BERKELEY — The competition between farmers and fish for precious water in California is intensifying in wine country, suggests a new study by biologists at the University of California, Berkeley. [Read more...]
Graduate student Thomas Azwell’s research spurred by Gulf oil spill
February 8, 2012
Thomas Azwell is testing bagasse-filled growth tubes as a clean medium for marsh plants in the Bay Jimmy Restoration Project in Louisiana. (Photo by Gavin Garrison)
BERKELEY — A graduate student at the University of California, Berkeley’s College of Natural Resources, deeply influenced by the Deepwater Horizon disaster, is helping to restore the Gulf’s blackened marshes with a project that could also aid threatened ecosystems nationwide, including in Northern California. [Read more...]
UC wildlife research team wants your gently-used socks
December 15, 2011
A University of California wildlife research team working in the Sierra Nevada near Oakhurst, Calif., is asking the public to donate clean, gently used socks for research on a rare weasel called the Pacific fisher. [Read more...]
Climate change blamed for dead trees in Africa
December 12, 2011
BERKELEY — Trees are dying in the Sahel, a region in Africa south of the Sahara Desert, and human-caused climate change is to blame, according to a new study led by a scientist at the University of California, Berkeley. [Read more...]
Can ‘Carbon Ranching’ Offset Emissions In California?
December 7, 2011
Professors Whendee Silver and Dennis Baldocchi speak with NPR correspondent Christopher Joyce about ‘carbon ranching’. [Read more...]
Scientists Propose Thinning Sierra Forests to Enhance Water Runoff
December 5, 2011
Scientists believe thinning forests could enhance water runoff from the Sierra Nevada.
Runoff from the Sierra Nevada, a critical source of California’s water supply, could be enhanced by thinning forests to historical conditions, according to a report from a team of scientists with the University of California, Merced, UC Berkeley and Environmental Defense.
The team proposes to test the hypothesis that forest-management strategies that use thinning to reduce fire risk and maintain the historical mix can also increase water yield and extend the snowpack in the Sierra Nevada.
Scientists believe thinning forests could enhance water runoff from the Sierra Nevada. They suggest that by selectively reducing the number of trees — which use large amounts of the water received through precipitation — the amount of water that is released from the forest as runoff could increase. This enhanced runoff could make things easier for farmers and water managers statewide.
As part of the Sierra Nevada Watershed Ecosystem Enhancement Project (SWEEP), the scientists plan to reduce forest density in test areas and examine the impacts on water runoff, forest health and other ecosystem services, and provide a template for broader forest management in the Sierra Nevada.
The thinning of forests, which are much denser now than in past centuries, is already a common practice to reduce the risk of wildfires. The scientists also believe thinning can be done in ways that enhance the forests’ overall ecological health.
“It is critical to test these thinning prescriptions in well-controlled, well-monitored experimental areas to evaluate and verify the effects before applying them statewide,” said lead author Roger Bales, a UC Merced professor and director of the Sierra Nevada Research Institute. “Reductions in forest density to enhance runoff have been attempted in past experiments, but never over a sustained period of time, and never under the conditions that currently exist in the Sierra Nevada.”
California’s water supply has been diminished by drought in recent years, and climate change is only exacerbating the problem, the researchers said. Warmer temperatures mean more rain and less snow, which leads to runoff that comes earlier in the year. Warming can also lengthen the growing season for trees and other plants, reducing runoff, and the warmer, drier conditions have been shown to increase the frequency and severity of wildfires.
Reducing forest density can help counter the effects of climate warming on runoff, they said, in addition to enhancing the runoff directly.
“Climate change is having and will have direct effects on the water supply and storage capacity of the Sierra Nevada forests,” said UC Berkeley Professor John Battles, one of the researchers on the project. “Management with an eye toward the water balance provides one potentially important mitigation tool.”
Other researchers on the project include Yihsu Chen, Martha H. Conklin and Philip Saksa of UC Merced; Kevin L. O’Hara and William Stewart of UC Berkeley; and Eric Holst of Environmental Defense.
Written by James Leonard, UC Merced | Read it at the source.
Taking bushmeat off the menu could increase child anemia
November 21, 2011
BERKELEY — A new study by researchers at the University of California, Berkeley, finds that consuming bushmeat had a positive effect on children’s nutrition, raising complex questions about the trade-offs between human health and environmental conservation.
