A keystone in an arch's crown secures ... environmentally sensitive areas. After the United States Congress passed the original Endangered Species Preservation Act in 1966, the gray wolf made ...

The gray wolf was once a "keystone species" in the western United States. Colorado voters soon will have the unique opportunity to help decide the fate of an entire species. A question on whether ...

How many types of trees are there in the United States? A U.S. Forest Service ... It is also called a "keystone" tree species because of its importance in diverse forest ecosystems within its ...

Oaks, Asters and 6 Other 'Keystone' Native Species to Plant for Biodiversity University of Delaware entomologist Doug Tallamy's research has identified “keystone” plant species that make up ...

SAN FRANCISCO— A first-of-its-kind analysis by 20 leading scientists has identified a network of 11 federally owned reserves where wolves and beavers could be restored across the western United States ...

Whitebark pine, or Pinus albicaulis, is a keystone tree species found in the greater ... high-elevation environments in the United States. Grand Teton National Park and NRCC Higher temperatures ...

was systematically eradicated from the continental United States in the 20th century and was added to the endangered species list in 1973. Gray wolves are considered a “keystone” species ...