The military in Hawai'i faces invasive-species threats or invasions on at least 15 bases and ranges across the state, and although it is spending millions on the problem, many observers say it's a losing battle.

There's fire-promoting fountain grass at the Army's vast Pokahuloa Training Area, in the saddle between Mauna Loa and Mauna Kea. And mangroves choking wetlands at Pearl Harbor, Kane'ohe and Bellows. And a fierce form of kiawe with 2-inch spikes at the Pacific Missile Range Facility on Kaua'i.

There are pigs, goats, coqui frogs, cats and dogs that threaten the native ecosystems of various parts of the state in different ways. And there are the threats that military aircraft could bring in brown tree snakes from Guam and mosquitoes that carry West Nile virus.

Invasive species are a problem across the state, not only on military land, and as a result, the U.S. Department of Defense has found numerous well-qualified partners to join it in the fight. The Sierra Club in Hawai'i is one of those partners, but its state director, Jeff Mikulina, says the problem seems insurmountable.

"We're happy with the progress: fencing, weed eradication, propagation of native species. We've worked with the Marines at Kane'ohe. We've worked with the military on miconia hunts. But I think overall, we're losing the war against 'invasives,' " Mikulina said.

The military's efforts to respond to the invasive-species threat in the Islands are significant. The armed services employ dozens of biologists and natural-resource technicians, bring the power of the military organization to bear, and have developed strong partnerships with volunteers from the community, from government agencies and from nongovernmental organizations. A cost estimate for the military's efforts was not available.

The situation is not just a local one. The National Wildlife Federation, with the assistance of the Department of Defense, issued a lengthy report on invasive-species threats at military facilities across the nation.

"Under Siege: Invasive Species on Military Bases" says the military has 400 installations on 25 million acres of land. In Hawai'i, the Department of Defense controls more than 200,000 acres in fee or lease, with the Army alone holding 160,000 acres.

The study describes invasive species as non-native invaders — whether plant, animal or microorganism — that can cause economic and environmental harm as well as possible harm to human health. For the military, alien invaders can also compromise a training range's ability to support its training function.

SEEKING BALANCE

"It's all about balancing the training mission with natural resources," said Michelle Mansker, natural resources manager for Army Garrison Hawai'i's Directorate of Public Works.

The National Wildlife Federation and the military say that sometimes, the training itself helps introduce and spread the invasives.

"The Army has recognized that there are unavoidable impacts associated with all its training activities in the Islands, and those threats cannot be eliminated despite their best efforts," said David Henkin, an attorney with Earthjustice.

The National Wildlife Federation study used the Marine Corps Base Hawai'i facility at Kane'ohe as one of a dozen case studies nationwide in which the military addresses its alien-species problem. The Marines a quarter-century ago faced continual intrusion by mangrove trees and pickleweed shrubs into swamp areas on the base. The intrusion promoted mosquitoes, reduced training areas and reduced habitat for endangered water birds.

The Marines launched an extensive project, inviting community groups to join them in removing the weeds, thus expanding habitat for the long-legged, endangered Hawaiian stilt. Additionally, the Marines each year run expedition vehicles through the pickleweed thickets before the stilt nesting season, to create nesting sites. The stilt population has increased from 60 in the early 1980s to 160, and represents 10 percent of the statewide population of the lanky birds.

FORMING PARTNERSHIPS

Such work can be expensive, but each of the services enters partnerships with volunteer groups, private conservation organizations and other government agencies when possible on its own land. And sometimes, the military lends its support to conservation efforts by other groups.

"We try to partner with volunteer groups, like the Boy Scouts and the ROTC, and they've done some of the clearing of the wetlands," said Gary O'Donnell, chief of environmental planning for the Air Force in Hawai'i. The agency involves the U.S. Department of Agriculture in its brown tree-snake monitoring efforts at Hickam Air Force Base, and joins forces with its neighbor at Bellows in Waimanalo, the Marine Corps.

The Army has teamed with The Nature Conservancy of Hawai'i in controlling rats near nests of the endangered forest bird 'elepaio at Honouliuli on O'ahu, with the state Department of Agriculture in controlling coqui frogs at Schofield Barracks, and with the state Department of Land and Natural Resources in other control efforts.

The Navy has worked with the U.S. Fish and Wildlife Service, the U.S. Attorney's Weed and Seed Program and the Hawai'i Nature Center in wetland-restoration efforts around Pearl Harbor; and with the Kaua'i Invasive Species Committee in planning to eradicate long-thorn kiawe on Kaua'i.

As the Marines found with efforts to aid the stilt at Mokapu, the services have found that weeding natural areas often lets endangered Hawaiian species recover naturally.

"After controlling invasive grass at Makua, native plants come back like gangbusters," notably the state flower, ma'o hau hele, or Hibiscus brackenridgei; and 'akoko, or Chamaesyce celastroides, Mansker said.

The Navy cleared buffalo grass and koa haole from the region east of the Kalaeloa airfield, and "we got this huge explosion of 'akoko," said Julie Rivers, a fish and wildlife biologist with Naval Facilities Engineering Command Pacific.

BEYOND CONTROL

But it's not all good news — some of the invasive species defy control.

"Pohakuloa has a huge invasive-species issue due to fountain grass. Fountain grass is pretty much uncontrollable there," Mansker said. The Army clears weeds around critical native-plant clusters, but is not trying to eradicate the grass.

Problems linked with fountain grass are that it is a great fuel for fires, fire destroys the natural cover troops require for realistic training, the grass can cause unexploded ordnance to go off, and the grass recovers from fire faster than most native plants.

"Each time you have a fire, it burns a little bit more into the native area, and spreads grasses," which are more fire-tolerant than most native plants, Mansker said.

One of the big problems for the military is that it moves a lot and can easily haul invasive species with it when it goes.

"Every time a ship shows up or a plane lands, there's another risk," Sierra Club's Mikulina said.

Those risks include brown tree-snakes coming from Guam to Hawai'i in aircraft, and fountain grass seeds hitchhiking from Pohakuloa to O'ahu in the wheel wells of vehicles.

"We've developed standard operating procedures involving cleaning their gear when they leave the PTA (Pohakuloa Training Area) to return to O'ahu. The vehicles are the big problem — mud is a great seed-transporter," Mansker said.

Reach Jan TenBruggencate at jant@honoluluadvertiser.com.