Posts Tagged: Rachael Long
Hedgerows enhance wildlife abundance and diversity around farmland without contributing to food safety problems in field crops, according to a new study published by a team of University of California researchers. The UC Agriculture and Natural Resources and UC Davis study documented that field edge plantings around farms are generally too narrow relative to the surrounding landscape to be a source of rodents and foodborne pathogens.
“This study is particularly pertinent right now when FDA's Food Safety Modernization Act (FSMA) is calling for farmers to co-manage wildlife and agriculture, instead of clear cutting wild habitat around their crops,” said co-author Rachael Long, UC Cooperative Extension farm advisor in the Sacramento Valley. “Our paper provides support for this ruling, showing that the presence of hedgerows does increase wildlife diversity, but does not increase wildlife intrusion into the fields and, more importantly, does not increase the prevalence of animals carrying foodborne pathogens.”
This is good news for hedgerows, rows of shrubs, trees, grasses and flowers that are planted on field edges. The plants bordering crop fields provide habitat and floral resources for beneficial insects, such as bees and natural enemies, that help with pollination and biocontrol of pests in adjacent crops. Hedgerows also help enhance biodiversity – especially for insect-eating birds – help reduce wind and soil erosion, and protect water quality.
The two-year study in Sacramento Valley walnut orchards and processing tomato fields was led by Long and Roger Baldwin, UC Cooperative Extension vertebrate pest control specialist at UC Davis, former graduate student Laurel Sellers, the Western Center for Food Safety at UC Davis's Michele Jay-Russell, Xunde Lib and Edward R. Atwill, and Richard M. Engeman of USDA National Wildlife Research Center.
The study, titled “Impact of field-edge habitat on mammalian wildlife abundance, distribution, and vectored foodborne pathogens in adjacent crops,” was published in the February 2018 Crop Protection (Sellers et al. 2018).
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This journal article supports a growing body of literature suggesting that plantings along the edge of fields do not substantially attract wildlife species that intrude on fields and transfer foodborne pathogens. For example, in a 2015 study, UC Davis researchers found more food pathogens when wildlife habitat was reduced on farms. This may be attributed to the vegetation filtering pathogens, a better breakdown of pathogens in diverse environments, and that removing vegetation may not deter wildlife from entering farm fields.
Relative to the larger crop acreage, hedgerows and similar field-edge habitats are generally too linear and small to serve as a significant source of rodents to damage nearby crops. However, cottontail rabbits favor hedgerows, and can sometimes cause damage to adjacent seedling crops.
“Overall, we found risk of crop loss or contamination of foodborne pathogens in crops bordered by hedgerows wasn't significant in our study in the Sacramento Valley, although potential damage could vary by the stage and type of crop and wildlife species present,” Long said. She will be presenting this work at the 28th Vertebrate Pest Control Conference, which will be held in Rohnert Park Feb. 26 to March 1.
In its Standards for the Growing, Harvesting, Packing, and Holding of Produce for Human Consumption, the U.S. Food and Drug Administration says, "We continue to encourage the co-management of food safety, conservation, and environmental protection.”
Hedgerow benefits align with food production and sustainability goals. http://calag.ucanr.edu/archive/?article=ca.2017a0020
Comanaging fresh produce for nature conservation and food safety. http://www.pnas.org/content/112/35/11126
California is in the middle of the Pacific Flyway, a major north-south flyway for migratory birds, and also bats, that extends from Alaska to South America.
“Every autumn, migratory bats, such as the Mexican free-tailed bats, travel to their overwintering grounds in Southern California and Mexico, where there's plenty of bugs to eat; they come back each spring to raise their families,” said Rachael Long, a UC Cooperative Extension advisor who studies bats.
Bats are beneficial because they feed on insects, including mosquitoes and pests such as codling moths that damage fruit and nut crops. The economic value of bats for pest control on farms has been estimated by some studies to exceed $23 billion per year. Long, who serves Sacramento, Solano and Yolo counties, is studying the value of bats for pest control in walnut orchards.
In the city of Davis, officials recently warned people to stay away from bats after bats found on the UC Davis campus tested positive for rabies. Long agrees with the warning, but worries that it might also result in healthy bats being killed.
