What happened to California’s wildflowers?

Chuck Bednar for redOrbit.com – @BednarChuck

Following several years of warmer, drier wintertime conditions in California, wildflowers native to the state are losing species diversity, according to a new study published Monday in the journal Proceedings of the National Academy of Sciences.

In the new study, Susan Harrison, a professor in the University of California-Davis Department of Environmental Science and Policy, and her colleagues analyzed 15 years of data on about 80 sampling plots at McLaughlin Reserve, a part of the school’s Natural Reserve System.

Their research revealed that the heat and lack of precipitation in the winter was creating a “direct loss of native wildflowers in some of California’s grasslands.” The study is said to provide “the first direct evidence of climate change impacts” in these regions, the authors added. Drought-intolerant species were said to be the most affected.

Large-scale extinctions, food web impact also possible

Harrison said that these diversity losses could foreshadow larger-scale extinctions, especially in parts of the state that are becoming increasingly dry. How serious is this threat? “All large-scale extinctions start as small-scale ones,” she told redOrbit via email. “We know of no reason why, if the current climate trends continue, there would not be large-scale extinctions.”

Furthermore, the researchers have identified similar trends in other Mediterranean environments, including those in southern Europe. They said that this strengthens the case for increased climate change awareness in semi-arid parts of the world, and that when combined with global warming predictions, it results in projections of less-productive grassland communities in the future.

As a result, these lands will provide less nutrition to herbivores and become more susceptible to invasive species. The adverse effects of these phenomena could have an overall impact on the food web, harming insects, seed-eating rodents, birds, cattle, and other species that rely upon California grasslands for their food.

“Our study points to the high risks faced by relatively drought-intolerant native annual forbs (wildflowers). Insects that pollinate or feed on these plants may be at risk too, although that is only speculative,” Harrison told redOrbit.

The professor added that she and her colleagues have “set up a watering experiment to see if we can bring back plant diversity” by alleviating the midwinter drought and/or by adding additional seeds to the affected areas. “We will also keep monitoring our long-term plots to see if the trends continue,” she noted. “We are fortunate to have a protected, university-operated natural reserve where this kind of work can be done.”

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