2024
2024 California Invasive Species Action Week Lunchtime Talks
Not on Our Watch!
Protecting California's bountiful agriculture and natural environments against invasive plants and animals requires constant vigilance. Fortunately, a broad coalition of government agencies, universities, and non-profit organizations is on the job, guarding possible pathways, seeking out new invaders, and managing outbreaks when they occur.
Monday, June 3
California's Marine Invasive Species Program
Presented by Chris Scianni
Commercial maritime shipping is the primary pathway for the introduction of non-native marine invertebrates, algae, and pathogens into California’s coastal and estuarine waters. Introduced species can outcompete native species for resources, introduce new diseases, alter habitats in dangerous ways that cascade up the food chain, and have major impacts on California’s coastal economy.
Ocean-going ships can introduce aquatic species via biofouling (the community of barnacles, mussels, algae, and many other organisms that attach to a vessel’s underwater hard surfaces) and ballast water (large volumes of water, and the organisms in the water, taken on board a vessel for trim and stability during cargo operations). When those species reproduce, fall off, or are discharged with the ballast water, they have an opportunity to become established in California’s coastal and estuarine environments.
Recognizing the threat posed by such invasive species, the California Legislature established the Marine Invasive Species Program in 1999 and has since greatly expanded its scope of activities. Chris Scianni, Environmental Program Manager at California State Lands Commission, will discuss the program’s mission and actions and how it relates to the broader goal of keeping invasive species out of California.
Tuesday, June 4
Invasive Beetles Establish New Beachhead in Northern California
Presented by Randall Oliver
Tiny tree-killing beetles that has plagued Southern California for more than a decade have made their way to the city of San Jose in Northern California.
Known commonly as invasive shothole borers (ISHB), the sesame seed-sized beetles attack and reproduce in more than 65 species of trees found in California, including both native and introduced landscape trees. In San Jose, infested trees have been identified in two of the beetles’ favorite host species – sycamores and box elders – and other highly susceptible hosts such as willows and cottonwoods also are common in the city’s riparian areas. Surveying and trapping efforts are just gearing up, so the full extent of the infestation is not yet known. However, based on the high level of infestation in some trees, it appears the beetles have been in the area for some time, perhaps several years. Additionally, it is possible they exist elsewhere in Santa Clara County and beyond.
One bright spot is that the tools and resources developed in Southern California over the past decade are available to help battle this new invasion.
Wednesday, June 5
Feral Cats in the Landscape
Lessons Learned From Down Under - Presented by Dr. Katherine Moseby
Feral cats are not owned and generally are unsocialized to people. They are among the 100 worst invasive species in the world due to the extensive impact they can have on the environment and the difficulty of controlling population size and expansion.
In areas with high feral cat densities, the cats have a significant impact on local wildlife. They are known predators of many species of birds, small mammals, and reptiles. Feral cats do not control invasive rodent populations, but they can have a significant negative impact on native rodents, as well as native and migratory bird populations. They also can carry diseases and parasites capable of infecting humans, wildlife, domestic pets, and livestock.
They are a widespread problem in California. In Los Angeles County alone, the feral cat population is believed to be more than half a million animals. Research suggests that these cats are rarely neutered.
Although non-native to Australia, they are a similar threat to native wildlife there. The Australian government has labeled feral cats “a nationally significant pest.” As reported recently in the New York Times, Dr. Katherine Moseby, the principal scientist and co-founder of Arid Recovery, a conservation nonprofit and wildlife reserve in South Australia, is working to protect native species such bilbies and bettongs and has devoted considerable effort to developing new tools for reducing the number of feral cats. In this presentation she will share some of the lessons learned over the last two decades.
A California Perspective - Presented by Cambria Wells
California Wildlife Center takes responsibility for the protection of native wildlife through rehabilitation, education, and conservation. It is dedicated to the rescue and rehabilitation of native California species, who otherwise would be left to suffer from the effects of human encroachment, habitat destruction and environmental damage. Wells will share what injuries their patients suffer, their general treatment approach to victims of domestic cat predation, and/or how they engage with cat owners and the community on the topic.
Thursday, June 6
Fruit Fly Invaders Threaten California Agriculture
Presented by David Pegos and Dr. Kyle Buecke (pronounced Berkie)
California is experiencing record detections of invasive fruit flies and currently has fruit fly quarantine zones in multiple counties. That includes the largest fruit fly quarantine in state history and the first-ever quarantines in the Western Hemisphere for two species — the Queensland fruit fly and the Tau fruit fly.
The California Department of Food and Agriculture and U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) are working with county agricultural commissioners to eradicate and prevent the statewide spread of several species including the Queensland fruit fly, Tau fruit fly, Mediterranean fruit fly, and Oriental fruit fly.
The agencies ask residents in quarantine areas to allow them access to their property to install and monitor insect traps and inspect fruit. They also urge those residents not to move homegrown produce from their property, although they are welcome to consume it on the premises.
Invasive fruit flies feed on over 400 crops, including citrus and other fruits, nuts, vegetables, and berries. They are a major concern for California, which produces one-half of the nation's fruits and vegetables and over 99 percent of some nuts and specialty crops.
This presentation will discuss the threat posed by fruit flies and California’s system to prevent them from entering the state, becoming established, and spreading to new areas.
Friday, June 7
Yellow starthistle - Controlling One of California's Most Invasive Plants
Presented by Dr. Brian Rector
Yellow starthistle is one of the most invasive plant species in California, where it was first introduced during the Gold Rush era in contaminated alfalfa. It is widespread throughout the state except in the high Sierras and desert regions. It has evolved to be a prolific seed producer, and has traveled long distances via machinery and vehicles as well as transport of contaminated hay and seed.
Like many invasives, it pushes out native plants, reducing vegetation diversity and wildlife habitat. It consumes much more water than native plants, leading to reduced soil moisture and non-functioning eco-systems. Infestations reduce pasture forage quality and the spines can injure the eyes, noses, and mouths of grazing animals. It is poisonous to horses. Yellow starthistle has also been known to cause problems in cereal crops, orchards, vineyards, and other agricultural lands. It reduces land value and limits access to recreational areas. The annual cost to California alone is estimated to be almost $1.5 billion.
Controlling this invasive requires an integrated pest management approach and ongoing maintenance. Controlling the extensive seed bank is critical. Options for control include grazing, mowing, burning, herbicides and biocontrols. Each method has its limitations. Deep roots make hand-pulling difficult, especially in large patches. Grazing can help to manage but not eliminate the plant. Mowing may actually expand an infestation. Burning can help, but only if repeated for several years or followed by an herbicide treatment. No treatment is effective in a single year.
Biocontrol options include insects that attack flower heads and a rust pathogen, and researchers have been seeking additional agents that attack immature plants. The yellow starthistle rosette weevil identified just a few years ago shows great promise in that area and is very specific to this plant. Researchers at the California Department of Food and Agriculture and elsewhere are now trying to mass produce these weevils for release across the state.
