Cooperative Extension San Joaquin County
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Posts Tagged: invasive

Early detection to prevent invasive pests – National Invasive Species Awareness Week

The Polyphagous Shot Hole Borer (PSHB) originated in Southeast Asia, and is now established across Southern California.
Many people have heard the well-publicized admonitions to “Buy it where you burn it” or “Don't pack a pest!” But why does it matter? Exotic pests (including plants and insects) are continually being introduced into California's landscapes, farms and natural habitats from plants sold in nurseries, transported firewood, fruits and vegetables, and even in an unsuspecting person's luggage.

According to the Center for Invasive Species Research (CISR) at UC Riverside, “California acquires one new exotic species, on average, every 60 days. At this rate, around six new species establish in California each year. Estimated losses arising from the uncontrolled population growth of these pests amounts to an estimated $3 billion per annum.”

Exotic plants and pests can quickly turn invasive in their new environments because they no longer subject to natural predators or diseases that kept their populations under control in their native territories. Once an invasive pest starts to rapidly colonize and spread, it becomes increasingly more difficult to eradicate, causing both environmental and economic damage.

Prevention and early detection is key

The UC Master Gardener Program and its more than 6,000 volunteers play a critical role in helping stop and prevent the spread of invasive plants and pests in California through early identification and prevention.

Mexican Feather Grass (Nasella or Stipa tenuissima) is popular in home landscapes because of its drought tolerance. (Photo: Melissa Womack)
For example, through its partnership with PlantRight, the UC Master Gardeners were at the forefront of educating the public about a beautiful but potentially devastating invasive grass. Mexican feathergrass (Nassella or Stipa tenuissima) was once loved for its delicate features and drought-tolerance. However, one Mexican feather grass plant is capable of producing tens of thousands of seeds which are easily spread by wind, animals and water. Once it becomes established, Mexican feather grass crowds out other grasses, threatening California's diverse native grass species. Through extension and outreach, UC Master Gardener volunteers not only educated the public about the dangers of this plant but also recommended the more sustainable options found on PlantRight's alternative plant list.

Another of the many ways UC Master Gardeners are making a difference in early detection and prevention of invasive species is the participation in PlantRight's annual Spring Nursery Survey. Every year volunteers visit hundreds of retail nursery locations tracking the location of invasive plants being sold. The annual Spring Nursery Survey information helps the nursery industry replace invasive plants with environmentally safe alternatives.

Trusted resources and information

Since 1981, the UC Master Gardener Program has been an industry leader in extending UC research-based information about home gardening to the public. The UC Master Gardener Program's enthusiastic volunteers engage the public, share information, identify pests and recommend sustainable solutions. Contact your local program for questions about invasives by visiting

A perfect example of invasive damage was the recent invasion of water hyacinth , Eichhornia crassipes (Mart.) Solms, in the waterways of Stockton, Calif.
The UC Master Gardener Program is a statewide program through UC Agriculture and Natural Resources (UC ANR). Another great resource for invasive species from UC ANR is the statewide UC Integrated Pest Management Program (UC IPM). UC ANR also has researchers and advisors working with the California Invasive Plant Council (Cal-IPC) to protect California's water and land resources from invasive species.

So this year participate in National Invasive Species Awareness Week (Feb. 21-27) and share this information and its trusted resources like an “invasive.” Educating friends, family and neighbors is an important step in early detection and prevention!

Posted on Wednesday, February 24, 2016 at 8:26 AM

Uncommon conundrum: When removing invasive species threatens endangered ones

The California clapper rail — a bird found only in the bay — has come to depend on an invasive salt marsh cordgrass for nesting habitat. (Photo: Robert Clark)
Can't live with them, can't live without them — at least not at first when it comes to the relationship between some invasive and endangered species.

Efforts to eradicate invasive species increasingly occur side by side with programs focused on recovery of endangered ones. But what should resource managers do when the eradication of an invasive species threatens an endangered species?

In a recent study published in the journal Science, researchers at the UC Davis examine that conundrum now taking place in the San Francisco Bay. The California clapper rail — a bird found only in the bay — has come to depend on an invasive salt marsh cordgrass, hybridSpartina, for nesting habitat. Its native habitat has slowly vanished over the decades, largely due to urban development and invasion by Spartina.

Their results, picked up by TIME magazine, showed that, rather than moving as fast as possible with eradication and restoration, the best approach is to slow down the eradication of the invasive species until restoration or natural recovery of the system provides appropriate habitat for the endangered species.

“Just thinking from a single-species standpoint doesn't work,” said co-author and UC Davis environmental science and policy professor Alan Hastings. “The whole management system needs to take longer, and you need to have much more flexibility in the timing of budgetary expenditures over a longer time frame.”

The scientists combined biological and economic data for Spartina and the clapper rail to develop a modeling framework to balance conflicting management goals, including endangered species recovery and invasive species removal, given budgetary constraints.

While more threatened and endangered species are becoming dependent on invasive species for habitat and food, examples of the study's specific conflict are rare. The only other known case where the eradication of an invasive species threatened to compromise the recovery of an endangered one is in the southwestern United States, where a program to eradicate tamarisk was canceled in areas where the invasive tree provides nesting habitat for the endangered southwestern willow fly-catcher.

“As eradication programs increase in number, we expect this will be a more common conflict in the future,” said co-author and UC Davis professor Ted Grosholz.

The scientists used data from Grosholz's lab as well as from the Invasive Spartina Project of the California Coastal Conservancy in their analysis.

Spartina alterniflora was introduced to the San Francisco Bay in the mid-1970s by the Army Corps of Engineers as a method to reclaim marshland. It hybridized with native Spartina and invaded roughly 800 acres. Eradication of hybrid Spartina began in 2005, and about 92 percent of it has been removed from the bay. The cordgrass has also invaded areas of Willapa Bay in Washington state, where efforts to eradicate it are nearly complete, and invasive Spartina has been spotted and removed from Tomales Bay, Point Reyes and Bolinas Lagoon in California.

The study, led by UC Davis postdoctoral fellow Adam Lampert, was funded by the National Science Foundation Dynamics of Coupled Natural and Human Systems Program.

Co-authors include UC Davis environmental science and policy professor James Sanchirico and Sunny Jardine, a Ph.D. student at UC Davis during the study and currently assistant professor at University of Delaware. 

“This work is significant in advancing a general, analytical framework for cost-effective management solutions to the common conflict between removing invasive species and conserving biodiversity,” said Alan Tessier, program director in the National Science Foundation Division of Environmental Biology.


Posted on Wednesday, June 11, 2014 at 6:44 AM
Tags: Clapper Rail (1), conservation (8), endangered (1), invasive (2), Spartina (1), UC Davis (24)
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