In the fight against invasive weeds, dozens of "early detection, rapid response" initiatives have been launched, but scientists with the Weed Science Society of America say one part of the equation is missing: prompt action.
Studies show that small, newly established invasive weed populations can expand at rates of up to 60% per year. As the size of the infestation increases, the cost of control soars while the probability of successful management plummets.
"Early detection creates opportunities for us to make smart decisions and eradicate new invasive weeds before they spread widely and become entrenched," says John Jachetta, Ph.D., chair of the Indiana Invasive Species Council and a member of the WSSA Science Policy Committee. "In those early stages, control efforts are typically easier, more successful and far more cost effective."
Crupina, 'killer algae' serve as examples
Unfortunately there are many examples of a known infestation unfolding without early intervention. One of those involves common crupina, a noxious weed in the sunflower family that can ruin pastures and prairies.
A native of Europe, common crupina was first discovered in the U.S. in Idaho in 1969. But there were no concerted efforts to destroy that small initial infestation. A decade later, the weed covered many thousands of acres and had earned a Federal Noxious Weed designation. Only then did research get underway to explore the possibility of eradicating the plant.
It took years, though, to complete a study, and years more to convene a task force to review the study results. By then common crupina had spread well beyond Idaho into other neighboring states – making true eradication a very costly, time consuming and unlikely proposition.
There are also examples, though, of a more effective approach. In California, early detection and early response prevented a potential environmental disaster triggered by "killer algae" (Caulerpa taxifolia).
A native of Europe, killer algae produces a chemical toxic to fish and other organisms, and it spreads easily.
In 2000, two small infestations of killer algae were discovered and a rapid response was coordinated. Black plastic tarps and chlorine were used to kill the algae at both sites. In addition, recreational divers were trained to spot the weed and to sound an early alarm if there were new outbreaks. As a result, what could have become a very costly problem appears to have been quickly and successfully resolved.
"We've long understood the value of an early response to diseases impacting human health," Jachetta said. "It's time to bring that same sense of urgency to our natural environment and to take prompt, effective action to stop harmful invasive weeds."
WSSA recommends seven steps for detection and response programs:
Identify: Both scientists and lay people are taught to identify problem plants.
Report: Online tools make it easy to submit information on a sighting.
Verify: Scientists validate reports of suspected invasive species.
Review: Data is used to keep tabs on the geography of an infestation – where the invasive weed has been spotted and how quickly it is spreading.
Assess: Experts evaluate the risk of the infestation to natural ecosystems, crops and the economy.
Establish a plan: An integrated plan is developed for managing the infestation.
Rapidly respond: The plan is quickly implemented and there is ongoing monitoring to gauge the effectiveness of control efforts.