The red-tinted hair and bloated abdomens of these three young girls in Madagascar are typical signs of kwashiorkor, a type of malnutrition that occurs when there is not enough protein in the diet. (Photo by Christopher Golden)
They further estimated that a loss of access to wildlife as a source of food – either through stricter enforcement of conservation laws or depletion of resources – would lead to a 29 percent jump in the number of children suffering from anemia. Among children in the poorest households, the researchers added, there would be a three-fold increase in the incidence of anemia. Left untreated, anemia in children can impair growth and cognitive development.
The findings are to be published the week of Nov. 21 in the journal Proceedings of the National Academy of Sciences.
“When thinking of creating protected areas for diversity, policymakers need to take into consideration how that will impact local people, both in livelihoods and from a health perspective,” said study lead author Christopher Golden, who did the research while a graduate student in UC Berkeley’s Department of Environmental Science, Policy and Management and at the School of Public Health. “We need to find ways to benefit the local population in our conservation policies, not hurt them.”
Hundreds of millions of people worldwide consume bushmeat a key source of bio-available iron, particularly for those living in rural communities. But when the menu includes endangered species, the researchers said, human nutritional needs must contend with efforts to manage wildlife resources.
Because bio-available iron is primarily sourced from meat, the researchers hypothesized that increased consumption of wildlife would result in a reduced incidence of clinical anemia. They tested their theory by monitoring the diet and hemoglobin levels of 77 children every month for a year.
The children, all under 12 years old, lived in the Makira Protected Area of Madagascar, one of the most critical biodiversity hotspots in the world. The Makira region is located in a remote part of eastern Madagascar, and its inhabitants rely heavily upon local wildlife – such as lemurs and bats – for food.
A man prepares an aye-aye, a rare type of lemur found only on the island of Madagascar, as his younger brother walks by. These primates are a source of food for local inhabitants, despite being critically endangered. (Photo by Christopher Golden)
Children there who ate more bushmeat had higher levels of hemoglobin, an iron-containing protein in red blood cells, even after factoring in such variables as consumption of domesticated meat, household income, sex, age and nutritional and disease status, the researchers found.
Eating domesticated meat is prohibitively expensive for many households, while wildlife is free, the authors noted. They found that, among impoverished people, bushmeat accounted for up to 20 percent of overall meat consumption. While many of the wildlife species are illegal to hunt, enforcement in the protected areas can often be lax.
“It is clearly not environmentally sustainable for children to eat endangered animals, but in the context of remote, rural Madagascar, households don’t always have a choice,” said Lia Fernald, UC Berkeley associate professor in the School of Public Health, who worked with Golden to design the study. “In places where a diverse range of nutritious food is unavailable, children rely upon animal-source foods – milk, eggs and meat – for critical nutrients like fats, protein, zinc and iron. What we need for these children are interventions that can provide high-quality food sources that are not endangered.”
The authors of the study, which received its primary support from the National Geographic Society Conservation Trust and the National Science Foundation (NSF), emphasized the need for site-specific and culturally relevant solutions.
“In our study area, domesticated meat is actually desirable, but unaffordable, so one possible solution is to support programs that allow the people there to raise chickens or goats,” said Golden, now a post-doctoral fellow at the Harvard Center for the environment and a visiting scientist at Harvard’s School of Public Health. “But in places like Africa’s Gabon or Equatorial Guinea, bushmeat is a desirable luxury item, so simply offering people there domesticated chicken meat as an alternative may not be successful. The sustainability of any type of conservation project relies upon local buy-in.”
Shown is a stew of fruit bats, a typical source of bushmeat for the inhabitants of rural Madagascar. (Photo by Christopher Golden)
In addition to Fernald, Golden was advised at UC Berkeley by associate professors Claire Kremen and Justin Brashares in the Department of Environmental Science, Policy and Management. All are co-authors of the study.
The intersection of human health, household income and wildlife populations has become an increasingly important focus of research at UC Berkeley, they said. For instance, the NSF recently awarded a five-year grant for a project led by Brashares to understand the links between human health, household wealth and natural resource use. Kremen, Fernald, Golden and other colleagues are also part of this project, which will take place at nine rural sites in Ghana, Kenya and Madagascar.
