These days, most of the recently arrived invasive species in Hawai`i are accidents. No one intended to bring the wiliwili gall wasp to the islands; it was apparently a hitchhiker on imported nursery plants. Certainly no one thought it would be a good idea to bring the stinging nettle caterpillar to the islands, but it’s here, having slipped through the less-than-solid barriers provided by Hawai`i’s quarantine system.
So have there been in recent years deliberate introductions of plants or animals that have become invasive or at least have that potential?
The short answer: Yes.
Corallimorph: Actinodoscus nummiformis was first noticed in Hawai`i waters a decade ago. This anemone-like animal is widely used in salt-water aquariums, and apparently someone hoped to establish in Hawai`i a reproducing colony that could be commercially exploited. Their hopes were fulfilled, and then some.
Now, the state Division of Aquatic Resources (part of the Department of Land and Natural Resources) and the Aquatic Invasive Species Response Team, with funds from the Hawai`i Invasive Species Council, has been working to eradicate this corallimorph. In 2006, they managed to suppress it at the site on O`ahu where it was introduced. Since then, they’ve been monitoring it periodically.
Sara Pelleteri, DAR’s aquatic invasive species coordinator, told Environment Hawai`i, “We have not found a new colony in over a year. We’re continuing to survey the area and not declaring eradication yet, but we’re hopeful. Maybe in a couple of months we’ll be ready to use the e-word.”
At one point, the Department of Agriculture was attempting to prosecute the case. The individual suspected of having introduced the corallimorph to Hawai`i possessed several other banned species. But, according to sources familiar with the case, the DOA had trouble pinning down the introduction of the species to the suspect.
Tokay gecko: Not your GEICO gecko or the innocuous and ubiquitous household gecko, this nocturnal critter can get up to a foot long – and it bites. According to the O`ahu Invasive Species Committee, the Tokay gecko (Gekko gecko) was most likely a deliberate introduction by someone hoping to profit in the illegal pet trade.
The Tokay gecko was added to the state’s list of prohibited animal species in 1997. The reptiles have been found in the Manoa and Makiki areas of O`ahu so far.
According to Rachel Neville of the O`ahu Invasive Species Committee, if you see one of these blotchy reptiles, you should not attempt to capture it yourself. Call OISC (643-7378) and have them send someone out. Neville told the Manoa Neighborhood Board last March that if a Tokay gecko sinks its teeth into you, the only way to make it let go is to “plunge it and your body part” into water and hold it there. The geckos are not very mobile, she said, and odds are good that it will not have traveled far by the time someone from OISC is able to respond to your alert.
The gecko gets its name not from the Hungarian sweet wine, but rather from its loud nighttime call, which to some sounds like “toe-KAY.”
Pampas grass: It’s easy to understand why this grass (Cortaderia jubata), with its striking, large white plumes, is a favorite of landscape designers. But as easy as it may be on the eye, it’s a bear to pull out. According to the Maui Invasive Species Committee, a full-size plant, with 10-foot-high fronds, can have a root mass that weighs half a ton. “These massive grasses must be yanked out with chains hitched to a powerful truck,” reports an article in the Fall 2006 issue of the MISC newsletter, Kia`i Na Moku o Maui Nui, or sprayed with herbicide. When the plants are found growing on mountain ridges or at the back of inaccessible valleys, herbicide is the only practical means of control. Even then, it’s difficult, requiring a skilled helicopter pilot, trained applicators, and good weather.
“Field crews are sometimes dropped by helicopter into remote areas, where they search under the tree canopy for plants that can’t be seen from the air,” the newsletter states.
The O`ahu Invasive Species Committee has a novel approach to controlling pampas grass on private property. Bearing native plants obtained from native plant nurseries, OISC staff approach landowners with a proposal to trade the noxious weed for more suitable native plants. To dig out the plants, field workers take a chainsaw to the root system, allowing them to pull it out in chunks.
C. jubata has been on the Hawai`i Noxious Weed List since 1992 and has been in the sights of the MISC since the group was formed in 1998. Yet Lloyd Loope, research scientist with the U.S. Geological Survey Biological Resource Division at Haleakala, has pointed out that a closely related species of pampas grass, C. selloana, could be an even bigger threat – and it does not appear on the Noxious Weed List.
“In the mid-1980s, the conventional botanical wisdom was that Hawai`i had only female plants of C. selloana, and that this attractive and benign species never set viable seed.” As a result, C. jubata was listed as noxious, but C. selloana was not.
Now, though, Loope writes, new science suggests that C. selloana has evolved and become “more invasive and damaging to California ecosystems than C. jubata.” New Zealand, Australia, and South Africa report similar experiences. “There is an excellent opportunity to eradicate C. selloana before it becomes aggressively invasive on Maui, but that will require strong public support,” Loope concludes.
Black List, White List
The same issue of Kia`i Na Moku o Maui Nui contains an essay by Teya Penniman, MISC manager, on the shortcomings of Hawai`i’s present regulatory framework concerning the importation of plants.
If a plant appears on the state Noxious Weed List, last updated in the early 1990s, it may not be imported. Everything not on the list is given a pass. This is the “black list” approach, and for a plant to be placed on the list, it must be a known bad actor.
New Zealand and Australia regulate with a “white list”: nothing can be imported unless the importer can show that it won’t be harmful.
Penniman lists several drawbacks to the black-list approach taken by Hawai`i. For one thing, it can take years to accumulate the evidence that a given plant should be placed on it. For another, while the state can enforce removal of black-listed plants from private land, it has little leverage to remove suspected harmful species – such as C. selloana – from private land if a landowner is uncooperative.
While many of those working on the front-lines of the battle against invasive species in Hawai`i have argued that the state should move to a “white list” approach, the USGS’ Loope urges a bit of caution.
A white list, he notes, permits the importation of species that are already here. But, “there’s no official list of what’s here and what’s not. So there’s no mechanism for determining whether a species being imported is actually here,” he said in a recent phone interview.
A bill introduced in the 2007 Legislature would have pushed Hawai`i in the direction of a white list. Senate Bill 639 would have continued to keep out the already black-listed species, but would also have prohibited the importation of “any new plant species” until it had been evaluated and approved by the state Department of Agriculture.
“Anyone who wants to challenge an inspector could simply claim that they’ve had this species for a long time,” Loope said. “Proving them wrong in a court of law would be nearly impossible,” he said, while the burden such a law would place on inspectors would be huge.
Loope will be going to Australia in September, where he hopes to learn more about how its white-list system works.
“It’s generally agreed that the rules we have are not working very well, with nothing added to the noxious weed list for 15 years,” he said.
— Patricia Tummons
Volume 18, Number 2 August 2007