging and maritime history, and American Indian life, is not maintained at a professional level due to lack of staff and appropriate storage facilities.
* At Sleeping Bear Dunes, the invasion of species that were not originally part of the local ecosystem, including the Baby's Breath plant in the park's namesake dunes, is threatening biodiversity. The invasive mussels' feeding habits lead to other problems such as shorebird deaths from botulism, which has killed hundreds of loons.
Farms, villages, lifesaving stations and lighthouses, and prehistoric archaeological sites are all in need of maintenance.
McClure says, "Park visitors expect to find healthy ecosystems, clean air, and well-maintained historic sites, but this is not always the case. Each of the Great Lakes national parks assessed in this report faces threats on those fronts. NPCA hopes that this report will inspire people to take action to protect and preserve those parks for present and future generations."
NPCA launched its State of the Parks program in 2000 to assess the health of national parks across the country. To read the full report, click here.
Source: http://www.ens-newswire.com/ens/oct2007/2007-10-11-01.asp
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Posted by Enviroadmin
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Monday, 24 May 2010 18:42 |
Engela Duvenhage
Research on the springtails of sub-Antarctic Marion Island, conducted by scientists from Stellenbosch University and from Norway, shows that interactions between climate change and invasive species pose a major challenge to biodiversity, and therefore to human welfare.
In a paper in the latest edition of the Proceedings of the Royal Society B: Biological Sciences titled "Phenotypic plasticity mediates climate change responses among invasive and indigenous arthropods", the scientists investigated the synergies between the effects of climate change and invasion.
These have long been thought to pose a major potential challenge to biodiversity.
"Empirical evidence for such synergy has been lacking," says lead author Prof Steven Chown, director of the DST-NRF Centre of Excellence for Invasion Biology (CIB) based at Stellenbosch University, "but our research has now shown how climate change benefits invasive species because of the way in which they respond to the environment."
"In essence, invasives like it hot, whilst indigenous species like it cold," he said, summarizing the study.
He was joined in the research by CIB colleagues Dr Sarette Slabber, Prof Melodie McGeoch and Charlene Janion, as well as Prof. Hans Petter Leinaas of the University of Oslo in Norway.
They showed that in a temperate terrestrial ecosystem, invasive and indigenous springtail species differ in the form of their phenotypic plasticity such that warmer conditions promote survival of dry conditions in the invasive species and reduce it in the indigenous ones. 'Phenotypic plasticity' is the ability of individuals to modify their behaviour, morphology or physiology in response to altered environmental conditions.
Significant declines were seen in the densities of indigenous species and little change in those of invasive species in a manipulative field experiment on Marion Island that mimicked climate change trends.
Marion Island has a cool, wet, windy climate that has shown substantial change over the past 50 years, including an increase in mean annual temperature of more than 1°C and a decline in precipitation of more than 500 mm per annum. In other words, it is showing global change-type drought.
The island is home to 16 springtail species. Five of these are invasive and thought to have been introduced following the establishment of the South African scientific station on the island in 1947. Samples of the six most commonly found species were subjected to controlled laboratory experiments as well as field experiments to test the impact that various temperature and precipitation levels had on their ability to survive.
"We suggest that it is not so much the extent of phenotypic plasticity that distinguishes climate change responses among these invasive and indigenous species, as the form that this plasticity takes," Prof Chown says.
"Nonetheless, this differential physiological response provides support for the idea that in temperate terrestrial systems experiencing global change-type drought, invasive species may well be at an advantage relative to their indigenous counterparts."
"Also, the density of indigenous species declined dramatically when exposed to dry conditions, while invasive species density was unaffected in field. The laboratory and field work nicely match to show that climate change will benefit invasive species at the expense of their indigenous counterparts."
Source: http://www.scienceinafrica.co.za/2007/august/climate.htm
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Posted by Enviroadmin
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Monday, 24 May 2010 18:41 |
Where are the worst alien invasive plant infestations in the Shongweni /Assegay area?
If you are interested to know more about the problem of invading alien plants in the Outer West, this is an
opportunity to meet residents and other concerned individuals and to be able to share ideas on how this
problem can be overcome.
WHEN - Sunday 12th August 9-30 for 10-00am
WHERE - Meet outside the Polo Pony Zenex filling station at Assegay
WHAT - A brief tour of the immediate area to see the extent of the problem, followed by an informal gathering
at the Giba Gorge conference centre (next to Stockville Quarry) where light lunches will be available. (See
menu below)
Note - Those who may also be planning to attend the Plant Fair volunteer orientation afternoon at Tonic Nursery
may continue from the Giba Gorge centre after lunch - it is just a short drive up the hill!
Interested?
Phone Wally Menne (wally_m @ iafrica.com 082-4442083) for further details and directions if required
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Posted by Enviroadmin
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Monday, 24 May 2010 18:41 |
* If you own land, keep it clear of invading alien plants (see note below).
