When wildfires burn in California, people often call them forest fires or brushfires, but the odds are high that an invasive weed is an unrecognized fuels component, says a UC Agriculture and Natural Resources scientist.
“We have all of the nasty non-native Bromus species here in California, and these weeds are key drivers of increasing fire frequency,” said Travis Bean, UC Cooperative Extension weed science specialist based at UC Riverside.
The invasive, non-native Bromus species aggressively outcompete native plants, forming dense stands that grow fast and dry out quickly, becoming highly flammable. Fire can move rapidly through these dense patches of dry grass, especially during windy conditions or on slopes.
“When you have understory of dry Bromus or other weedy grasses, their ease of ignition can allow fire to spread from areas like roadsides where ignition sources are plentiful to more pristine native plant communities,” Bean said. “Additionally, these fast-moving fires can throw embers that allows the fire to jump long distances or even reach high into the air, igniting structures.”
Identifying fire fuel
Bean would like to see the fuels in wildfires identified so people have a chance to consider managing them to mitigate the increasing frequency of catastrophic wildfire across the state.
With training, citizen scientists such as California Naturalists could help cities, counties, utilities and government agencies identify the invasive plant species that fuel urban wildfires.
“On a landscape scale, I would focus on managing Bromus anywhere human-caused ignitions occur,” Bean said. “Resources for management are scarce, and these species are widespread and can't be controlled everywhere they occur. Roadsides, hiking trails, and campgrounds are critical areas where people can start fires that spread, so It makes sense to concentrate management there.”
Cheatgrass (Bromus tectorum) is widespread at higher elevations, while ripgut brome (B. diandrus) and red brome (B. madritensis spp. rubens), also called foxtail brome, are pervasive at lower elevations. Along with other invasive winter annual weeds, they have successfully replaced large areas of the native vegetation in Southern California.
“When I talk to land managers about these species, they recognize that some areas will have to be sacrificed and it may not be possible to eliminate these species from the landscape,” Bean said. They are prioritizing areas with smaller invasive populations where there is an actual chance to eliminate them, or are managing larger populations for containment so they don't spread.”
Timing is everything
The key to reducing the spread of invasive, non-native Bromus species or any annual weed is preventing the plants from producing seeds, Bean said. “Whatever control method you chose, if deployed too early or too late, you gain nothing for considerable expense.” Too early and the plants may simply resprout, while too late and they will have already set seed and further contributed to next year's weed crop.
Herbicide is an effective and inexpensive means of control, though many prefer non-chemical methods. Hand pulling can be effective in small areas, but is discouraged for large patches due to the sheer amount of labor required and risks of actually spreading the weed seeds.
Another way land managers can try to prevent the weeds from spreading is by mowing or grazing with goats, sheep or cattle, Bean said, adding that using livestock can require more intensive management and proper timing is critical.
“For mowing and grazing, the key is to wait until the plants have started to flower, but the seeds are not mature,” Bean said. “If you mow when there's mature seed, you'll just spread the seed and make the problem worse. And once the seedheads mature, grazing animals won't eat it.”
Prescribed fire is another option for containing invasive grasses, but is generally discouraged as there's a very high chance of exacerbating the problem. These Bromus species are very fire-adapted and tend to increase following burns. Prescribed fire should only be used by professional land managers. If this strategy is used, a burn plan, permits and training are essential. If not done correctly, prescribed burns may escape control and become wildfires, producing smoke that impairs visibility on highways, impacts air quality and human health, and damages native vegetation.
“Timing is everything,” Bean said, explaining the temperature difference between the plant and soil surface. “The grass has to be dry enough to carry fire, but not so dry that the seeds have fallen from the plant to the soil surface, where temperatures are much cooler than just a few inches up in the air where the seedheads are. Some research has shown this strategy to have been successfully used for certain invasive grasses like barb goatgrass (Aegilops triuncilias), but is not recommended for Brome species.”