B.J. Rodolph Rasolofoniaina, a seven-year member of Golden’s research team and a research associate at the Wildlife Conservation Society in Madagascar, was another co-author of the study.
Written by Sarah Yang, UC Berkeley Media Relations | Read at the source
Study: Without Action, SF Bay Tidal Marshes Will Disappear
November 16, 2011
An alarming 93 percent of San Francisco Bay’s tidal marsh could be lost in the next 50 to 100 years with 5.4 feet (1.65 meters) of sea-level rise and low sediment availability, according to a new study led by PRBO Conservation Science (PRBO). These figures represent the high-end sea-level rise scenario, which researchers say is increasingly likely.
The study, published this week in the journal PLoS ONE, assesses impacts of sea-level rise, suspended sediment availability, salinity and other factors on San Francisco Bay’s tidal marshes.
Tidal marshes are vital to migratory birds, commercial fisheries, other wildlife and people. Marshes act like giant sponges, protecting highways, businesses, homes and other structures by reducing flood impacts in large storm events and as sea levels rise. Tidal marshes also filter out pollutants and sequester carbon.
PRBO’s study indicates that not all marshes will be lost and that society’s actions today can keep more marshes intact as sea levels rise.
“Tidal marshes are incredibly resilient to changes in sea level, depending on how fast seas rise and how much sediment is available. Unfortunately, marshes cannot keep up with the high-end sea-level rise predictions on their own. They will need our help,” said Diana Stralberg, the study’s lead author.
Lisa Schile and Maggi Kelly, of the University of California, Berkeley, were co-authors on the study.
Written by Ann Brody Guy
Feeding the world: It’s all about starting small
November 8, 2011
When American families sit down to dinner, often the concern is to avoid eating too much. Yet in 2010, the United Nations’ Food and Agriculture Organization (FAO) estimated that more than 900 million people around the world were undernourished. By 2050, the world’s population is projected to rise to somewhere around 9 billion — and more people will likely be eating more meat, which takes more resources and energy to produce than most crops.
How on earth will our agricultural systems feed all those mouths, especially while coping with climate change, soil degradation and erosion, water shortages, and rising energy prices? And can it be done without increasing the environmental damage attributed to industrial farming practices?
Maybe, if we can learn to see landscapes through the eyes of a bee. That may seem a tall order for such a tiny insect, but Claire Kremen believes that understanding what is good for bees is a first step toward shaping agricultural ecosystems, or “agroecosystems,” that can sustain both humans and natural biodiversity, without the need for the huge inputs of chemicals and energy that have made industrial farming practices so damaging.
Kremen, a conservation biologist and associate professor in the Department of Environmental Science, Policy, and Management (ESPM), was studying the effects of natural habitat on the crop pollination services of wild bees when she made an observation that would alter the focus of her research. The farms in her study that were more biodiverse, growing multiple crops with organic techniques, interspersed with natural habitat, seemed able to “grow their own bees,” providing sufficient food and nesting resources to act as oases for wild pollinators in the midst of otherwise intensively farmed landscapes. These farms could rely to a large degree on wild bees to pollinate their crops, while farms growing only one crop had to import European honeybees for pollination.
This discovery put Kremen on the road to realizing that most or even all of the inputs that modern commercial farms require — chemical pesticides and fertilizers, wasteful amounts of water and energy, imported pollinators — were needed only because the monoculture-dominated landscapes created by industrial agriculture lacked biodiversity.
Animals integrated within a diversified farming system
“From studying the pollinators, I realized that the way we conduct agriculture has basically required us to replace all of the ecosystem services that used to be in the agricultural ecosystem with substitutes,” she says. If farmers could bring back many of the traditional practices that supported biodiversity, enhanced by the application of modern ecological science, Kremen believes that the world could produce more food while reducing agriculture’s harmful effects, making it more sustainable over the long term.
A growing number of policy-makers and researchers are thinking along the same lines. A 2008 report released by the International Assessment of Agricultural Science and Technology for Development, a multinational effort spearheaded by the World Bank and the FAO, concluded that modern agriculture would have to shift rapidly away from industrialized systems and toward sustainable, small-scale, diversified farming systems in order to meet the challenges of population growth, hunger, environmental degradation, and climate change.
