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A Region of Wounds: Severing the U.S.-Mexico Borderlands

By Tom Leskiw
  


The American Southwest is a place of astounding beauty and biological diversity. How, one wonders, can such abundance flourish in a land with scant water resources? The ecological bargain struck long ago by humans and wildlife alike was one of movement and migration in order to escape extremes of heat and cold and to procure the resources necessary to survive. These movements were generally north-south or upslope-downslope, in response to changing seasons. In addition, seemingly random movements in search of food, cordage, and plants used for medicine occurred—the irregular, mosaic-like distribution of resources reflecting geology and soil type, slope aspect, localized rainfall, and more.

Apache del Bosque on the Rio Grande in New Mexico

 

Bosque wetlands on the Rio Grande River south of Socorro, New Mexico.
Photo Simmons Buntin.
  

Long before the concept of political borders emerged, human and wildlife movement was tied to natural borders: desert and oasis, oak woodland and grassland, forest and brush field. Mountain ranges—later termed “sky islands”—were linked to valley “seas” of grass and brush by the riparian corridors of the Santa Cruz, San Pedro, and Rio Grande Rivers. The health of the landscape depended upon connectivity and movement—of birds and creatures such as coyote as agents of seed dispersal, of fire to periodically cleanse the grasslands of competing vegetation, of fish migrating upstream or down in search of more favorable conditions, and of water, to transport and deliver wood, sediment, and nutrients.   

For millennia, these peregrinations continued unabated—as evidenced by the presence of palm trees at isolated oases and human trails worn a foot deep along the path used to procure salt from the Gulf of California. Today, the media portray trans-border movements as a one-way highway, always northward. However, a substantial number of Catholics on the U.S. side still make a yearly pilgrimage to the old mission community of Magdalena de Kino, some sixty miles south of the Arizona-Sonora border, for the Fiesta de San Francisco.

In 1854, the Gadsden Purchase was ratified by the U.S. Senate. It included lands south of the Gila River in Arizona and in southern New Mexico. The revision of the U.S.-Mexico border was part of the negotiations needed to finalize issues that remained unresolved from the Treaty of Guadalupe-Hidalgo, which ended the Mexican-American War of 1846-1848.

For a number of years, the newly drawn political boundary affected neither the movement of wildlife nor that of borderland residents. Indeed, as recently as 1930, some members of the Tohono O’odham—formerly known as Papago—had no knowledge of the redrawing of the boundary and believed they lived in Mexico.

With the opening of the West, however, came railroads, vast water reclamation projects, roads, and utility lines. Since then, the overarching theme of Southwestern settlement has been the elimination or degradation of the connectivity so vital for the health of ecosystems and their denizens.  Half of southern Arizona was formerly grassland. Historically, the U.S. Forest Service encouraged overgrazing to reduce grass, which carried ground fire. As a result, the current boundaries of vegetative communities—mesquite, introduced grasses, and tamarisk—bear little resemblance to historical distribution. Livestock fences also cut upon traditional migration routes of wildlife, including pronghorn antelope, javelina, and bison.

Predators like the Mexican wolf were extirpated while populations of jaguars, ocelots, and jaguarundis were reduced or eliminated from the Southwest. Conservationist Aldo Leopold, an avid wolf hunter early in his career, grew to realize that “[o]ne of the penalties of an ecological education is that one lives alone in a world of wounds.”

Javelina near new border wall just east of the San Pedro Riparian National Conservation Area in Arizona.
Javelina near new border wall just east of the San Pedro Riparian National Conservation Area in Arizona.
Photo by Matt Clark, courtesy Defenders of Wildlife and Northern Jaguar Project.

 

  

Overuse of ground and surface water adversely impacted water courses, springs, and riparian vegetation, resulting in population declines for many of the 80 percent of vertebrate species in the borderlands region dependent on streamside areas for at least part of their life cycle. The wounds inflicted upon aquatic resources were noted by Leopold in 1937:  “Somehow the watercourse is to dry country what the face is to human beauty. Mutilate it and the whole is gone.”  

In the wake of 9/11, the security of the United States’ borders has come under increasing scrutiny. Owing to the influx of undocumented workers from Mexico, one “solution” now under implementation is the construction of a wall along our southern border. In 2006 Congress, in response to a national outcry about our porous border, approved the Secure Fence Act. The law authorized the U.S. Department of Homeland Security to construct 845 miles of double-layered fencing along the southern U.S. border, which spans nearly 2,000 miles. The wall carries a price tag of $49 billion for construction and 20 years of maintenance. Impact from the wall is exacerbated by associated infrastructure: access roads, cameras, sensors, and stadium-style lighting in some locations.

