Suburban sprawl rolling over imperiled wildlife

Posted: 17 January 2005

Author: J.R. Pegg

The rapid conversion of American open space and farmland into subdivisions, shopping centers, roads and parking lots has emerged as a leading threat to the nation's biodiversity and animals, environmentalists say.

A new study finds runaway sprawl in many metropolitan areas is wiping out essential wildlife habitat for some 1,200 imperiled species and could doom some to extinction.

Suburban sprawl, USA. Photo: University of California-Berkeley
Suburban sprawl, USA. Photo: University of California-Berkeley
Suburban sprawl has been shown to cause health problems for humans - now environmentalists say it poses survival problems for some wildlife.© University of California-Berkeley
"The bottom line is, we live where the wild things are," said report co-author Reid Ewing, an urban studies professor at the University of Maryland. "We need to do a better job accommodating the natural environment along with the human environment." The study calls on policymakers to stem the tide of habitat loss by changing local land use patterns and improving state and federal natural resource and transportation policies.

"Better planning must play in both protecting threatened wildlife and improving our cities and towns," said Don Chen, executive director of Smart Growth America, which collaborated on the report with NatureServe and the National Wildlife Federation.

The organizations contend the study is the first ever to quantify the impact of sprawling development on wildlife nationally - it relates sprawl to the loss of open space and natural habitat.

The report integrates common measures of development density and projections of population growth with a new analysis of data on 4,173 rare and endangered species in the lower 48 states.

Urban threat

Florida panther threatened by habitat loss. Photo: D.W. Pfitzer/Fish and Wildlife Service
Florida panther threatened by habitat loss. Photo: D.W. Pfitzer/Fish and Wildlife Service
The primary threat to the Florida panther is habitat loss and fragmentation - a problem that has worsened as development in Southwest Florida has boomed in recent decades.© D.W. Pfitzer/Fish and Wildlife Service
The findings show that imperiled wildlife is very much a part of urban and suburban America - some 60 per cent of the species studied inhabit metropolitan areas.

The nation's fastest growing metropolitan areas, each with more than a million residents, are home to some 1,200 imperiled species - 29 per cent those studied in the report.

If current rates of sprawl continue, these metropolitan areas will have developed some 22,000 square miles of natural habitat - roughly the size of West Virginia - by 2025.

The concern is even greater for 553 of the imperiled species that are found only in the fast growing large metropolitan areas, which are concentrated in the western and southern regions of the country.

West Indian Manatee, Florida: Photo: Florida Wildlife Extension
West Indian Manatee, Florida: Photo: Florida Wildlife Extension
Florida's official state mammal, the West Indian Manatee, is declining as a result of human sprawl.© Florida Wildlife Extension
The study authors took their analysis another step - to the county level - and found "an even more alarming story."

"In at least three dozen rapidly growing counties found mostly in the South and West, open space on non-federal lands is being lost so quickly that essential wildlife habitat will be mostly gone within the next two decades, unless development patterns are altered," the report finds.

Imperiled species

A total of 287 imperiled species are found in counties that will likely lose half or more of their available non-federal open space by 2025, according to the study.

Those at risk from sprawl include Florida's West Indian manatee, the arroyo toad in California, the mountain plover and alkali mariposa lily in Nevada, and the Hine's emerald dragonfly in Illinois.

The collision course between suburban sprawl and wildlife is a particular concern in California - the state is home to 16 of the top 20 fastest-growing metropolitan counties for imperiled species.

The Hine's emerald buttefly is classed as federally endanagered. Photo: Illinois Natural History Survey
The Hine's emerald buttefly is classed as federally endanagered. Photo: Illinois Natural History Survey
The Hine's emerald buttefly is classed as federally endanagered.© Illinois Natural History Survey
California's San Diego County leads with 99 species followed by Los Angeles County with 94 species, and San Bernardino County with 85.

Nevada's Clark County - home to Las Vegas - is another hotspot, with 97 imperiled species, as is Florida's Miami-Dade County with 58 vanishing species.

The report recommends federal, state and local lawmakers provide incentives for development in existing urban and suburban areas, build new development at higher densities, and set aside natural areas as off limits to new development.

"With proper planning, it does not have to be a question of us versus them or development for people versus habitat for wildlife," Ewing said.

Source: Copyright Environment News Service (ENS) 2005. All Rights Reserved. Related link:

Read the report, Endangered by sprawl

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