Kremen and a group of UC Berkeley colleagues from a variety of disciplines are leading the charge, establishing a new Berkeley Center for Diversified Farming Systems to bring together researchers, writers, and practitioners from many fields to focus on feeding the world’s growing population through diversified, multifunctional agriculture that also addresses the poverty and lack of access to land that are the root causes of hunger. Thanks to support from the Neckowitz Family Foundation, the Berkeley Institute of the Environment has already hosted a series of roundtables and presentations on topics related to diversified farming systems, with more to come. up agroecological practices.
In addition to Kremen, affiliated faculty include Altieri, Lynn Huntsinger (ESPM), Nathan Sayre (Geography), Alastair Iles (ESPM), Christy Getz (a Cooperative Extension specialist in the College of Natural Resources), David Zilberman (Agriculture and Resource Economics), and Justin Brashares (ESPM).
Berkeley is uniquely positioned to host this interdisciplinary research and education center, Kremen says, because of its world-renowned faculty in the fields of agroecology, science, technology, society, agricultural economics, and rural sociology. Notes Huntsinger: “That’s the beauty of our College, that we can bring all these things together.”
Promoting Biodiversity Across Scales
Generally speaking, a diversified farming system is one that promotes biodiversity across spatial scales, from plot to field to landscape. Crops are planted and livestock raised in combination, resulting in interactions that sponsor the functioning of the farming systems in ways that replenish natural ecosystems. Methods employed within a diversified farm may include minimal soil tillage, growing multiple crops together, planting cover crops, and interspersing trees and shrubs with crops and livestock.
These practices also provide pollination, pest and disease control, water purification, and erosion control. They help to build healthy, productive soil and reduce water use, as demonstrated by research conducted in both the Altieri and Kremen labs on farms in Napa, Sonoma, and Yolo counties (see On the Ground). “Diversified farming systems produce and regenerate the ecosystem services that the agricultural system needs,” Kremen says. This allows farmers to forgo the harmful inputs and practices required in industrial farming, which is beneficial for the biodiversity that in turn produces the services. “I see it as a cycle.” At the landscape scale, diversified farming practices include coordination among land managers to protect wildlands in and around agricultural areas, and the support of ecological practices on rangelands and in forests. “In California, 35 million acres of rangelands are providing all kinds of services, from habitat for pollinators to livestock products to viewsheds,” says Huntsinger, a range ecologist and manager (see “Preserving Rangeland Biodiversity”).
Some heritage systems, like the Ifugao rice terraces of the Philippines, maximize the use of mountainous terrain for rice production while incorporating stands of managed forest and a variety of aquatic and terrestrial wildlife. Other systems combine traditional farming techniques with modern ecological science and innovative marketing and distribution methods; Kremen points to Full Belly Farm in California’s Capay Valley, which successfully raises more than 80 different crops, wresting a huge amount of produce from a small area. Even industrial farms can become more biodiverse through the application of improved techniques. Monocrops such as vineyards, for example, can be broken up with flowering cover crops, hedgerows, and corridors that help control pests without chemical inputs.
How to Feed 9 Billion?
For all their potential benefits, the question remains: Can diversified farming systems feed a growing, changing world? Perhaps a better question might be, can we feed the world without them? Despite the tremendous crop yields made possible by industrial farming and the technologies of the Green Revolution of the 1960s and ’70s, 900 million people still do not get enough to eat, and starvation has become a recurrent feature of life in sub-Saharan Africa. Increasing the food supply is not enough; that food needs to get to those who can least afford it.
“The Green Revolution didn’t solve world hunger; it solved the number of calories,” Kremen says.
Most of the food consumed in developing nations is produced by small farmers, many of them still using subsistence methods. Their farms are where the productivity gains must come from, and the question, Kremen says, is whether countries will adopt policies that favor industrial intensification, or sustainable intensification based on agroecological principles.
One of the key reasons that the Green Revolution bypassed the world’s poorest farmers is that they couldn’t afford its technologies. In his report to the UN, De Schutter pointed to evidence that agroecological methods outperform chemical fertilizers in boosting the amount of food produced by subsistence farmers. Many of these methods are inexpensive but require more labor — which could create more rural jobs and help to alleviate poverty.
“We won’t solve hunger and stop climate change with industrial farming on large plantations,” De Schutter said in a statement accompanying the report’s release. “The solution lies in supporting small-scale farmers’ knowledge and experimentation, and in raising incomes of smallholders so as to contribute to rural development.”