Not only is the wall the latest in a long series of actions severing the connectivity between wildlife and its habitat, but it also bisects some of the most biologically rich areas in the U.S.

Opponents of the wall have voiced a number of concerns, which include:

  • 36 laws, including the Endangered Species Act and Clean Water Act, were waived to expedite certain segments of the wall.
  • Erecting a wall along 42 percent of our southern border is simply not a viable method for strengthening our border.
Spring blooms at Organ Pipe Cactus National Monument.

 

Spring blooms at Organ Pipe Cactus National Monument.
Photo Simmons Buntin.
  

The following four case studies examine impacts—hydrologic, biologic, cultural, and economic—from four segments of the wall’s construction, as one would encounter them, west to east:

Case Study: Organ Pipe National Monument, Arizona

In 2006, DHS proposed the construction of a 5.2-mile-long fence in Organ Pipe Cactus National Monument, along the U.S.-Mexico border. Comments in the Draft Environmental Assessment included concerns that the structure could impede floodwaters and that debris could be trapped by the wall, leading to backwater pooling and lateral flow that would damage the Border Patrol road and other infrastructure in both the U.S. and Mexico.

The response to these concerns in the Final EA and Finding of No Significant Impact was that “the wall would be …designed and constructed to ensure proper conveyance of floodwaters and to eliminate the potential to cause backwater flooding on either side of the U.S.-Mexico border.” In addition, Kiewit Western Co., the contractor building the fence, furnished a handout that stated the design (6-inch x 24-inch openings in the wall where it crossed drainages) would “permit water and debris to flow freely and not allow ponding on either side of the border” because the drainage crossing grates “met hydraulic modeling requirements.”

The wall, finished two weeks prior, received its first test during a July 12, 2008 storm, where one to two inches of rain fell in 90 minutes. Fine and coarse sediment and debris plugged the grates in least five arroyos, creating stream diversions (lateral movement of water beyond their respective floodplains) ranging from 100 feet to 1,110 feet. Headwaters Wash flowed over 200 feet to the east along the wall and through the international port of entry at Sonoyta, Sonora, Mexico. Floodwaters damaged private property, government offices, and commercial businesses in Lukeville, Arizona, and Sonoyta, Sonora.  


Flooding at the Lukeville, Arizona border entry following a July 12, 2008 storm.
Photo courtesy U.S. Department of Interior.

Concerns voiced by the wall’s opponents proved to be well-founded, as the rainfall received on July 12 was not unusual; statistically, it is estimated to occur at least once every three years. Based on precipitation records that span 60 years at Organ Pipe, the rainfall intensity experienced on July 12 occurs every:

Amount of Hourly Precipitation
Estimated Frequency
> 2"
once every 5 years
1.5 - 1.99"
once every 3 years
1.0 - 1.99"
nearly once every year

Case Study: Nogales, Arizona

Jaguar photo taken from a camera trap in southern Arizona.
Male jaguar photographed by a southern Arizona camera trap in 2004.
Photo by Emil McCain, courtesy Jaguar Conservation Team.

 

  

The Atascosa Mountains lie just northwest of the border town of Nogales, about 70 miles south of Tucson. I’m among those that were surprised to learn that a wildlife study has documented the presence of two jaguars in the area. An adult male jaguar, dubbed Macho B, was photographed north of the border for over 11 years, and he resided in Arizona continuously and year-round from 2004-2007. A jaguar named Macho A was also photographed during this time frame in the same study area.

Analysis of spot patterns confirms that at least four jaguars have been recently photographed in the Southwest, as the jaguar in extreme southeastern Arizona in 1996 and the one photographed February 2006 in the Animas Mountains of southwestern New Mexico are different individuals.  

Policy changes in the 1960s and 1970s led to a sudden decrease in jaguar reports in this region. In 1969 it became illegal to kill jaguars. Establishment of the Endangered Species Act in 1972 resulted in fear of federal restrictions on private property and general animosity toward endangered or threatened species. Put simply, the sudden decrease in jaguar reports gave the false impression that they’d disappeared from the Southwest.  

Javelina near new border wall just east of the San Pedro Riparian National Conservation Area in Arizona.

