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Author: Jennifer Forman Orth

Invading your brain since 2002.

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Tuesday, April 22, 2003

Algae Madness

No new sightings of Caulerpa taxifolia in the Agua Hedionda Lagoon (Carlsbad, California) since last summer, according to this article from the North County Times. The current management plan, where divers seek out and destroy patches of the invasive algae by covering it with a tarp and pumping chlorine underneath, seems to be working well. But then again, this "killer algae" can reproduce from tiny floating fragments that are extremely difficult to spot, and because of that, chances are it's not quite gone. Just to be safe, the consultants spearheading the management project want to extend it for another year. As part of a compromise, a portion of the lagoon may be reopened, but only for "passive," non-motorized boats.

Meanwhile, alarms are ringing on the opposite coast as Floridians cope with the invasion of C. taxifolia's lesser-known cousin, C. brachypus. According to this article from The Stuart News, the algae is threatening the Indian River Lagoon, having arrived there this March. You can read a previous blog entry about C. brachypus in Palm Beach County by clicking here.

Monday, April 21, 2003

Last day to enter ISW contest!

Tuesday is the last day you can submit entries to the Invasive Species Weblog "Birthday Blog Contest." Details can be found here.

Sunday, April 20, 2003

Barbs from Barbados

There's an interesting "Letter to the Editor" in the April 9th Barbados Advocate. Written by the president of the Barbados Herpetological Society, the letter addresses the public to inform them about the illegal importation of several species, including the black piranha (Serrasalmus rhombeus) and the African clawed frog (Xenopus laevis), and the threat they pose if released into the environment.

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Saturday, April 19, 2003

Those nasty plant alerts

According to this article from NEPA News, Maryland has issued a "nasty plant alert" for giant hogweed (Heracleum mantegazzianum). Though the species has not yet been spotted in that state, it has been seen in neighboring states. Maryland is taking a proactive stance by sending out the alert, warning people of the dangers of coming into contact with the plant's phototoxic sap (link to .pdf file), and holding workshops to teach people to identify it. Giant hogweed is on the Federal Noxious Weed List because of the danger it poses to humans, but it can also be an aggressive invasive plant in its own right.

Friday, April 18, 2003

You say crayfish, I say crawfish

The New Orleans Times-Picayune recently published this great article about species of crayfish native to America that are wreaking havoc abroad. The red swamp crayfish (Procambarus clarkii), a staple of many folks' diets in Louisiana, are gobbling up native plants and animals in places like Italy and Spain. They have also been introduced to African countries, including Kenya, where a study was done showing a link between the crayfish and a reduction in snail-borne disease in humans. The article also discusses the impact of the introduction of several other crayfish species. (If your from NOLA, the previous sentences will make more sense if you replace "crayfish" with "crawfish." :-)

Thursday, April 17, 2003

The road not taken...has fewer invasive plants

This press release from U.C. Davis describes the results of a study published this month in the journal Conservation Biology. Researchers studied a variety of different pathways through natural landscapes, from paved roads to 4-wheel-drive tracks. They found that the more "improved" the road was, the higher the density of non-native plants. Turns out some places really are better off if we just leave them alone.

Wednesday, April 16, 2003

Pining Away  

Fort Zachary Taylor Historic State Park in the Florida Keys is going native. But before they do, they're taking precautions to make sure the public understands why they want to get rid of all those shade-giving Australian pines (Casuarina equisetifolia). According to this story from, park managers will hold a public information session to reassure park visitors that the revegetation project will be completed in a sound environmental way and still maintain important recreational features such as shelter and shade.


Tuesday, April 15, 2003

News to You

Science News is a great little journal for those of you that prefer your science on paper, but don't have time to deal with a thick and meaty Nature or Science. This week they've generously posted the full text of their article "Is your yard a menace to parks and wild lands?" It's a well-done, detailed examination of cultivated plants that can become invasive in natural areas, complete with a list at the end of some of the culprits.

Thanks to a member of the ALIENS-L listserver for posting a link to this article.

