Cooperative Extension San Joaquin County
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Cooperative Extension San Joaquin County

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Residential runoff still contains banned chemicals

Pesticides that have not been sold at the retail level for years are still regularly found in residential runoff water, according to research in Sacramento and Orange counties by UC scientists. So called “legacy pesticides” are probably old products that homeowners still have on their garage shelves and are still using to control pests.

An earlier study by the California Department of Pesticide Regulation and the UC Integrated Pest Management Program found that 60 percent of pesticides sold to consumers are for ant control. For that reason, UC Cooperative Extension specialist in landscape horticulture Loren Oki of UC Davis and UC Cooperative Extension water resources/water quality advisor Darren Haver focused on ant control pesticides in their residential runoff research project. The scientists collected 830 water samples from the storm drains in four Sacramento County neighborhoods and four Orange County neighborhoods between 2006 and 2010.

“In Sacramento County, we trained a team of about 25 volunteer UC Master Gardeners to collect the samples,” Oki said. Orange County samples were collected by Haver and his staff. All the samples were sent to UC Riverside for analysis.

“Pesticides that have been off the market since 2004 are still found in the water,” Oki said. “We found organophosphates – diazinon and chlorpyrifos – in differing amounts, typically more in Orange County than Sacramento County. We also found a fairly new pesticide, fipronil, in most of our water samples.”

The scientists also noted random spikes in the amount pesticides in runoff water, unconnected with storms or other conditions, which suggested that they were directly associated with particular pesticide applications in the neighborhoods.

There are several ways homeowners can help prevent contamination of the California water supply. For one, dispose of old pesticides properly. Most cities and counties have programs for disposal of household hazardous waste.

When using pesticides, Oki suggests residents carefully read the label and use common sense.

“Don’t put pesticides on impervious surfaces, like concrete walkways and driveways,” he said. “Don’t put pesticides in garden areas where runoff might be generated. That runoff will carry the pesticides with it.”

Residents can also minimize the amount of water runoff from the property. Oki suggests reducing irrigation and targeting the water application properly. In addition, promote soil infiltration by promoting soil health.

“If you don’t generate runoff, you won’t have pesticides running off too,” Oki said.

Residential runoff can convey pesticides into water supplies.
Residential runoff can convey pesticides into water supplies.

Posted on Wednesday, June 29, 2011 at 9:22 AM
Tags: Darren Haver (2), Loren Oki (2), pesticides (4)

Rangelands conservation helps farmers

As it turns out, the farmer and the cowman should be friends, as the classic “Oklahoma!” song suggests. According to a just-published UC Berkeley study, wild bee species pollinate California crops to the tune of $937 million to $2.4 billion per year. That amounts to more than one-third of all pollination “services” to the state’s crops.

Many of those crop-pollinating wild bees live in rangelands – chiefly ranches that graze cattle.

“This means that preserving rangelands has significant economic value, not only to the ranchers who graze their cattle there, but also to farmers who need the pollinators,” said Claire Kremen, UC Berkeley associate professor of environmental science, policy and management, and senior author of the study.

The assumption that wild pollinators were not a significant source of crop pollination is more than just conventional wisdom – it’s business: a majority of farmers rent European honeybees to ensure crop pollination.

But beekeepers have suffered high rates of colony losses due to diseases, pesticides and management factors, increasing the uncertainty of both supply and rental prices.

The California native bee species Bombus vosnesenskii, the yellow-faced bumble bee, forages on almond flowers that are located right next to rangelands habitat. (Alexandra Maria-Klein photo)

And wild pollinator species have also shown declines in abundance and diversity on farmlands, most likely due to habitat loss from the intensive monoculture, or single crop, production system that typifies much of California’s agricultural lands.

The result? They are most scarce precisely where they are needed the most.

“Currently, wild pollinators are least abundant in intensive monoculture production areas such as sunflowers, almonds and melons, where demand for pollination services is largest,” said Kremen.

