A rare butterfly in Nanjing, capital of east China's Jiangsu Province, is disappearing because of the city's expansion, experts told China Daily yesterday.

The butterfly, the Chinese Tiger Swallowtail, is only found in China and has been around for about 80 million years.

According to Wu Qi, a 68-year-old man who has been researching the butterflies for more than 20 years, the insects will be extinct in Nanjing within five years if no action is taken.

The butterfly lives in cities like Wuhan, Nanjing and Hangzhou, but is now rarely seen, said Wu.

Wu said he believes the fall in butterfly numbers is directly related to a decrease in the city's plant diversity.

As Nanjing has grown, although green spaces have been included in the expansion, plant diversity has been ignored, he said.

Trees and flowers considered beautiful are planted in large numbers, while common and less colourful species are destroyed.

The Chinese Tiger Swallowtail butterfly likes eating wild ginger, a plant which has disappeared rapidly during the city's development.

But numbers of another kind of butterfly are increasing because more and more camphor, which they feed on, is being planted.

"The expansion of the city does harm to some animals and the environment," said Xu Dong from Nanjing Agriculture and Forestry Bureau.

"In the 1990s, people built many things and planted trees, but rarely considered environmental protection," he added.

Xu appealed to construction departments to ensure the environmental impact of their plans was evaluated before work began, a measure which could save animals, protect the environment and safeguard people's health.

But Xu said he was pleased to see increasing awareness of environmental issues.

People have begun to attach great importance to the environment, and more and more volunteers are researching threatened species, he said.

Local governments have been protecting the butterfly for more than a decade.

(China Daily November 9, 2005)