 

Topographic relief map of the study area, showing United States–Mexico border (solid black line), general observed minimum ‘‘range’’ of adult male jaguar Macho B from May 2006 to April 2007 (white oval), important cross-border corridors for jaguars and other wildlife (heavy white double-arrows), 4- to 5-m-tall steel pedestrian fences (existing or under construction; solid white lines), increased border security with vehicle barriers, chain-link fences, virtual fencing, surveillance towers, and agent patrols (white dashed lines), and funneled illegal immigrant and resulting law enforcement traffic (black arrows).
Map courtesy Emil McCain.
  

The conservation of wildlife populations at the periphery of their range is now considered extremely important to the long-term survival of endangered species. The preservation of sufficient core and connective habitats to avoid population fragmentation is seen as crucial to reducing the probability of extinction for species such as jaguar. Therefore, the construction of a nine to 15-foot-high fence across approximately 70 percent of the Arizona border does not bode well for the small, northernmost population of jaguars, as it will isolate them from the larger source population in northwestern Mexico.     

Case Study: San Pedro River, Arizona

The San Pedro River is unique because it flows south-north across the border, connecting the ecologies of the tropics and the Sierra Madre Mountains with those of the far north. Biologists estimate that 400 bird species, 83 mammal species, and 47 amphibian and reptile species inhabit the San Pedro, the longest undammed river in Arizona. The San Pedro was the first site in the Western Hemisphere to be designated as an Important Bird Area by the American Bird Conservancy. It hosts some 4 million migrating songbirds each year. 

Ten percent of the roughly 530 species on the federal endangered species list can be found along the San Pedro. It is home to more mammal species—including jaguar, coati mundi, and javelina—than any place on Earth, except Costa Rica.

The cottonwood-willow forests that were once common along Southwestern rivers have been greatly impacted relative to pre-settlement conditions.

UA college students and San Pedro River
University of Arizona graduate students explore the San Pedro River 20 miles north of the Mexico border.
Photo by Simmons Buntin.

 

  

In the late 1800s, fur trappers removed an estimated one million beaver from the San Pedro watershed. The extirpation of beaver—a keystone species—in 1900 was especially devastating to the watershed, as their dam-building had reduced the river’s erosive power. The resulting stair-stepping watercourse buffered the watershed during seasonal floods. Large pools spread the water outward, fostering a network of wetlands that were effective in recharging ground water. 

The devastated rangeland, shorn of grasses by too many horses and cows, had lost its ability to hold soil in place when a multi-year drought ended and the rains returned in 1893. The once stable, slow-moving, marshy perennial river transformed into an unstable, flood-prone, intermittent stream. Stream downcutting largely eliminated the wetlands, resulting in a lowering of the water table. In 1870, Arizona rancher H.C. Hooker had described the San Pedro River Valley as “having an abundance of timber with large beds of sacaton and grama grasses. The river bed was shallow and grassy … its banks with luxuriant growth of vegetation.” 

His description of the same area in 1900 told a different story: “The river had cut ten to 40 feet below its banks with its trees and underbrush gone, with the mesas grazed by thousands of horses and cattle.” Recognizing the importance of beaver to watershed health, the U.S. Bureau of Land Management reintroduced them to the San Pedro in 1999.

More than 350,000 people travel to Arizona annually to view birds. They
bring in an estimated $1 billion, making bird watching Arizona’s most lucrative tourist activity, according to Joe Yarkin, watchable wildlife manager for the Arizona Department of Game and Fish. “Economically, it ranks above golf and the other big boys of tourism.”

Opponents of the wall voiced concerns regarding its construction across the San Pedro River, its floodplain, and over 60 seasonal streams and desert washes in the vicinity. In late 2008, the U.S. Army Corps of Engineers constructed a “temporary” vehicle barrier across the San Pedro. This new placement follows roughly two miles of fence already existing within the San Pedro Riparian National Conservation Area. Project photos depict a Normandy-type beach fence that cuts across the river bed and an access road that has been graded to the river’s edge.

Looking south into Sonora, Mexico from the Tumacacori Highlands.

 

Looking south into Sonora, Mexico from the Atascosa Mountains—prime habitat for hundreds of species. And jaguars, too?
Photo by Simmons Buntin.
  