He expects the changing climate to lead to more invasive plant species. “Invasive plants can be more resilient during drought and can quickly bounce back when rain returns, overwhelming natives,” Bean said. “And invasive species are often key drivers of wildfires and increasing fire frequencies and intensities, which prevents the recovery of native plants.“
California has legalized marijuana, but commercial cannabis growers have been slow to obtain the required state and local permits. To find out what deters them from complying with new laws, University of California scientists are asking cannabis growers to participate in a survey about their experiences with the regulated market.
“The majority of cannabis farmers are not joining the legal market and we want to know why,” said Van Butsic, UC Cooperative Extension specialist in the Department of Environmental Science, Policy & Management at UC Berkeley. “The objective is to identify barriers to joining the legal market.”
The researchers plan to share the results with policymakers as well as with the cannabis farming community and other researchers.
“Cannabis growers will have an opportunity to tell us what's wrong with the regulatory system so we can advise policymakers on changes they could make to improve compliance,” Butsic said.
Butsic estimates that less than one-third of cannabis growers in Humboldt County have completed the permit process. He says it's difficult to estimate statewide how many cannabis growers are operating illegally because laws vary from county to county and in many parts of the state, local governments don't allow cannabis growing.
One impact from cannabis growers not joining the regulated market is the state receives lower revenues from cultivation taxes.
Beginning on Jan. 1, 2018, two taxes went into effect: a cultivation tax on harvested cannabis that enters the commercial market and a 15% excise tax on purchases of cannabis and cannabis products.
Prop. 64, approved by voters in 2016, stated: “The revenues will provide funds to invest in public health programs that educate youth to prevent and treat serious substance abuse, train local law enforcement to enforce the new law with a focus on DUI enforcement, invest in communities to reduce the illicit market and create job opportunities, and provide for environmental cleanup and restoration of public lands damaged by illegal marijuana cultivation.”
Legalization was projected to create $1 billion annually in new state revenue, but initial tax revenue has been significantly lower. In the Governor's May 1 budget revision, cannabis cultivation and cannabis retail salesrevenues were projected at $288 million in 2018-19 and $359 million in 2019-20.
Compliance is important not only for tax revenue, but also for the environment, Butsic said. Research has shown that illegal cannabis production causes environmental damage, including rodenticide poisoning of forest wildlife.
“We know there are environmental impacts from non-permitted farms,” Butsic said. “The more growers are able to comply, the better off our environment will be.”
The survey can be anonymously filled out online at https://ucanr.edu/sites/compliance until Aug. 1. Cannabis growers who wish to provide more information can volunteer to give the researchers an interview.
The University of California Statewide Integrated Pest Management Program (UC IPM) is celebrating its 40th anniversary. Established July 1, 1979, with funding from the California Legislature, UC IPM built upon a growing movement to reduce dependence on pesticides. Drawing on expertise across the University of California system, UC IPM develops and distributes UC's best information on managing pests using safe and effective practices that protect people and the environment.
Over the years, UC IPM expanded its efforts beyond agriculture to include residential audiences such as schools, landscape and structural professionals, and public health agencies; public agencies; and natural resource managers. UC IPM works through Cooperative Extension to deliver information to clientele in every California county.
Since its inception, UC IPM delivered science-based integrated pest management (IPM) information. There's no plan to change this, but it's exciting to think about the next 40 years. Improvements in technology have changed how people learn and who they get information from. UC IPM's website and online tools need to grow and change as our users change the way they like to get information. And some of these changes will be mandatory as our funding sources have changed as well.
Some things haven't changed like the IPM advisors and affiliated advisors solving problems and providing local, practical, trusted pest management information. Over the last 40 years, pest management successes happened in both agriculture and communities.
- UC IPM and Cooperative Extension advisors joined a multi-government and grape industry team to develop and extend a low-impact pest management program for European grapevine moth and conduct research to inform regulatory policy. In 2016, European grapevine moth was declared eradicated.
