GAINESVILLE, Fla. --- Local climate may be more important than carbon dioxide levels in determining what types of plants thrive and what types dont do so well, a team of scientists reports in this weeks edition of the journal Science.
Their findings suggest that rising global carbon dioxide levels tied to global warming may not be as crucial in determining the composition of plant communities as other, localized climate shifts, such as droughts or temperature changes.
Nobody really knows what the increases in carbon dioxide are going to entail in terms of future changes in vegetation types, said Mark Brenner, a UF assistant professor of geology and co-author of the paper, which appears in Friday in Science. But it looks like climate changes in different areas may be more important than carbon dioxide, at least carbon dioxide by itself.
The team, composed of six geologists and geographers from around the world and led by Geologist Yongsong Huang of Brown University, based their conclusions on an analysis of sediment from two lake bottoms, one in northern Mexico and one in northern Guatemala.
The sediments came from core samples retrieved by driving a hollow tube into the lake bottom. Over time, these sediments which include terrestrial plant remains -- are deposited layer by layer, like a wedding cake, with the oldest layer on the bottom. Such cores provide an environmental archive that allows researchers to obtain a continuous record of changes in climate, vegetation and land use.
The cores were retrieved as long ago as 1980 by UF researchers and currently are kept in the core storage facility at UFs Land Use and Environmental Change Institute. The researchers used new techniques that allowed them to analyze only the remains of land plants, specifically their leaf waxes. The technology has come on line to allow us to do studies that we couldnt do at the time we collected these samples, Brenner said.