America’s Proposed Border Wall: Effective or Deadly?

Donald Trump ran his campaign with the promise of significantly stopping illegal immigration by building a concrete border wall.

The 2016 presidential election, as highlighted by republican candidate Donald Trump, saw the rise in the desire for a U.S.-Mexico border wall among American voters.  The reason for building a wall is to prevent immigrants from illegally entering the United States. One of the largest misconceptions is the negative association between immigrants and crime rates (Jones, 2012).  However, almost all crimes committed in the U.S. were by citizens, not illegal immigrants (Carson & Anderson, 2016).  The main crimes committed in the United States by illegal immigrants include drug trafficking, rape, assault, reckless driving, and driving under the influence (Federation for American Immigration Reform, 2017).  However, Carson and Anderson (2016) state that only about 5% of inmates in the state and federal prisons consist of noncitizens.  This means American citizens account for 95% of the crimes committed in the United States. Of the total, only 1.67% are noncitizen federal inmates in prison for immigration offenses (Carson & Anderson, 2016 p. 33). In former president Barack Obama’s keynote speech, he discussed current crimes rates and illegal immigration, and stated that the illegal immigration and crime rates are lower than they have been in decades (Emery, 2016).  

Border walls are built to greatly increase the difficulty of crossing international borders. According to Greenberg (2015), approximately 40% of illegal immigrants that reside in the United States actually come by air. Those 40% of immigrants have visas to come to the United States but overstay the expiration date, meaning that the wall will only increase the difficulty to 60% of illegal immigrants (Greenberg, 2015 para. 6). U.S. Immigration (2011) states that they can’t fully seal the border. They explain that if there is a product sold across the border, people will always find a way to get it across to make money. (U.S. Immigration, 2011). 90% of all illegal immigrants that are deported for non-criminal reasons are detained around the border (U.S. Immigration and Customs Enforcement, 2015 para. 2).  Most of whom are first-time offenders that are seeking a better financial life in America. There are also people that own the land around the border that do not always follow the immigration laws of America. Many of these citizens own ranches and have agreements with the cartels that allow immigrants/drugs to pass through their land (Barry, 2016). This will not change even if there was a wall; these ranchers will continue these agreements with the cartels and still allow them to cross over their ranches.

Legislation is the best way to appropriately attempt to stop illegal immigration without building a costly barrier. We propose that homeland security and Immigrations and Customs Enforcement (ICE) be better funded to improve the performance of their jobs.  The true cost of the wall is disputed between political parties but according to Kate Drew of CNBC, a known opposition to Donald Trump, the wall will cost between $15 billion to $25 billion. We are also proposing that that money, whatever the final cost will be, should be used to improve the technologies and manpower of the men and women who protect America from foreign invaders.  The United States spends about $9 billion a year to secure the border and enforce immigration laws.  There were 1,200 National Guard troops stationed on the southern border, and 20,000 Customs and Border Patrol agents deployed as of 2010.  Even with all the money and manpower spent on the border, Customs and Border Patrol (CBP) agents estimate that only 44% of the border is under “operational control”.  By funding more CBP agents and national guard troops, the United States can add large chunks of the border into their “operational control” category, and therefore control who and what crosses.  The average salary of a CBP agent is $75,000 a year, totaling about $1.5 billion annually in costs (U.S. Immigration, 2011 para. 2).  Adding additional agents to patrol the border would give supporters of the wall a better feeling of safety at a substantially lower cost.  Walls only work if there are people guarding them. An unguarded wall would only act as a speed bump for immigrants willing to take great risks to enter the country.  Better funding towards the agencies that protect America helps alleviate the perceived issue of illegal immigration and is less costly to the American taxpayers’ wallet. Walls are not always effective when it comes to human beings and their migration paths, but they are effective in negatively impacting threatened species, like the jaguar, pygmy owl, and Peninsular big horned sheep.

In the United States, there have been six jaguars spotted in the past two decades (Mahler, 2016 para. 2). Historically, the U.S. jaguar population was robust, spanning from southern California and across Texas. However, due to deforestation, draining wetlands, and poachers, their range has diminished by 40% to the U.S.-Mexico border region as depicted in figure 1 (International Fund for Animal Welfare, 2010; Arizona Game and Fish Department, 2013). Not only does this negatively affect the jaguars, but it also has a cascading effect on their entire ecosystem. The jaguar is a keystone species driving a top-down trophic cascade, meaning any alteration in the behavior of this species can have wide-scale domino knock-out effects for the entire ecosystem (McCallum, Rowcliffe, & Cuthill, 2014; The University of Kentucky, 2004). As a keystone species, the jaguar is at the top of their food chain and maintains the structural integrity of their environment. Through their hunting, they directly control the local populations of herbivores, like deer and sheep (Eisenberg, 2015). The jaguars not only control these populations in number, but also in behavior. It is seen that by introducing a predator to the environment, the fear of predation keeps the prey on the move, further preventing overgrazing in a single area (Sojka, 2014). Building on this, an additional study explains the impact that human activity will have on this migration by reducing the abundance of potential prey species from the lack of landscape, therefore forcing the jaguars to relocate to find other prey (Torre & Medellin, 2017). The activity associated with the border wall will prevent the jaguar from hunting on boths sides of the border, limiting them to whatever is in their existing ecosystem. However, when these prey species are over hunted, the United States’ jaguar will fail to exist, leading to the further decline of their species.