Kremen equated depending mainly on one species – the European honeybee – with putting all our retirement savings in one stock.

“The wisdom of diversification holds true for agriculture as well and yet, many Calfornia farmers rely solely on European honeybees for crop pollination,” Kremen said, adding that the unpredictability associated with climate change amplifies the importance of diversification.

“Some insect species will thrive in changed climate conditions, and other won’t. Maintaining a biodiverse stock of pollinators is like the insurance that a diversified stock portfolio brings: some will be up, some will be down, but having a portfolio of many different species ensures viability into the future,” Kremen said.

While it’s common sense that healthy crops result in a healthy food supply, a separate study led by Kremen, also just published, put a number on the human health benefit of ensuring the viability of pollinators. The researchers estimated that up to 40 percent of some essential nutrients provided by fruits and vegetables could be lost if there were no pollinators around to do the job.

Payment for services rendered

Placing a value on ecosystem services is an established part of conservation science, and this new finding comes at a time when there is growing interest within the ranching community in providing ecosystem services. For example, as part of conservation efforts, California ranchers have been asked to maintain flowers for endangered butterflies and to keep small spring wetlands known as vernal pools healthy – using grazing as a tool to manipulate the grassland.

Darrel Sweet, a fifth generation cattle rancher from Livermore and a former president of the California Cattlemen's Association, said that placing a dollar value on rangelands pollination services lends powerful support to these efforts.

“The value of grazing and other land stewardship practices of California’s ranchers is being increasingly acknowledged as not only a preferred land use, but also as an essential resource management tool,” said Sweet. “I hope this study is just the beginning of comparable findings that show how ranching is a critical – and multifaceted – element of California agriculture.”

The state’s rangelands have been decreasing steadily, as the foothills and oak-dotted grasslands can be highly desirable for residential development. California lost 105,000 acres of grazing lands to urbanization between 1990 and 2004, according to the state Department of Conservation. The California Oak Foundation projects that the state could lose another 750,000 acres by 2040.

Kremen said the findings suggest that if farmers paid ranchers to stay on the land and maintain the habitat, the farmers would be increasing their sources of pollination and developing critical diversification to support their agricultural practices.

Posted on Wednesday, June 22, 2011 at 1:01 PM
  • Author: Ann Brody Guy

Scientists complete eventful fisher monitoring season

The UC Berkeley Sierra Nevada Adaptive Management Project (SNAMP) Fisher Team has just finished closely monitoring reproductive-age female Pacific fishers living in the Sierra National Forest near Bass Lake for the spring 2011 denning season.  Each year the denning season for fishers starts around late March and ends in mid June.

Female fisher F01 about to squeeze into the opening for a den cavity inside a black oak tree. The cavity opening is about 25 feet up the tree.

The fact that one of the study's radio-collared female fishers moved her kit from a natal den tree (where the kits were born) in the Sierra National Forest to a maternal den tree in the Mariposa Grove area of Yosemite National Park was a highlight. The event was significant for the park service because it represents the first known fisher den tree location in Yosemite National Park. The National Park Service produced a news release detailing the story.

The Fisher Team also hosted a visit to the project area by a reporter and photographer from the Fresno Bee, which resulted in positive coverage in that newspaper and in the Sacramento Bee.

Below are images captured by den tree cameras this spring. The images illustrate the types of photographic evidence the SNAMP Fisher Science Team uses to document natal and maternal den trees being used by fishers.

Fisher leaving a den tree (the oak in the background) to forage.

Fisher climbing down her maternal den tree.

One of the projects key goals during the denning season is to estimate the typical number of kits that adult females produce each year. One way to do this is by climbing the den tree while the mother fisher is out foraging, and then lowering a specialized camera down into the den cavity. Below is an edited portion of the video footage recorded from inside the den cavity of female fisher F07. The one-minute clip shows two fully furred fisher kits snuggled up together inside the F07 den tree cavity.