* Do not buy invasive alien plants from nurseries, and do not support nurseries that sell such plants.
* Join a volunteer clearing or hack group
* Buy firewood, charcoal, crafts, furniture, toys, building material, mulch, etc made from invading alien plants.
* Do not bring foreign plants and animals into our country – and do not send ours to other countries (see research section, paper on vectors).
* Inform authorities about land-owners who are causing the spread of invading alien plants.
* Encourage your local authority, agricultural union, school, community, etc to work with the programme.
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Posted by Enviroadmin
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Monday, 24 May 2010 18:40 |
By Guy Rogers Environment & Tourism Editor
The Herald - 31 Jan 2006 - http://www.theherald.co.za/herald/news/n27_31012006.htm
LONG-crested eagles, once thought to be on the decline in the region, appear to be making a comeback, as alien trees are cut back and natural water sources freed up.
That’s the assessment of Endangered Wildlife Trust field biologist Adri Bark- huyzen, the co-ordinator of the East Cape Raptor Conservation Forum, who identified a strangely top-knotted bird spotted and photographed by The Herald’s Fredlin Adriaan.
Adriaan was travelling along Willow Road, which bisects a large piece of open land in Overbaakens, when he saw the bird perched on a lamppost.
Barkhuyzen said it was, unmistakably, a long-crested eagle – a chocolate-brown, medium-size raptor, most recognisable by its whip-like black feather crest.
“It’s a very exciting sighting because it’s another confirmation of what we have being noticing over the last five years or so – that these birds are starting to return.”
Historically, the species occurred in moist areas on the eastern side of sub-Saharan Africa and it was a familiar resident as far south as the Garden Route. By 20 years ago, however, it was hardly seen at all south of Transkei and concerns were raised that it could be dying out.
The Working for Water Project (WWP), aimed at eradicating alien trees, was launched in 1998. These aliens suck up much more water than indigenous species and also lead to the destruction of biodversity – the myriad different plants and animals that occur naturally.
Barkhuyzen said a number of vleis around the metro and further afield where the WWP had been working had been restored or expanded through this work.
This in turn was bringing back the prey species that the long-crested eagle loves eating, especially vlei rats.
“The bird photographed here is probably a youngster travelling through, looking for a good feeding zone.”
Long-crested eagles build small platforms of sticks and leaves in the upper forks of big trees and while they prefer indigenous forest where it is available – as in The Island Nature Reserve on the Sea- view Road or out at Woody Cape – they have been recorded as nesting in alien gum trees.
Barkhuyzen said this conundrum might have been avoided if the city fathers had replanted yellow-woods and other indigenous trees after clearing out so many from watercourses like the Baakens.
“The big trees we have now are the gums and pines. Getting rid of aliens is great in terms of restoring the water table and bringing back prey, but we need these alien trees to take the place of the indigenous ones we removed.”
Overbaakens and Fairview had been earmarked for large-scale housing development, but ways could and should be found to save some space for the many raptors in the area, he said.
By Guy Rogers Environment & Tourism Editor
The Herald - 31 Jan 2006 - http://www.theherald.co.za/herald/news/n27_31012006.htm
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Posted by Enviroadmin
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Monday, 24 May 2010 18:39 |
From Science in Africa - http://www.scienceinafrica.co.za/2005/september/biodiesel.htm
Introducing an alien species into the environment, even if it could potentially contribute to rural employment and poverty alleviation and an alternative source of bio-fuel, is not an easy consideration. The social, economic and environmental implications need to be well understood. Investigations are currently underway to determine the potential for South Africa to 'grow' its own energy in the form of a bio-diesel producing tree. Lani Holtzhausen reports.
A three-year hydrological investigation is currently underway to determine the potential impact of the bio-diesel producing Jatropha curcas tree on local water resources.
The Jatropha curcas tree, which originates from Mexico, has long since been cited as a way for South Africa to increase its use of renewable energy sources. The prime ingredient in the manufacture of bio-diesel is vegetable oil (e.g. sunflower oil, soya or peanut oil); however, these oils are edible and generally fetch high prices, which preclude them from being used in bio-diesel production.
Research indicated that Jatropha curcas, whose oil-producing seeds are inedible (toxic) to humans, and most animals and birds, merited serious consideration as a viable alternative. Now initiatives have been proposed to introduce this exotic species for large-scale planting and bio-diesel production in the country.
Growing Bio-diesel
A small tree or shrub with a maximum height of 5 m, Jatropha curcas reportedly grows readily in areas of low rainfall (from 250 mm a year) and in poor soils, however, yield is strongly affected by growing conditions. The trees are easy to establish (from seeds or cuttings), grow relatively quickly (producing seed after their second year) and are hardy to drought, although they are relatively sensitive to frost.
