Wednesday, July 09, 2008

Alaskan pike: wicked species inconveniently invade

As a member of the National Invasive Species Advisory Committee (ISAC), I was privileged to attend a meeting in Alaska in May 2008. As part of a spectacular tour, ISAC went to Lake Cheney to learn about pike invasions, which, in the words of an article by S.J. Komarnitsky, published in The Anchorage Daily News, July 8, 2008,“has wiped out a popular rainbow trout and landlocked-salmon fishery.” We found that the usual flexible fuzzy understanding of key words such as native, alien, exotic, and invasive were in full play.
Invasive species are by federal definition in the United States alien, exotic, non indigenous species. For those who do not live in the world of definitions or do not think clearly about what the words mean, a fish that is native (to Alaska) could therefore not be invasive, and so transporting it from one eco-system, with in Alaska to another surely could not be harmful at least in the world of invasive species issues. The appearance of the pike outside of its natural range strongly suggests that a well-meaning fisherman, a member of one of the many invasive species stakeholder groups, attempted to increase the sport fishing at the local lake by bringing “native” Alaskan pike to Anchorage….Alaska.
The wicked inconvenience of invasive species issues, the complexities inherent in any effort to find clear, concise and inarguable positions or solutions (Saturday, September 29, 2007; Invasive Species Conundrum: A Wicked Inconvenience & Sunday, February 18, 2007 Invasive Species; Wicked Inconvenience: part two ) comes forth vividly in the article. The reporter writes that “Besides Cheney Lake, the state hopes to use rotenone in Arc Lake near Soldotna and in a series of ponds in Yakutat known as the "Village" or "Post Office" ponds.” For some stakeholders, this is a perfectly reasonable response to a major problem and threat, for although the loss of a few fishing holes is not in themselves a critical threat, the proximity to major tributaries and salmon runs most certain is. The writer notes that “At all three sites, biologists are worried about the pike spreading to nearby salmon streams. Arc Lake is only two miles from Soldotna Creek, which feeds into the Kenai River. Cheney Lake is just a hop and a skip from Chester Creek.”
Because invasive species issues are engaged by multiple stakeholders whose interests and definitions may be or become at cross purposes, improbable obstacles arise quite quickly. In an effort to protect the environment, which is what the several interested parties want by virtue of their interest, one group would use chemical control to return the pre invasion status quo, while a second equally determined to protect the environment states that there can be no chemical control. “(A)n resident who also sits on the council, however, said he would oppose any use of the chemical. He has read concerns on the Internet about rotenone and is distrustful of using any chemical that kills an animal no matter the assurances about its safety. ‘I'm of the opinion that the use of any kind of chemical or pesticide has side effects,’ he said.”
So here at a small lake in great Alaska, the forces of humanity decide to wage battle. Do we use any resource starting with the least harmful and working our way up the chain (IPM) until we get control, or do we allow the damaged eco-system to evolve on its own and do nothing? Do we apply chemicals to increase crop production to feed the world, or do we share our crops with other hungry species? How much diversity versus how many human lives? And at a higher level of complexity, do we act now in short term interest and deal with long term effects somehow, or do we suffer now for the potential good of the eco-system down he road. Ultimately, some could seem to be asking if the world would be better off without Homo sapiens.
I note with some interest, that plants and insects use chemicals many times to create their own “safe” special place in the world. The chemical under consideration the author points out is rotenone, “… a naturally occurring chemical that comes from a member of the bean family. According to a manual on rotenone distributed by the American Fisheries Society, a professional society for fisheries scientists, a 160-pound person would have to drink 23,000 gallons of water treated at 0.25 milligrams of rotenone per liter of water (the highest allowable treatment rate for fish management) at one sitting to receive a lethal dose.”
It seems strange that a black walnut, some beans and other species can use chemicals to help insure survival, but humanity should not. That said the practice of integrated pest management should always be a core part of the decision and execution process. Start with the least harmful and the least amount and work one’s way up to a tolerable level; begin with an assumption that working with the local eco-system is a strong basis for survival.

Tuesday, July 01, 2008

Yet Another Invasive Species: Killer Fungus

Invasive species and gardeners do not always get along. Gardeners from time to time are passionate in their right to plant any species for the glory and betterment of the design. The concepts of invasive species detection, control and eradication cause a great amount of angst in the world of horticulture as the purveyors feel that their right to complete freedom of choice is being potentially denied by restrictive lists and suggestions.

On the other hand, the same gardeners with equal passion demand the interdiction and elimination of pests and pathogens from their gardens, and are among the first to recognize the invasive, pervasive and destructive nature of foreign, alien and exotic insect and disease species. It is worthwhile to remember that invasive species are not limited to horticultural specimen plants, but to all taxa, and are part of a interconnected web of cause and effect.

The surge of invasive species is a consequence of climate change, as well as a result of the fragmenting and loss of biological diversity in eco-systems and habitats.

Tree-Killing Fungus Officially Named by Scientists Asheville,NC --

The USDA Forest Service Southern Research Station (SRS) today announced that an SRS scientist and other researchers have officially named the fungus responsible for killing redbay and other trees in the coastal plains of northeastern Florida, Georgia, and South Carolina.
Lead author and Iowa State University Plant Pathologist Tom Harrington, co-author and SRS Plant Pathologist Stephen Fraedrich, and Azerbaijan National Academy of Sciences Researcher D.N. Aghayeva unveiled the name, Raffaelea lauricola, in an article published in the April-June 2008 issue of Mycotaxon, the international journal of fungal taxonomy and nomenclature.

“Until now, the fungus was known as ‘the laurel wilt pathogen’ because of the devastating disease it causes in redbay trees and other laurel species like sassafras and avocado trees in the Southeast,” said Fraedrich, based in Athens, GA. “Now arborists, foresters, researchers, and regulatory officials have a formal, scientific name and description of the fungus, as well as a detailed explanation of how the pathogen compares to similar fungi.”

Raffaelea lauricola is one of many species of fungi carried by ambrosia beetles, a group of highly specialized wood-boring insects that feed on symbiotic fungi, which they carry from tree to tree in specialized sacs. The beetles feed on their own special ambrosia fungi, much as the Greek gods were believed to exist on their "ambrosia." R. lauricola is the principle ambrosia fungus of an invasive species from Asia, the redbay ambrosia beetle. R. lauricola is the only known tree pathogen among the ambrosia fungi and differs from other Raffaelea species in its DNA sequence and spore sizes. The fungus also grows faster than similar fungi.
Ambrosia beetles introduce the fungus into redbay or other laurel tree species by burrowing into the trees and laying eggs. The fungus serves as a food source for beetle larvae. The pathogen moves through a tree’s vessels causing a vascular wilt disease similar to Dutch elm disease.

In an April 3 press release, SRS announced the first description of the fungus and its association with the redbay ambrosia beetle and laurel wilt. The press release, posted online at, provides more information about the fungus and the threat it poses to the laurel family. []