Invasive Species Weblog

Monday, July 19, 2004

Beware the Burr Chervil!

Could burr chervil (Anthriscus caucalis) have mutated into the next purple loosestrife (Lythrum salicaria)? According to this article from Today@Idaho, that's what one University of Idaho biologist hopes to find out. While a graduate student at the same university in the early 1990s, Dr. Tim Prather noted that burr chervil was not an aggressive weed. Now Prather notes that the plant is much more common, expanding its geographic range and showing up in unexpected habitats. He hopes that molecular techniques may identify a genetic change that explains burr chervil's sudden success.

Jennifer Forman Orth 10:28 PM | 0 comments |

Saturday, July 17, 2004

How Now Brown Trout?

PennState Live has a story about research by Dr. Caleb Tzilkowski that focuses on the potential invasive effects of the brown trout (Salmo trutta levenensis). Dr. Tzilkowski, a researcher at Penn State University, is about halfway through a study to estimate the impact of the repeated stocking of these non-native fish by the Pennsylvania Fish & Boat Commission, in streams throughout the state. He has found some evidence that the brown trout are displacing native trout species, but has also found that the brown trout do not appear to have any direct negative effects on endangered ironcolor shiner (Notropis chalybaeus) populations.

Jennifer Forman Orth 2:59 PM | 0 comments |

Friday, July 16, 2004

More On Goldfish

Seems Indiana is not the only state having problems with burgeoning wild goldfish (Cyprinus auratus) populations. The Baltimore Sun is reporting that there are about 50 large goldfish now residing in a pond in Sewells Orchard Park in that state. There is a grassroots effort underway to contain the problem by netting the goldfish (with adoption likely for the ones they catch). The story also contains an update for a story posted on the ISW last year about using bass to control the goldfish.

Jennifer Forman Orth 10:44 PM | 0 comments |

Thursday, July 15, 2004

In a pinch

Officials in Toronto are not happy about the spread of the rusty crayfish (Orconectes rusticus) through the rivers and creeks of the region, according to this article from The Globe and Mail. The province of Ontario already has its share of native crayfish species, but none of them seem to have the attitude problem of the slightly larger rusty crustaceans. They are more aggressive than their native cousins, will out-compete them in the grab for food, and tend to have voracious appetites. They're also more likely to attack your toes than to run away if you disturb them. Rusty crayfish are considered native to the U.S., including some of the Great Lakes states, but have greatly expanded their range over the past several decades.

Jennifer Forman Orth 10:40 PM | 0 comments |

Wednesday, July 14, 2004

Three shall be the number of the counting, and the number of the counting shall be three

Scientists are concerned about the number of black carp (Mylopharyngodon piceus) they're finding in the Mississippi River...even though that number currently stands at three. As reported by MSNBC, the fish have been caught over the last 1.5 years, and are thought to have escaped from catfish ponds, where they are employed to eat snails that carry disease-causing parasites. The carp are supposedly sterile, meaning that the risk of them reproducing in the wild is small, but there is still the possibility of a negative impact on native mollusk populations if these long-lived fish escape into the wild. Read an older ISW post about the black carp problem by clicking here.

Labels: carp, fish

Jennifer Forman Orth 10:45 PM | 0 comments |

Tuesday, July 13, 2004

60 seconds to invasion

As reported by Greenwich Time, a wetlands officer in Greenwich, Connecticut was on a routine inspection of an estate when he accidentally stumbled upon an invasive plant that is only known in a few sites in that state. It turned out that a compost pile filled with dead nursery stock and other materials was also home to a 5 x 20 foot swatch of mile-a-minute vine (Polygonum perfoliatum), a thorny vine that grows almost as fast as its common name implies. Landscapers on the property have been instructed to dispose of the plant separately, preferably by incineration.

Jennifer Forman Orth 9:23 AM | 0 comments |

Monday, July 12, 2004

Kitty De Carcass (bonus points to any non-Bostonian who gets that ref!)

If you live in Richmond Shire, Queensland, Australia, you can earn some extra money this fiscal year, but you have to have a hankering for cat hunting. According to this story from the Townsville Bulletin, officials are offering $5 AUS for every feral cat (Felis silvestris) carcass brought in by town residents. Animal rights groups are upset, as is to be expected, pointing out that any culling should be done in a humane way. The mayor of Richmond, John Wharton, noted that feral cats dine on several native bird and marsupial species, and claimed that his shire was "...leading the way in wildlife conservation." Where I live, cats are pretty much the only thing keeping moles, voles and chipmunks from completely overrunning the neighborhood. Hope Richmond has some hungry native carnivores out there.

