By Deborah Zabarenko, Environment Correspondent

WASHINGTON, Sept 6 (Reuters) - More beetles and fewer spruce trees in Alaska, whiter coral and fewer scuba-divers in Florida and more wildfires in Arizona already show the impact of climate change on U.S. lands and waters, a congressional watchdog agency reported on Thursday.

But the federal agencies that manage over 600 million acres (242.8 million hectares) of federal land -- nearly 30 percent of the land area of the United States -- and more than 150,000 square miles (388,500 sq km) of protected waters have little guidance on how to deal with the effects of global warming, the Government Accountability Office said.

"Undertaking activities that address the effects of climate change is currently not a priority" for the five U.S. agencies that manage this territory, the report by the nonpartisan investigative arm of Congress said.

These agencies are the Bureau of Land Management, Forest Service, Fish and Wildlife Service, National Park Service and the National Oceanic and Atmospheric Administration.

The Interior Department, which includes three of the five agencies, ordered them in 2001 to analyze potential climate change effects on U.S.-managed lands, but has not yet provided direction to managers on how to plan for climate change, the report said.

Resource managers at the other two agencies echoed that sentiment, according to the report.

"Resource managers are uncertain about what actions, if any, they should take to address the current effects of climate change and to plan for future effects on their resources," the report's authors wrote.

DWINDLING GLACIERS, INVADING GRASSES

The authors based their conclusions on discussions with scientists, economists and federal resource managers, and field studies of four federal areas that represent distinct ecosystems.

These are: the Florida Keys National Marine Sanctuary, representing coasts and oceans; the Chugach National Forest in Alaska, representing forests; Glacier National Park in Montana, representing fresh waters; and the Bureau of Land Management's Arizona field office, representing grasslands and shrublands.

In the Florida Keys, they found rising sea levels that can be attributed to climate change have already affected low-lying areas, and saltwater intrusion on land has cut the fresh water and habitat that support native plants and animals.

In the future, the report said global warming may hamper fishing and tourism in this ecosystem, notably by causing coral to bleach, cutting down on fish habitats and lessening the coral's draw for snorkelers and scuba-divers.

Warmer temperatures and reduced precipitation associated with climate change in Alaska's Chugach National Forest have contributed to outbreaks of insects, such as the spruce bark beetles which have killed some kinds of spruce trees over the forest's 400,000 acres (161,900 hectares), the report said.

In Montana, the glaciers that give Glacier National Park its name are dwindling, down from 150 in 1950 to 26 now, according to the report.

Arizona's Mojave Desert is suffering more virulent wildfires due at least in part to climate change, the report said, because drought has damaged native plants and allowed invasive grasses to take over, making it easier for fires to start and harder to extinguish them.

The Agriculture, Commerce and Interior departments all generally agreed with the report's recommendation to develop clear plans for resource managers at the five agencies, the report said.

AlertNet news is provided by