Monday, April 14, 2003

Oldie but Goody

This site hasn't even been updated in a while, but it deserves some attention, if only because of its cute name: Encycloweedia. Stop by to get a glimpse of California's noxious weed list, fact sheets, and a great photo gallery of your favorite invasive plants.

Sunday, April 13, 2003

Birthday Blog (and Contest)!

The very first entry of the Invasive Species Weblog was April 13, 2002, making it one year old this week! To celebrate, I'm having a contest. Submit an entry to the blog and you could win a free item from the Invasive Species Weblog store! Entries should include a link to a current article or recently updated website that has information about invasive species, as well as a brief summary. All entries will be posted here, and the best entry will win the prize (limit 3 entries per person). Contest ends April 22 (Earth Day).

Friday, April 11, 2003

Insert Plug Here

An extremely interesting article about sexual reproduction in the invasive plant Japanese knotweed (Fallopia japonica) appears in the latest issue of the American Journal of Botany. :-)

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Thursday, April 10, 2003

Biocontrol out of control

The New Scientist web site recently posted this story about the unintended effects of the introduction of the rosy wolf snail (Euglandina rosea) to the island of Tahiti as a biological control for the invasive African land snail (Achatina fulica). It seems the predatory Euglandina has developed a taste for Partula snails, and has now wiped out 56 of the 61 species in that genus that lived on the island.

Thanks to a member of the ALIENS-L listserver for posting a link to this article.

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Tuesday, April 08, 2003

Stoats and Toads

According to this article from The Dominion, New Zealand has commissioned a group of inventors to produce 100,000 of their traps, after test proved that they were highly effective at capturing stoats (Mustela erminea). The stoats were introduced to New Zealand from Britain over a century ago, and are now the most common invasive predator mammal there, as well as a key threat to rare New Zealand bird species.

From Dave Barry's blog, of all places. Dave also posted a link to this article about cane toads (Bufo marinus) last week. Spread the word Dave!

Monday, April 07, 2003

But officer, I LOVE my camphor tree!

In a story that would make residents of Palm Beach County cringe, the peculiarly named Natal Witness is reporting that private landowners in Pietermaritzburg, South Africa are under siege by "plant police." The police are patrolling every inch of the town, in many cases demanding that certain invasive plants be removed from gardens. Citizens, who face fines or jail time if they flout the law, are coming up with various excuses for not removing the plants, including cost, sentiment, and even religion.

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Sunday, April 06, 2003

Wild on Canada

It's National Wildlife Week in Canada, April 6-12. The theme this year is "Native Species, Nature's Choice," and of course you can't say too much about native species without addressing invasive non-natives. Canadians can find activities in their area by clicking here (though I have to say it's a disappointingly short list). If you want to know more about what's invasive in Canada, be sure to visit the new Invasive Species of Canada online database.

Friday, April 04, 2003

Baby steps

For those of you who missed it (I sure did), the National Aquatic Invasive Species Act passed its first House subcommittee about a month ago, and has moved on to the House Science Committee. You can read the story, from the Kansas City Star, by clicking here.

Thursday, April 03, 2003

Dead ant, dead ant.....

There was an imported red fire ant (Solenopsis invicta) conference in California this past week, and some attendees are sounding more optimistic than ever about eradicating the annoying invasive insects. According to this article in the Orange County Register, the county has gone from being heavily infested to having the ants restricted mostly to median strips and landscaped areas. No information in the article about how they did it, but apparently the region had some help from its dry climate and sage scrub habitat, both of which inhibit the ants' ability to colonize and reproduce. You can click here to see the entire conference agenda.

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Wednesday, April 02, 2003

The little conference with the big, big name

You can now submit abstracts online for the IPINAMS-EMAPI7 Conference. That giant acronym stands for "Invasive Plants in Natural and Managed Systems/7th International Conference on the Ecology and Management of Alien Plant Invasions" (whew!). The conference, held from November 3-7, 2003 in Ft. Lauderdale, Florida, will be an opportunity for anyone interested in invasive plants to hear great talks and meet a lot of great people. Abstracts for posters and oral presentations are due by May 15th.

