by Whit Gibbons

August 2, 2009

Old ecologists frequently tell young ecologists that to fully appreciate the earth's myriad mutualistic and competitive plant and animal interactions they must visit the tropics. Seldom does anyone suggest visiting the other end of the environmental spectrum--the frozen northland. I hereby correct that oversight by recommending a trip to Glacier Bay National Park (GBNP) in southeastern Alaska.

GBNP, which encompasses 5,150 square miles, is the largest national park. It is larger than the states of Rhode Island and Delaware combined. About 20,000 years ago, following the end of the last ice age, the region warmed up. The phenomenon of retreating ice revealed open rocky terrain that became habitable by wildlife, a consequence of microscale climate change in a formerly unvegetated habitat. During the ensuing, relatively warmer, times, the region became biologically productive to a level that humans, the Tlingits, inhabited the region. Then came the so-called Little Ice Age. Giant glaciers formed in Alaska and advanced down the valleys, forcing the Tlingits inland to warmer areas in the 1600s. As in earlier ice ages, the region was covered with thousands of square miles of snow, glaciers, and other forms of ice--and no open water.

Captain George Vancouver of England sailed to the region in 1794. His ship's log did not mention Glacier Bay as a majestic place to visit. Simple explanation. At the time, 215 years ago, the bay was not majestic. It was barely a bay. Instead of an expanse of water, Vancouver found a hunk of ice known as the Grand Pacific Glacier, solid-packed ice roughly 20 miles wide and three-fourths of a mile thick. In 1879, 12 years after Seward's Folly had been purchased from Russia, came another visitor, John Muir. He traveled by water 40 miles farther up Glacier Bay than Vancouver had. In less than a century, a solid, impenetrable glacier had retreated almost 50 miles, leaving a scoured valley filled with navigable seawater. Today, the face of the glacier has retreated another 25 miles, creating a wide, 65-mile-long bay with numerous fjords and more than a dozen side glaciers, most of which retreat farther every year.

In 1925 President Calvin Coolidge designated Glacier Bay and surrounding areas as a national monument. Congress made it a national park in 1980, and the United Nations recognized the area as a world heritage site in 1992. This vast and impressive region deserves all the environmental recognition and protection we can give it. The wildlife is astounding--on land, sea, and in the air. Humpback whales, seals, and sea otters abound. Puffins, bald eagles, and glaucous-winged gulls add another level of environmental magnificence. And bears, moose, and mountain goats inhabit a land often covered by magnificent virgin spruce forests.

Environmental views concerning Alaska and its natural resources run the gamut. Some people see a land where rugged independence translates into unrestrained oil exploration in the Arctic National Wildlife Reserve and clear-cutting in old-growth national forests. Others feel just as strongly that unspoiled habitats and environmental sustainability should be the order of the day. Some of the debates will not be resolved for decades.

One point, at least, is not debatable. Glacier Bay offers a fascinating environmental lesson in ecosystem development. Starting at the cold end, near the face of the glacier, only mosses and lichens cover the exposed rocky surfaces. Along the many cascading streams of melting ice that flow into the bay, willows develop after a few years. Then come alder and cottonwoods, followed eventually by hemlocks and spruce forests. Although any plant might appear at any time, the biological succession is a relatively orderly process from lichens to mature spruce forests. Soon after plants become established the terrestrial mammals appear--moose, mountain goats, bears, and wolves. Birds and sea mammals arrive when the waterways open up, providing an abundance of fish. The ecosystem is elegant in its simplicity and offers many lessons in ecology.

I concur with the common wisdom that young ecologists should visit wild tropical ecosystems with their intricate evolutionary relationships created over eons. Indeed anyone interested in nature would benefit from such a visit. But I also recommend a visit to Glacier Bay, which offers a simple yet dramatic view of how ecosystems are born.

If you have an environmental question or comment, email

(Back to Ecoviews)