Opponents question whether federal officials will be able to remove the barriers, as promised, during high-water periods such as the monsoon season. BLM managers have little power in light of the waiver of environmental laws for the wall’s construction. The Borderlands Conservation and Security Act of 2007 (H.R. 2593), sponsored by Rep. Raul Grijalva (D-AZ), sought to force DHS to create a strategy that had the dual goals of securing the border while best protecting public forest and park lands along it. The bill never became law and, because it was introduced in a previous session of Congress, no more action can be taken.

Case Study: Lower Rio Grande Valley, Texas

Four climatic zones converge in south Texas, and the U.S. Fish and Wildlife Service has identified 11 distinct habitats in the lower Rio Grande Valley. More wild cats—ocelots, jaguars, and jaguarundis—live here than anywhere else in the United States. Because of the Rio Grande River’s sinuosity and the need to construct straight fences, some segments of the wall are slated to be constructed 2 .5 miles from the river—in effect, ceding to Mexico portions of prime wildlife habitat that include the Lower Rio Grande Valley National Wildlife Refuge and  the Audubon Society’s Sabal Palm Preserve.

In late December 2008, a property owner in the Lower Rio Grande Valley received notice that DHS had filed suit to condemn a portion of the property. The complaint stated that the amount of $114,000 offered by DHS was deemed “just compensation” for the slightly more than 8 acres the 18-foot-tall, concrete-and-steel barrier wall will occupy—a 60-foot-wide strip of land slated to cross 6,000 feet of the landowner’s property.

The owner felt that the amount offered was grossly insufficient compensation for a property purchased in 1999 for $2.6 million. The fence, slated to be constructed 1.5 miles from the Rio Grande River would, in effect, cede more than 700 of the 1,034-acre property to Mexico. Most importantly, the full-time caretaker’s residence and all the property’s facilities are located on what is to become Mexico’s side of the wall.

The Nature Conservancy owns the subject property: the Lennox Foundation Southmost Preserve. The site harbors a native plant nursery that supplies reforestation projects throughout South Texas, a compatible agriculture demonstration, a rare sabal palm forest, and habitat for Texas’ highly imperiled wildcats, the ocelot and jaguarundi.

Kayakers at the mouth of Santa Elena Canyon, Big Bend National Park in Texas.
Kayakers at the mouth of Santa Elena Canyon on the Rio Grande River, Big Bend National Park in Texas.
Photo by Eric Leonard, courtesy National Park Service.

 

  

The preserve also serves as a living laboratory for university students and researchers from various parts of the country who spend periods of time living on the property while they study its unusual birds and amphibians. Despite repeated requests to the DHS for information about access and safety issues that will arise once the fence is built, Conservancy staff have not received a response.

“The financial offer we received from the federal government is shortsighted and only takes into account the footprint of the border fence itself,” said Laura Huffman, the Conservancy’s Texas state director. “It doesn’t begin to make up for our inability to manage the more than 700 acres of our preserve that lie between the proposed fence and the Mexican border.”

Science makes clear that the wall will impede the movement of animals such as ocelots, jaguars, and jaguarundis through the borderlands. The wall—yet another “agent of fragmentation”—will adversely impact the genetic viability of wild cats such as ocelots, which are thought to number fewer than 100 in south Texas. As Fritz Knopf, Roy Johnson, and other authors conclude in their paper Conservation of Riparian Ecosystems, “Vertebrate conservation within riparian ecosystems, especially, needs to be based upon the perspective of whether local management programs create or sever dispersal corridors.”  

The wall’s opponents fear that its construction will serve to isolate wide-ranging species in nonviable habitat islands. As Michael Soule and John Terborgh have written, “Connectivity is not just another goal of conservation: it is the natural state of things.”  Furthermore, owing to the impacts of global warming, the preservation of migration corridors is critical so that species can adapt to changing climatic conditions.  

There is also an environmental justice aspect to the wall’s construction. The Texas Observer reported that in south Texas, the wall will end abruptly at Sharyland Plantation, a 6,000-acre gated golf community owned by Dallas billionaire Ray L. Hunt, a close friend of George W. Bush, who donated $35 million to help build Bush’s presidential library.

As of February 2009, 601 miles of the 845-mile wall have been completed at a cost ranging from $200,000 to $15 million per mile. DHS has admitted—albeit obliquely—that its waiver of nearly 40 laws to expedite construction has come at a price to the environment. DHS has since given $90 million to the U.S. Department of the Interior to restore wildlife habitat and cultural sites damaged by construction and maintenance.

