Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

US-Mexico border wall could threaten wildlife species

09.07.2009
A 700-mile security wall under construction along the United States' border with Mexico could significantly alter the movement and "connectivity" of wildlife, biologists say, and the animals' potential isolation is a threat to populations of some species.

However, technology and alterations to the design could dramatically improve the potential for animals to move more freely between the two countries, the scientists added.

Results of their study are being published in the journal Conservation Biology.

"The biggest concern is that this barrier will break small populations of animals into even smaller pieces that will result in fewer animals interacting," said Clinton Epps, a wildlife biologist at Oregon State University and co-author on the study. "A major barrier such as this could lead to significant degradation of connectivity for many different species, ultimately threatening their populations."

In their study, the authors looked at the potential effects of the security wall on two species – the pygmy owl and bighorn sheep – primarily because they already had studied those animals in that region. They found that the low-flying pygmy owl made three-fourths of its flights below the height of the security wall, which is approximately four meters high, and that juvenile owls had lower colonization in areas of disturbance or areas with less vegetation.

"Some of the potential damage to pygmy owls could be mitigated with a few tweaks to the system," Epps added. "Putting in poles near the fence could allow the owls to swoop down from a perch, and planting brush to provide better cover could help them avoid predation by larger avian species and improve their chances for colonization."

Maintaining or augmenting trees that are taller than the fence, and that are associated with patches of dense, low vegetation should not only promote permeability, agreed lead author Aaron D. Flesch, a biologist from the University of Arizona – they may be critical.

"Movement of pygmy owls from Mexico to Arizona may be necessary for the persistence of the Arizona population," Flesch pointed out.

The security wall could have a bigger impact on the movement of bighorn sheep, which range widely among the hilly terrain. The scientists' study estimated that at least nine populations of sheep in northwestern Sonora, Mexico, are linked genetically with animals in neighboring Arizona and an interruption of that connectivity could threaten populations on both sides of the fence.

An impermeable barrier would isolate sheep populations and potentially reduce their genetic diversity, but the scientists say slight adaptations in the design of the fence could improve the animals' potential for connectivity while maintaining the desired security goals along the border.

"The key is to have gaps in the fence that are sufficient to allow passage of animals, while at the same time meeting security needs," Epps said. "A 'virtual' fence could be an alternative to a solid wall in some places, especially in steep terrain that is ideally suited for bighorn sheep. The use of cameras, radar, satellite monitoring and vehicle barriers could provide security and be great alternatives for wildlife."

Though their study focused on pygmy owls and bighorn sheep, the scientists also recognized other animals that could be affected by the security wall. Flesch said black bears, jaguars, pronghorn antelope, desert tortoises and ground-dwelling birds including wild turkeys and quail could be affected by restricted movement.

"Ultimately, the effects of the fence will vary among species," Flesch said. "Populations that are relegated to patches of habitat that are small and naturally fragmented are most likely to be affected by the fence, especially species that have low rates of movement among habitat patches."

Epps, who is an assistant professor in the Department of Fisheries and Wildlife at Oregon State, did his doctoral dissertation on bighorn sheep, including populations in the northern Sonora desert. He says mountain ranges act like habitat islands and thus bighorn populations are geographically fragmented. Adding an impenetrable fence through those ranges, without a strategy promoting the passage of wildlife, could be harmful.

"Bighorns in places like the Sonoran desert will form small populations – sometimes with only 10, 15 or 20 animals," Epps said. "Yet they will occasionally move back and forth and mix with other groups. That connectivity is critical to their survival. Without it, they can still sometimes re-colonize, but often that small group will go extinct.

"Isolating populations not only reduces genetic diversity," he added, "it makes the animals more susceptible to disease, drought and other weather extremes, and predation. We've seen one or two mountain lions knock down populations of sheep once they get a taste for mutton."

The scientists say the wall along the U.S.-Mexican border is not the only issue for wildlife. Human activity, vehicular traffic, amplified noise and artificial lighting associated with the barrier can all affect how animals behave.

"There is a political reality and a biological reality to the border wall," Epps said. "We've talked to people who work along the border and the sheer number of people moving across the landscape is stunning. The crackdown on urban crossings has forced people into wild areas and the amount of human activity – both people crossing and the border patrols seeking them – has to have an effect on wildlife.