Figure 1. Migration Range of the Jaguar (Arizona Fish and Game Department, 2013)


The proposed border wall will obstruct animals from connecting to other members of their own species and may force some to remain in habitats that do not fully support their survival.  Ascensão et al. (2016) describes the “barrier effect” and how it can have serious consequences to animals.  The barrier effect occurs when animals living in the wild stray from normal behavior due to the appearance of man-made structures (Ascensão et al., 2016). These results showed that animals would stay to one side of a highway and not venture over this man-made structure.  This shows how barriers can potentially leave species vulnerable to isolation. Roads and barriers built all along the southern border to properly construct the wall could have a deadly consequence for many animals that call the region home.

It is estimated that the border will cut off a significant amount of the surrounding wildlife’s current range: 29 local species at the border are most at risk from current barriers, while the barrier would cut through 75% of 16 species ranges (Lasky, Jetz, & Keitt, 2007 p. 679). One of the most significant impacts of the proposed U.S.-Mexico border wall is the decrease in population connectivity between local species. Population connectivity is defined as the exchange of individuals among populations that are separated (Woods Hole Oceanographic Institution, 2017). Although each jaguar in America is currently alone, they maintain the balance in their ecosystem. However, the fact that they are alone also means they must travel a great distance in order to mate. Since the U.S. jaguar population has essentially disappeared, any jaguars found in the United States must travel over the border to Mexico to reunite with the larger jaguar populations. In a study of the threatened jaguars along the U.S.-Mexico border using camera surveillance, there were 154 sightings over the course of three years of a group of jaguars crossing over the border (McCain and Childs, 2008 p. 55). The creation of the proposed U.S.-Mexico border wall will impede all travels. Although there are groups that aim to rejuvenate the U.S. population, without interbreeding with the populations over the border there will be a decrease in the genetic diversity (Northern Jaguar Project, n.d.). This diversity is imperative to the health of the individuals and the group as a whole.With conservation efforts by various agencies along with an absence of the proposed U.S.-Mexico border wall, there is hope for revival of the U.S. jaguar population. Although large animals, like the jaguar, will be affected, smaller animals will too. Although commonly overlooked, the predator may influence other species through top-down predation, meaning any alteration in the behavior of one species can have wide-scale domino knock-out effects for the entire ecosystem (McCallum et al., 2014).

The U.S.-Mexico border wall will impact threatened species not only on the land, but also those that flying. Flesch et al. (2010) found that a barrier would have a negative effect on Pygmy owl connectivity. Flights of these owls leveled off at 1.4 meters above the ground on average. Only 23% of the Pygmy owls studied could exceed 4 meters (Flesch et al., 2010 p. 178). The proposed wall on the US-Mexico border is estimated to be a minimum of 9 meters tall (Pike, 2017 para. 13). 77% of the Pygmy owls would get stuck on one side of a 4-meter wall (Flesch et al., 2010 p. 178), which is significantly smaller than the proposed wall. From the average of 1.4 meters above the ground that this study has shown, the Pygmy owls would not  make it over the 9 meter wall.

One of the most devastating outcomes of the loss population connectivity is a disruption in the gene flow of the local border species. Gene flow is described as any movement of genetic material from one population to another (The University of California Museum of Paleontology, 2017). It is predicted that the proposed border wall will create a decrease in the gene flow and thus an increase in inbreeding (Buchalski et al., 2015; Atwood et al., 2011). Although the proposed border wall is not constructed, there are already decreases in gene flow due to the current border fence in place. In Peninsular big horned sheep populations already cut off by the existing wall, the level of homozygosity is high (Buchalski et al., 2015). High levels of homozygosity indicate an increased level in inbreeding, exposing the populations to a higher incidence of genetic malformations and diseases (Lorimer, 2002). Similarly, in a different population in the Arizona-Mexico region, Atwood et. al (2011) studied hair samples to examine the level of inbreeding. Out of 258 samples of hair collected, 26% of them were the same, therefore indicating a high level of inbreeding (Atwood et al., 2011 p. 2857). As it is already, the current border fence restricts many of the existing local populations and the effects are detrimental. By elongating and making the border wall taller, it is predicted that these populations, among others, will continue to be negatively affected. The proposed U.S.-Mexico border wall will negatively impact the local wildlife populations through disrupting the gene flow and population connectivity. Due to this disruption of gene flow and population connectivity from the proposed U.S.-Mexico border wall, the U.S. should not build the wall, but use politics and increased legislation to reduce the negative impacts to wildlife.

While building a menacing wall spanning the 2,000 mile U.S.-Mexico border may seem like the best solution to the perceived illegal immigration problem, the effects on wildlife are devastating. Jones (2016) discusses how barriers do not stop the flow of immigrants entirely, and notes a direct correlation between migrant tunneling with the construction of new barriers already existing on the wall (Jones, 2016). It is seen that existing barriers constrict local wildlife populations, especially by decreasing their gene flow. By doing so, this is putting the species at an increased risk for genetic malformations and diseases. Due to all of the negative impacts on wildlife and ineffectiveness of its intended purpose, we propose the U.S. should not build the wall.  Though we realize the growing concerns to better secure our border with Mexico, as emphasized in the 2016 presidential election, we think there are more effective and cheaper ways of doing so that do not drastically impact threatened wildlife in the region.  Instead of building the wall along the border, we should increase funding for homeland security and/or U.S. Immigration and Customs Enforcement (ICE). By doing so, it is in the hopes that the populations of local threatened species on both sides of the border will prosper and continue to exchange their genetic material.


Alec Picard – Building and Construction Technology

Christina Parrella: Pre-Veterinary Science

Sheryl Steeves: Natural Resources Conservation

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