Category Archives: Abstracts



19th Annual Central California Invasive Weed Symposium

Thursday, November 2, 2017

The cost of weed management in California and Cal-IPC Inventory updates. Ramona Robison. California Invasive Plant Council, Berkeley, CA.

The first half of the talk will be about the cost of invasive plant management in California. In 2008 we estimated that invasive plants cost California $82 million per year. Information will be provided on the latest cost estimation research as well as the typical operating budget of Cal-IPC. In 2016 our operating budget was $550k, with an additional $200k going to contractors. The second half of the talk will present information on the Cal-IPC invasive plant Inventory, focusing on changes made to it in 2017. In 2017 we completed a major update, adding 10 new plants as High, Moderate or Limited, and adding a new category called “Watch” plants.  In order to develop the Watch plants list we screened over 200 species with a 20-question risk assessment tool, and those which scored as “High Risk” are included as the new category of Watch plants.  These include 86 species which are already in California, or occur nearby, and which could escape and cause harm, based on the risk assessment. Suggestions for future Inventory updates are always welcome, as well as additional documentation on plants which are escaping into our wild areas.

Biological control of Cape-ivy and other weeds of coastal riparian, rangeland and forest habitats in California: opportunities and considerations.

Authors: Dr. Patrick J. Moran (Research Entomologist), and Dr. Scott L. Portman (Postdoctoral Research Entomologist)

Summary: Cape-ivy (Delairea odorata Lemaire, Asteraceae), a vine-like plant native to South Africa, has invaded coastal riparian, forest, and scrub habitats all along the California coast and the southwestern corner of Oregon. Cape-ivy smothers other vegetation, degrading habitat quality, and can clog coastal streams, threatening water resources.  The U.S. Department of Agriculture-Agricultural Research Service, Exotic and Invasive Weeds Research Unit in Albany, working with South African collaborators, identified two insects in the native range in South Africa that were found only on Cape-ivy in the field, and appeared to be causing a lot of damage. One of these is the Cape-ivy shoot tip-galling fly, Parafreutreta regalis Munro (Diptera: Tephritidae). Adult females lay eggs in Cape-ivy shoot tips, which develop galls, and the larvae feed inside the galls, emerging as adults after two to four months. Host range tests, which included 84 plant species found in California (native and nonnative) and 15 species from the fly’s home range of South Africa, showed that the Cape-ivy fly can make galls only on Cape-ivy. One generation of the Cape-ivy fly reduced shoot growth and biomass of potted plants by 30-50%. A release permit was issued in May 2016, and initial releases were made in the Bay Area during the fall of 2016. Releases continued in spring 2017, and by July 2017, well over 70 galled shoot tips had been observed at sites from Sonoma County to northern Monterey County. New releases were made along the coast, from Humboldt County in the north, Sonoma and San Mateo Counties, through the Morro Bay/San Luis Obispo area, to Santa Barbara County in the south. Cape-ivy density and abundance of other plant species at release sites are being monitored to document fly establishment and early impact. The cost to develop and release the Cape-ivy fly (and also complete lab testing for one additional biocontrol agent, still to be permitted for field release) is estimated at $2.9 million since 1997. Future costs for this approach will be minimal, as the fly will spread and have impact on its own. This investment thus compares favorably to the cost of chemical and physical/hand control of Cape-ivy, which requires 10 years of effort at each site, and is estimated to have cost at least $500,000 per year and $10 million statewide cumulatively since 1997, with continued high costs expected if biocontrol is not implemented.

Challenges of Invasive Species Management to Protect Endangered Species in Sand Parkland Habitat

Jen Michelsen,Environmental Programs Manager, San Lorenzo Valley Water District

The rare and unique habitat called Sand Parkland is rich in biodiversity and found only in the Santa Cruz Mountains. It is home to several threatened & endangered species and has been reduced to only 57 acres. The Sandhills also provide a valuable community resource – groundwater! Impacts from mining, development, and other human activities have lead to habitat fragmentation, invasive species, and reduced aquifer storage. Managing this sensitive habitat to protect endangered species and aquifer recharge present many challenges including cost, regulatory hurdles, and public support. Jen Michelsen will discuss some of the challenges and successes that a community water district has experienced as it has embarked on a management plan for their Sand Parkland property.

Ecosystem Services – Why Stewardship Matters

Chris Coburn, Executive Director, Resource Conservation District of Santa Cruz County

Natural beauty from the mountains to the sea, mild weather, fertile soils, leading recreational activities and proximity to the Silicon Valley are a few of the elements that contribute to the economic activity and quality of life in Santa Cruz County. A strong stewardship and conservation ethic, decades of conservation leadership by land managers, resource agencies and organizations along with innovative land use policies have significantly highlighted and protected these natural resources. However, we continue to struggle with legacy impacts from historic extractive industries and new challenges that affect the sustainability of our health, community and economic viability. In partnership with the Santa Clara Open Space Authority and the Sonoma County Agricultural and Open Space District, the Resource Conservation District of Santa Cruz County (RCD) conducted the first-ever comprehensive economic valuation of natural capital and ecosystem services completed for Santa Cruz County. The Report highlights the basic idea that we must consider our natural resources as capital assets that provide a significant and sustained flow of economic benefits and require investment in order to do so.  Just as we must maintain our built capital investments such as roads, bridges and buildings, so must we steward our natural resources to ensure their long term health. Invasive weed management is but one of the types of stewardship required to realize the potential that our natural resources hold. The numbers documented in this report are staggering – natural capital in Santa Cruz County provides a stream of ecosystem services valued at $800 million to $2.2 billion to the local and regional economy every year. Importantly, in contrast to built capital, the value of natural capital can actually appreciate with effective conservation and stewardship. This talk will provide an brief overview of the study, including the methodologies used, the results, and the implications for land stewardship.

Wild Oats, Goats, and Lost Notes

John Chapman

“The Santa Clara Valley Water District is the primary provider of flood protection, water supply, and watershed stewardship in Silicon Valley. Winter 2016-17 presented many challenges to our normal business practices, particularly with regard to vegetation management after four long years of drought followed by two winters with above average precipitation. Resources were stretched thin during the rainy season and creek inspections took a back seat to flood fighting and sandbag distribution throughout the county. Just as the rains let up and a sense of normalcy returned, the weeds all bolted. Already behind on vegetation management schedules, facility access was nearly impossible in many parts of the county because of the biomass covering access roads, fuel breaks, and pedestrian trails. Challenged by staffing vacancies, regulatory hurdles, saturated roads, and many creek side residents concerned about their safety, a unique approach to weed abatement was mandatory. Additional resources were brought in to tackle the weed problem and meet fire code compliance before July 1. Expenditures to date for weed abatement and access pruning on SCVWD properties in 2017 has exceeded any previous year’s spending. Since maintenance was delayed or was not accomplished before many of the worst weeds went to seed, we will be recovering from this winter for years to come.”