Posts Tagged: land management
Officials release new weevil to battle yellow starthistle
In April 2021, scientists released weevils from the Mediterranean region of Europe at the Bureau of Land Management Magnolia Ranch day-use area in El Dorado County to join the battle against yellow starthistle. Yellow starthistle rosette weevil is a newly approved natural enemy of yellow starthistle, which was introduced in California more than 150 years ago and, with no natural enemies in its new location, became one of the state's most harmful weeds, infesting nearly 15 million acres.
In California, yellow starthistle can grow to shoulder height, forming massive, thorny patches that block hiking trails, crowd out native plants and present a wildfire danger. The plant is toxic to horses and its flowers are encircled by inch-long sharp spines that can pierce the eyes of grazing animals.
UC Cooperative Extension has worked for decades with landowners to manage yellow starthistle-invested land.
“Over the years, we have developed effective control strategies for yellow starthistle – including well-timed mowing, grazing, hand pulling, burning, cultivation and herbicide application,” said Scott Oneto, UC Cooperative Extension natural resources advisor in El Dorado County. “But these treatments are rarely implemented on a scale large enough to combat our enormous starthistle infestations.”
Efforts to introduce natural enemies from yellow starthistle's home range began in the 1960s. Several species were released to attack starthistle flower heads. These insects lay eggs, hatch and feed on developing seeds, reducing seed production.
“Although the flower head insects sometimes attack high proportions of flowers, yellow starthistle is a very prolific seed producer with an individual plant producing as much as 100,000 seeds,” Oneto said. “Even if the insects reduce seed production by 50%, that still leaves a lot of seeds.”
The newly introduced yellow starthistle rosette weevil, first collected in Turkey as a prospective biocontrol agent in 1984, attacks the plant at the base. Since 2001, United States Department of Agriculture research entomologist Lincoln Smith has studied the insect at the USDA Agricultural Research Service laboratory in Albany.
“Larvae of the weevil develop and feed inside the root crown during spring, adults emerge in June, and then they spend the rest of the year hiding,” Smith said. “There is only one generation per year, so populations will grow slowly, which will gradually reduce yellow starthistle populations.”
The weevil presents no risk to other plants in California except bachelor's buttons, which is an introduced plant from Europe, but not considered a noxious weed. Successful biological control with the weevil is expected to reduce yellow starthistle, but not completely eliminate the weed.
This was the second release of the beneficial insect in North America. The first release occurred in Solano County in April 2020.
Bureau of Land Management and University of California Cooperative Extension researchers will be monitoring the Magnolia Ranch site intensively over the next several years to determine the rate of rosette weevil reproduction and efficacy at feeding on yellow starthistle.
For more information, see A New Warrior Released in the Battle to Control Yellow Starthistle by Scott Oneto on the UC Weed Science blog.
Survey: How should wildlands in California be managed for climate change mitigation and adaptation?
Reposted from the UCANR News
Do you have an opinion on how California wildlands are managed? UC Cooperative Extension specialists Safeeq Khan, Tapan Pathak and Toby O'Geen are conducting a need assessment survey about land management and ecosystem climate solutions.
Khan, Pathak and O'Geen are part of the Innovation Center for Ecosystem Climate Solutions (CECS), a state-funded collaboration between eight California research institutions, including UC ANR, working to develop innovative solutions to managing California's wildlands to reduce negative impacts of drought and climate change. Their goal is to identify land management practices that simultaneously enhance carbon sequestration, reduce wildfire severity, protect watersheds, and increase ecological and community resilience.
Khan would like your help in identifying problems and issues like wildfire and water supply, multiple benefits and beneficiaries of wildlands management, data and information gaps, and major implementation barriers.
To help the research team better understand stakeholder needs and develop data/information solutions for active ecosystem management, please take the survey at https://ucmerced.az1.qualtrics.com/jfe/form/SV_8ptCWlrQBTILyAd. It should take about 30 minutes to complete.
Please feel free to share the survey with your colleagues. To get more involved in the project, contact the team at wildlandsurvey@ess.uci.edu.
