Image credit: Ken Lund/Flickr
"Southern Arizona has been getting hotter and drier for the last 25 or 30 years," says D. Lawrence Venable, a director of research at the University of Arizona, "and as a result, the desert annuals we've been studying...have been changing." Some of the changes, however, are not the sort that researchers expected.
Cold-loving flowers, they have found, are gaining an edge in the Sonoran Desert.As a whole, the number of winter annuals in the desert has been declining since 1982. Species that germinate and grow in lower temperatures, however, have become more common.
Sarah Kimball, a research associate at the University of Arizona in Tucson, commented that, "it's an unexpected result—that global warming has led to an increase in cold-adapted species." The cause of this counterintuitive development, researchers believe, is that the winter rains have been pushed later into the year.
Though overall, the winter growing season is getting warmer, these first rains are falling during colder temperature periods then they had previously. "What's important in this system," Kimball explained, "is that the growing season is initiated at a later date under colder temperatures."
Water-use-efficient species that favor colder temperatures, like popcorn flower and red filaree, have become noticeably more common as a result.
Kimball concluded: "This demonstrates that the response of organisms to climate change can be unexpected."
Read more about climate change:
Desert Soils Losing Nitrogen & Fertility Thanks to Global Warming
The Footprint of Flowers: Carbon and Social
Climate Change Could Extinguish Two-Thirds of California's Plant Species