Thanks to Val C. for sending the link to this article.

Labels: feral cats

Jennifer Forman Orth 10:31 PM | 0 comments |

Sunday, July 11, 2004

Hunting Hydrilla

Scientists think they've got hydrilla (Hydrilla verticillata) under control in the Rio Grande in Texas, according to this report from The Brownville Herald. The surface area covered by the invasive aquatic weed has decreased by about 50% since May 2003. The weapon of choice in this case? Grass carp (Ctenopharyngodon idella), though the scientists point out that there was likely also a benefit from heavy rainfalls that swept some of the hydrilla out to sea.

Labels: carp, fish

Jennifer Forman Orth 10:33 PM | 0 comments |

Saturday, July 10, 2004

In Search Of

Don't forget that there are over two years of posts (almost 700 entries) here at the ISW. Whether the post you are looking for has slipped off the screen, or you want to see what else has been posted about your favorite nasty invader, there's a search bar located in the left column that is here to help you. Atomz, the company that indexes this site, provides reports listing the top words and phrases. The most popular searches for the month of June were for purple loosestrife, feral cats, or some iteration of Japanese knotweed.

Jennifer Forman Orth 6:09 PM | 0 comments |

Mitey Fine

Scientists from the Agricultural Research Service have honed in on a species of mite that they hope has eyes only for the invasive Old World climbing fern (Lygodium microphyllum). According to this report in Agricultural Research Magazine, populations of the tiny mite (Floracarus perrepae) that prefer the fern have been found in Australia and Thailand. To test the potential biocontrol's appetite, researchers took along tiny sporelings of Old World climbing ferns currently growing in Florida. You can read about previous efforts at controlling this species from older ISW posts. Bonus points to ARS Magazine (as usual) for using scientific names.

Jennifer Forman Orth 5:41 PM | 0 comments |

Friday, July 09, 2004

A soda apple a day does not keep the USDA away

Agricultural officials in Texas have mobilized following the discovery of tropical soda apple (Solanum viarum) on a ranch in the town of Jasper. As reported at Science Daily, a rapid response team made up of workers from the USDA, Texas Cooperative Extension and weed specialists are now studying the situation to determine the best way to contain the invasion of this federally listed noxious weed.

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

Jennifer Forman Orth 3:21 PM | 0 comments |

Thursday, July 08, 2004

Boom!

In the charmingly-titled article "Bullfrog explosion plaguing B.C." CBC News describes the problems British Columbia is experiencing as a result of skyrocketing populations of American bullfrogs (Rana catesbeiana). The bullfrogs were introduced to B.C. almost 80 years ago as part of a marketing scheme to provide frog's legs to the restaurant industry. Many of the frogs were released into the wild after the industry failed. Now there are concerns that the bullfrogs are endangering native frog species...by eating them!

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

Labels: amphibians, frogs

Jennifer Forman Orth 11:32 PM | 0 comments |

Wednesday, July 07, 2004

Sudden Spread

Sudden Oak death (Phytophthora ramorum) continues its spread across the eastern U.S., following its escape several months ago via contaminated California nursery stock. APHIS is reporting (.pdf) that the presence of this fungus has recently been confirmed in Nassau County, New York. Check that document for a list of nurseries across the country where the pathogen has been found. The Beaufort Gazette is reporting that two infected plants have also been found in South Carolina over the past month, marking the first occurences for that state.

Thanks to members of the Yahoo! group ma-eppc for posting about SOD.

Jennifer Forman Orth 10:07 PM | 0 comments |

Tuesday, July 06, 2004

Parrot Parade

Seems parrots are poised to take over England. According to this report from BBC News, the thousands of wild parrots that call Britain their home are increasing their numbers at a rate of 30% per year. BBC News, after summarizing the results of an Oxford University research project, then goes on to add a slew of anecdotal information from local readers who've sighted parrots in their neighborhoods.