Unfortunately, the 2011 denning season was not without life/death drama for the population. Last year two denning females were killed, leaving five orphan kits  behind. The Fisher Team rescued and later released the orphan kits into the wild. This year it was looking like there would not be any denning females killed during den season, up until Saturday, June 4, just two weeks before the typical end of den tree use.

On that day the researchers found the predator-killed carcass of adult female F28 about 150 yards from her den tree. After last year's orphan rescue, the California Department of Fish and Game (DFG) worked with a group of wildlife researchers (including the SNAMP Fisher Team) and agency stakeholders to develop an official policy to help guide researchers on how to deal with orphan kit situations.

In keeping with this new policy, the SNAMP Fisher Team carefully considered the characteristics of the den tree structure (a rotting white fir snag), consulted with DFG, and reached the difficult decision not to attempt to rescue the one or two orphan fishers in the den tree. Attempting to climb the tree would have been dangerous and overly risky for the SNAMP Fisher Team crew. Therefore, in this specific case, nature was left to take its course; F28’s fisher kits perished in a den cavity somewhere near the top of the white fir snag.

The SNAMP Fisher Team is currently preparing information on a wide variety of preliminary results and findings from the ongoing research, which will be reviewed during the SNAMP Fisher IT Meeting in Fresno on July 19. More analytical details from the spring 2011 denning season will be presented at that venue.

The SNAMP Fisher Study is funded by the USDA Forest Service. The agency also provides an airplane and full-time pilot to assist in locating radio-collared fishers living in remote parts of the forest. The image below is a logo for the SNAMP Fisher Project affixed to the tail section of the Cessna 185 airplane used to track fishers by aerial radiotelemetry.

SNAMP logo on the Cessna 185 Tail
SNAMP logo on the Cessna 185 Tail

Posted on Wednesday, June 15, 2011 at 8:11 AM
  • Author: Rick Sweitzer

These bees 'cut it'

We're in the midst of a housing crisis, so why not build a 30-unit, high-rise condo in your yard?

No, not for people--for native bees.

We just installed a bee condo for leafcutting bees (Megachile spp.), on a five-foot high pole overlooking catmint, lavender and salvia.  The "housing development" is actually a wooden board drilled with small holes to accommodate our tiny tenants. Comfy and convenient. Rooms with a view. No housing permits or EIR required. Rent-free, mortgage-free.

Leafcutting bees, aka leafcutter bees, are about the size of a honey bee but darker, with the characteristic light-banded abdomens. They are important pollinators.

Why are they called leafcutter bees? Because the females cut leaf fragments to construct their nests to raise their brood. In nature, they build their nests in soft, rotted wood or in the pithy stems of such plants as roses, raspberries, sumac and elderberry. 

Unlike honey bees, which are social, the leafcutting bee is a solitary nesting bee.  She provisions her leaf-lined nest with nectar and pollen, lays an egg, and seals the cell before leaving.

Commercially made bee condos are available at beekeeping supply stores or on the Internet. You can make or buy a board with different sized-holes so other native bees, such as blue orchard bees, aka mason bees, receive a "home, sweet home," too, and deliver pollinator services.

And enable you to tell your family and friends that you're a "bee landlord" or beekeeper.

The Xerces Society for Invertebrate Conservation offers tips on building bee condos on its website and in its publications, including Farming for Bees: Guidelines for Providing Native Bee Habitat on Farms.

If you don't want bee boards housing your tenants, you can provide straws or hollow bamboo stems.

At the UC Davis Department of Entomology, doctoral candidate Emily Bzdyk is doing research on leafcutter bees. "Basically I'm doing a revision of the subgenus Litomegachile, part of the large genus Megachile, which includes leafcutter and resin bees," she said. "They are native to North America. My goals are to find out how many and what the species are in Litomegachile, and find out as much as I can about their biology, or how they make a living."

"I also want to identify clearly what the boundaries between the species are, or how to tell them apart from one another," said Bzdyk, whose major professor is Lynn Kimsey, director of the Bohart Museum of Entomology. "Litomegachile are very common and hard-to-identify to species, and I feel they deserve attention."

