Warming climate could give exotic grasses edge over California natives

Robert Sanders in the UC Berkeley News Center: California’s native grasses, already under pressure from invasive exotic grasses, are likely to be pushed aside even more as the climate warms, according to a new analysis from the University of California, Berkeley.

In the study, which has been accepted for publication in the journal Global Change Biology and is now available online, UC Berkeley biologists catalogued the ranges of all 258 native grasses and 177 exotic grasses in the state and estimated how climate change – in particular, increased temperature and decreased rainfall – would change them. They concluded that many of the traits that now make exotic grasses more successful than many natives also would allow them to adapt better to increased temperature and likely expand their ranges.

“When we looked at current patterns, we found that warmer temperatures favor certain traits, and these are the traits possessed by exotic species,” said coauthor Emily Dangremond, a graduate student in the UC Berkeley Department of Integrative Biology. “This led us to predict that, if the mean temperature increases in all zones in California, there is an increased likelihood of finding exotic species, and an increase in the proportion of species in a zone that are exotic.”

...“The ‘trait-based’ approach lets us test hypotheses about plant distributions in relation to climate without tying them to the identity of particular species,” Ackerly wrote in an email from South Africa, where he is on sabbatical. “As a consequence, the analyses can be generalized beyond California to other grassland areas.”...

From the UC Berkeley website: At Tom's Point in Marin Co., Calif., the exotic grass Holcus lanatus is common. (Credit Brody Sandel)