Jennifer Forman Orth 11:54 PM | 1 comments |

Monday, July 05, 2004

Attack of the Killer Goldfish

The Indiana Post-Tribune is reporting that the state's Spectacle Lake is infested with, of all things - goldfish (Cyprinus auratus). Concerned about the native (?) bass in the lake, local environmentalists are asking the state to remedy the situation by treating the water with rotenone, which will kill -all- fish, and then restocking with bass. This is actually the second time in fifteen years that Spectacle Lake has been overrun with goldfish, which perhaps explains why the state isn't exactly hurrying to fill it with piscicide. Goldfish can destroy bass nests when they kick up bottom sediments. When they reach critical population levels, they can also drop the dissolved oxygen content of the water to a point that is tolerable to them, but deadly to bass. That makes the idea that these folks had last year, to introduce bass to a lake to control goldfish, sound like a bad one.

Jennifer Forman Orth 9:32 PM | 0 comments |

Saturday, July 03, 2004

Nick of Time?

As reported by the Coolidge Examiner, a National Park Service employee discovered zebra mussels (Dreissena polymorpha) on the hull of a houseboat, fortunately before the boat was launched. The boat was brought to Lake Mead over Memorial Day weekend, all the way from Kentucky. The unlucky boatowner must now wait thirty days before his/her boat can be retrieved from quarantine. This map shows the known distribution of the zebra mussel in 2003 - Arizona isn't anywhere near there...yet.

Jennifer Forman Orth 9:56 PM | 0 comments |

Friday, July 02, 2004

Snakehead Banners?

Following repeated discoveries of northern snakeheads (Channa argus) in Maryland waterways, that state's Department of Natural Resources introduced a draft regulation this week that make owning the fish illegal. As reported in the Virginian-Pilot, the DNR is painting with a broad brush, proposing to ban 29 different species of snakehead. The Maryland Association of Pet Industries points out that few people own northern snakeheads, and many of the listed species require tropical conditions for survival.

Labels: snakehead

Jennifer Forman Orth 10:32 PM | 0 comments |

Thursday, July 01, 2004

An Herbe à l'ail by any other name, still stinks

There is an interesting piece by Paul Wiegman in the Pittsburgh Tribune-Review, about his trip to Europe and subsequent discovery of garlic mustard (Alliaria petiolata) in its native habitat. He goes on to wax poetic about the invasive herb's history in North America, and invasives in general. A good read.

Thanks to a member of the Yahoo! group ma-eppc for posting a link to the story.

Labels: garlic mustard

Jennifer Forman Orth 11:34 AM | 0 comments |

Wednesday, June 30, 2004

Water primrose primer

Workers at The Nature Conservancy's Long Island, NY chapter are spreading the word about the recent discovery of established populations of an invasive water primrose (Ludwigia sp.) in the Peconic River. A smart biologist has already documented the invasion with photos (see below). As reported by the ISW back in 2003, water primrose is prime mosquito habitat. If you're in the area and you think you've spotted this plant, you can find contact information for TNC's Long Island office here. TNC is considering their options for eradication or management as they study the situation more closely.

Ludwigia sp. on the Peconic River

(Thanks to Andy Senesac for granting permission to use his photos.)

Labels: aquatic plants, insects, mosquitoes, New York, plants

Jennifer Forman Orth 7:37 PM | 0 comments |

Tuesday, June 29, 2004

Not so new, but still rings true

Back in 2001, Don Schmitz and Daniel Simberloff published an article titled Needed: A National Center for Biological Invasions. In it, they discuss the necessity of having coordination among the various regional and federal agencies, experts, and non-governmental groups involved in invasive species management. It may be three years old, but the article is still quite valid today. Sharing of resources will likely be the key to controlling invasives, especially in a time where environmental funds are being stretched thin. And invasive species (humans notwithstanding :-)) don't give a darn about political boundaries.

Jennifer Forman Orth 9:34 PM | 0 comments |

Monday, June 28, 2004

Florida is in deNile

The News-Press has another article about the Nile monitor lizard (Varanus niloticus) eradication program currently in effect in Cape Coral, Florida. So far biologists have caught and euthanized about 60 of the estimated 500-1000 lizards thought to be living in the city. The first ISW post about this was back in July 2003 (unfortunately that older article is no longer available on the web). Also from The News-Press is this article about a temporary reprieve for other exotic animals in Lee County, including iguanas (Iguana iguana) and peacocks (Pavo cristatus).