“This is most unfortunate for people and bats, but not a surprise at this time of year. Right now, thousands of bats are flying through our great Central Valley, migrating south for the winter, just like ducks and geese, so there's a higher chance of contact,” she said “We just don't see bats as much because they are flying at night, using the stars, earth's magnetic field, and landscapes to navigate.”
Their journey south is lengthy, from as far north as Washington state to Mexico, and exhausting, so bats need to rest along the way.
“Sometimes you'll see one or more tucked up in the corner of your house, such as under an eave,” Long said. “If so, use this as an opportunity to share with others the amazing life of a bat that can fly over a thousand miles to their overwintering grounds and back again in the spring. Leave them alone, let them rest, and they will fly away after they've rested and recovered.”
If you have to move a bat, she notes you should wear gloves and not handle a bat with bare hands because they will bite in self-defense.
“If you find a bat on the ground, place a box over the bat and using a piece of card, slip it under, then gently and carefully slide the bat into the box,” Long said. “Place the box at 4 to 5 feet off the ground and open it (bats usually can't take off from the ground). The bat can then crawl out of the box in its own time and fly away.”
“If the bat does not fly away within 30 minutes, it is probably sick or injured. In this case, contact a wildlife rescue unit in your area.”
Long noted that animal control officers have to euthanize bats to test for rabies.
“The bat may be perfectly healthy, just tired,” she said. “If no people or pets have obviously touched the bat, you can call a wildlife rescue organization. If in doubt, call animal control.”
If a bat does have rabies, Long said, “Rabies dies within five to 10 minutes after the bat dies.”
For more information on the benefits of bats, see Long's post in UC ANR's Green Blog, “Bats in the Belfry? No, Bats in Walnut Orchards” at http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=17395.
River of No Return, written by UC Cooperative Extension advisor Rachael Freeman Long, chronicles the third summer at the family cabin for Jack, where he meets up with his animal pals from the previous books: Pinta the bat and Sonny the coyote. The trio were introduced in Gold Fever, and reunited in Valley of Fire. In River of No Return, Jack, Pinta and Sonny team up with other animal friends and foes – including Lux and Lacy the wolves and Midas the raven – to defeat and bring to justice the last of a band of poachers tormenting wildlife in the Black Rock Desert.
The loss of Sonny's loving parents, Lux's near fatal injuries, and the dark rage of Sarge, a greedy Air Force veteran who is willing to poach endangered species to become “the richest man in the world,” sets a somber stage. But Jack's commitment to his animal friends, his courage and ingenuity take the sting out of the story, even as he braves pitch dark tunnels, a raging underground river, and dreadful villains. Riveted as the novel unfolds, children may not realize that they are learning about wildlife and natural history.
All three books in the Black Rock Desert Trilogy are peppered with facts about animals, but Long gives bats, a focus of her agricultural research for UC Cooperative Extension, the spotlight. For example, readers learn that Pinta the pallid bat has big, pink ears that twitch constantly as they echolocate, when using sound waves to see in the dark. Later, Pinta tells Jack, “Remember, we migrate to the desert southwest during wintertime where it's warmer and there's plenty to eat.” Readers also learn that bats pollinate flowers, when Pinta turns yellow with pollen.
“The characters have been in my head for 20 years,” Long said. “It's sad to let them go.”
She may be hanging up the tale of Jack, Pinta and Sonny, but Long plans to keep writing children's books. Her new series, called Animal Adventures, will begin with A is for Alligator, in which two 8-year-old boys visit a city zoo.
“They wonder what it's like in the animals' natural habitat, and a portal takes them to the Everglades, where they learn everything they need to know about alligators,” Long said.
The series will continue, next is B is for Bear, for 26 volumes, one for each letter of the alphabet.
“I'm hoping to do something fun and teach kids about our natural world,” Long said. “There are a lot of books that are negative about school and authority. My series will focus on courage, resilience and goodness.”
All of Long's books are available on Amazon.com.
UC Agriculture and Natural Resources and UC Berkeley researchers analyzing hedgerows in Yolo County have found that not only are farmers diversifying their land by planting hedgerows, but those hedgerows are attracting natural enemies that provide economic benefits.
The two-year study of hedgerows planted adjacent to processing tomatoes showed higher numbers of natural enemies such as lady beetles (aka lady bugs) and fewer crop pests compared with conventionally managed field crops edged with residual weeds.
