Two of the world's worst water weeds are on the loose in Adelaide. There are fears the weeds could spread from backyard ponds and water features into creeks and rivers, where they smother native wildlife. The Adelaide and Mount Lofty Ranges Natural Resources Management Board is running a campaign to seek and destroy the weeds, spurred on by reports the plants were offered for sale at northern suburbs markets and garage sales. Three investigations are under way, as authorities crack down on the illegal trade. Salvinia and water hyacinth are both declared pests. Their movement or sale can incur fines of $10,000 to $50,000, says Michael Garrod from the NRM Board.
"Both of these plants grow very quickly, and form dense mats that reduce water quality, increase evaporation, impede water flow, block irrigation channels and threaten aquatic ecosystems," he said. "If they get into our waterways, we could expect to see the deaths of many native fish, crustaceans and other aquatic animals, as well as serious damage to our water supply infrastructure." He said the weeds had been "circulating for a while through personal networks" but the fact the plants were now being offered for sale was of "great concern, as the circulation increases dramatically". "We encourage people to purchase, preferably natives, from reputable nurseries, which will minimise the risk of purchasing and spreading rogue plants."
David Newble from West Lakes Shore said his wife became concerned about the plants in her pond when she saw an advertisement in the paper. The authorities were called in and the suspects identified as water hyacinth, "the world's worst aquatic weed". "It just floats on the surface and seems to reproduce quite rapidly, which of course was quite good as far as we were concerned, but not so good for the waterways of Australia," he said. He said they'd picked up the weed from friends, "they say `We've got a good weed that grows in the pond, would you like some?". *Adelaide Now
Some of the world’s worst introduced invasive noxious water weeds have escaped from garden ponds into local Australian waterways. Native provenance water plants and any edge plants play an important role in nutrient buffering, bank stabilisation and sediment trapping.
Oxygen is the single most important water quality parameter and submerged native plants help to oxygenate the water. Native aquatic plants also play an important role in providing habitat for many organisms, particularly birds, amphibians, fish and many insects and other small pond creatures. Floating plants give shade, reduce evaporation rates, provide shelter for small fish, and keep the water temperature more constant.
Introduced noxious plant species blanket the entire water surface, causing oxygen depletion – this destroys the under-surface ecosystem and kills native aquatic species They compete with native species and reduce biodiversity, and impact on the aquatic habitat of bird species and cause them to relocate or die.
Some free floating plants that are declared noxious weeds in Australia include the introduced salvinia, (Salvinia molesta), the water hyacinth (Eichhornia crassipes), water lettuce (Pistia stratiotes), and the noxious weed alligator weed (Alternanthera philoxeroides) which may also grow on land.
Not all aquatic plants produce viable seed but spread and multiply from fragments of stem, root or leaves. Examples include noxious water weeds Salvinia and Alligator weed, and South American Parrotfeather. Other aquatic weeds produce seed and are also able to propagate from stem, root or leaf fragments.
So how did these introduced weeds get here? Most were brought in legally and illegally, for fish tanks. In Queensland in the 1980's, the Queensland Dept of Primary Industries illegally bought in over 400 plants from around the World to provide feed for cattle. Although not all were released, one that has created huge problems in Queensland waterways is Hymenacne. This invasive plant blocks waterways, in tropical and subtropical areas. Although it does not grow in water over 4 feet deep, it has smothered streambanks, replacing native rushes and other edge plants.
Control of these introduced noxious water weeds is very difficult. Sprays kill wildlife such as frogs, fish, and insects, and also polute the waterways. Hand removal is expensive and time consuming. In some ponded ares dredges have been used to remove surface weeds, but the weeds always grow back from leaf and stem pieces.The best option for controlling aquatic plants in a body of water is to take the necessary steps to prevent the problem from occurring in teh first place.
An example of the devastation that can result from uncontrolled aquatic noxious water weeds is the salvinia infestation that occurred in the Hawkesbury–Nepean River in 2004, which cost $1.6 million to control.
Salvinia, or hymenacne, or water hyacyinth, and/or alligator weed can be found in almost every waterway, dam and creek in Queensland, NSW, and Victoria, along with many other imported water plants that are considered less of a weed. Removal or effective control of these plants is almost impossible. This blog reports on the issues of noxious water plants in Australia.
Oxygen is the single most important water quality parameter and submerged native plants help to oxygenate the water. Native aquatic plants also play an important role in providing habitat for many organisms, particularly birds, amphibians, fish and many insects and other small pond creatures. Floating plants give shade, reduce evaporation rates, provide shelter for small fish, and keep the water temperature more constant.
Introduced noxious plant species blanket the entire water surface, causing oxygen depletion – this destroys the under-surface ecosystem and kills native aquatic species They compete with native species and reduce biodiversity, and impact on the aquatic habitat of bird species and cause them to relocate or die.
Some free floating plants that are declared noxious weeds in Australia include the introduced salvinia, (Salvinia molesta), the water hyacinth (Eichhornia crassipes), water lettuce (Pistia stratiotes), and the noxious weed alligator weed (Alternanthera philoxeroides) which may also grow on land.
Not all aquatic plants produce viable seed but spread and multiply from fragments of stem, root or leaves. Examples include noxious water weeds Salvinia and Alligator weed, and South American Parrotfeather. Other aquatic weeds produce seed and are also able to propagate from stem, root or leaf fragments.
So how did these introduced weeds get here? Most were brought in legally and illegally, for fish tanks. In Queensland in the 1980's, the Queensland Dept of Primary Industries illegally bought in over 400 plants from around the World to provide feed for cattle. Although not all were released, one that has created huge problems in Queensland waterways is Hymenacne. This invasive plant blocks waterways, in tropical and subtropical areas. Although it does not grow in water over 4 feet deep, it has smothered streambanks, replacing native rushes and other edge plants.
Control of these introduced noxious water weeds is very difficult. Sprays kill wildlife such as frogs, fish, and insects, and also polute the waterways. Hand removal is expensive and time consuming. In some ponded ares dredges have been used to remove surface weeds, but the weeds always grow back from leaf and stem pieces.The best option for controlling aquatic plants in a body of water is to take the necessary steps to prevent the problem from occurring in teh first place.
An example of the devastation that can result from uncontrolled aquatic noxious water weeds is the salvinia infestation that occurred in the Hawkesbury–Nepean River in 2004, which cost $1.6 million to control.
Salvinia, or hymenacne, or water hyacyinth, and/or alligator weed can be found in almost every waterway, dam and creek in Queensland, NSW, and Victoria, along with many other imported water plants that are considered less of a weed. Removal or effective control of these plants is almost impossible. This blog reports on the issues of noxious water plants in Australia.
Sunday, July 25, 2010
Noxious water weeds found in Adelaide!
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