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

Labels: Florida, lizards, reptiles

Jennifer Forman Orth 9:50 PM | 0 comments |

Sunday, June 27, 2004

Registration Required

The Minneapolis Star Tribune just finished an excellent series on invasive species in the Great Lakes. Unfortunately, you will have to proceed through an annoying but free registration process to read all of the articles. Most interesting is this article from June 9th, which contains a list of 179 species in the Great Lakes marked as invasive (and describes the sources, bravo!). There's also this article about the lack of thorough ship-checks, a story about a woman's unpleasant encounter with a silver carp (Hypophthalmichthys molitrix), and an interesting piece about the attempt to prevent the spread of carp via an electric barrier. To see all related stories, you'll have to search the Star Tribune's archives.

Jennifer Forman Orth 10:33 PM | 0 comments |

Tuesday, June 22, 2004

Monk Parakeets II: Problem or Not?

Monk parakeets are here to stay in many areas of the United States. Even a coordinated campaign would probably fail to eradicate them altogether, given their large numbers, fast, powerful flight, intelligence, and adaptability in nesting and feeding, not to mention the problems associated with removing them from urban environments. Should the state even try at this point? Are Monk Parakeets even a threat?

One characteristic of monk parakeets has already caused frustration among people, and considerable destruction: their attraction to utility poles as a nesting substrate. Electrical utilities in Florida, Texas, and Chicago refer to them as "feathered rats", and have taken to removing nests from their poles. In some cases the heavy bulk of sticks have caused the transformers to overheat and catch on fire. The removal is usually met by an outraged public...in Chicago the electrical company knocked down a nest containing several eggs and nestlings a few years ago. This "strategy" of nest removal is a PR nightmare, and ultimately ineffective. After three different nest removals in Chicago, I witnessed the birds immediately rebuilding the nests after the workers left. Are monk parakeets an agricultural threat? Data from their native range are hard to come by, and what has been published is often in Portuguese. No estimates of actual crop damage by monk parakeets are available. Typically, they are blaimed for much more damage than they cause because they are much more visible than an insect or a fungus. One Brazilian study found moderate percentages of corn and wheat in the crops of monk parakeets, but the sample size was small. This method can also be biased by the timing and location of sample collection. In the United States, a master's student studying monk parakeets in Florida told me a few years ago that she had observed monk parakeets and other naturalized parrot species feeding in groves of exotic fruit species (e.g. mango, lychee, longan). However, I don't think she was ever able to quantify the damage. No reports exist of monk parakeets feeding in other agricultural crops (e.g. the extensive grain fields surrounding the Chicago area). I suspect that monk parakeets will become a minor problem in Texas and Florida fruit orchards, but in harsher environments like Chicago or New York they will be unable to spread to agricultural areas. I found in my study that monk parakeets almost exclusively eat bird seed from backyard bird feeders during the winter months. They might be unable to spread without supplemental feeding by urban and suburban residents. Do monk parakeets compete with native species? An interesting question, but it can't really be answered yet. Their numbers are not that large, they don't nest in cavities like many parrots, and they occur mostly in disturbed environments. Monk parakeets might outcompete some species at bird feeders in Chicago (such as Cardinals). Some people (mostly non-scientists) have argued that the monk parakeet could fill the niche of the long-extinct Carolina parakeet, but that assertion seems fanciful at best. Overall, monk parakeet populations don't offer much cause for concern yet, but close monitoring is needed in Florida and Texas. Could control measures be taken against these local oddities even if the authorities desired it? Maybe at their first appearance, but favorable public opinion is now entrenched in favor of the birds in many places. When federal authorities threatened to wipe out the Hyde Park, Chicago, population in the 1980's (shortly after Mayor Harold Washington's death...he was a big supporter), a Hyde Park lawyer formed the Harold Washington Memorial Parakeet Defense Fund and thwarted the authorities. When the oldest monk parakeet nesting tree cracked and fell a few weeks ago in Hyde Park, the authorities actually helped transport young parakeets to a nearby tree! Many people in the neighborhood have adopted fallen parakeet chicks as pets over the years...those parakeets are untouchable at this point (except for those on the utility poles, but I hear they have been slowly moving to the trees as their nests are continually destroyed). For an independent example of people falling in love with an introduced parrot species, check out this website, book, and documentary film about a man who looks after the Red-headed Conures breeding in San Francisco! This story (and others like it) is ultimately more about the satisfaction that humans derive from animals, rather than about the animals themselves or the environment. I'm sure these parrots would have been just fine without someone feeding and taming them. Let's hope these birds don't become a pest in California, because they certainly aren't going anywhere.

