Study: Border fences blocking black bear migration between Arizona, Mexico
There is a new political animal in America’s age-old immigration debate: the black bear.
A recently published study (PDF), to be disseminated to the U.S. Department of Homeland Security, reports that barriers built to keep out illegal immigrants are blocking black bears in Arizona from their relatives in Mexico. Border fences are choking off bear migration corridors that are already under stress from urban encroachment, according to the study authored by the Department of Agriculture’s Todd C. Atwood and Julie K. Young, and other biologists.
“While black bears are not a species of concern in [the] U.S., they are in Mexico, which represents the southern extent of their historic and current range,” the study reads, noting that border bears “may be particularly vulnerable to further loss of habitat due to urbanization and border security activities.”
The study focused on Arizona’s desert Sky Island mountain ranges, which are also home to mountain lions and jaguars and encompass one of the nation’s most biologically diverse regions.
Its findings come as the State of Arizona is soliciting private donations to build a wall in an attempt to secure the remaining 82 miles of the state’s 388-mile border with Mexico that isn’t fenced.
A mishmash of barriers currently cover about one-third of the 2,000-mile U.S.-Mexico border with nearly half of them in Arizona and the rest equally split between California, New Mexico and Texas.
The U.S. Border Patrol first began erecting barriers in 1990 to deter illegal entries and drug smuggling in San Diego and, in 1996, Congress passed the Illegal Immigration Reform and Immigrant Responsibility Act, which bestowed what is now the Department of Homeland Security broad authority to construct fencing. Then in 2005, Congress passed the REAL ID Act, authorizing Homeland Security to waive all legal requirements to expedite the construction of border barriers. The Secure Fence Act of 2006 directed Homeland Security to build 850 more miles of border fencing, though that requirement was later modified to authorize fencing along not fewer than 700 miles.
Republican congressmen and women from Colorado have historically voted for federal fence-building while Democrats such as Mark Udall and Diana DeGette have opposed it and questioned the effectiveness of barriers, their cost, environmental impacts and diplomatic ramifications.
Border security doesn’t come cheap. The Government Accountability Office estimates (pdf) the federal government doled out between $400,000 to $4.8 million for every mile of border fencing it constructed and that another $6.5 billion is needed for its maintenance over the next 20 years.
Atwood, Young and the other biologists urge government officials and policymakers to identify opportunities to maintain and restore suitable wildlife habitat to protect borderland migrations.
“Currently, in the western U.S., there is opportunity to integrate connectivity conservation with land-planning. For example, land-use planners in the Tucson metropolitan area have developed a regional conservation plan with a specific focus on maintaining wildlife linkages and increasing the permeability of transportation corridors. The information we present here, if incorporated into land-use planning, may aid in ameliorating the adverse effects of inevitable urbanization and border security activities. If connectivity can be maintained, there is greater likelihood of the longterm persistence of species such as black bears, mountain lions, and jaguars along the U.S.-Mexico border.”
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