It's not just the heat: why animals suffer

Habitat changes can affect wildlife in a wide variety of ways

from the June 21, 2007 edition

Page 2 of 2

Page 1 | 2

THE HAWAIIAN HONEYCREEPER

The Hawaiian Islands are home to many bird species found nowhere else. In 1826, humans inadvertently introduced mosquitoes there. The mosquitoes carried avian malaria and pox. In the past 25 years, six species of honeycreeper, a small colorful bird, have disappeared due to habitat loss and mosquito-borne disease. Many remaining species live only at higher elevations beyond the mosquitoes' reach.

Now scientists worry that a warming climate will allow the mosquito to move farther up the mountains. On Kauai, only 5,000 feet high, mosquitoes could push the 1,400 remaining honeycreepers off the mountain entirely. In an effort to lessen the threat, scientists are attempting to eliminate pools of water that serve as mosquito breeding grounds. Humans and feral pigs – another pair of invasive species to Hawaii – often create these stagnant bodies of water.

THE PINE BEETLE

In recent years, the tiny pine beetle has wreaked havoc on pine forests from New Mexico to Alaska. This year, there are reports that its European counterpart is eating its way through Scandinavian forests. Scientists suspect higher winter temperatures are allowing more beetles to survive the winters. Warmer conditions permit them to move up mountains and into forests where conditions were previously too cold. Drought also may be playing a role.

Pine trees repel insect attacks by secreting sap. But more frequent hot and dry spells have weakened these defenses. And because the beetle's life cycle is largely determined by temperature, scientists think warmer summers allow them to mature more quickly.

In parts of Alaska, the beetle used to complete its life cycle in two years, but now takes only one.

In the northern Rockies, the beetle has decimated whitebark pine forests that produce a pinecone essential to the grizzly bear's diet. Hoping to control further infestation, foresters are researching ways to manipulate the beetle's behavior with its own pheromones, chemicals that direct them when and where to infest new trees.

1 | Page 2