Fleeing the Fleas

Tiny crustaceans known as Spiny Water Fleas (Bythotrephes cederstroemi) are annoying fishermen and worrying environmentalists in Canada and the Great Lakes region. This freshwater species, introduced from Europe and fairly recently discovered in North America, establishes huge populations that are physically disturbed by the dragging of fishing lines. The result is fishing gear covered with a slimy, smelly mess, and the potential of the species being spread in this manner to even more water sources. Another recent Canadian article discusses the negative impacts that this invasion could have on the vacation/real estate markets.

Christmas Trees

Today I went to pickup my tree seedling from the Quincy Public Works Department. The city has an "Evergreen Program", which I think is a great idea: you drop off your Christmas tree to be recycled, and they give you a coupon to pick up a baby tree in the spring. They're planning on planting 12,000 trees in the city. The letter I received promised me a Bracted Balsam Fir (Abies balsamea), which is native. Unfortunately, when I got home I realized my seedling was a Norway Spruce (Picea abies). It's ironic to me that most of Europe has been reforested with American tree species over the past few centuries, and now we're growing and planting European trees here. While Norway Spruce is not considered invasive in the U.S., it is on the "watch lists" of some groups studying invasive species, and has been identified as a problem species in Canada.

Trashing the South Pole

People are still ironing out the definitions used in invasive species ecology. Specifically, what constitutes an "invasive" species is a subject of contention among scientists and policy makers alike. Some contend that an invasive species has to have been introduced by humans, either accidentally or intentionally.

Of the species that are naturally dispersing into new habitats on a regular basis, there are very few that can do so on a continental scale. (One example that comes to mind is the Sea Beans, a group of plants whose water-dispersed seeds can cross oceans.) Now comes this story from the BBC about marine creatures hitchiking across the ocean on trash. For thousands of years, organisms like mollusks and corals have attached to natural debris that floats on ocean currents. But now surveys show that more than half of the debris found near the Antarctic is man-made. Not only is there a lot more debris than is natural, but it is even easier for organisms to survive on the more-durable artificial materials. So, if one of these species starts spreading aggressively, is it invasive or not? (Story tip from The Daily Grist)

Pike on the run

In California, the Department of Fish and Game has found a better way to deal with introduced freshwater fish than poisoning entire bodies of water...they're blowing the fish up!! The northern pike (Esox lucius) introduced to Lake Davis are aggressive predators, and have taken over the lake. After a previous attempt at poisoning the fish affected water quality, caused health problems, and prevented all fishing for months, Fish and Game has turned to a less toxic option. Explosions are set off underwater and dead fish are then scooped off the surface. If the detonations turn out to significantly harm the trout that also inhabit the lake, officials will look into other management options.

Though this method is obviously one of control rather than eradication, it makes sense in this situation. Since the pike were reintroduced intentionally after the lake was cleared the first time, it is likely introductions will continue to occur. Northern pike is a popular game fish, and though it has been introduced by humans to many lakes, its range is considered circumarboreal. You can read more about the effects of northern pike introduction in this .pdf file. (Thanks to a member of the ALIENS-L listserver for posting the link to this story.)

Beetle Battle

In an effort to fight the spread of the Asian Longhorned Beetle, New York will be enlisting the aid of fancy new acoustic devices that detect the noises beetle larvae make as they chew their way through tree trunks. The acoustic sensors, which attach directly to the trees, will be accompanied by a wide-scale insecticide treatment program.

Shoo Fly?

Used to considering fruit flies as a household and office pest (my office being adjacent to biological labs), I was surprised to read this story in the New York Times about a non-native species causing problems in the western U.S. (NYT requires a user name and password). It turns out that there are many native species of fruit flies whose populations have been in decline since the arrival of Drosophila subobscura, a European native. Unfortunately native Drosophila suffer from a lack of attention due mostly to the fact that they're, well, flies. If you don't want to deal with logging in to the NYT, you can read a similar article from 2000 from the Seattle Post Intellingencer. For more detailed information, check out this book, though it might be in German.

"You took off like a Jetbead..." (Okay, no one's going to get that obscure Brit pop reference, I know.)

A member of the Yahoo! group ma-eppc posted requesting reports on Jetbead sightings. Known by the scientific name Rhodotypos scandens, this shrub should now be coming into flower, though it is probably easier to identify once it has developed its distinctive 4-fruited clusters. Often planted as an ornamental, this Asian native is being monitored in several eastern states due to reports of its escape from cultivation.