Environmental Science 14th Edition by Tyler Miller ,Scott Spoolman

Exercise 10

What is the key concept for this section What major environmental threats affect national parks in the world and in the United States Why are many U.S. national parks considered to be threatened islands of biodiversity Describe some of the ecological effects of reintroducing the gray wolf to Yellowstone National Park in the United States. What percentage of the world's land has been set aside and protected as nature reserves, and what percentage do conservation biologists believe should be protected