Industrial agriculture isn’t likely to disappear any time soon, and many experts believe that any solution to the twinned problems of hunger and resource depletion will require some combination of industrial and sustainable methods. Some, like agricultural economist Zilberman, argue that modern industrial technologies, particularly genetic engineering, could have a crucial role to play in helping agriculture to wean itself from the worst of its chemical abuses, through pest-resistant crop varieties, and to adapt to climate change by developing heat- and droughttolerant varieties.
“Diversified farming systems are crucial to the future of the University, California, and even to global food production, but the concept really has to be inclusive of modern biotechnologies,” Zilberman says. “It has to take the best of science that’s sustainable and combine it with environmentalism.”
Kremen says that, while the economics perspective is a key one for this growing interdisciplinary group, she is skeptical about the ultimate value of genetic engineering, arguing that genetically modified organisms are just another variety of the reductionist, high-tech approach that has led to so many of industrial agriculture’s worst abuses.
“People love technological fixes,” she says. “But spending so much effort to produce these engineered varieties that then have severe vulnerabilities or cause new problems is not, I think, a very good strategy. I’d rather see that effort put into coming up with agroecologically designed communities that do the same thing — that use water and nutrients really efficiently.”
Altieri, who calls agroecology “the antithesis of transgenic technology,” says that “there is not one acre of transgenics that feeds the one billion poor people. Transgenic corn and soybean are produced to feed cattle that the poor cannot afford, and for biofuels, canola, and cotton that don’t feed anybody.”
Investing in Research
Creating and supporting diversified agricultural systems, both in developing and developed countries, will require a substantial investment in research, and not just in the natural sciences. Work in fields like economics, sociology, and public policy can help societies grow a sustainable, biodiverse system of food production and distribution that allows farmers to not merely survive, but thrive.
“Structurally, one of the biggest challenges to truly sustainable agriculture is the push to do everything as cheaply as possible,” says Christy Getz, who studies farm labor conditions and other societal factors (see “The People Behind Our Food”). “Most profits in the organic sector go to the largest players in the food chain; very few small organic farmers make significant profits. Continued industrialization, concentration, and consolidation are changing the face of organic agriculture.”
Another challenge is to identify the best methods for encouraging farmers in developed countries to switch from industrial to diversified farming practices, research that Iles, whose field is environmental law and policy, is pursuing (see “Getting the Policies Right”). Among the questions he’s investigating are: How can farmer motivations be better linked to the science of agroecology? Through setting rules, or through creating economic incentives, or by creating peer pressure? How can we evaluate the effectiveness of different types of policies?
The goal of establishing the Center for Diversified Farming Systems is to close some of these research gaps — by providing a venue where scholars can share their work, and by helping to train future leaders in the field who in turn will translate agroecological scientific advances into practice. Ultimately, the aim of Kremen and her Berkeley colleagues is to create a place where ideas about how to create a sustainable future for human agriculture can be debated, and the best winnowed from the crop.
Written by Eileen Ecklund | Farm photography by Paul Kirchner Studios | Read at the source
Oak killing mold spreads in East Bay
October 28, 2011
By Mike Taugher, Contra Costa Times
The tiny culprit behind a deadly oak disease has spread in the East Bay and appears to have crept closer to residential areas in parts of Oakland and Berkeley, according to the latest survey.
“It may be an early warning sign,” said Matteo Garbelotto, who heads UC’s Forest Pathology and Mycology Laboratory.
Whether it was the rainy weather or the fact that surveys this year were much more intensive than previous years, it appears that the funguslike pathogen that causes sudden oak death is showing up more frequently at lower elevations in the Oakland hills. That means it could further spread next year, particularly if we have another wet winter, Garbelotto said.
“The jump was higher than we expected,” Garbelotto said
Sudden oak death, which has killed millions of trees along the Northern California coast since it was first detected about a decade ago, is established in several of the East Bay Regional Park District’s properties in the hills. But the disease remains patchy there and has not spread as aggressively as it has in infected areas closer to the ocean.
But the latest survey results show for the first time that the pathogen is much more widespread in the East Bay.
“We’re still looking at what is likely the early stage,” Garbelotto said.