Tuesday, April 01, 2003

Super NOVA

Airing tonight on PBS, and all through the month, is "Deep Sea Invasion." Brought to you by the folks from the science program NOVA, it's the story of the invasive marine algae Caulerpa taxifolia and its impact on the environment. If you're in the U.S., you can go here to find out when the program is airing in your area.

Thanks to a member of the ALIENS-L listserver for posting information about the program.

Monday, March 31, 2003

Something Fishy This Way Comes is reporting that environmentalists in Queensland, Australia are calling on the government to hasten their response to the presence of the invasive fish tilapia (Tilapia spp.) near a dam in north Queensland. While screens are supposed to be installed at the end of 2003, there are complaints that this is not soon enough, and great concern that the tilapia will escape in to the Gulf of Carpentaria. For another take on tilapia control, see this previous blog entry.

Sunday, March 30, 2003

Thanks for sharing

One important nugget of information comes from this report from ABC News (and virtually every other news source) about a speech Interior Secretary Gale Norton gave for the National Wildlife Federation: "When I talk with the president about invasive species, he understands firsthand because he manages those issues himself on his own ranch." Well, I feel much better now.

Friday, March 28, 2003


The Guardian has a story about the report on invasive species just released by the UK Department for Environment Food and Rural Affairs. The report outlines goals for a comprehensive program to limit the ecological and economic impact of invasives, with a focus on prevention and rapid response to species in the earliest stages of invasion. You can read either the entire report or a summary by going here.

Thursday, March 27, 2003

Pulling and pulling and pulling...

After about five weeks, crews at Lake Wilson in Hawaii have managed to remove 26,000 cubic yards (19,900 m^3) of the Salvinia molesta that has infested lake waters, which amounts to about 25 percent. According to this article from the Honolulu Advertiser, the weeds they're pulling are dead after being sprayed with herbicide a few weeks ago. The article also mentions a similar project going on at Kawainui Marsh, where volunteers are removing salvinia as well as water lettuce (Pistia stratiotes). It is probably frustrating for Hawaiians to know that no matter how good of a job they do, this is likely a lifetime maintenance project, given the difficulty in eradicating any aquatic species. You can read previous blog entries about Lake Wilson by clicking here.

Wednesday, March 26, 2003

Spring, when young Japanese knotweed rhizomes burst forth with new shoots...

A sure sign it's spring: hits on The Knotweed Page, one of my other web sites, are way up, especially from people in the UK. Getting frustrated while searching for the perfect knotweed antidote? Take a break and check out photos of the UMass Boston Japanese knotweed exhibit from this year's New England Spring Flower Show, or maybe buy yourself a cute Knotweed-Hating Teddy Bear. And if you are from the UK, a good starting place for resolving your Fallopia japonica, Reynoutria japonica and Polygonum cuspidatum problems is the Japanese Knotweed Control Forum for Cornwall web site.

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Tuesday, March 25, 2003

Food or Foe?

As entrepreneurs in several countries turn to tilapia (Tilapia spp.) aquaculture as a new food source/income, Townsville, Australia held their annual tilapia fishing competition this past weekend. The fish are considered a pest species in Australia's rivers, and are known locally by the affectionate nickname "toad of Townsville's waterway" (not a very nice thing if you're a toad I guess). Unfortunately, as reported in the Townsville Bulletin, only one tilapia was caught that day.

Monday, March 24, 2003


An annoyingly worded article from the Financial Times reports that France has "declared war" on the American bullfrog (Rana catesbeiana). The frogs have become invasive in southwestern France, where they are causing harm to other amphibians, mostly by eating them. American bullfrogs have also caused problems across the U.S. and in Canada.

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Sunday, March 23, 2003

Read it and weep

Here are links to abstracts for a few interesting articles that have appeared recently in the biological journals:

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