Hawaii is a lush, tropical and isolated paradise. But this jewel in the Pacific is in big trouble from invaders. One third of all threatened and endangered plants and birds in the United States live only in the Pacific island state of Hawaii. Hawaiians want to preserve the natural treasures they have. But invasive species are crowding out the native flora and fauna faster than conservation programs can protect them.
One of the major culprits is miconia, a plant with broad green and purple leaves that grows into a 10-meter tall tree. No one dreamed this South American ornamental plant, which was sold in garden centers in the 1960s, would jump the backyard fence and take over hillsides and native forests. "They can go from seed to fruiting tree in about four years," says Christy Martin, who works with the Coordinating Group on Alien Pest Species, a multi-agency task force dedicated to protecting Hawaii from harmful alien pests.
She leads us to a hillside outside the gates of the Hawaii Tropical Botanical Garden on the Island of Hawaii. She likens the spread of miconia, which cover 45,000 hectares on the Big Island, to a green cancer. "Each fruiting tree can have 3 million seeds, two or three times a year. So each fruiting tree can have 9 million seeds," she says. "When you talk about the reproduction of these plants, it is just amazing. Other plants can't keep up. Certainly they can't keep up with their growth rate, and they can't compete with the amount of seeds putting out. "
Making her way into an area carpeted by young miconia, Christy Martin says the idea is to kill the plant before it seeds. Its shallow roots make it easy to pull up by hand. "Let's try this one," she says tugging at a plant. "These can start re-rooting, if you just lay them on the ground. They are amazing plants. We have even seen where some people will pull off the leaves and leave them on the ground. Our crews will go back to the area and the leaf will have sprouted roots. We have to hang these up in a tree to make sure that the roots are in the air and will dry out completely and won't fall back down and grow again."
The short-term goal is containment. Much like fighting a forest fire, miconia control begins at the outer edges and moves slowly inward to thicker more densely vegetated areas.
This is the same strategy used to stop the coqui frog. In the late 1980s the frog -- no bigger than a thumbnail -- hitchhiked a ride with nursery plants in a container ship from Puerto Rico. The coqui have reached densities of 55,000-per hectare in Hawaii, which is more than double their native range.
Coqui frogs hide by day and chirp loudly at night. Kim Tavares, who is starting a new group called Hawaii Invasives Management, follows their sound, marking coordinates on a pocket-sized global positioning system. Her coqui maps help community groups contain the infestation. On this evening, dressed in camouflage fatigues and headlamp, she surveys a densely forested subdivision.
"It seems as if the frogs are taking over," says one resident who estimates that there are 50 on his side of the street alone.
Ms. Tavares notes that last year there were only like six in the same area, but isn't surprised that they've multiplied so fast. "If they breed every two months and if only half of the 24 eggs are males," she says, "you can see how fast the numbers are going to grow and that's exactly what's happened."
Last year Kim Tavares and landowner Darrell Silva drove a pickup truck into this thick rainforest to clear a trail. The plan is to spray the mapped coqui area with a diluted solution of citric acid that will kill the frogs. "This trail is probably about 400 meters to the end of the coqui," she says. "That is a lot of hose. I am not sure how we are going to deal with it yet. But we are at least going to work on the perimeter, the outside edge and try to keep it contained if we can't do anything else."
Darrell Silva says that it is a standoff: "As far as trying to stop the invasion, it is going to take a lot more help and a lot more people and a lot more education on it all," he says. "I just don't want it in my backyard, and it's not going to stop unless we all do something about it."
Volunteers like Darrell Silva are the foot soldiers in the battle against invasive species in Hawaii. Only time will tell whether coordinated efforts by the state and private groups are any match for these tenacious and destructive alien species.