Eco-diversity under threat
A new study points out that doubling the amount of carbon dioxide in the air significantly reduces the number of plant species that grow in the wild.Updated: Jun 28, 2003 20:26 IST
A new study on climate change in California points out that doubling the amount of carbon dioxide in the air significantly reduces the number of plant species that grow in the wild.
The findings published in the Proceedings of the National Academy of Sciences (PNAS), show that exposing open grasslands to large doses of CO2 gas for three years, caused a 20 per cent reduction in wildflower species and an eight per cent decline in plant diversity overall. The addition of excess nitrogen and other predicted climate changes caused diversity to plunge even further.
"I was surprised how quickly we lost species over such a short time. It only took three years in our experiment. What does that say about the impact global change will have on plant diversity in the longer term?" said lead author, Erika S. Zavaleta.
The Global Change Project relies on a system of infrared heat lamps, sprinklers and emitters to simulate four conditions which climate experts predict could exist a century from now, as a result of continued fossil fuel consumption and deforestation.
Elevated CO2 caused a loss in species, while added precipitation caused an increase. One school of thought believed that elevated CO2 added moisture to the soil, which tended to extend the growing season of the dominant plants, leaving less room for other species to grow.
The study also revealed that heat in the absence of other treatments had no significant impact on diversity. However, when experimental plots were exposed to higher temperatures along with excess nitrogen, carbon dioxide and water, the number of wildflower species crashed.
First Published: Jun 28, 2003 00:00 IST