Wildlife and the Trump Border Wall


With one graceful leap out of the water, the jaguar latched on to the neck of its victim and surrendered it unconscious using its powerful jaw. The crocodile was in complete and utter alarm due to the incredible hunting abilities of the jaguar (National Geographic, n.d.). Today it is a rare to witness this breathtaking species in the southwestern United States. The jaguar is currently listed in the United States as one of the most imperiled species because of a predator removal program in the 1900’s that treated jaguars as game (Eisenberg, 2014). In 2016 a jaguar was spotted in Arizona, providing hope that a few jaguars may be established in the southwestern U.S. This sighting suggests that the animal crossed the border from Sonora, Mexico to the U.S. This jaguar, now known as El Jefe, may be one of the last remaining jaguars in the U.S, creating an urgent need for conservation of this iconic species in the borderland regions (Bruillard, 2016). El Jefe was photographed north of the border when he likely crossed through a small gap in the border wall to get to the Huachuca Mountains in southeastern Arizona (Schyler, 2017).

President Trump’s proposed border wall threatens the fate of Panthera Onca Arizonesis, a subspecies native to the southeastern United States and Mexico (Feline Worlds, n.d.). The proposed wall intends to stop the flow of illegal immigration into the United States. However, the negative effects of this barrier on the borderland jaguars are not being considered. These jaguars rely on open corridors to breed and migrate. Although a border fence would impede the flow of humans across the border, disastrous effects on jaguar populations will occur (Sullivan, 2016). Recovery of the estimated five U.S. jaguars is dependent upon the estimated breeding population of 120 jaguars in Sonora, Mexico (McCain & Childs, 2008, p. 7; Northern Jaguar Project, n.d., Threats & Opportunities para. 1). Trump’s proposed border wall will inhibit migration of the borderland jaguars, and drive the population to extinction in Arizona and New Mexico.

In order to sustain a healthy population of jaguars in the United States, the population must carry an adequate gene pool. Gene pools indicate high genetic diversity and greater reproduction and survival, all necessary for expanding the current U.S. jaguar population. Researchers have proven that barriers bottleneck wildlife populations by drastically reducing their size, resulting in higher risks for mutation due to inbreeding and eventual extinction (Lasky, Jetz & Keitt 2011). Specifically, researchers have found that road barriers disrupt gene flow in peninsular bighorn sheep [PBS] and wood mice. Ascensão et. al (2016) found that when a road barrier was established in wood mouse habitat, there was only a 5% migration rate between both sides of the barrier (p. 9). Over time inbreeding caused low genetic variation and infertility, which led to the inability to further the population. Additionally, Buchalski et. al (2015) concluded PBS separated into two subpopulations north and south of a major highway in Mexico, which also led to inbreeding when mate choice was demographically limited. Researchers believe that these impacts will also affect the last remaining  jaguars if migration pathways are blocked (McCain & Childs 2008). The proposed barrier will likely expedite the reduction of the jaguar’s gene pool in the U.S. if case studies with larger population sizes of wood mice and PBS have been shown to inbreed. A reduced gene pool will drive the borderland jaguars to extinction if they are forced to reproduce with populations of relatives.

As a native species to the southwest United States, jaguars naturally return to this area through open migration pathways at the border (Schyler 2016). Reintroduction of jaguars to their native habitat range in the U.S. is likely to drive a trophic cascade, an ecological process defined by a predator decreasing the population numbers of its prey, and thereby the next lower trophic level increases (Agnos & Agnos 2014).  It is likely that reintroducing this apex predator will have profound effects on the food chain. Jaguars are remarkable in that they have a broad diet consisting of over 85 different species (Eisenberg, 2014, p. 222). Additionally they have been known to kill according to prey abundance, for example in areas with more peccaries (a species of small boar) than deer they will choose the peccary as a food source (Eisenberg, 2014). A well known trophic cascade is the predator reintroduction program at Yellowstone National Park in 1995. Just as farmers fear for livestock predation by jaguars in the southwest, ranchers outside the park questioned the efficacy of the reintroduction of the wolf. Wildlife biologists, however, deemed that this top down predator was essential for the ecosystem. The reintroduction of breeding populations of wolves ensured that the booming elk population was in check, and as a result populations of willows were not over grazed (Farquhar 2017). The growing vegetation stabilized river banks and unexpectedly transformed the physical geography of the river as a result of fewer grazing elk (Agnos & Agnos 2014). Currently the most important ecological role the jaguar plays north of the border, occurs via food web subsidies they provide for other species. A jaguar typically eats their fill of prey and leaves the carcass for other species such as coyotes, bears, and birds of prey to opportunistically feed on (Eisenberg, 2014). Although the full extent of the trophic cascade that will result from the reintroduction of jaguars cannot be predicted, it is likely that it will have positive, and potentially unexpected results similar to an apex predator like the wolf.  

