The world's plants face mass extinction if climate change remains unchecked and more efforts are not taken to encourage plant conservation, warned experts on the second day of the Third Global Botanical Gardens Congress in Wuhan, central China on Tuesday.
"About half of the earth's 400,000 plant species and 100,000 unclassified plant species will be threatened with extinction if the temperature rises by 2 to 3 degrees Celsius in the next 100 years," said Dr David Bramwell, director of the Jardin Botanical Gardens in Las Palmas, Spain.
A recent study of six biodiversity-rich regions covering 20 percent of the world's land areas including South Africa, Brazil, West and Central Africa, and Australia, indicates that up to 37 percent of all species in these regions will be extinct by 2050, he said.
Huang Hongwen, director of the Wuhan Botanical Gardens, said plant and animal species around the world were growing at higher altitudes and nearer to both the North and South Poles to keep pace with global warming.
"A spate of recent studies show how hundreds of species -- from butterflies to birds, plants, bats and rats -- have moved towards the North and South Poles by up to 300 kilometers in the last 50 years. This was triggered by a temperature rise of only 0.6 degrees Celsius over the last century and is only a prelude to the consequences of global warming," said Huang.
He said the Intergovernmental Panel on Climate Change (IPCC) report published in 2001 predicted that the earth's temperature would rise by two to six degrees Celsius over the course of the 21st Century.
"A temperature rise of five degrees Celsius in addition to habitat loss and other factors might cause the extinction of up to 80 percent of the world's plant species by the end of this century," said Peter H. Raven, president of the Missouri Botanical Garden in the US.
Sara Oldfield, the secretary-general of the Botanical Gardens Conservation International (BCGI), said, "Mankind will face the sixth massive extinction of plant species, following the fifth one which can be traced back to 65 million years ago, the last time the earth heated up due to natural factors.
"This time, the extinction will be caused mainly by human activities which are closely related to habitat loss, climate change, and over-exploitation of plant resources and pollution," she said.
"Faced with climate change and the prospect of mass extinction of biodiversity, we have to conserve the most at-risk plant species because biodiversity is so important for the future of mankind," said Dr Bramwell.
He said that more than 2,000 botanical gardens and many more plant research institutes around the world should jointly establish and contribute to the seed banks for the endangered species, similar to Kew Garden's millennium seed bank.
He suggested that local and regional seed banks should also be built, where endangered plants are moved from their habitats and cultivated in botanical gardens or other natural reserves.
"Botanical gardens can also play a major role in monitoring the effects of climate change," said Bramwell.
Bramwell also called for a United Nations-led program to be established to pool action plans from various countries to save the planet's fauna from becoming "depauperate.”
(Xinhua News Agency April 18, 2007)