Posts Tagged: invasive species
Californians can help in the fight against invasive species by learning and participating during California Invasive Species Action Week, June 2–10.
During the week, the UC Statewide Integrated Pest Management Program invites the public to spend lunch learning about invasive tree killing pests, aquatic nasties like quagga mussels and nutria, and how the invasive weed/wildfire cycle is altering our ecosystems. http://ucanr.edu/sites/invasivelunch/
The invasive species killing trees is causing sugar volcanoes to erupt on avocado trunks and branches that might be infected with Fusarium dieback. Fusarium dieback is a invasive, beetle-vectored disease that causes damage on avocado and more than 39 other tree species. The disease has spread in urban forests and wild lands in the Los Angeles basin since early 2012, and in Orange and San Diego counties since early 2013 and Ventura County in 2015.
The symptoms — staining, sugary exudate, gumming and beetle frass — are often noticed before the tiny beetles (1.5–2.5 mm) are found.
As its name suggests, these beetles bore into trees. Near or beneath the symptoms, you might notice the beetle's entry and exit holes into the tree. The female tunnels into trees forming galleries, where she lays her eggs. Once grown, the sibling beetles mate with each other so that females leaving the tree to start their own galleries are already pregnant. Males do not fly and stay in the host tree.
Shothole borers have a special structure in their mouth where they carry two or three kinds of their own novel symbiotic fungi. Shothole borers grow these fungi in their tree galleries. It's these fungi that cause Fusarium dieback disease, which interrupts the transportation of water and nutrients in the host tree. Advanced fungal infections will eventually lead to branch dieback.
Early detection of infestations and removal of the infested branches will help reduce beetle numbers and therefore, also reduce the spread of the fungus.
- Chip infested wood onsite to one inch in size or smaller. If the branch is too large to chip, solarize them under a clear tarp for several months
- Avoid movement of infested firewood and chipping material out of infested area
Avocado is one tree host. Shothole borers successfully lay eggs and grow fungi in many tree hosts, with some of these trees susceptible to the Fusarium dieback disease. For more information about tree host species, where the shothole borer is in California, and what symptoms look like in other tree hosts, visit the UC Riverside Eskalen Lab website or the Invasive Shot Hole Borers website.
Content in this post taken from the UC IPM Avocado Pest Management Guidelines. Faber BA, Willen CA, Eskalen A, Morse JG, Hanson B, Hoddle MS. Revised continuously. UC IPM Pest Management Guidelines Avocado. UC ANR Publication 3436. Oakland, CA.
Ag leaders, scientists set priorities to prevent invasive pest threats to the environment and economy
The gypsy moth, an interloper from Europe and Asia, is threatening California's majestic oaks in Ventura County.
Invasive desert knapweed, which comes from Africa, has made its first North American appearance in in California's Anza-Borrego Desert, where it has started to crowd out native plants.
Asian citrus psyllids are slowly spreading the devastating huanglongbing disease in Southern California citrus.
River rats from South America, called nutrias, are munching voraciously on wetland plants in some areas of Stanislaus, Merced and Fresno counties.
These are just a few of the insects, weeds, animals and diseases that have entered the state of California from elsewhere on the globe, causing tremendous ecological damage and huge economic losses to agricultural crops, which ultimately affect every resident of California.
Based on historical data, a new invertebrate species establishes itself in California about every six weeks, on average. They don't all become serious pest problems, but many evade eradication efforts, disrupt carefully balanced integrated pest management programs, hijack sensitive ecosystems, and spoil valued recreational resources and urban landscapes.
A diverse group of university scientists, federal and state government representatives, county agricultural commissioners and non-profit organization leaders who are battling these pests converged at a summit in the state capitol Jan. 11 and 12 to coordinate their efforts, pool intellectual resources, and plot a strategy for protecting agricultural crops, natural resources, unique ecological communities, cityscapes and residential neighborhoods.
“We are a big, beautiful, special place, blessed with great weather and diverse geography,” said California Department of Food and Agriculture Secretary Karen Ross at the summit. “That means a lot to our many visitors – including pests.”
“We know that collectively, we have the tools and expertise to prevent invasive species from entering California, spreading and becoming established,” Humiston said. “I am so pleased with the numbers of people here today, and the expertise that you bring.”
A fundamental component of the fight against damaging invasive species is research, Humiston said, adding that the European grapevine moth in an apt example. The pest was detected in California's wine country in 2009, and later found as far south as Fresno County. A multi-agency collaboration responded quickly.