Border wall west of Nogales.

 

New border fence and access road west of Nogales, Arizona.
Photo courtesy Department of Management Information Systems, University of Arizona.
  

Property owners who’ve resisted the construction of the wall across their property have found themselves subjected to condemnation lawsuits filed by the U.S. Government. The terms and conditions of these legal rulings are onerous: the government need only pay for the land on which the barrier sits, regardless of how much property winds up inaccessible or uninhabitable. Eloisa Tamez, for example, is a 72-year-old woman who still lives on a portion of the 12,000 acres her ancestors received in a Spanish land grant. In the 1930s, the federal government condemned more than half her holdings to build levees—she still has not received compensation.

In August 2007, a U.S. Border Patrol agent told Tamez her land was in the path of the proposed wall and that she needed to sign a release form so engineers could survey her land. She refused to sign the paperwork, her courage inspiring 300 other Texan property owners—political progressives and property rights advocates alike—to do the same. Tamez received less than $14,000 for the wall that now bisects her property. Similarly, on Leonard and Debbie Loop’s 1,000-acre farm, 800 of its acres will be exiled to the “Mexican” side of the wall.

During his February 21, 2008 debate with Hillary Clinton, candidate Barack Obama stated that the wall was ineffective and counter-productive. He later pledged to evaluate whether or not to continue the wall’s construction in the Lower Rio Grande Valley. Opponents of the wall had hoped that once President Barack Obama took office, plans to build fencing along the Rio Grande Valley's wildlife corridor would be suspended. However, an Obama spokesperson recently told TIME magazine that the president supports the fence “as long as it is one part of a larger strategy on border security that includes more boots on the ground and increased use of technology.”

In January 2009, the government allocated an additional $50 million for wildlife mitigation. According to Rick Schultz, the U.S. Department of the Interior's national borderland coordinator, it will likely be spent in the lower Rio Grande Valley to restore or recreate the habitats of native species. But there’s a catch: the mitigation efforts must compensate for the impacts to resources “managed, protected, or under the jurisdiction of the Department of the Interior,” according to federal documents. That stipulation excludes Brownsville area sites that are privately owned, such as Sabal Palm and Southmost Preserve. 

On July 8, 2009, the Senate adopted an amendment proposed by Senator Jim DeMint (R - S.C.) that requires the completion of 700 miles of fencing along the Southwest border. The amendment passed by a 54-to-44 roll call vote. The amendment was added to the 2010 Homeland Security spending bill and requires the completion of the fence by the end of the 2010 calendar year.

Southmost Preserve in south Texas.
The Southmost Preserve in south Texas, home to sabal palms and rare animal species, is threatened by the border fence.
Photo courtesy The Nature Conservancy.

 

  

Chicana poet and activist Gloria Anzaldua characterized the U.S.-Mexico borderland as “una herida abierta”—an open wound. Clearly, the issues associated with our borderlands are murky, tangled, complex. Illegal immigration is an issue that needs a solution. The question is: Are we seeking appropriate, valid solutions—ones that minimize impacts to irreplaceable natural and cultural resources? As former Arizona governor and current DHS Secretary Janet Napolitano has stated, “The voters of my state understand that building a fence is not a solution. Indeed, what I'm fond of saying is, you show me a 12-foot fence and I'll show you a 13-foot ladder.”

What are taxpayers to make of a project initially estimated to cost $49 billion, and plagued with huge cost overruns, for which one of its chief proponents, former DHS Secretary Michael Chertoff, admitted in 2007, “The idea that we are going to solve the problem by simply building a fence is undercut by the fact that yesterday we discovered a tunnel. So the idea that fencing alone is a solution I think is overly simplistic.”

History is full of examples where ideology trumped a more carefully considered course of action… and reason. Clues—metaphorical breadcrumbs left by our forefathers to help us find the way—are there for those who wish to follow the advice of Socrates “to lead an examined life.” Opponents of the wall near Lukeville, Arizona, were assured that it would not allow ponding on either side of the border because the drainage crossing grates “met hydraulic modeling requirements.” And yet the wall failed catastrophically during its first rainy season. Does this not underscore the need for fresh models, literally and figuratively?
 
Some politicians and resource managers exercise humility, acknowledging that not all sociopolitical problems have technological solutions. As long-time borderland resident Elizabeth Garcia says, “We have coexisted for so many years together. La frontera [the border] is both sides of the river, not one side or the other.”