"Gaps in the fence could help, but that might channel more people to use those open areas for crossing, negating the benefit for wildlife and the purpose for constructing the wall in the first place," he added. "It may be time to re-examine the structure of the wall and do more research on potential outcomes."

By Mark Floyd, 541-737-0788 (mark.floyd@oregonstate.edu)
Sources: Clint Epps, 541-737-2478 (Clinton.epps@oregonstate.edu); Aaron Flesch, 520-730-4656 (flesch@Ag.arizona.edu)

Clinton Epps | EurekAlert!
Further information:
http://www.oregonstate.edu

More articles from Ecology, The Environment and Conservation:

nachricht How to detect water contamination in situ?
22.09.2016 | Tomsk Polytechnic University (TPU)

nachricht Quantifying the chemical effects of air pollutants on oxidative stress and human health
12.09.2016 | Max-Planck-Institut für Chemie

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: OLED microdisplays in data glasses for improved human-machine interaction

The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP has been developing various applications for OLED microdisplays based on organic semiconductors. By integrating the capabilities of an image sensor directly into the microdisplay, eye movements can be recorded by the smart glasses and utilized for guidance and control functions, as one example. The new design will be debuted at Augmented World Expo Europe (AWE) in Berlin at Booth B25, October 18th – 19th.

“Augmented-reality” and “wearables” have become terms we encounter almost daily. Both can make daily life a little simpler and provide valuable assistance for...

Im Focus: Artificial Intelligence Helps in the Discovery of New Materials

With the help of artificial intelligence, chemists from the University of Basel in Switzerland have computed the characteristics of about two million crystals made up of four chemical elements. The researchers were able to identify 90 previously unknown thermodynamically stable crystals that can be regarded as new materials. They report on their findings in the scientific journal Physical Review Letters.

Elpasolite is a glassy, transparent, shiny and soft mineral with a cubic crystal structure. First discovered in El Paso County (Colorado, USA), it can also be...

Im Focus: Complex hardmetal tools out of the 3D printer

For the first time, Fraunhofer IKTS shows additively manufactured hardmetal tools at WorldPM 2016 in Hamburg. Mechanical, chemical as well as a high heat resistance and extreme hardness are required from tools that are used in mechanical and automotive engineering or in plastics and building materials industry. Researchers at the Fraunhofer Institute for Ceramic Technologies and Systems IKTS in Dresden managed the production of complex hardmetal tools via 3D printing in a quality that are in no way inferior to conventionally produced high-performance tools.

Fraunhofer IKTS counts decades of proven expertise in the development of hardmetals. To date, reliable cutting, drilling, pressing and stamping tools made of...

Im Focus: Launch of New Industry Working Group for Process Control in Laser Material Processing

At AKL’16, the International Laser Technology Congress held in May this year, interest in the topic of process control was greater than expected. Appropriately, the event was also used to launch the Industry Working Group for Process Control in Laser Material Processing. The group provides a forum for representatives from industry and research to initiate pre-competitive projects and discuss issues such as standards, potential cost savings and feasibility.

In the age of industry 4.0, laser technology is firmly established within manufacturing. A wide variety of laser techniques – from USP ablation and additive...

Im Focus: New laser joining technologies at ‘K 2016’ trade fair

Every three years, the plastics industry gathers at K, the international trade fair for plastics and rubber in Düsseldorf. The Fraunhofer Institute for Laser Technology ILT will also be attending again and presenting many innovative technologies, such as for joining plastics and metals using ultrashort pulse lasers. From October 19 to 26, you can find the Fraunhofer ILT at the joint Fraunhofer booth SC01 in Hall 7.

K is the world’s largest trade fair for the plastics and rubber industry. As in previous years, the organizers are expecting 3,000 exhibitors and more than...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Experts from industry and academia discuss the future mobile telecommunications standard 5G

23.09.2016 | Event News

ICPE in Graz for the seventh time

20.09.2016 | Event News

Using mathematical models to understand our brain

16.09.2016 | Event News

 
Latest News

Chains of nanogold – forged with atomic precision

23.09.2016 | Life Sciences

New leukemia treatment offers hope

23.09.2016 | Health and Medicine

Self-assembled nanostructures hit their target

23.09.2016 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>