- UC IPM and the UC Master Gardener Program are key partners in assisting the general public with pest issues around the home and garden. UC IPM trains more than 600 UC Master Gardener volunteers each year on topics ranging from pest identification to understanding home-use pesticides.
- UC IPM partnered with stormwater agencies and state regulators to train IPM Advocates. IPM Advocates work as consultants to help retail stores provide information about less toxic products and the safe use of pesticides. Surveys after the IPM Advocates program indicated that 76% of participating stores used the UC IPM website for identifying pests or solving problems, more than 70% increased shelf space for green or less-toxic pest management products, and more than 76% increased sales of green products.
- UCIPMandCooperativeExtensionadvisors worked together with commodity boards and the United States Department of Agriculture (USDA) to develop a successful mating disruption program to prevent codling moth damage in pears without pesticides. In 2009, 95% of California pear acreage used pheromone mating disruption, eliminating the need for codling moth pesticide sprays.
UC IPM has dedicated program staff at the UC Agriculture and Natural Resources (ANR) headquarters in Davis. The staff provides IPM leadership, training, content development, and is the magical information technology (IT) presence behind UC IPM's website and online tools. UC IPM is also the home of the Pesticide Safety and Education Program (PSEP) in California, which trains pesticide safety trainers to teach pesticide applicators, pesticide handlers, and fieldworkers safe practices.
UC IPM will continue conducting research to solve important pest problems, extending IPM programs to practitioners, providing training, and developing outreach material. Over UC IPM's next 40 years, be on the lookout for changes for the better. Changes that engage users by using new technology, adapt UC IPM's existing knowledge into easy to use decision-making tools, and facilitate the development of new products—products that Californians seeking pest solutions can use to safely and effectively solve their pest problems.
Happy Pollinator Week! For 2019, it's June 17-23. Most people think of bees when they think pollination, but don't stop there. “Think the "b" alliteration: bees, birds, butterflies, bats and beetles. But don't forget the flies, ants, mosquitoes and moths!” writes Kathy Keatley Garvey in her Bug Squad blog.
Did you know…
- Three-fourths of the world's flowering plants depend on pollinators
- 35% of the food we eat depends on pollination by animal pollinators
- There are 25,000 different species of bees
- 1.6 million colonies of honey bees are needed to pollinate California's 800,000 acres of almond trees.
- Honey bees will fly up to 4 miles from the hive to collect water, nectar and pollens.
“Loss of a species, especially a pollinator, diminishes our global environment,” said the late bee expert Robbin Thorp, distinguished emeritus professor of entomology at the University of California, Davis, in a 2010 interview. “Bumble bees provide an important ecological service--pollination. This service is critical to reproduction of a huge diversity of plants that in turn provide shelter, food (seeds, fruits) to diverse wildlife. The potential cascade of effects from the removal of even one localized pollinator may affect us directly and indirectly.”
Launched 12 years ago, National Pollinator Week focuses on the valuable ecosystem services provided by bees, birds, butterflies, bats and beetles, according to Pollinator Partnership, which manages the national celebration. Other pollinators include syrphid or hover flies, mosquitoes, moths, pollen wasps and ants. They transfer pollen from the male anther of a flower to the female stigma.
Bats are very important pollinators in tropical and desert climates. More than 300 species of fruit depend on bats for pollination.
UC ANR's California Naturalist Program promotes environmental literacy and stewardship through discovery and action. To become a certified California Naturalist, participants enroll in a course with one of our partner organizations. To receive certification, every UC California Naturalist completes a capstone project that benefits nature. Many California Naturalist projects benefit pollinators. For example, California Naturalist Cynthia from the USC Sea Grant SEA LAB course made houses to support native mason bee population in Palos Verdes. She made the bee houses out of repurposed scrap wood and cardboard, paper coat hanger tubes, used toilet paper and paper towel rolls, and giftwrap rolls.