For decades, south Texas wildlife proponents have worked to turn fragmented habitat at sites that include the Sabal Palm Audubon Center, Bentsen-Rio Grande Valley State Park, Lower Rio Grande National Wildlife Refuge, and the Lennox Foundation Southmost Preserve into an interconnected whole by maintaining wildlife corridors between the sites. The construction of the wall is a giant leap backwards, severing the string of pearls— and their attendant biodiversity.

Arroyo at Franklin Mountain State Park.

 

Arroyo at Franklin Mountain State park, just north of El Paso, Texas.
Photo Simmons Buntin.
  

The future looks increasingly murky. Border wall stadium-style floodlights are disorienting the migration of birds, bats, and butterflies. Are we bequeathing a world where our offspring will be able to see jaguars and ocelots—if only for an instant in the shadows of dense cover? Will beaver continue to ply the waters of the Southwest, their dams slowing the awesome force of runoff from mid-summer thunderstorms? Are we up to the challenge of water conservation and reuse—so that trout, beaver, and all aquatic organisms can find refuge during times of drought?  
  
This false separation—that the fate of the human and non-human worlds are not intertwined—has proved our undoing. Aldo Leopold and Gloria Anzaldua both characterize the Southwest borderlands as a region of wounds. That wildlife biologist and social activist share similar assessments is a clear statement that any proposed solutions to the ills of the borderlands must be inclusive. Solutions must spring from an interdisciplinary framework that sees the human-wildlife-landscape links for what they truly are: inseparable and inviolate.

  
 

Tom Leskiw recently retired from a career as a hydrologic/biologic technician for Six Rivers National Forest in northwestern California. His essays have appeared in Birding, NILAS, Watershed, Pilgrimage, This Watery World: Humans and the Sea, and elsewhere. New work is forthcoming in The LBJ: Avian Life, Literary Arts. Catch up with him at www.TomLeskiw.com.
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Resources.
 
 

Borderlands & Boundary Waters: Center for Biological Diversity

Borderlands Conservation and Security Act of 2007

BorderLinks: Raising Awareness and Inspiring Action

Border Wall: Broadest Waiver of American Law in History: Dinah Bear

Lennox Foundation Southmost Preserve

Lower Rio Grande Valley National Wildlife Refuge

No Border Wall

Northern Jaguar Project

Organ Pipe Cactus National Monument

The Rivers of the Southwest:

Sabal Palm Preserve

San Pedro Riparian National Conservation Area

Secure Fence Act of 2006

Sierra Club Borderlands Campaign

Southmost Preserve Threatened by Border Fence: The Nature Conservancy

Texas Border Fence and Wildlife: Refuge Watch

U.S. Customs and Border Protection (U.S. Border Patrol)
  

 
     

References

Campo-Flores, Arian and Andrew Murr. 2008. Newsweek. "Brownsville’s Bad Lie." May 5, 2008, pp. 40-42.

Foreman, Dave, Rurik List, Barbara Dugelby, Jack Humphrey, Bob Howard, and Andy Holdsworth. 2000. Wild Earth. Spring 2000., pp. 31-42.

Knopf, Fritz L., R. R. Johnson, Terrell Rich, Fred B. Sampson, and Robert C. Szaro. 1988. "Conservation of Riparian Ecosystems in the United States." Wilson Bulletin, 100(2), pp. 272-284.  

McCain, Emil B., and Jack L. Childs. 2008. "Evidence of Resident Jaguars (Panthera onca) in the Southwestern United States and the Implications for Conservation." Journal of Mammalogy, 89(1):1-10.

U.S. Department of the Interior, National Park Service. 2008. "Effects of the International Boundary Pedestrian Fence in the Vicinity of Lukeville, Arizona, on Drainage Systems and Infrastructure," Organ Pipe Cactus National Monument, Arizona.

Williams, Ted. 2008. Paradise Lost. Audubon. July-August 2008.

Sierra Club. 2008. Wild Versus Wall (DVD).

Terborgh, John and Michael E. Soule. 1999. "Why We Need Megareserves: Large-Scale Reserve Networks and How to Design Them." In Soule, Michael E. and John Terborgh, eds. Continental Conservation: Scientific Foundations of Regional Reserve Networks. Washington, D.C. Island Press,  p.199.  

 

    
  
 
   
    
  
 
   

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