Urban
As the population of the United States grows, more and more land is being used for human habitat. Urban areas include buildings, pavement, and concrete, with lights and noises not normally found in the desert. These things completely alter the natural habitat and the way animals and plants live. Presently, the desert is undergoing a rapid change as more people are moving into it from the east and west coasts of the United States.
Certain animals have adapted well to urban environments. Peregrine falcons were almost extinct when someone had the idea of releasing them into cities where they could use tall buildings as nesting cliffs. Because of this experiment, their numbers are on the increase and they seem to be doing well. In the desert urban ecosystem, Gambel's quails, mourning and white-winged doves, roadrunners, hummingbirds, and many other birds thrive because people like to see them and put out feeders. Coyotes, foxes, and bobcats have learned that people leave food and water for their pets which is accessible to them. The cats and small dogs themselves sometimes make good meals for these same predators.
Conflicts also occur. When people build in areas where mountain lions and bears have historically lived, the animals have often been left with less space to live, breed, and hunt. Thus, sometimes humans are injured or even killed through increased encounters with these large predators. When we build new roads that go through the home range of animals, they can be accidentally killed or hurt by automobiles. In many cases, the presence of human homes or businesses in an animal's former range may mean that the animal no longer has a place to live, or can no longer find its historical food.
It has become necessary to examine what the results of building will be upon animal and plant species. We are more concerned about these issues than we were in the past because we now realize that an ecosystem is an integral unit and each part, big or small, is important. As the human population spreads into new areas, we continue to struggle with solutions to these problem.