Budget cuts denied Hawaii island invasive species experts the ability to identify and count their axis deer population. On Oahu, a spending squeeze is making it difficult for workers to keep the fast-growing miconia plant out of forests.

Years of economic downturn and the resulting cuts to invasive species spending are having consequences in Hawaii. Some are noticeable now, but many more may remain hidden until newly introduced species establish themselves in the forests, farms and backyards.

"It’s normal with biological invasions that unless it bites or stings, you don’t really notice it until it’s pretty much too late. And there could be things that get in before we get fully up and running again that are going to just wreak havoc," said Christy Martin, spokeswoman for the Coordinating Group on Alien Pest Species. "Who knows what that’s going to be? We’re playing a very dangerous game of roulette every time a plane lands."

Invasive species are a particularly serious problem in Hawaii, which is home to more endangered species than any other state.

The archipelago’s ecosystem is exceptionally vulnerable to introduced species because plants and animals evolved here in isolation for millions of years before the first humans arrived and brought with them competing species from other parts of the world.

Today, extensive trade routes and airplanes linking the islands to the rest of the world mean a new pest lands in Hawaii every 18 days.

The Hawaii Invasive Species Council, one of the main players in the fight against harmful non-native plants and animals, had a budget of $4 million in 2009. This year, it only has $1.8 million to spend.

The state Department of Agriculture slashed the number of inspectors it had checking for incoming pests at air and sea ports to 50 from 95, dramatically weakening Hawaii’s first line of defense. Fewer eyes examining incoming ships and planes means fewer pests are being spotted and stopped.

State Department of Agriculture data show 663 pests were intercepted on Oahu between July and December of 2009. During the same six months of 2010, only 87 were.

On Kauai, 29 pests were found during the last part of 2009. None was found during that same period in 2010.

It was only on Maui, where interceptions fell to 639 from 722, that authorities still managed to catch a significant number of pests in the last half of 2010.

And that’s primarily because most of Maui’s inspectors happen to be funded by the federal government and weren’t affected by the state budget cuts.

Gov. Neil Abercrombie’s administration has since announced it would restore 32 inspectors around the state, but the inspector numbers will still fall short of pre-recession strength.

Efforts to control pests already in the islands are also under strain.

Miconia, a weedy tree from South and Central America first brought to Hawaii as an ornamental plant, is causing problems on Oahu.

Each mature tree can produce 3 million seeds a year, allowing it to spread rapidly in the forest. Miconia seeds also survive in the soil for a long time, so infestation sites must be monitored for several years after the plants are removed.

But budget and staff cuts are making it hard for the Oahu Invasive Species Committee to make the necessary rounds to check seedlings, said Mark Fox, the invasive species point person at The Nature Conservancy of Hawaii.

The Big Island Invasive Species Committee, meanwhile, was hoping to receive enough money this year to identify and count axis deer, recently found to be living on the island.

But Joshua Atwood, coordinator for Hawaii Invasive Species Council, said the council was only able to give the committee half the money it requested. The committee has since had to lower its ambitions to target a few known populations of the deer instead.

Fox understands the state needed to cut spending on all of its programs, and he’s grateful the state has been able to minimize the cuts. Even so, he warns Hawaii will suffer if harmful pests aren’t kept in check.

"If our forest is overrun with invasive species, it’s not going to work properly in the way that it’s supposed to work to capture rain water, put it into our aquifers and streams, keep the soil on the side of the mountain instead of the reef," Fox said.