Sudden oak death has not been a major threat for East Bay homeowners, since most of the infections have been in more forested areas. But if it takes hold in residential areas it could force homeowners to consider expensive treatment options or other measures.
“It’s not going to happen everywhere, but locally it may become a problem,” Garbelotto said.
One of the volunteers who collected infected samples this spring in Dimond Canyon near Joaquin Miller Park in Oakland, signed on because two large oaks anchor the hillside on which her house sits.
“I asked an engineer and he said it’s $50,000 to shore up the hillside if those oaks go,” said Kathleen Harris, who lives slightly more than a mile from the infected bay laurel tree she found. “I’m very interested in sudden oak death prevention.”
The infected tree Harris found is in a redwood-studded canyon and is one of three positive samples found west of Highway 13.
Sudden oak death was first noticed in the mid- to late-1990s with large numbers of tanoaks dying in Marin and Santa Cruz counties.
It was given its name in 2000 after majestic oaks were found dying and scientists identified the cause of the disease — a previously unknown water mold they named Phytophthora ramorum.
Researchers feared it would devastate large swaths of coastal oak woodlands, but so far the spread has not been as bad as initially thought. Still, Garbelotto said the pathogen has spread through about 10 percent of its potential range in California, meaning it could become more much widespread.
“It is better to be prepared and cautious and assume the epidemic can reach its highest levels, rather than assume nothing is going to happen and be wrong,” Garbelotto said.
It favors cool, moist and foggy climates and is less common east of the Oakland hills, though it has been found in Orinda, Moraga and in Briones Regional Park, said Brice McPherson, an associate specialist at UC’s department of Environmental Science, Policy & Management.
Last spring’s volunteer survey was the largest since it began in 2008, with nearly 500 volunteers collecting 10,000 samples from 2,000 trees from Humboldt County to Carmel.
Bay laurels spread the disease but are not killed by it. Finding infected bay laurels is a sign that the disease could appear in surrounding oaks or other trees, which is why the volunteer survey focuses on bay laurels.
The survey turned up “epidemic” levels of the mold along Skyline Boulevard in Los Gatos and Saratoga, and in general higher levels of infection than in previous years, which may be attributable to the wet year.
The only good news: there was no evidence the pathogen spread beyond a single infected tree in San Francisco’s Presidio.
“It’s the first time we have a real extensive survey of the East Bay,” Garbelotto said.
SUDDEN Oak death meeting
Sausal Creek watershed area residents can learn more about sudden oak death treatment options and prevention at a meeting from 7 to 9 p.m. Nov. 16 at the Dimond Library, 3565 Fruitvale Ave. For information about the meeting, visit www.sausalcreek.org.
For more information about sudden oak death go to: http://nature.berkeley.edu/garbelotto/ and http://www.suddenoakdeath.org/.
Bay Area Sudden Oak Cases Jump, Survey Says
October 4, 2011
Peter Fimrite, San Francisco Chronicle
The deadly pathogen known as sudden oak death is spreading throughout the Bay Area, infecting more trees in more places than have ever been seen before, according to scientists tracking the disease. [Read more...]
Bees outpace orchids in evolution
September 22, 2011
BERKELEY — Orchid bees aren’t so dependent on orchids after all, according to a new study that challenges the prevailing view of how plants and their insect pollinators evolve together.
A male orchid bee collects fragrance compounds from flowers of a Notylia orchid. Female orchid bees choose mates based upon the mix of these chemical compounds. (R. B. Singer photo)
A long-standing belief among biologists holds that species in highly specialized relationships engage in a continual back-and-forth play of co-evolution.
“What we found was that this reciprocal specialization did not exist for orchid bees and orchids,” said study lead author Santiago Ramirez, post-doctoral researcher in the lab of Neil Tsutsui, associate professor at the University of California, Berkeley’s Department of Environmental Science, Policy, and Management. “The bees evolved much earlier and independently, while the orchids appear to have been catching up.”
The bond between specific bees and the orchid plants they visited has been well-documented by botanists and naturalists, including Charles Darwin. Biologists discovered that male bees needed the specific perfume compounds produced by the flowering plants in order to mate with female bees.