Labels: birds, monk parakeets

The Munshi-South Family 3:55 PM | 1 comments |

Sunday, June 20, 2004

Monk Parakeets I

Jason South of Borneo Chela here, pitching in while your regular host braves the verdant jungles of Costa Rica.

Here is the first of two posts on Monk Parakeets (Myiopsitta monachus), an introduced parrot that has established several breeding populations in the United States.

Many invasive species are subject to human disdain, or at least indifference, because they are a diminutive weed or foul, slimy thing that chokes up pleasant ecosystems with a bland uniformity. However, some nonnative species have been intentionally or unintentionally released in to the environment due to their cultural significance (i.e. beauty, popularity as companions). The ubiquitous house sparrow (Passer domesticus) and common starling (Sturnus vulgaris) are archetypal; both were intentionally released in to the US on several different occasions by English immigrants to provide a constant reminder of home (one particular individual wanted to populate the US with the birds mentioned by Shakespeare!). Over the past 30 years, more than a dozen parrot species have escaped or been released in to the wild in the US. The most numerous by far, in terms of both geographic locations and numbers of individuals, is the monk parakeet. This medium-sized parrot is native to the temperate grasslands of Argentina, Paraguay, Uruguay, and southern Brazil, and is common throughout its range. THe planting of eucalyptus has allowed the monk parakeet to expand its range in the pampas region of Argentina, due to increased availability of nesting substrates. Thousands of these parrots were imported into the United States in the late '60's and early 70's to be sold as pets under the name "Quaker parakeet". Shortly thereafter, the first free-flying populations began appearing, mostly near dense population centers such as Chicago and New York City. As of 2001, monk parakeets had been recently recorded nesting in 14 states across the country. Texas and Florida harbor the largest breeding populations. Population estimates are not available, but thousands of monk parakeets are likely flying free in Austin and the east coast of Texas, and throughout South Florida (especially Miami-Dade county and the Sarasota area). The parakeets in Florida have actually been counted, but the data have not been published because of fears that the state or federal government might seek to control the population (more on that in part II). A few dozen are nesting in Brooklyn, NY, especially on the stadium lights of a particular high school. The population I studied in Hyde Park, Chicago (location of the University of Chicago) contained between 200 and 300 birds in Spring 2000 by my own count, with several dozen more nesting throughout the city and suburbs. How did so many parakeets make their way in to the wild? A combination of accidental escapes and intentional release. The story in New York, perhaps apocryphal, is that a crate containing monk parakeets fell and broke open at JFK airport in the early 1970's. The story in Chicago is even less clear, but newspaper articles suggest that the birds were first widely noticed in 1971, and were confirmed as breeding in 1979. These parakeets, and others around the country, were probably intentionally released by frustrated owners. Monk parakeet are incredibly friendly, gregarious, and easy to tame, but also ear-splittingly loud. They can be heard, even if far out of sight, all over Hyde Park as they call to each other in flight. How do they survive in the wild? The mild subtropical climates of Texas and Florida are a welcoming environment, but what about the harsh winds and winters of Chicago? Nests and birdseed are the likely answers. Monk Parakeets are the only parrots to build a nest that they use all year round for roosting. A pair will chew off hundreds of twigs that are then woven into a closed chamber with a single opening...once one of these chambers is built, other pairs will build their chambers on to the first one, thus creating a large social complex. A few birds huddled together in a chamber surrounded by other birds and chambers are likely to be warmer than a birds roosting on a naked branch. Monks also have a voracious appetite for bird seed, and will sit at feeders for hours in Chicago when it is cold outside (this supplemental feeding might limit their range in the northern states, however).

In a few days I will report on the problems they present as non-native species, as well as the social factors that will likely prevent government authorities from taking action against their spread in most parts of the United States. A few states have banned monk parakeets as pets, but only California strenuously enforces their own regulations. The state of California will confiscate and euthanize both pet and wild monk parakeets, even though they have allowed ten other species of parrots to breed unchecked in the wild!

Labels: birds, monk parakeets

The Munshi-South Family 4:35 PM | 1 comments |