UC ANR academics studied the moth's biology, life cycle, host range and proven management practices. They developed a pest management program that relied on mating disruption with pheromones and application of carefully timed insecticides. In short order, the moth population plummeted, and the state was declared free of European grapevine moth, lifting a quarantine, enhancing farmers' ability to export its product, and preserving the communities' economic wellbeing.
“This multi-agency collaboration contributed to a successful, science-based response plan to a serious pest threat,” Humiston said.
She noted, however, that prevention is the best option.
“This is critical,” Humiston said. “Once the pests are here, they cost us millions upon millions of dollars to manage, not to mention the devastation and destruction inflicted on our crops, natural resources and the damage to local economies.”
In 2010, CDFA created a strategic framework for addressing California's ongoing invasive pest problems and potential future introductions. Successful implementation of the framework requires partnerships involving government from the state to local levels, the agriculture industry and commodity groups, non-governmental organizations committed to the environment, and researchers at UC and other universities.
UC Cooperative Extension advisor emeritus John Kabashima was instrumental in bringing the summit to fruition. Kabashima, who retired in 2015, continues to lead a battle against invasive shot hole borer pests in Southern California. The insects, originally from Asia, are killing thousands of Southern California trees, and have the potential to kill millions of trees in urban areas, natural areas and even on farms in parts of the state as far north as Sacramento.
“We convened this meeting to bring together experts in the field and people who are feeling the impacts,” Kabashima said. “We're trying to start a 21st century invasive pest program that would then be implemented and funded to address the urgent issues before they cause any more devastation.”
At the end of the two-day summit, the participants voted to decide the most pressing issues and best strategies to take forward to their agencies, coalitions, research groups, legislators and constituents. Key strategies that emerged were:
- Analyze the economic impacts of invasive species management and the cost of “doing nothing.”
- Develop and maintain statewide surveys and map high-risk surveys.
- Increase funding to study invasive species' biology.
- Create a standing rapid response workgroup to guide response to new invasive species. Fund a rapid response emergency fund.
- Enact regulations to control high-risk vectors, such as soil, green waste, gravel, forage, straw and firewood.
- Formalize the Invasive Species Council of California (ISCC) and the California Invasive Species Advisory Committee (CISAC).
Mark Hoddle, UC Cooperative Extension biological control specialist and director of the Center for Invasive Species Research at UC Riverside, said the summit was a valuable part of the ongoing battle against invasive pests.
“It's good to see the number of agencies and organizations involved with invasive species issues,” Hoddle said. “I'm impressed with the energy in coming up with these priority lists.”
Summit outcomes will include sending recommended action items to the Legislature for funding consideration.
“Without financial support, many of the management tools that prevent unwanted incursions, find and monitor incipient pest populations, and develop sustainable, cost-effective management programs won't be possible,” Hoddle said.
View Glenda Humiston's opening remarks here:
In agricultural systems, invasive species may reduce yields, render crops unmarketable, or make rangeland unfavorable to livestock. In natural areas, they may squeeze out native species, change soil quality, and increase the frequency or intensity of wildfires.
Some of these species have been introduced intentionally (e.g., yellow sweetclover, which was originally imported from Europe as a forage species for livestock), while others arrived by accident (e.g., the glassy-winged sharpshooter which came to California inadvertently through nursery stock shipments).
The spread of invasive pests has become more prevalent in recent decades, and is linked to several factors, including global travel, produce trade and climate change. Many invasive pests spread by human movement — medusahead, for example, has long awns on its seeds that easily attach to clothing and animal fur, to be carried to other locations. A recent study by UC scientists also determined that due to climate change, invasive weeds are shifting their ranges at a faster rate than native plants, and will likely cause more problems in agriculture and natural resources in the future. The yellow starthistle, an invasive plant that dries out soil and degrades rangelands, is one of the pests that will expand its range further north in California (and beyond) due to climate change.
While invasive pests can be a major challenge to growers and land managers, there are successful stories of stopping exotic pest invasions with well-coordinated eradication efforts. Recently, the California Department of Food and Agriculture (CDFA) declared the European grapevine moth eradicated from California after no moths were found in the state from 2015 to 2016. This was due to a rapid response, largely by UC Cooperative Extension scientists after the moth was discovered in Napa vineyards in 2008.
Here's what you can do to keep from introducing or spreading invasive species:
- Fully cooperate with agricultural inspections at the California state border and in your fields. When coming into California from another state, declare any plant or animal material that you have in your vehicle. Inspectors will thoroughly examine your materials or crops to make sure that they do not hold any invasive pests. This greatly reduces the chance that your activities will spread harmful invasive species.
