The coqui (Eleutherodactylus coqui), a tiny tree frog native to Puerto Rico, continues its spread through the islands of Hawaii. According to this article from the Honolulu Advertiser, their spread is being aided by the nursery industry, which is accidentally transporting the frogs in shipments of plants like bromeliads and palms. The frogs hide in the soil and under leaves, and are difficult to find. The search for an effective control continues: application of caffeine, while quick, was determined to be too expensive and potentially dangerous to other organisms. Hawaiians are now considering citric acid, but the acid also damages many plants.
Tuesday, December 31, 2002
Saturday, December 28, 2002
A risk assessment for invasive plants in Idaho and Montana was recently published online. Using geographical and biological characteristics for over 500 species, the authors categorized 29 recently introduced plants (prior to 1950) as noxious weeds. Interestingly, less than half of these plants were on any noxious weed list from the Pacific Northwest. If you want to go directly to the list of noxious plant species, click here.
Thursday, December 26, 2002
This just in: "Some ornamental plants become exotic plants in the wild."...Okay, I'm being a bit sarcastic there. This is actually a link to a decent article from the Visalia Times-Delta in California. It's always great to see a piece warning gardeners about invasive plants, in this case made even better since it's written by Jeanne Rose, a Master Gardener.
Tuesday, December 24, 2002
Entomologists have seen a sharp rise in the number of exotic pests entering Southern California over the past few years, according to this report from the San Gabriel Valley Tribune. Things have gotten so bad that a new pest is now discovered every 60 days (on average). While many of these are discovered through the usual routes, including airports and harbors, researchers also rely on information from gardeners in the area who find suspect organisms on their plants.
Saturday, December 21, 2002
Though the federal quarantine on trees infested with the emerald ash borer (Agrilus planipennis) is being delayed until February, Michigan officials are stepping forward to put into place their own eradication program. According to this article from The Detroit News, five zones will be created that encircle the core of infestation, with less severe treatments for the outermost zones. As the trees in the center of the zones die, they will be replaced with other species that are not susceptible to this devastating insect.
Friday, December 20, 2002
WMTW News is reporting that Maine officials confirmed that they have found Hydrilla (Hydrilla verticillata) in Pickerel Pond, in the town of Limerick. This is the first occurrence of this aggressive invader in Maine. You can read the official report from the Maine Department of Environmental Protection here. They already seem resigned to the fact that their goal must be to keep the species under control, not eradicate it.
Tuesday, December 17, 2002
Hard finding time to update the blog this week, as I am defending my thesis Friday. So here's a neat tile you can use as your computer's desktop background, designed from a European water chestnut (Trapa natans) fruit, that I made for my Powerpoint presentation:
Monday, December 16, 2002
From Stateline.org comes this politically-oriented perspective on invasive species issues. The article touches on one of the main problems with invasive species, which is that people tend to want proof that a non-native species will causing damage before outlawing it, yet information is difficult to come by until the species has already caused the damage. Included are some specifics from Florida, possibly the number one state for plant invasions.
Sunday, December 15, 2002
Greg Moore has written a nice piece for the Idaho Mountain Express about Blaine County's dealing with the invasive Spotted knapweed (Centaurea biebersteinii, formerly C. maculosa). The county is waging a constant battle against the weed, which often quickly re-colonizes places it is eradicated from. A lack of funding doesn't help matters, forcing the county to spend all its time and money in an attempt to prevent new populations and spray large ones to keep them from spreading; there is rarely a chance to shrink current populations.
Saturday, December 14, 2002
Are you a fifth grader, or do you think like one? Even if you don't fit into either category, you may be interested in checking out the free activity book "Understanding Invasive Aquatic Weeds." Developed by the Aquatic Plant Management Society, the book is full of information and activities to help kids learn about aquatic weeds. You can download the acticity book for free, but if you don't have a good printer, you can also order paper copies and pay only the cost of postage.
Thanks to a member of the ALIENS-L listerserver for posting information about this topic.
Thursday, December 12, 2002
Hawaiian officials are concerned that last weekend's Supertyphoon Pongsona will increase the risk of the brown tree snake (Boiga irregularis) invading Hawaii. According to this story in the Star Bulletin, many of the fences around the airport in Guam were destroyed during the storm, meaning that more snakes could be hitchiking over to Hawaii on airplanes. Even with strict prevention and inspection procedures, four brown tree snakes were found in cargo flown to Hawaii last year.
Wednesday, December 11, 2002
In the field of invasive species ecology, time is limited and funds are scarce, making it hard to do those intensive, long-term studies that would really let us know how a non-native species is affecting the ecosystem. As a result, the fact that very few species have been shown to have gone extinct due to the introduction of a non-native species is sometimes presented as evidence that invasive species are not really a problem. But as reported at Science Daily, a new study being published in the journal American Naturalist demonstrates that non-native birds and plants are establishing on islands in great numbers, pushing up tallies of local biodiversity while increasing global homogenization. There is evidence that this massive influx of species is influencing the ecosystem regardless of the fact that native species aren't disappearing. You can read the article abstract by going here and scrolling down the page.