To create habitat for pollinators in your garden, the UC Master Garden Program recommends planting a variety of plants to provide diverse sources of nectar and pollen. The UC Master Gardener volunteers in San Mateo and San Francisco counties have compiled a list of pollinator-friendly plants.
The UC Master Gardener volunteers also collected data on pollinator habitat in California by zip code and created an interactive map.
'Attention is the beginning of devotion' --Mary Oliver
This quote resonates this month, amidst a variety of environmental holidays and celebrations including World Environment Day, World Ocean Day, California Invasive Species Action Week, and finally National Pollinator Week (this week) and Month. It seems in this increasingly digitally connected world, one day, week, or month doesn't pass us by in the calendar year without an official opportunity to observe, act, or celebrate nature.
As these official observances pop up, we can also contemplate all the unofficial ways people celebrate, protect, and educate about nature in their daily lives. There are both small and incremental and heroic acts taken every day to make this a more livable world for all creatures. There is momentum behind a movement that says “we're paying attention and the environment is worth our time and energy and devotion despite all the other worthy competing causes.”
In celebration of National Pollinator Week, we want to highlight just a few of the many California Naturalists whose efforts benefit pollinators. Every UC California Naturalist completes a capstone project of their choice to receive certification. These final projects require at least eight hours of volunteer service, and are often built upon by subsequent naturalists in following cohorts. They always benefit nature, and often benefit the recipient communities and organizations. Most California Naturalists would tell you they benefit the individual, too. Capstone projects are a culmination of service, learning, and “paying it forward.” Our community celebrates both the projects and the creativity, labor, and intentions of these naturalists.
Inspired by the intersection of science and art, California Naturalist Rose from the Hopland Research and Extension Center created this gorgeous outreach poster in both English and Spanish from her original pollinator garden painting for the Redwood Valley Outdoor Education Project. Her goal is to spread awareness of the important ecological roll our native pollinators play and to share Xerces Society resources. Animal pollinators include bees, butterflies, moths, wasps, flies, beetles, ants, bats and hummingbirds. According to Xerces Society, the ecological services that pollinators provide is necessary for the reproduction of over 85% of the world's flowering plants, including more than two-thirds of the world's crop species. Honeybees get a lot of media attention, yet many other pollinator species like native bumblebees are in precipitous decline. The UC Berkeley Urban Bee Lab is another excellent source of native bee information.
California Naturalist Cynthia from the USC Sea Grant SEA LAB course made houses to support native mason bee population in Palos Verdes, CA. The bee houses were made from repurposed scrap wood and cardboard, paper coat hanger tubes, used toilet paper and paper towel rolls, and giftwrap rolls. She reached out to a local Girl Scout troop to help make three types of houses. The Girl Scouts leveraged the new learning opportunity and service work to receive an "Outdoor Journeys" badge. Then she met with four kindergarten classes of 24 students each and together built houses to take home. The houses in the picture aren't examples of her model but were ones she found online.
Mason bees are solitary bees named for their behavior of using mud in constructing their nests. Mason bees may defy some assumptions about bees. They don't sting, they don't live in a hive, and they don't make honey. They do, however pollinate flowers and fruits and vegetables and need a safe place to lay their eggs. When available, some species use hollow stems or holes in wood made by wood-boring insects which is where mason bee houses come into the picture. UC Davis Department of Entomology compiled this list of resources on where to find and how to make nesting sites for native bees.
Sue from the Tuleyome course built bat boxes for her local home owners association to hang in Arnold, Calaveras County. At least 45 species of bats inhabit the United States and Canada and there are at least 27 known species of bats in California. Bats are very important pollinators and seed dispersers, particularly in tropical and desert climates. In addition, they serve a very effective agricultural pest control purpose. Although they provide vital environmental services, bat populations are in decline globally. To make your own bat boxes, UC ANR offers a guide to build songbird, owl and bat boxes.