- Check and clean your clothes, shoes, and equipment before you move from one location to another. For example, thoroughly cleaning your shoes with water and a disinfectant after hiking through an area known to have sudden oak death will prevent you from tracking the pathogen into uncontaminated areas. Similarly, checking your clothes or shoes for weed seeds before leaving an area will keep you from spreading invasive weeds.
- “Burn it where you buy it.” Burn firewood in the same place you purchased it, rather than buying it and transporting it elsewhere. If you must transport firewood, be sure to declare it at the border and have it inspected, as described above.
- Report invasive pests in your area. CDFA has a tool for reporting pests, but you can also contact your agricultural commissioner or UC Cooperative Extension to do so.
To learn more about invasive species, visit the UC IPM website. You will find a list of invasive insects, plants, diseases, and vertebrates in California, as well as links to other organizations and regulatory agencies that are also working to reduce their numbers.
You don't have to dig too deep into the scientific literature and popular media to find perspectives on threats posed to biodiversity in California and around the globe. Two UC Davis scientists in the Department of Wildlife, Fish and Conservation Biology have published fresh insights into endangered species in recent months.
Endangered Species Act sets a high standard
After passage of the ESA, Moyle and his graduate students initially searched for three species they suspected were in trouble: Modoc sucker, rough sculpin and bull trout. They found the sucker in trouble but easy to protect, the sculpin reasonably secure, and the bull trout near extinction in California. It has since vanished.
"As an untenured professor then, I thought it a bit risky to base a career on finding rare fish," Moyle wrote in an opinion piece published in The Sacramento Bee. “So I also undertook a study of Delta and longfin smelt, which at the time were two of the most abundant fish in the Sacramento–San Joaquin Delta.”
Moyle began a monthly sampling program to keep track of smelt populations and other fish in the Suisun Marsh. A few years later smelt counts dropped dramatically. The data eventually led to the U.S. Fish and Wildlife Service listing the Delta smelt as a “threatened” species under the ESA.
His ongoing research has recorded a statewide decline of most native fishes. With other researchers, Moyle has just completed detailed accounts of the biology and status of more than 60 native fishes — all potential candidates for ESA listings. This study will soon be released by the California Department of Fish and Wildlife.
“Most of our recommendations for preventing extinctions call for more and better water for the fish, or at least for protecting existing water they depend on,” Moyle said. “Funny how it almost always comes down to fish needing water.
“The Endangered Species Act sets a high standard in this regard because it not only forbids extinction; it also mandates recovery of each species to a more sustainable state.”
Moyle's opinion piece can be viewed in its entirety here.
Human longevity an indicator of endangered species
The researchers analyzed data from 100 countries, representing 87 percent of the world's population. They examined 15 social and ecological variables, such as tourism, per capita gross domestic product, water stress and political stability. The study showed that as human life expectancy increases, so does the percentage of invasive and endangered birds and mammals.
“It's not a random pattern,” Lotz said. “Out of all this data, that one factor — human life expectancy — was the determining factor for endangered and invasive birds and mammals.”
New Zealand, the United States and the Philippines had among the highest percentages of endangered and invasive birds. The study has been reported in the Los Angeles Times and other news media. Read more about the study's findings in our news release here. The journal article can be viewed here.
At least 13 of the 102 aquarium species that are imported into California have been introduced into California marine waters, according to a recent report by Susan Williams, professor in the Department of Evolution and Ecology at UC Davis and a marine ecologist the Bodega Marine Laboratory. These introduced species have a high success rate (69 percent) in establishing themselves.
Two very invasive species — the predatory lionfish and Caulerpa seaweed (aka “killer algae”) — have reportedly come from the aquarium trade. The lionfish, which has established itself along the East Coast where it eats smaller fish and threatens reef ecological systems, has not yet reached California waters, but the Caulerpa seaweed cost California more than $6 million to eradicate from two Southern California lagoons a decade ago.
At least 34 aquarium species were found to be potential invaders in California marine waters.
“Globally, the aquarium trade has contributed a third of the world’s worst aquatic and invasive species,” Williams said. "Lionfish are voracious predators in their native habitats, and in their invaded habitat any predator is a potential threat to the native ecosystem."
Williams’ advice: "To avoid releasing aquarium species into natural water, don’t dump your aquarium where they can become an expensive and harmful pests.”
She said that people should contact the vendor where the fish was purchased or the California Department of Fish and Wildlife to learn how to dispose of aquarium species responsibly.
- Complete UC Davis news release, by Kat Kerlin
- Our AmazingPlanet report
- Environmental News Network report
- Science on NBC News report