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Saving the Mojave desert tortoise

Saving the declining populations of Mojave desert tortoise is a big challenge. But scientists think that raising newborn “hatchling” tortoises in a controlled environment in the Mojave National Preserve for a year, then releasing the juvenile tortoises into the wild, may help save this threatened species.

The protected tortoises — which live up to 80 years and can go without water for a year — have existed for eons, but are now being decimated by habitat loss and predation. Professor Brian Todd, in the Department of Wildlife, Fish and Conservation Biology at UC Davis, worries that the increasing use of Southern California deserts for solar and wind energy, will add to the loss of tortoise habitats, and add further pressure to regional wildlife habitats. While developing renewable energy to combat climate change is a good thing, in this case it impacts desert species and their habitats.

Professor Brian Todd, UC Davis, with a Mojave desert tortoise.
Stepping up to the plate to save the Mojave desert tortoises is a triad of academics, government agencies, and corporations, who recently created the Ivanpah Desert Tortoise Research Facility. The new facility, located in the Mojave National Preserve, was designed for scientists to conduct research on juvenile tortoise survival. It was constructed largely by Chevron and Molycorp, and is managed by the National Park Service. Scientists from the University of California, University of Georgia, and elsewhere, are conducting a 15-year study to see if hatchlings released into the wild and/or relocated elsewhere can survive and reverse the population decline.

We can all keep our fingers crossed that this research will preserve desert tortoise populations, and serve as a model for conserving biodiversity.

Additional information:

  • “Protecting the desert tortoise,” video of UC Davis researchers and desert tortoises.
  • “Habitat selection, space use, and factors affecting recruitment of desert tortoises in the Mojave National Preserve”; Brian Todd website, UC Davis
  • “Baby desert tortoises get a headstart in the Mojave,” by Andy Fell and Kat Kerlin, Egghead blog, UC Davis. With a video of tortoises and scientists.
    A hatchling Mojave desert tortoise.
  • “Tortoise territory,” by Robin DeRieux, CA&ES Outlook magazine (see pages 2 and 10), UC Davis, spring/summer 2012.
  • “Mojave National Preserve celebrates dedication of Ivanpah desert tortoise,” Mojave National Preserve website.

Desert tortoises are well camouflaged in the California desert.

Posted on Tuesday, September 16, 2014 at 9:44 AM

Almond farmers relying on groundwater to cope with drought

California has emerged as the world's almond orchard because of near-perfect conditions for the crop, but in terms of production, it may have hit its peak, reported Jennifer Rankin in The Guardian.

"The future for farming almonds in California will always be there," said David Doll, UC Cooperative Extension farm advisor in Merced County. "It is more about coming into balance with our water resources."

The story quoted from a UC report that California farmers have spent an extra $500 million this year pumping extra water to cope with the drought.

Co-author of the study, Richard Howitt, professor in the Department of Agricultural and Resource Economics at UC Davis, cautioned against singling out particular crops.

"Don't blame almonds for the problem," he said. "The problem is one of water mismanagement."

He suggested changes in how California manages water so farmers monitor their groundwater use and replenish supplies when there is more rain.

"[The farmers] should be repaying what they are taking. And if they are taking more, as they always are in droughts, then they should be making plans to repay it back in wet years. If you treat your groundwater the way you treat your retirement account, then everything would be OK."

More information about water stress in almonds may be found in David Doll's blog, The Almond Doctor.

Leaves dying and dropping early in a Merced County almond orchard most likely due to water stress.. (Photo: James Nichols)

 

Posted on Monday, September 15, 2014 at 10:46 AM

Farmers are feeling the impact of the drought

Because of the drought, California almond farmers have been forced to drill new wells, rely on salty groundwater for irrigation and bulldoze some trees, reported Robert Rodriguez in the Fresno Bee.

The story presented results from the USDA National Agricultural Statistics Service, which worked with state ag officials to send surveys to 688 California almond farmers; 458 of them responded.

The survey found that nearly 70 percent of almond farmers have only groundwater to irrigate their trees. About 23 percent said they had to drill new wells and 32 percent were reconditioning existing wells.

Normally growers mix surface water with groundwater to dilute the salts in water that has been pumped up from wells. But for many farmers, that hasn't been possible this year.

"Consequently, the amount of salt in the trees has placed them under stress and it is being reflected in smaller nut size, reduced growth and the potential for small crops in the future," said Bob Beede, University of California Cooperative Extension emeritus adviser who specialists in nut crops. He added that salt buildup can kill a tree.

