Travel Reference
In-Depth Information
Living Things
A YELLOWSTONE SAMPLER
No one thought in 1872 that such a relatively small tract of land in the vast western territories
would actually become a preserve for bears, wolves, bison, and thousands of other common
living things. But during the next century, these animals disappeared from most of the country,
and Yellowstone became an island of wilderness within a sea of human settlement.
According to modern ecologists, the Yellowstone island is not large enough to adequately
protect the unique resources found here. Several Yellowstone animals and birds have been
listed as threatened or endangered under the 1973 Endangered Species Act. As of 2012, the
Canada lynx remained on the list and Yellowstone grizzly bears were restored to the list in re-
cognition of the diminishing supply of whitebark pine nuts essential to their diet. Court de-
cisions removed gray wolves from the list in Montana, Idaho, and, most recently, Wyoming,
though the latter is being contested. Removing federal protection allows hunting of wolves in
Yellowstone's surrounding areas.
In this chapter, after pointing out some small living things that occur throughout the park
(along with a couple of not-so-small rare snakes), we introduce you to some of the more com-
mon plants and animals living here, grouping them into three quite different
ecosystems,
or
communities of organisms that function as a unit of nature.
Ecosystems are defined by the geology and soil types, the elevation, the latitude, and the
amount of precipitation. The elevation in Yellowstone ranges from about 5,300 feet (1,615 m)
to over 11,000 feet (3,350 m). For every 1,000-foot (300 m) increase in elevation, average daily
temperatures are 3.5°F (about 2°C) lower, spring arrives about ten days later, and autumn about
ten days earlier. The latitude here is about that of Bangor, Maine—between 44 and 45 degrees
north. Precipitation varies greatly, and the snowpack at 9,000 feet (2,750 m) remains almost
two months longer than at 7,000 feet (2,130 m). More rain falls on western mountainsides than
in sheltered valleys east of the mountains.
Many of the plants and animals mentioned here occur in two or more of the ecosystems.
Read about fish at the end of the chapter.
THE SMALLEST LIFE FORMS
Microorganisms
