Tropical species prove more resilient

INCREASES IN atmospheric carbon dioxide brought about by climate change will potentially increase biodiversity in tropical regions, an international conference in botany heard yesterday.

Dr Ian Woodward from the University of Sheffield said that an increase in carbon dioxide could increase diversity in some regions.

His modelling system predicts the well established decline in diversity in increasing latitude.

Other analysis on plant species in Europe has forecast reductions in diversity later this century. However, his model predicts an increase in the number of species found in more tropical climates.

“Increasing CO2 appears to be stimulating any area of ground to accommodate more species,” he said. Dr Woodward was speaking at the three-day conference on Climate Change and Systematics at Trinity College Dublin. He said that with constant carbon dioxide there would be a downturn in the number of species in tropical regions. He said that species alien to a region will become naturalised in those circumstances.

“All species are getting around easily and quickly,” he said. For example, there were 10,000 alien species “knocking on the door” of Australia. That situation, he said, was associated with global warming and increased carbon dioxide. Some contributors to the debate wondered would that lead to a drop in native species or alien species dominating. Dr Woodward said the species were mixing very well in the tropics. He also pointed out that in Hawaii, alien trees had raised the level of the tree canopy.

Dr Stephen Hopper, the director of the Royal Botanical Gardens in Kew, issued a caveat on climatic models used to predict plant extinctions as a result of climate change. “Are present models accurate enough to place full confidence in them?” he asked.

“More factors need to be included in modelling if we are not to be seen to be crying wolf.” He said that some species are more resilient than expected. He said plants “can hang on through some rugged climate change”.

Dr Hopper said the botanical gardens at Kew had set itself a new mission to inspire and deliver science-based conservation worldwide.

One of its key objectives is to document and describe species, using systematics to underpin conservation actions aimed at minimising the extinction of plants.

He pointed out the difficulties involved in this saying that some 2,000 new species were recorded each year, making the task of achieving a global inventory of plant life more difficult.