By TOM CALLIS
Tribune-Herald staff writer
The list of unwelcome plants in Hawaii County sprouted recently after a four-year-long roadside survey found several more invasive species previously not known to inhabit Big Island soil.
Jimmy Parker, a botanist working with the Big Island Invasive Species Committee, said the study completed late last year identified over 80 new nonnative species, including approximately a dozen considered invasive due to their harmful impacts on native vegetation.
Parker said the study, which took place along 3,000 miles of roadway, is intended to give the island an edge against pugnacious plants by identifying them early.
“We’re not finding every plant but we hope we are finding any new natural populations,” he said.
“Just getting out there and looking is definitely a big part of the fight.”
The invasive plants, which push out native species, have long been considered a detriment to the state’s ecosystem.
But you can’t fight what you don’t see.
That’s why the committee found it not just prudent, but necessary to conduct the lengthy, if not tedious, study, said Program Manager Jan Schipper.
“We’re trying to get a snapshot,” Schipper said.
“We take all the data back and then select a target so then we can select achievable targets.”
The work, all done by Parker and Program Associate Bobby Parsons, has already proved fruitful.
Parker said the committee has removed all of the identified plants from three of the newly discovered invasive species: the fast-growing princess tree of the southwest; the Barbados gooseberry, a leafy cactus that widely populates Florida; and the palo verde, a thorny shrub from Mexico.
While he acknowledges that doesn’t mean that those plants are now gone from the island, Parker said the early strike and identification will help avoid expensive plant removal efforts if they were left to spread.
“Once they get established, they become the next albizia,” he said, referring to the nonnative tree that has spread across much of the island.
Schipper said the committee will follow-up with other property owners to begin removing invasive species, but he noted such work does take their consent.
“We need every property owner to be on board,” he said.
Other islands have also conducted similar surveys.
Forest Starr, a University of Hawaii biologist, helped get the state’s first roadside survey started on Maui in 1999.
A second survey, which only took six months on the much smaller island, took place in 2008 and 2009.
Starr said the surveys found dozens of new nonnative species on Maui, with approximately 10 percent considered invasive.
He said that’s more than was expected.
“I think the first time we did it we were a bit naive,” Starr said, adding he was surprised to learn how quickly the landscape changes.
“When you actually … compare the data over the decade, it’s pretty impressive.
“But day-to-day it appears the same.”
Parker said that’s why the goal is to conduct a roadside survey every five years.
Since the first one took four years to complete, Parker and his colleague may just have one more year before they start scouring Hawaii’s roadsides again.
“The more you look, the more you find,” he said.
Emai Tom Callis at email@example.com.