The decision to make environmental changes is one that should never be taken lightly. This is especially true when the consequences of the changes being made could be out of your control once the process is initiated. Therefore, it has been good to hear more details on a plan to introduce herbicide into local waterways Chena Lake and Chena Slough in an effort to defeat the invasive water plant Elodea. In public meetings on the issue, representatives of the Fairbanks Soil and Water Conservation District have built a credible case that the weed can be eliminated without danger to other marine life.

The knee-jerk response is to be skeptical of efforts to manage habitats through measures, like herbicides, that are relatively heavy-handed. When possible, the human instinct is to favor more traditional measures (in the case of weeds, pulling them) that won’t have downstream effects — literally, in this case — we may not be able to foresee. Natural systems, especially aquatic ones, are complex and not fully understood.

But sometimes the simpler methods we prefer fail. In the case of aquatic plants in the Elodea genus, this owes to the hardiness of the invading weeds. Elodea is a plant often found in home aquariums; it was introduced to Fairbanks-area waters, officials think, by a resident dumping an aquarium into the slough. Now Elodea is choking up hundreds of acres of Chena Lake and Chena Slough, and traditional removal methods have been maddeningly ineffective: More than 500 hours of weed pulling in recent years has cleared fewer than two acres of the plant. Efforts are further frustrated by the fact that the plant can spread if even a tiny piece of it floats away and takes root elsewhere. Poor weeding technique could easily spread it further.

Elodea is, however, uniquely susceptible to poisoning via introduction of a chemical called fluridone. The herbicide has been used on it in other areas to good effect, including within the state in recent years in lakes on the Kenai Peninsula. Armed with information about how that eradication effort took place, watershed management officials have drawn up a local plan they say will kill the weed but not lead to adverse effects for native species.

The recent history of fluridone against Elodea in Southcentral is compelling and does much to assuage concerns that the chemical might have some yet-unknown adverse effect in northern waters. Local residents who have spoken out have so far been overwhelmingly supportive of the plan, describing the negative effects Elodea has had on the waters it infests.

But the plan needs funding, estimated at about $800,000. That’s not a huge price to pay to eradicate a virulent invasive species, but money is tight at the state level, where control of waterways typically resides. Given that about $200,000 of the necessary work would need to be done at Chena Lake, a borough-run park, perhaps the municipal government could cover costs for that location, with the state responsible for Chena Slough, which will require three times as much funding. It’s roughly the same cost-sharing percentage as was standard in school bonds prior to this year. It also reflects the greater amount the state has at stake. Chena Slough is connected to the Chena River and thus the greater Tanana-Yukon drainage, and further spread of Elodea if it isn’t stopped now would make for a much more extensive — and expensive — eradication effort.

If the fluridone plan does go into effect, it will require careful monitoring by officials and the public to ensure there aren’t undue adverse effects on species other than Elodea. But so far, watershed officials have made a good case.

— Fairbanks Daily News-Miner,

June 23