Tuesday, December 10, 2002
As reported in the Austin-American Statesman, the invasive aquatic plant hydrilla (Hydrilla verticiallata) has invaded Lake Austin, and the state of Texas wants to introduce invasive grass carp (Ctenopharyngodon idella) to keep it under control. Hydrilla is an extremely pervasive aquatic weed that causes ecological damage to the flora and fauna of the lake and also impedes recreational activities like boating and swimming. At first glance, the grass carp may seem like the ideal biological control for a closed freshwater system like Lake Austin. But as fishermen pointed out at a public hearing on the subject, there's no way to control the grass carp once they're introduced; if they eat more than just hydrilla they could be reducing food sources for other fish in the lake. I'm a little skeptical about the claims made by officials that testing showed that they can keep the carp in the lake, given the risk of flooding, but it is likely that they will be using functionally sterile triploid carp, reducing the risk that populations would establish in the wild.
Thanks to D.V. for sending in the link to this article.
Monday, December 09, 2002
Researchers at Portland State University and the Smithsonian Environmental Research Center have joined together to develop a system to monitor ballast water exchange, according to this article from The Columbian. The scientists are interested in creating standards that will allow them to determine whether a ship has exchanged ballast water mid-ocean. While this is considered to be better for invasive species prevention than dumping ballast in port, it is not a perfect solution, and the search continues for technology that will prevent all non-native species introductions.
Thanks to the Protect Your Waters web site for posting a link to this article.
Sunday, December 08, 2002
In a followup to a story reported in the Invasive Species Weblog last month, officials in Hawaii caught not one but 6 live veiled chameleons (Chamaeleo calyptratus) last week on the island of Maui. As reported in the Star Bulletin, there is great concern that establishment of these reptiles, often kept as pets, will be to the detriment of native Hawaiian birds and insects. The captured chameleons were a mix of males and females, and have no known natural enemies in Hawaii. You can read the government's original press release here.
Saturday, December 07, 2002
Get caught selling water hyacinth (Eichhornia crassipes) in Australia, and it could cost you $1000 AUS. The West Australian is reporting that the Department of Agriculture is spreading the word after officials discovered the plant being sold and traded at swap meets. Regardless of the problems known to be caused by this species, there continues to be a demand for it for use in aquariums and ponds. The Dept. of Agriculture is hoping a public information campaign will help spread the word to the general public.
Thanks to a member of the ALIENS-L listerserver for posting the link to this article.
Friday, December 06, 2002
In a case of too little too late, the Colorado Department of Agriculture has banned the sale of Russian olive (Elaeagnus angustifolia) by nurseries in that state, according to this article from the Glenwood Springs Post Independent. The invasive tree/shrub is already a major problem in Colorado, as it is in many part of the western U.S., and nurseries sell so little of it that the ban, which starts Jan. 1, 2003, will barely impact their sales. Hopefully this gesture will help build public awareness about the dangers of planting Russian olive and other invasive species. The Dept. of Agriculture is recommending people consider the native silver buffaloberry (Shepherdia argentea) as a replacement species.
Thursday, December 05, 2002
Last weekend a dozen volunteers converged on populations of the South African ice plant (Carpobrotus edulis) located on a beach in Santa Cruz County, California. As reported in the Santa Cruz Sentinel, the goal was to remove the invasive species from sand dunes and hopefully allow the native plant populations there a chance to recover. There is some controversy about this project that stems from the very reason ice plants were introduced in the first place: they are very effective at dune stabilization. With the ice plants removed, it is likely that the dunes will revert to a natural state, which means they'll be moving around. This may cause problems for those charged with maintaining the beaches, which are park of the state park system. Here's a story about a similar project in Marin County.
Wednesday, December 04, 2002
For those times when you find yourself without computer access (horror!), there are several recently (or about to be) published books about invasive species:
- Biological Invasions: Economic and Environmental Costs of Alien Plant, Animal, and Microbe Species, edited by David Pimentel, primary author of this incredibly well-cited article.
- Predicting Invasions of Nonindigenous Plants and Plant Pests, which you can read for free online! The hard copy will cost you about $35.
- The new text book Invasion Ecology, available in teacher and student versions.
- Tim Low's Feral Future: The Untold Story of Australia's Exotic Invaders, recently updated with a new preface.
- For kids interested in invasive species, you might want to pick up a copy of Aliens from Earth: When Animals and Plants Invade Other Ecosystems, which will be published in March 2003.
Tuesday, December 03, 2002
Australian officials were initially so concerned about the invasion of the tropical algae Caulerpa taxifolia that they banned most recreational activities around the West Lakes waterway system. Now, according to this article from The Advertiser, the restriction has been lifted in some areas, and beaches were opened for swimming just in time for the start of summer. Authorities aren't concerned with beachgoers spreading the algae, because so little of it grows near the edge of the water. But they may have another reason not to worry, at least for now: barely anyone is showing up to swim. Fishing and other boating bans remain in effect.
Monday, December 02, 2002
Florida's Herald-Tribune is reporting on an interesting technological advance in the fight against invasive plants. Called the "pepper grinder," the machine, which shreds wood and turns it into mulch, is being used to target the pervasive Brazilian pepper tree (Schinus terebinthifolius). There is currently some controversy about the pepper grinder, designed by a Florida company and used by Enviro-Friendly Vegetation Control, since there is evidence that company did some damage to native mangrove trees. But for right now, Charlotte County officials are remaining open to the idea, especially since it is a cost-effective method of invasive species control and an alternative to completely clearing invaded land.