The researchers discovered that the increase in natural enemy activity in the hedgerows extended 600-feet into adjacent tomato crops and resulted in a reduction of aphid pests and an increase in stink bug egg predation by parasitoid wasps. Tomato fields adjacent to hedgerows required fewer pesticide treatments than the tomato fields without hedgerows.
The scientists concluded that hedgerow restoration on field edges could enhance pest control, reducing the need for chemical pest control, as reported in the Journal of Agriculture, Ecosystems and the Environment.
Additional research has shown that hedgerows are important for pollinators, such as native wild bees, that feed on flowers and nest in the ground or holes in plant stems. More wild bees are present on farms with hedgerows than with conventionally farmed field edges. Native bees are important in crop pollination, especially with the decline of the honey bee population.
Hedgerows cost about $4 per linear foot to plant and manage for the first three years for a single row of shrubs and native grasses about fifteen feet wide. The Natural Resources Conservation Service (NRCS) offers cost-share programs through USDA's Environmental Quality Incentives Program (EQIP) that covers about 50 percent of the establishment costs. However, due to less pesticide use, a hedgerow can pay off in about 15 years. Add pollination services in areas without an adequate number of honey bees for crop pollination, and that time can be significantly reduced.
With a grant from the California Department of Pesticide Regulation, the Yolo County Cooperative Extension Service seeks to spread the word about the ecosystem service benefits provided by hedgerows planted on farmland. During the past two-years, the researchers hosted workshops in Northern California on the value of hedgerows on farms, reaching hundreds of farmers and landowners. The researchers also offer advice on hedgerow plantings, including plant selection and how to establish and manage hedgerows. Planting hedgerows does not take land out of production; it's using areas that cannot be farmed, such as along fence lines or terraces from land leveling, and providing economic benefits.
Additional examples of hedgerows on Yolo County farms:
What's the economic value of bats to the agricultural pest control? It probably exceeds $23 billion per year, according to recent studies. However, very little data exists on the benefits of bats for individual crops, such as walnuts.
UC Agriculture and Natural Resources researchers, together with UC Davis, are launching a survey to better understand the value of bats (and birds) on managed lands. The voluntary survey, focused on growers and landowners in California's Central Valley, may be completed online.
Work is already underway to assess the pest-control impact of bats on walnut production in the Central Valley with a grant from the U.S. Environmental Protection Agency STAR (Science to Achieve Results).
California produces almost all of the nation's walnuts. Farmers grow some 500,000 tons of walnuts on 290,000 acres, with the annual crop valued at $1.8 billion. Due to popular demand, new orchards are planted every year, calling for more intensive farming practices to manage costly crop pests. For walnuts, the key pest is the codling moth, a larva that feeds on developing nuts. The adult moths begin to fly and lay eggs on the nutlets in May and produce up to four generations per year.
Bats forage in walnut orchards for codling moths and other insects. Colonies of bats double their activity on farms when they roost in bat houses attached to barns in the orchards. The Mexican free-tailed bat is the most abundant species, followed by the Yuma and California myotis, and five other species, including the pallid bat.
In an effort to quantify the economic impact of bats' consumption of codling moths, we captured 36 Mexican free-tailed bats over a three-night period in an 80-acre walnut orchard in Yolo County. Some 3,000 bats live in the bat houses in an abandoned shop on the property.
The research procedure: We opened our mist net from 11 p.m. to 2 a.m. to correspond with codling moth flights and bat activity, and captured the bats as they returned to the roost after feeding. We placed the bats individually in sterile cloth sacks and kept them there until they defecated, then we released them. We quickly froze the guano pellets and shipped them to a USDA lab, where scientists genetically tested them for the presence of codling moths.
Our preliminary data suggest that 5 percent of these bats – about 150 bats from this colony of 3,000 – consumed at least one codling moth per night. We calculated 30 nights per generation for the codling moth, and four generations per year, with each female moth laying 60 viable eggs on individual nuts.
The next steps: we are refining our economic data and determining whether these insect-hunting bats help reduce pesticide use in walnut orchards.
Bats provide these pest control services for free while farmers enjoy a decrease of pests in their orchards and an increase in profits.
Co-authors: Rachael Long, UC ANR advisor; and Katherine Ingram, Department of Wildlife, Fish and Conservation Biology, UC Davis.