What happens when you build a road through a forest? How do the animals adapt? Shifts in land use have profound consequences on the living things in the environment. Examine the charts below to learn how Phoenix’s land use has changed over time. As you read the passage below, consider the impact of such changes on the environment.
Source: United States Environmental Protection Agency
Habitat Loss and Fragmentation
The effects of land development on the environment are particularly important because development patterns have long-term effects that are not easily reversible.
Habitat loss and fragmentation are two of the most direct impacts of development on previously undeveloped land. 1 According to recent studies, habitat destruction is the main factor threatening 80 percent or more of the species listed under the federal Endangered Species Act; more than 95 percent of listed species are endangered to some extent by habitat loss or alteration. 2
Housing developments, roads, and associated infrastructure have the potential to destroy existing forests and vegetation and also cause fragmentation of natural habitats. Road infrastructure in the United States is extensive and growing. In 1997, public roads occupied an estimated 17,345 square miles of land, a 2 percent increase over the road area in 1990. 3 Fragmentation negatively affects wildlife in a number of ways. It interferes with wildlife travel, decreases habitat size, and reduces interaction with other wildlife communities. Fragmentation produces declines in both the number of species (diversity) and populations (abundance).
Habitat impacts from human development have been documented extensively. See: Dobson, A. P., J. P. Rodriguez, W. M. Roberts, D. S. Wilcove. “Geographic Distribution of Endangered Species in the United States,” Science, Volume 275, Number 5299. January 24, 1997. pp. 550-553; LaRoe, Edward T., Gaye S. Farris, Catherine E. Puckett. Our Living Resources - A Report to the Nation on the Distribution, Abundance, and Health of U.S. Plants, Animals, and Ecosystems. U.S. Department of the Interior, National Biological Service, Washington, 1995; Noss, Reed F. and Robert L. Peters. Endangered Ecosystems: A Status Report on America’s Vanishing Habitat and Wildlife. Washington, DC: Defenders of Wildlife, December 1995; Peters, Robert L., Evan Frost, and Felice Pace. Managing for Forest Ecosystem Health: A Reassessment of the ‘ Forest Health Crisis. Washington, DC: Defenders of Wildlife, April 1996; Boucher, Norman, “Species of the Sprawl,” Wilderness. Defenders of Wildlife, Washington, DC, Summer 1995. pp. 10-24; Soule, Michael E. “Land Use Planning and Wildlife Maintenance - Guidelines for Conserving Wildlife in an Urban Landscape.” Journal of the American Planning Association. Volume 57, Number 3, Summer 1991. pp. 313-323.
Flather, C.H., L.A. Joyce, and C.A. Bloomgarden. 1994. (as cited in: Noss, Reed and Fobert Peters. Endangered Ecosystems: A Status Report on America’s Vanishing Habitat and Wildlife. Washington, DC: Defenders of Wildlife, December 1995. p. 46)
Estimate based on data from U.S. Department of Transportation, Federal Highway Administration. “Highway Statistics:” 1990, 1995, 1996, and 1997. Table HM-60.
Tolley, R.S. and B.J. Turton. “Transport Systems, Policy, and Planning: A Geographic Approach.” Longman Scientific and Technical. 1995. There is a large literature on urban wildlife, critical habitat, and wildlife corridors. See: Beatley, Timothy. Habitat Conservation Planning and Urban Growth. Austin, Texas: University of Texas Press, 1994; and Leedy, Daniel and Lowell Adams. “Wildlife in Urban and Developing Areas: An Overview and Historical Perspective.” in Integrating Man and Nature in the Metropolitan Environment: Proceedings of a National Symposium on Urban Wildlife, 4-7 ed. Adams and Leedy. Columbia, MD: National Institute for Urban Wildlife, November 1986.
Source: Environmental Protection Agency. “Our Built and Natural Environments: A Technical Review of the Interactions between Land Use, Transportation, and Environmental Quality.” January 2001.
1. What do you notice about the changes in land use over time?
2. Describe the relationship between urban growth and habitat loss and fragmentation.