The project is funded by the Strategic Growth Council of California.
New project to build climate resilience through improved land management
A $4.6 million grant to UC Merced and UC Irvine will help UC Agriculture and Natural Resources researchers develop new tools and methods for California land owners to better manage the state's forests, shrub lands and grasslands.
California's Strategic Growth Council agreed to fund the Innovation Center for Advancing Ecosystem Climate Solutions, a three-year program co-led by UC Merced Professor Roger Bales and UC Irvine Professor Michael Goulden. The money comes through California Climate Investments, a statewide initiative that puts billions of cap-and-trade dollars to work
The goals include reducing wildfire risk, improving long-term carbon sequestration and bolstering resilience in the face of climate change, with an emphasis on California's rural regions and low-income communities.
“Our part of the project is to work with stakeholders and identify areas where we can focus management practices to promote healthy forests, minimize wildfires, improve water security and increase carbon sequestration,” said Toby O'Geen, UC Cooperative Extension soil resource specialist at UC Davis.
“Right now, many of California's forests, shrub lands and grasslands are carbon sources, and we need to change them into carbon sinks,” said Bales, director of the Sierra Nevada Research Institute and distinguished professor of engineering. “Our research will address information bottlenecks to guide decision making, build local capacity for science-based land management and develop methods for translating benefits of land restoration into financing for land restoration.”
California's recent drought, tree die-offs, wildfires and rising temperatures all point to the necessity of improved forest stewardship, Goulden said.
“Officials in the state government and agencies recognize this need, but uncertainty over how to proceed has sometimes slowed progress,” he said.
Most of the work will be conducted by scientists at Merced and Irvine, but collaborators from UC Berkeley, UC Davis, Stanford University, San Diego State University and the University of California Division of Agricultural and Natural Resources, as well as state agencies, will play important roles.
“This research will enable UC Cooperative Extension advisors to provide better advice to land managers to reduce the severity of wildfires,” said Glenda Humiston, UC vice president for agriculture and natural resources. “Severe wildfires are not only releasing greenhouse gases, but polluting the air of many communities, aggravating the health of people in less-affluent, inland areas such as Tulare, Yuba and Mariposa counties.”
At UC Merced, an interdisciplinary group of researchers from two departments — Civil & Environmental Engineering and Management of Complex Systems — will collaborate with UC Cooperative Extension and engage with local stakeholders. The group will study and identify the most-effective land-management practices, in terms of water conservation, forest health, fire resistance and carbon capture.
“We will develop the spatial data and analysis tools to plan landscape restoration, develop local capacity for better managing the state's wildlands in a warming climate, and enumerate the greenhouse gas and other benefits from investments in land management,” Bales said.
Goulden, professor of Earth systems science, said UC Irvine researchers will use a big-data approach to analyze observations collected by satellites since the 1980s to measure the efficacy of thousands of past and ongoing forest treatments, while UC Merced takes a different approach.
“We will work with groups in rural communities to systematically evaluate how well, or poorly, our products can support decision making,” Bales said, “and then develop both implementation pathways and policy recommendations to better and more-quickly implement landscape-restoration and carbon-capture projects across the state.”
Because there are critical gaps in the understanding of carbon cycles, uptake by forests and negative feedback from climate change, this project initiative has been established to develop new knowledge through measurements and modeling. Researchers will synthesize the resulting data to produce actionable information for stakeholders.
Bales and Goulden agreed the Innovation Center will target low-risk, high-yield opportunities to reduce California's greenhouse-gas contributions.
Just a small improvement in management efficiency will have meaningful benefits — on the order of several million metric tons of CO2 per year, Goulden said.
The program will also benefit low-income communities in the state by reducing wildfire risk, which disproportionately impacts poorer areas in California; by maintaining water quantity through better vegetation management; by fostering tourism in disadvantaged locales; and by preparing students in these areas for careers in sustainability and climate resilience.
Controlled Burn at SFREC
If you live in the area, you may have noticed that SFREC was on fire last Tuesday. This controlled...