In order for successful jaguar reintroduction to occur, open migration pathways must be maintained between the breeding population 125 miles south of the border and the U.S.  (Northern Jaguar Project, n.d.). With climate change increasing the severity of droughts, it is more crucial than ever to maintain open border regions for the species to migrate back and forth between the reserve, the 800,000 acres of protected national forests, and ranches north of the border. The policy in these protected areas prevents the killing of jaguars. (Schyler, 2017; Northern Jaguar Project, n.d.) The Northern Jaguar Reserve located in Sonora, Mexico may be one of the last attempts to maintain this breeding population of jaguars that migrates to the U.S. It is in this protected area that the effects of the jaguar as a top down predator and umbrella species can be appreciated. The jaguar is known as an umbrella species because protecting them has an indirect affect on the many species that make up the ecological community. As a result, the flora and fauna are kept in check by ocelot species in this reserve (Northern Jaguar Project, n.d.).

The critical corridors for jaguar dispersal to the southwest border include passage through the Sky Islands and river corridors that span the region (Schyler, 2017). The Sky Islands consist of high deserts and grasslands that border Sonora, southwestern New Mexico, and southeastern Arizona. They are home to a bio diverse community of species besides the jaguar. The orientation of mountain ranges in this area runs north-south from the U.S. to Mexico and the abundance of rivers provide key passageways for the movement of jaguars. With the rapid changing of the climate, protection of these corridors are more essential than ever for the species to migrate. In order to continue the success that this natural corridor provides, a wide array of animals must remain free from any barriers. A current proposal for protecting the grasslands predicts that this range will provide the jaguar with corridors between mountain ranges. It is also likely that the jaguar will face fewer threats towards overall species survival by reduced poaching and fragmentation if the jaguar disperses within the Sky Islands (NFWF, n.d.).

Although the idea of a massive border fence is a relatively new subject in the United States, it is not unique to this country. A security border wall constructed between Slovenia and Croatia separates  home ranges of three core large carnivores from focal species in the Dinaric Mountain range. More than half of this wall would cover an area that is home to brown bears, wolfs and lynx. These species come with a challenge to conservation due to their large home ranges and low population size. These factors open them up to risks of inbreeding and extinction.  Slovenia and Croatia built a border wall to prevent the flow of refugees, which unfortunately affects these 3 large carnivores as the majority of their home ranges are present on only one side of the border (Linnel et al., 2016). These species’ survival depends on individuals traveling amongst subpopulations in their home ranges and therefore can not survive on one side of the border. The barriers not only cause genetic isolation and death of animals trying to pass through, but it also diminishes the efforts of organizations such as the European Wilderness Society [EWS]. EWS chairman Max Rossberg states that “Europe holds some of the best-preserved wildlands on the continent and some of its healthiest wildlife populations” (O’Donnell, 2016, para. 6). This fragmentation in Europe resulting from security barriers should be a lesson when understanding how a wall at the US-Mexico border will affect species of large carnivores, particularly the jaguar.

Various case studies across the world utilize alternative corridors to allow for passage of key species. An example of a successful program to mitigate the effects on species was implemented in the Ustyurt region in Kazakhstan (Olson, 2014). The population of antelope migrate to the northern part of their home range in the warmer seasons, and must cross a border to the south during the cold winter seasons (Bekenov et al., 1998). The government installed a fence where the bottom portion was removed to allow a 60 cm underpass for species to access both areas of land on either side of the barrier. This shows that a border can be installed with the intent to keep people out, but allow native species to migrate freely (Olson 2014).

Additionally, wildlife overpasses in Switzerland effectively allow for a variety of migratory invertebrates to cross highways if corridor are at least 60 meters in length (Corlatti, Hacklander & Frey-Roos, 2009, p. 551). Wildlife also prefer to use multiple corridors as seen in Germany’s 30 overpasses over a road barrier (Corlatti, et al., 2009). The ideal scenario of transboundary cooperation between nations occurred via complete removal of fences in western Europe. The reintroduction of the grey wolf (Canis lupus) demonstrates that threatened species can recover if barriers are removed (Linnel et al., 2016).  Researchers studying jaguars in the southern Mayan forest that spans Mexico and Guatemala determined the minimum width a jaguar corridor can be effective is 240 meters wide (Torre, Nunez & Medellin, 2016, p. 278). If various wildlife are successful in crossing openings and overpasses then jaguars are likely to cross through the Sky Islands that span approximately 75 miles of the US-Mexico border (Google maps, n.d.).

