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Posts Tagged: climate

Drought is impacting California’s wildflowers

Harrison PNAS
Native wildflowers in California are losing species diversity after multiple years of drier winters, according to a study from the University of California, Davis, which provides the first direct evidence of climate change impacts in the state's grassland communities.

The study, covered in TIME, LA Times, and elsewhere, was published in the journal Proceedings of the National Academy of Sciences. It's based on 15 years of monitoring about 80 sampling plots at McLaughlin Reserve, part of UC Davis' Natural Reserve System.

"Our study shows 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 and a member of UC Agriculture and Natural Resources' Conservation Biology workgroup. “Such diversity losses may foreshadow larger-scale extinctions, especially in regions that are becoming increasingly dry.”

The researchers confirmed that drought-intolerant species suffered the worst declines.

Global trend

Similar trends have been found in other Mediterranean environments, such as those of southern Europe, bolstering the case for increased climate change awareness in the world's semi-arid regions.

Taken together with climate change predictions, the future grassland communities of California are expected to be less productive, provide less nutrition to herbivores, and become more vulnerable to invasion by exotic species, the study said.

The researchers expect these negative to cascade up through the food web—affecting insects, seed-eating rodents, birds, deer and domesticated species like cattle, all of which rely on grasslands for food.

Rescue effect may be too late

Grasses and wildflowers may be able to withstand the current drying period through their extensive seed banks, which can lie dormant for decades waiting for the right conditions to germinate. 

However, California's drought is expected to intensify in the coming decades, so this rescue effect may end up being too late for some species.

Author: Kat Kerlin

Posted on Wednesday, July 15, 2015 at 4:00 PM
Tags: California (7), climate (3), drought (163), Susan Harrison (1), UC Davis (210), wildflowers (6)

Feeding billions in the face of climate change

As drought dries the landscape and rising global temperatures make for decreasing crop yields, farmers are faced with the question of how to feed billions of people in a way that both reduces global greenhouse gas emissions and adapts to the realities of climate change.

Scientists and policymakers from around the world will gather today through Friday, March 20-22, at the University of California, Davis, to grapple with the threats of climate change for global agriculture and recommend science-based actions to slow its effects while meeting the world's need for food, livelihood and sustainability.

The Climate-Smart Agriculture Global Science Conference, planned in coordination with the World Bank, builds on a 2011 international meeting on this theme in the Netherlands.

"Climate change, which brings severe weather events and more subtle but equally menacing temperature changes, presents unprecedented challenges to the global community," said UC Davis Chancellor Linda P.B. Katehi.

"In California, where we rely heavily on snowmelt for irrigation to grow half of our nation's fruit and vegetables, we are acutely aware that scientists and policymakers must join forces to lessen the potential effects of climate change," she said.

Katehi will open the conference on Wednesday, March 20, along with Thomas Vilsack, secretary of the U.S. Department of Agriculture (via video). The public is invited to attend the opening day’s program (8:45 a.m.-12:30 p.m), free of charge; and the closing day’s afternoon program (noon-3:45 p.m.), also  free of charge. These will be held in Jackson Hall of the Mondavi Center for the Performing Arts. (Lunches not included.)

Catherine Woteki, USDA undersecretary, will speak Thursday evening, March 21.

Other speakers will include: Ben Santer, climate researcher at Lawrence Livermore National Laboratory and a member of the National Academy of Sciences; Joseph Alcamo, chief scientist for the United Nations Environmental Program; and Patrick Caron, general director for research and strategy of the French Agricultural Research Center for International Development. Also speaking will be outstanding scientists from dozens of universities and research institutes from around the world.

Conference topics will focus on the implications of cutting-edge agricultural, ecological and environmental research for improved design of policies and actions affecting agricultural management and development; identifying farm and food-system issues, determining research gaps; highlighting emerging research initiatives; and developing transformative policies and institutions.

The conference will conclude with participants developing and endorsing a declaration regarding the key research and policy messages that result from conference presentations and discussions. This declaration is expected to point toward science-based policies and actions for global agriculture that will mitigate climate change and encourage adaptation to maintain food security, livelihoods and biodiversity.


Posted on Wednesday, March 20, 2013 at 6:45 AM

Ancient tree discovered in Southern California

Scientists believe that a tree - or rather a genetically identical thicket of Palmer's oak - nestled in a gulch on Riverside County's Jarupa Hills is the oldest living plant in California. According to an article in the online plant science journal PLoS ONE, the solitary plant has been growing in that spot for more than 13,000 years.

The discovery was covered widely in the press, including the New York Times, the Los Angeles Times, the Riverside Press-Enterprise, KQED Public Radio, the BBC and several Southern California TV stations.

"If you planted a seedling there now, I doubt very much whether it would grow," UC Davis plant scientist Jeffrey Ross-Ibarra was quoted in the LA Times story. He is one of five UC Davis and UC Riverside scientists who jointly authored the journal article.

Press-Enterprise reporter David Danelski interviewed another author, UCR museum scientist Andrew Sanders, on the steep ridge where the tree grows. Sanders told the reporter the thicket first took root at the close of the last ice age, a cooler and wetter time when glaciers capped nearby San Gorgonio Peak. Palmer's oaks were plentiful then.

As the climate became warmer and more dry, all the oaks except the one growing in this spot died off. The location offers the tree natural protection from wind and nearby boulders funnel rain to its roots.

Danelski reported that human activity is changing the environment. Tract homes are on the hillside below one side of the ridge, and a cement mixing plant is at the bottom of the hill on the other side.

"A Corona beer bottle and a dirty fragment of fabric littered the thicket. A motorcyclist buzzed past on a nearby hillside," Danelski wrote.

Sanders told him he hopes the land will be protected so the plant can continue to beat the odds.

Even at the age of 13,000 years, the Palmer oak is not the country's oldest plant. A clonal colony of a single male quaking aspen in Utah is estimated to be 80,000 years old, according to Wikipedia.

A poster presentation with more information about the California Palmer oak discovery titled A Pleistocene Clone of Palmer's Oak in Southern California is available in pdf format on the UC Davis plant sciences Web site.

Scientists counted growth rings to determine the plant's age.
Scientists counted growth rings to determine the plant's age.

Posted on Friday, January 8, 2010 at 7:44 AM
Tags: ancient (1), Andrew Sanders (1), climate (3), ice age (1), plant science (1)
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