Almond farmers use mechanical shakers to knock the nuts to the ground for harvest.

Read more here: http://www.fresnobee.com/2014/09/12/4120382_survey-finds-almond-growers-deeply.html?rh=1#storylink=cpy
Almond farmers use mechanical shakers to knock the nuts to the ground for harvest.
Almond farmers use mechanical shakers to knock the nuts to the ground for harvest.

Read more here: http://www.fresnobee.com/2014/09/12/4120382_survey-finds-almond-growers-deeply.html?rh=1#storylink=cpy
Posted on Monday, September 15, 2014 at 9:28 AM

Giant King Grass harvested at UC research center

Harvesting Giant King Grass (Photo: Viaspace Inc.)
The first crop of Giant King Grass, a hybrid grass with biofuel potential, was harvested at the UC Desert Research and Extension Center in Holtville this month, reported Ethanol Producer Magazine.

Giant King Grass is a fast-growing, high-yield grass that grows under a variety of soil conditions, according to Viaspace Green Energy Inc. It is propagated vegetatively and, with sufficient rain or irrigation, can grow 15 to 18 feet high in six months.

At the UC Desert Rec, scientists compared two planting processes:

  • Planting single nodes that grow into individual plants with some space between them.
  • Planting whole stalks continuously end to end, which results in a dense row of plants about six inches apart.

Preliminary results showed the whole stalk planting germinated earlier and grew more quickly. The individual plants had a significant number of skips where the nodes failed to germinate.

Two harvesting regimens were tested:

  • Harvest when the plant is 6 to 8 feet tall every two months for animal feed and to produce biogas for anaerobic digestion.
  • Harvest when the plant is 15 to 18 feet tall for bioenergy applications, such as direct combustion in a power plant, energy pellets or cellulosic biofuels.

"It was 108 degrees when I arrived in Holtville last Monday evening (Sept. 8, 2014) at 6 p.m.," said Carl Kukkonen, CEO of Viaspace. "Giant King Grass is planted in the worst soil at the University of California site, and still the results are good. I am pleased that Giant King Grass grows well in this extremely hot and dry environment."

Posted on Friday, September 12, 2014 at 1:15 PM

A disheartening new pest invades California vegetable gardens

Bagrada bugs feeding on a tomato. (Photo: Jennifer Evangelista, San Luis Obispo)
California gardeners harvesting their summer produce may encounter a new pest – the bagrada bug. The native of Africa made its first California appearance in Los Angeles County six years ago and has been moving eastward and northward ever since.

“Citizen scientists have been instrumental in reporting the occurrence of bagrada in various counties and are helping map its current distribution,” said Surendra Dara, UC Cooperative Extension advisor in San Luis Obispo, Santa Barbara and Ventura counties. “This is a very serious pest. It is wiping out gardens, and is of great concern for small-scale and organic growers.”

Bagrada bugs are major pests of cruciferous vegetables, such as cabbage, kale, cauliflower, Brussels sprouts and broccoli, but they don't appear to be picky eaters. They have been known to feed on a wide variety of garden vegetables in California, including green beans, cantaloupe, corn, peppers, potatoes, tomatoes and sunflower. Even landscape plants are not immune. Bagrada bugs have been found feeding on ornamental plants in the mustard family, like sweet alyssum, stock and candytuft.

Bagrada bugs congregating on sunflowers. (Photo: Larry Adcock, Arroyo Grande)
The adult bagrada bugs are about the size of watermelon seeds and have shield-shaped black backs with white and orange markings. Young bagrada bugs – with their red, black and white markings – are sometimes mistaken for ladybugs. But bagrada bugs have piercing and sucking mouthparts which cause dead spots on plant leaves and stems when they feed, and result in stunted growth, plant deformities and plant death.

Dara said scientists had hoped cold winter temperatures in northern counties of California would limit the bagrada's northward march, but that hasn't been the case so far.

“Bagrada bugs can survive the winter or cold nights by entering the top layer of the soil around crops,” he said. "They start appearing again in early spring and move from weeds to young vegetables."

For more information on bagrada bugs, see the Pest Note produced by the UC Integrated Pest Management Program. In addition, Dara regularly posts bagrada bug updates on his blog, Strawberries and Vegetables.

Distribution of bagrada bug in California, September 2014.
Distribution of bagrada bug in California, September 2014.

Posted on Friday, September 12, 2014 at 9:28 AM

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