Posts Tagged: pollinators
"The use of synthetic chemical pesticides is central to current agricultural practices worldwide. But what is the cost to wildlife via...
Scott McArt of Cornell will speak on "Pesticide Risk to Pollinators: What We Know and What We Need to Know Better" at the Wednesday, May 4 virtual seminar hosted by the UC Davis Department of Entomology and Nematology.
Ready to learn about mammoth wasps, medflies, nematodes and pesticide risks to polilnators, or delve into such topics as "Mystery of the Missing...
Bees will be among the spring seminar topics hosted by the UC Davis Department of Entomology and Nematology. UC Irvine faculty member Tobin Hammer will speak on "Mystery of the Missing Microbes: Why Do Bees Keep Losing Their Symbionts?" (Photo by Kathy Keatley Garvey)
The Mediterranean fruit fly will be the topic of UC Davis distinguished professor James R. Carey's seminar on May 25. (Photo by Scott Bauer, U.S. Department of Agriculture)
There they were. Together. The scene: A honeybee (Apis mellifera) and a bumblebee (Bombus vosnesenskii) nectaring on a purple coneflower...
A honeybee (Apis mellifera) and a bumblebee (Bombus vosnesenskii) nectaring on a purple coneflower (Echinacea purpurea) in a UC Davis bee garden. (Photo by Kathy Keatley Garvey)
This is the cover of the American Journal of Botany, featuring several species of bees on a sunflower, Helianthus sp, (Cover photo by Kathy Keatley Garvey)
In late February, in an almond orchard in the Sacramento Valley, the fall-planted cover crop mix of grasses, brassicas and legumes had barely produced a green fuzz above the soil surface, and it was unclear when it would bloom. Unfortunately, this scene is becoming more frequent across California, as climate change causes more prolonged droughts and rain-dependent winter cover crops can barely grow, which delays or reduces bloom, essential for supporting pollinators. Fortunately, California native plant species have evolved with drought and have developed many strategies to survive and reproduce in those conditions.
Would it be possible to capitalize on the over 9 million acres of cropland in California for drought resilience and habitat restoration by utilizing more native species as cover crops? Our team at the UC Sustainable Agriculture Research and Education Program (UC SAREP) spent some time considering various native plant species and their potential ecological and operational attributes as cover crops. For a full list of species and their attributes, see https://ucanr.edu/sites/covercrops/.
Many native species are so well adapted to drought that they will still germinate and bloom during extremely dry years, for example, annuals like Tidy Tips (Layia platyglossa) and California poppy (Eschscholzia californica). Alternatively, perennial bulb species like Prettyface (Triteleia ixioides) and Bluedicks (Dipteronstemon capitatus) become dormant during the dry summer, retaining their bulbs below ground and re-growing when the rains return. These species could perhaps fit well in no-till orchard systems. Summer dormancy is important for tree nut growers because they usually need clean ground under the trees during harvest. Moreover, the costs to terminate and reseed would potentially be eliminated. While these species are well-known by Native Americans for their edible bulbs, at this point in time, we are not aware of any cover cropping trials having ever been conducted with these species.
Another species with strong reseeding and more availability is the annual Lacy Phacelia (Phacelia tanacetifolia), which offers an intriguing historical precedent for developing a native species for cover cropping purposes. Native to California, it was introduced into Europe in 1832 by Germans. It is very attractive to pollinators and experienced a boom there in the early 1990s. European beekeepers and farmers have been using Lacy Phacelia as a cover crop ever since, and it has recently been gaining traction on California farms as well. California has many species of phacelia, with another, described as being even more attractive to native bees, being the annual Great Valley Phacelia (Phacelia ciliata). Besides supporting native bees, other native plant species can contribute nitrogen to the soil, such as annual Lupine (Lupinus spp.) and perennial Deerweed (Acmispon glaber), which are legumes and form an association with nitrogen-fixing bacteria in their roots.
Cover crops are not usually considered marketable crops. However, we should not preclude the potential for some plants that are useful as cover crops to provide a harvestable product as well. Native perennial fiber plants such as Indian hemp dogbane (Apocynum cannabinum), narrow leaf milkweed (Asclepsias fascicularis), and common nettle (Urtica dioica) could offer the opportunity to cultivate summer cover crops that have a market value, especially in cases where farmers are already willing to irrigate their cover crops to improve their development and amplify the benefits. Bowles Farming in the San Joaquin Valley is experimenting with growing these three species for fiber production. All three also attract native bees and important butterfly species such as monarchs (as long as farmers avoid spraying insecticides).
While we believe that some native species could open new opportunities for farmers as cover crops, we still have insufficient studies testing the effects and viability of these species. Organizations like the NRCS Plant Materials Center at Lockeford and the Xerces Society are conducting practical studies with native species, creating plant guides and working with farmers to expand their use. In addition, researchers Lauren Hale of the USDA Agricultural Research Service and Anil Shrestha of California State University, Fresno, are using a 2021 UC SAREP small grant to study the effects of native species mixes on water demand and weed populations in San Joaquin Valley grape vineyards. Hale suggests that below-ground ecosystems may benefit as much from native plants as above-ground ecosystems. Says Hale, “Because plants and their microbiomes have evolved together for millennia, it seems logical that native plants would promote a good response from the native soil microbiota.”
For additional information:
UC SAREP List of California Native Species for Potential Use as Cover Crops: https://ucanr.edu/sites/covercrops/
Xerces Society lists of pollinator-friendly native species for California: https://xerces.org/pollinator-resource-center/california
NRCS California Plant Materials Center plant guides: https://www.nrcs.usda.gov/wps/portal/nrcs/publications/plantmaterials/pmc/west/capmc/pub/
UC SAREP Cover Crops Database: https://sarep.ucdavis.edu/covercrop
If you want to draw pollinators to your yard, think of the plants for sale at the teaching nursery maintained by the UC Davis Arboretum and...
A honey bee foraging on Salvia "Hot Lips." (Photo by Kathy Keatley Garvey)
A honey bee, proboscis (tongue) extended, takes a liking to the Salvia "Hot Lips." (Photo by Kathy Keatley Garvey)
The honey bee checks out the photographer. (Photo by Kathy Keatley Garvey)
Flight time! The honey bee prepares to leave Salvia "Hot Lips." (Photo by Kathy Keatley Garvey)
Nursery manager Taylor Lewis of the Arboretum Teaching Nursery, UC Davis Arboretum and Public Garden, tends to plants in the nursery. An online public sale is set May 20-24. (Photo by Kathy Keatley Garvey)
These carts will be in use with the UC Davis Arboretum's online plant sales take place May 20-24. Delivery is curbside.(Photo by Kathy Keatley Garvey)