In the study, published in the Sept. 23 issue of the journal Science, the researchers screened more than 7,000 individual male bees and sequenced DNA from 140 orchid pollinaria, which are small packages that contain all the pollen grains produced by a single flower. The researchers were able to infer the evolutionary history of both bees and orchids, and establish which species of bee pollinates what species of orchid. The researchers also quantified and analyzed the perfumes collected by orchid bees and compared them with the compounds produced by orchid flowers.
To their surprise, the scientists found that the bees evolved at least 12 million years earlier than their orchid counterparts. Additionally, they found that the compounds produced by the orchids only accounted for 10 percent of the compounds collected by their pollinators. The remaining 90 percent could be coming from other sources, including tree resins.
Male orchid bees can find the fragrance compounds they need for mating from decaying logs, as shown here, as well as from orchids. (B. Jacobi photo)
“It appears that the male bees evolved a preference to collect these compounds from all kinds of sources, and the orchids converged on that chemical preference millions of years later,” said Ramirez.
In essence, orchids need their bee pollinators more than the bees need them.
The findings have implications in conservation biology, particularly because of the alarming decline over the past 15 years of bee pollinators worldwide.
“Many plant species are extremely dependent on their pollinators,” said Ramirez, who began this work while he was a Ph.D. student in the lab of Naomi Pierce, Harvard University professor of biology. “If you lose one species of bee, you could lose three to four species of orchids. Many of these orchids don’t produce any other type of reward, such as nectar, that would attract other species of bee pollinators.”
“Our study is consistent with the emerging theory that insect sensory biases have played a major role in driving reproductive adaptations in flowering plants,” said Ramirez. “It highlights the ecological and evolutionary inter-dependence of flowering plants and their specialized pollinators, suggesting that new threats to insect pollinators may have profound effects on the ecosystems they inhabit.”
Written by Sarah Yang, UC Berkeley Media Relations | Read at the source
New paper co-authored by Damian Elias describes how hummingbird feathers ‘sing’ during courtship
September 9, 2011
When males perform courtship dives for females, neighboring fluttering tale feathers produce interaction frequencies. In some species, four or five species may interact with one another to produce sounds. Credit: Anand Varma
A new paper co-authored by Professor Damian Elias and published in the recent edition of Science magazine identifies the cause of sounds made by some hummingbird species during courtship.
While courting, a male hummingbird will typically climb into the air five to 40 meters and then quickly dives down past a perched female. When the male bird bird reaches the lowest point of his dive, he rapidly spreads and closes his tail feathers, causing them to flutter and generate sound.
Lead author and UC Berkeley alumnus Christopher Clark explains how hummingbirds generate sound with their tail feathers in the video below. Credit: Christopher Clark
Gene sleuths trace tree-killing pathogen back to California
September 2, 2011
A row of Italian cypress trees near Siena, a city in Italy's Tuscany region. A number of trees show symptoms of cypress canker disease. Researchers have traced the origin of the pathogen responsible for the disease back to California. (Photo by Robert Danti, Italian National Research Council)
BERKELEY — A new study by UC Berkeley and Italian researchers spotlights the hazards of planting trees and other vegetation in regions where they are not native. [Read more...]
There’s something in the California air
August 25, 2011
UC scientists built and worked in towers as part of the largest single atmospheric research effort in the state. The data they’ve collected will guide policymakers dealing with air pollution. [Read more...]
Ecosystems take hard hit from loss of top predators
July 14, 2011
A paper reviewing the impact of the loss of large predators and herbivores high in the food chain confirms that their decline has had cascading effects in marine, terrestrial and freshwater ecosystems throughout the world. [Read more...]
How Safe is Mist Netting? First Large Scale Study into Bird Capture Technique Evaluates the Risks
July 12, 2011
Frequently Captured Birds Found to be at Less Risk of Injury Compared to Birds Captured Once [Read more...]
Latinos Have Higher Exposure to Nitrate-Contaminated Drinking Water, Study Finds
June 23, 2011
San Joaquin Valley communities with large Latino populations are exposed to disproportionately high levels of the agricultural chemical nitrate through their drinking water, [Read more...]
Wild pollinators worth up to $2.4 billion to farmers, study finds
June 20, 2011
California agriculture reaps $937 million to $2.4 billion per year in economic value from wild, free-living bee species that serve the critical function of pollinating crops, according to a new study by scientists at the University of California, Berkeley, published this week in the June issue of the journal Rangelands. [Read more...]
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