How to study cannabis
Soon after Van Butsic arrived in California in 2013 to join UC Agriculture and Natural Resources, he noticed a pattern. “Fire, water and weed are the three land-use issues that come up no matter who I talk to in this state,” he said. Fire and water were well-covered by UC and other researchers already. But cannabis looked to be an unexploited niche.
UCCE Assistant Specialist Van Butsic uses satellite imagery to analyze the environmental impacts of cannabis production.
So Butsic, a UC Cooperative Extension (UCCE) assistant specialist in land systems science in the UC Berkeley Department of Environmental Science, Policy and Management, decided to build part of his research portfolio around understanding the scope, intensity and landscape impacts of cannabis cultivation in California (a research paper from another area of his research, ecosystem service valuation, appears on page 81 of this issue).
While the environmental impacts of cannabis production have drawn substantial media attention, and though it is by many estimates the state's most valuable crop, data beyond anecdotes is scarce.
Butsic attacked the problem by visually analyzing satellite-based imagery, identifying remote plantations and greenhouses in Humboldt County and mapping them using GIS.
This approach required many hundreds of hours of manual inspection of satellite images, and one of the first challenges was figuring out how to do this labor-intensive work. It wasn't difficult to find UC Berkeley undergraduates interested in working for course credit. Nearly 25 students have now contributed to the project, and two (so far) have moved on to full-time GIS jobs after graduation. An anonymous nonprofit organization provided financial support for a part-time staff researcher and to purchase more recent high-resolution satellite data.
This series of satellite images shows the development of a greenhouse complex in a Humboldt County forest. Using satellite imagery in combination with GIS layers showing topopgraphy, watercourses, zoning and other variables, Butsic and his colleagues can characterize cannabis production sites in a variety of ways, such as average slope, proximity to streams, and whether they are located on land zoned for agriculture.
The team has built a GIS data layer for about half of Humboldt County's land area, identifying roughly 300,000 cannabis plants (equivalent to a wholesale value of perhaps $150 million) based on 2012 imagery, with an updated estimate now in the works. The data layer enables a variety of analyses — from the zoning of the land used by cannabis growers (only about a quarter of the 1,429 grows identified were on land zoned for agriculture); to the slope of cannabis production plots, a factor influencing erosion (almost a quarter are on very steep ground, with slope exceeding 30%); to proximity to salmon streams (more than 200 grows were found within 100 meters of critical habitat for steelhead and chinook salmon) (Butsic and Brenner 2016).
Butsic and his colleagues identified approximately 4,400 grow sites in their research. Five percent of those, including the site pictured above, were within 100 meters of salmon streams.
Butsic estimates the absolute volume of water used to irrigate cannabis to be fairly modest — on the order of a few thousand acre-feet. But that figure probably understates the habitat impact of water diversions; water is withdrawn from small watersheds during summer months when water is scarce, and some creeks are known to have been completely dewatered.
The information is helping to inform local debates. Humboldt County recently adopted an ordinance requiring all new cannabis grows to be developed on land zoned for agriculture (existing grows on nonagricultural land are grandfathered in). This policy raises concerns about rapid inflation of agricultural land, as cannabis growers bid up prices beyond what other farm or livestock operations can support. Butsic's work provides insights into the characteristics and geography of lands that are likely to be developed for cannabis production.
Forest fragmentation occurs when cannabis growers clear land and build roads to access their grow sites. The Butsic team's analysis indicates that 68% of grows were located more than 500 meters from developed roads.
Related to this issue, Butsic and several Humboldt County–based UCCE academics — County Director Yana Valachovic, Area Fire Advisor Lenya Quinn-Davidson, and Livestock and Natural Resources Advisor Jeffery Stackhouse — are currently surveying Humboldt County landowners about cannabis-related land use issues.
Butsic's next steps include continued mapping of cannabis production in California, with Mendocino County to be completed by the end of 2017. Given the uncertainty around federal restrictions on cannabis production under the Trump administration, Butsic said it's difficult to predict what the most essential research questions surrounding cannabis will be. Nonetheless, “by continuing to document on the ground patterns of cannabis production, we will be in a position to answer those questions,” he said.