The study is calling for a greater awareness of climate changes in the world’s semi-arid regions, based on 15 years of monitoring of 80 sampling plots in the McLaughlin Reserve, a part of the University of California Davis’ Natural Reserve System.
Researchers claim that “15 years of warmer and drier winters are creating a direct loss of native wildflowers in some of California’s grasslands,” said lead author Susan Harrison, a professor in the Department of Environmental Science and Policy. “Such diversity losses may foreshadow larger-scale extinctions, especially in regions that are becoming increasingly dry.”
On the Backbone Trail, at Circle X Ranch Park — in the Santa Monica Mountains National Recreation Area, California.
The scientists are most concerned about the many drought intolerant native annual forb (wildflowers) species and have documented similar trends in other Mediterranean environments, such as those of southern Europe. They say this is most indicative in climates that are becoming much more arid and less productive.
The scientists said that based on climate change predictions, the future grasslands of California can be expected to become less productive, along with having less nutritional value to herbivores. This will also make the grasslands more vulnerable to invasion by exotic species.
This negative impact is also expected to climb on up the food chain, affecting insects, seed-eating rodents, birds, deer, and domestic animals, like cattle. These are all species that rely on the grasslands for food. It is pointed out that the grasslands and wildflowers may be able to withstand the current drought because of extensive seed banks.
The seed banks are seeds that can lie dormant for years, waiting for the right conditions to germinate, but, California’s drought is expected to intensify in the next few decades, and this may make it too late for many wildflower species.
The study, entitled “Climate-driven diversity loss in a grassland community,” was published in the journal Proceedings of the National Academy of Sciences on June 22, 2015.
Co-authors include Elise Gornish, a UC Cooperative Extension specialist in the UCD Department of Plant Sciences, and Stella Copeland, a doctoral student in the Department of Environmental Science and Policy.