Many argue the point that a physical wall is the most cost efficient and secure option to keep out illegal immigrants. However, there are many alternative options that can be used in the Sky Islands and have much more positive effects for the security of our nation. Joselow and Neubert (2017) assess the practicality of nations with constructed borders and compare them to nations that use alternative security measurements to regulate their borders instead. Joselow and Neuberts’ (2017) assessment determine that alternative measurements for security would be much more effective for protecting the nation’s border. One option is the use of computer linked motion sensors and monitors and long range security cameras with clear visibility up to fifteen miles. Therefore, these measurements would allow the U.S government to strictly monitor the border using real time footage and detection software. This is most beneficial in situations when border agents are not available, but can still pinpoint the location of assailants. This would cut down the use of millions in tax dollars by using employed agents to patrol the proposed border wall. Other technological alternatives include the use of unarmed drones, helicopters, and other patrol vehicles/vessels. These security measurements would expand monitorial access of the border without the use of a physical wall. A wall does far less in apprehending and observing illegal immigration than technology and surveillance can provide (Joselow & Neubert, 2017).

Alternative security measures have proven itself effective in Europe. Frontex, Europe’s equivalent of the U.S. Border Control, uses surveillance systems (i.e. drones, long distance thermal surveillance) to secure pieces of the 9,300 mile border. Frontex’ missions include the monitoring of migratory flows through technology, development of risk analysis reports for member states and deployment of guards when action is detected. A network of National Coordination Centres [NCC] are established in member states to monitor surveillance and share information regarding border crossings amongst states (Frontex, 2017). Although this technology is a relatively new in border protection, Frontex has made great strides towards tightening the security across borders in the European Union [EU]. Security experts detected 87% less illegal-border crossings in July-September 2016 compared to the same period in 2015 (Frontex Risk Analysis Unit, 2017, p. 8). The success of the surveillance systems in the EU is largely contributed to the security teams that develop risk analysis reports to constantly analyze data and evolve the technology to tightly monitor border gaps (Frontex Risk Analysis Unit, 2017). The United States would greatly benefit from using similar security systems as Frontex in the Sky Island corridors.

It is crucial for wildlife conservationists to be present in national and international debates regarding border security to voice concerns on endangered species like the jaguar. Senate leader Mitch McConnell quoted the cost of President Trump’s proposed wall will be between 12 and 15 billion dollars to cover the remaining length of the 2,000 mile border (Drew, 2017, para. 3). Critics of the wall argue that border walls are effective in areas with remotely populated human populations, but not in areas where people must cross through mountains to get through the border (Drew, 2017). Additional costs to maintain the proposed wall in rugged areas would cost nearly 750 million dollars per year that would require the U.S. government to pay for the upkeep (Min Kim, 2015). It is more logical to keep the Sky Islands corridor region open since this region has low human populations and a high diversity of species that inhabit the grasslands and mountain ranges (Schyler, 2017). Trump’s proposed border wall could be erected in cities, however the Sky Islands should remain open and be maintained by alternative security measures to allow for migration of the jaguar. The U.S. government could therefore invest the money it would cost to build the wall in this region towards alternative security measures, while still keeping heavily populated cities secure using barriers.

One of the most important factors for the continuation of North American Jaguar populations (along with other species) is the variety of gene pool within these species. This may seem like a mundane factor when considering all factors as a whole, but without an extensive gene pool, the jaguar would cease to exist in this area. For this species to thrive, the individual jaguars need a substantial amount of potential mates in order to expand their species. Without access to these mates, the jaguars have no other option than to mate with their relatives (i.e brothers, sisters, etc.) which would cause a variety of genetic mutations. These mutations would cause many health problems including infertility, birth defects, and weakened immune systems. With these apparent health problems, over time the jaguars would cease to exist because of the inability to produce healthy, genetically viable offspring who would need to continue the reproduction process (McCain & Childs 2008).

The problem of a smaller genetic pool would be solely contributed to the proposed border wall.  As of right now, about 5% of the North American jaguar population lives within the continental United States (McCain & Childs, 2008, p. 7). This number may seem insignificant, but this population is extremely important to the species as a whole. These jaguars travel in between Mexico and the U.S. in order to reproduce with the rest of the population that lives within Mexico and to search for food. If the wall were to be constructed this would make it impossible for this population of jaguars to have the access they would need in order to reproduce. If this were to happen, the gene pool within the 5% would become smaller as time went on these jaguars would die out, which would further decrease the overall number of jaguars and drive them to extinction (McCain & Childs, 2008). This is why the alternative forms of security would need to be put in place, because it would allow the jaguar population to reproduce normally while maintaining a secure border.

The proposed idea of massive border wall would help stop the flow of human traffic across the US and Mexico border, but it would also stop the flow of jaguars. This would be a disaster for the ecology of the borderlands. Beyond jaguars, other borderland species are already endangered and require special habitat. As a nation we are concerned about the safety of our borders. However, we should assess what means are necessary to make our border secure without impeding on the valuable wildlife that also call the borderlands home.



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