The seeds of the Jatropha contain high percentages (30%-35%) of oil, which can be extracted easily for further processing (transesterification) and refinement. This processed oil can then be used in diesel engines after minor modifications. To avoid engine modifications the bio-diesel can also be blended with convention-al diesel. On average, each mature tree produces about four kilograms of seed per year.
The byproducts of the bio-diesel processing plant are nitrogen-rich press cake and glycerol, which are said to have good commercial value as fertiliser and as a base for soap and cosmetics respectively. The leaves, root and bark could also have potential for numerous other industrial and pharmaceutical uses.
Assessing the potential impact
However, while this could provide welcome income to rural communities, the potential impact of the crop on the country's environment has to be considered. There are several concerns around the affect of such a species on the country's already scarce water resources as well as the possible invasive nature of the plant.
The Water Research Commission (WRC) has launched a three-year research study into the water re-source-related impacts of large-scale planting of Jatropha curcas. Two sites have been identified in KwaZulu-Natal where the water use patterns of existing Jatropha trees are currently being studied, namely at the Owen Sithole College of Agriculture near Empangeni, and on the Makhatini Flats between Jozini and the Makhatini Research Station.
Mark Gush of the CSIR Land Use Hydrology Group in Pietermaritzburg, who is leading the technical research team, explains that transpiration (sap-flow), climate and site water balance measurements are being conducted at each site. This includes soil moisture measurements beneath the selected trees in comparison with the soil moisture of unplanted grassland sites nearby.
An automatic weather station has been set up at each site for climatic measurements. These include rainfall, wind direction/speed, solar radiation, and temperature and humidity measurements.
The heat pulse velocity technique is being applied to determine the water use of the trees. This is done by measuring the sap-flow (transpiration) through the trees. A short pulse of heat is injected by means of a probe into the sap-conducting wood (xylem) of the tree. As the pulse of heat is carried up the tree by the sap, temperature-sensitive thermocouples detect the sap-flow velocity from the rate of ascent of this pulse in the stem. Sap-flow velocity by the cross-sectional conducting wood area gives the volume flow of water per unit time.
In addition, soil moisture and soil water potential sensors have been imbedded in the soil at the two sites. The project will look at hydrological impacts of Jatropha curcas by means of detailed plant water use, soil moisture, and site water balance measurements.
The data should reveal whether there is movement of water down through the soil into the groundwater table (i.e. excess water) or whether there is a net loss of water from the ground-water system. The team will also be able to determine where the tree is getting its water from i.e. near the surface or from deep underground sources.
Remote data collection
Measurements are taken hourly and all of the data are fed into a logging system. Data are downloaded remotely to the CSIR Pietermaritzburg office via cell phone link. While saving time and transport costs it also allows for rapid analysis of potential problems.
WRC Research Manager Renias Dube tells the Water Wheel that measurements will be taken for the next year to determine the Jatropha's water requirements throughout the seasons. Hereafter a modelling exercise will be undertaken wherein site-specific simulations of water use will be verified against the measured data and extrapolated to a larger scale.
While it is still early in the project, the research has already yielded some interesting results. For example, early indications are that the trees at the Owen Sithole site are using more water than the nearby grassland.
There are clear diurnal patterns to the sap-flow with no transpiration occurring at night. The trees, which are deciduous, also seem to effectively 'shut down' during dry periods and in winter when they lose their leaves. Peak transpiration rates occur during the warm, wet summer months.
Once this project has been completed the relevant national government departments are expected to undertake specific environmental impact assessments to determine whether this wonder species is destined to be introduced on a wide scale in South Africa. The verdict is likely to weigh up the negatives such as potential for invasiveness, likely hydrological impacts, and the feasibility of using alternative seed-oil producing species, against the potential benefits to local communities and the national economy, of this species.
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Posted by Enviroadmin
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Monday, 24 May 2010 18:39 |
Invading alien plants (IAPs) are the single biggest threat to plant and animal biodiversity. IAPs have become established in over 10 million hectares of land in South Africa. The cost of controlling IAPs in South Africa is estimated at R600 million a year over 20 years. If IAPs are left uncontrolled, the problem will double within 15 years. IAPs waste 7% of our water resources; reduce our ability to farm; intensify flooding and fires; cause erosion, destruction of rivers, siltation of dams and estuaries, and poor water quality and can cause a mass extinction of indigenous plants and animals.
KEY STATISTICS:
750 tree species and 8 000 herbaceous species introduced into South Africa
1 000 introduced species are naturalised, 200 are invasive
84 species introduced from South and Central America
14 from North America
30 from Australia
29 from Europe
36 from Asia
45% of species from Australia have become important pests
From: http://www.dwaf.gov.za/wfw/problem.asp
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Any advice will be most welcome.
