http://smh.com.au/articles/2003/10/30/1067233325030.html
Natural pesticide
By James Woodford
October 31, 2003
Moving day ... a Royal Botanic Gardens horticulturist, Matthew Bollinger, prepares one of the 10 eastern water dragons at Darling Harbour for its change of address. Photo: Rick Stevens
Today the Royal Botanic Gardens will unleash 10 new pest controllers, relying on technology developed over the past 100 million years.
An eastern water dragon is formidably insectivorous, able to eat many thousands of tiny insects or dozens of bigger ones such as slugs and snails in a single sitting.
It lives for more than 25 years, grows to 80 centimetres and can regulate its own populations because the sex of young lizards is decided by the temperature at which their eggs were incubated.
In short, they are the perfect replacement for pesticides.
Before the arrival of Europeans there would almost certainly have been many of the reptiles in the area now occupied by Sydney. But today, feral animals and habitat degradation have almost banished the species from the city.
In spite of this, in other parts of the metropolitan area, the reptiles are known to be good survivors of disturbed environments and can even cope with moderate levels of pollution.
Recently staff at the Royal Botanic Gardens learnt there was one bizarre stronghold of water dragons in the CBD - at Darling Harbour's Chinese Gardens.
It is thought a pair of water dragons was dumped there some time after the gardens were established. Today the colony has more than 100 adults, keeping invertebrate populations in check and providing a surprise wildlife encounter for tourists.
This year the Royal Botanic Gardens applied to the NSW National Parks and Wildlife Service for a licence to move 10 of the water dragons to a new home on the other side of the city.
Pat Houlcroft, co-ordinator of botanic horticulture, said the gardens had embarked on a program of reducing pesticide, fertiliser and water use.
"The water dragons fit in very neatly with our policy of wherever possible eliminating our use of pesticides," he said. "They will live very happily on slugs, snails, caterpillars and aphids."
The dragons will be released near the botanic gardens' tropical centre, where there is also a thriving population of frogs.
"I don't think we are playing God too much. They're native to this area - they have just been squeezed out. Increasingly botanic gardens are about biodiversity and the inter-relationship between flora and fauna rather than a rarefied collection of plants."
The manager of the reptile section at Taronga Zoo, Peter Harlow, kept one individual in captivity for 26 years. They can live near almost any body of water, running or still, and can stay underwater for over an hour.
A leading reptile expert at the University of Sydney's School of Evolutionary Biology, Professor Rick Shine, said it was possible the water dragons would wander a bit but some would eventually decide their new home was "an acceptable piece of real estate".
"It can only add to the beauty of the Royal Botanic Gardens to have these glorious reptiles sitting beside the water."
Natural pesticide
By James Woodford
October 31, 2003
Moving day ... a Royal Botanic Gardens horticulturist, Matthew Bollinger, prepares one of the 10 eastern water dragons at Darling Harbour for its change of address. Photo: Rick Stevens
Today the Royal Botanic Gardens will unleash 10 new pest controllers, relying on technology developed over the past 100 million years.
An eastern water dragon is formidably insectivorous, able to eat many thousands of tiny insects or dozens of bigger ones such as slugs and snails in a single sitting.
It lives for more than 25 years, grows to 80 centimetres and can regulate its own populations because the sex of young lizards is decided by the temperature at which their eggs were incubated.
In short, they are the perfect replacement for pesticides.
Before the arrival of Europeans there would almost certainly have been many of the reptiles in the area now occupied by Sydney. But today, feral animals and habitat degradation have almost banished the species from the city.
In spite of this, in other parts of the metropolitan area, the reptiles are known to be good survivors of disturbed environments and can even cope with moderate levels of pollution.
Recently staff at the Royal Botanic Gardens learnt there was one bizarre stronghold of water dragons in the CBD - at Darling Harbour's Chinese Gardens.
It is thought a pair of water dragons was dumped there some time after the gardens were established. Today the colony has more than 100 adults, keeping invertebrate populations in check and providing a surprise wildlife encounter for tourists.
This year the Royal Botanic Gardens applied to the NSW National Parks and Wildlife Service for a licence to move 10 of the water dragons to a new home on the other side of the city.
Pat Houlcroft, co-ordinator of botanic horticulture, said the gardens had embarked on a program of reducing pesticide, fertiliser and water use.
"The water dragons fit in very neatly with our policy of wherever possible eliminating our use of pesticides," he said. "They will live very happily on slugs, snails, caterpillars and aphids."
The dragons will be released near the botanic gardens' tropical centre, where there is also a thriving population of frogs.
"I don't think we are playing God too much. They're native to this area - they have just been squeezed out. Increasingly botanic gardens are about biodiversity and the inter-relationship between flora and fauna rather than a rarefied collection of plants."
The manager of the reptile section at Taronga Zoo, Peter Harlow, kept one individual in captivity for 26 years. They can live near almost any body of water, running or still, and can stay underwater for over an hour.
A leading reptile expert at the University of Sydney's School of Evolutionary Biology, Professor Rick Shine, said it was possible the water dragons would wander a bit but some would eventually decide their new home was "an acceptable piece of real estate".
"It can only add to the beauty of the Royal Botanic Gardens to have these glorious reptiles sitting beside the water."