Bzdyk noted that some Megachile are used in commercial alfalfa production. The alfalfa leafcutter bee, native to Europe, is used for commercial pollination of alfalfa, she said. "The Litomegachile is probably very closely related."  

The alfalfa growers erect giant bee condos in their fields to draw bees to their plants.

With home gardeners, the effect is the same.

If you build them, they will come.

Leafcutting bees, aka leafcutter bees (genus Megachile) head toward a bee condo built for these and other pollinators. (Photo by Kathy Keatley Garvey)
Leafcutting bees, aka leafcutter bees (genus Megachile) head toward a bee condo built for these and other pollinators. (Photo by Kathy Keatley Garvey)

Leafcutting bees, aka leafcutter bees (genus Megachile) head toward a bee condo built for these and other pollinators. (Photo by Kathy Keatley Garvey)

Home sweet home: Oblivious to ants, a leafcutter bee heads for home. (Photo by Kathy Keatley Garvey)
Home sweet home: Oblivious to ants, a leafcutter bee heads for home. (Photo by Kathy Keatley Garvey)

Home sweet home: Oblivious to ants, a leafcutter bee heads for home. (Photo by Kathy Keatley Garvey)

Male leafcutter bee (genus Megachile) sips nectar from a rock purslane. (Photo by Kathy Keatley Garvey)
Male leafcutter bee (genus Megachile) sips nectar from a rock purslane. (Photo by Kathy Keatley Garvey)

Male leafcutter bee (genus Megachile) sips nectar from a rock purslane. (Photo by Kathy Keatley Garvey)

Posted on Wednesday, June 8, 2011 at 9:41 AM

Forest Biology Research Center opens at UC Davis

A Forest Biology Research Center has been created at UC Davis, bringing good news for students, researchers, and all of us who like to breathe clean air.

“Trees are as important as agriculture to the landscape of California and the world,” says UC Davis Department of Plant Sciences Professor David Neale, a forest geneticist and the driving force behind the new center. “Creation of the center culminates the work of many people over many years to bring a visible presence to forest biology research and education on the UC Davis campus.”

UC Davis is a prime location for forest biology research and education because of its proximity to the Sierra Nevada and coastal mountain forest ecosystems and its extensive faculty expertise in all aspects of forest biology, says UC Davis Plant Ecology Professor Mark Schwartz, director of the John Muir Institute for the Environment (JMIE) where the new center is located.

“The creation of this forest-focused center is both an affirmation of what UC Davis has been doing really well for a long time, and a big step forward in JMIE’s efforts to rally faculty expertise around the central environmental issues facing California and the world”, Schwartz says. “As California joins Europe in adopting carbon standards, developing a better understanding of the role of forests in carbon sequestration has become a priority for environmental organizations.”

The new center will also provide a framework for the cross-disciplinary work so central to forest biology.

“Forest biology draws from many of the core biological sciences such as genetics, ecology, plant pathology, entomology, plant biology, and geography,” Neale explains. “Before this framework was in place, graduate students could study genetics with me, for example, but they couldn’t really go broader into other areas of forest biology. Now when they come to UC Davis to do graduate work in, say, ecology, they will also have access to interdisciplinary work in forest biology.”

The Forest Biology Research Center is working to develop a certificate program in forest biology that can be awarded along with a degree from an existing graduate program.

At the Forest Biology Research Center website, you can learn more about the 24 UC Davis faculty and affiliated members of the US Forest Service who founded the center. They look forward to working with others to help develop forest biology research and education at UC Davis.

In addition to Neale and Schwartz, the executive committee includes UC Davis Plant Pathology Professor Dave Rizzo, UC Davis Plant Biology Professor Alison Berry, and Research Ecologist Malcolm North with the UC Davis Department of Plant Sciences.

Posted on Wednesday, June 1, 2011 at 10:46 AM
  • Posted By: John Stumbos
  • Written by: Diane Nelson,, (530) 752-1969

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