Thursday, August 10, 2017

Just Another Brick in the Wall

I grew up in deep South Texas.  The part of Texas where, when people ask you which part you're from, you just give a cardinal direction.  The part where people assume you mean Houston, and you have to say "No no, six and a half hours south of there".  The part in red:

I didn't love it.  I won't pretend that I did.  I moved away as soon as I graduated from high school and haven't looked back.  But for all of the tedium, and the poverty, and the fact that not a single bar has ginger ale, it is an interesting place culturally and an important place ecologically.

I grew up in the Rio Grande Valley- not a mountain valley like many assume, but more of a river delta.  It's kind of an ecological wonder- it exists in a shift between the tropical environment of Central America and Mexico and the temperate climate of the United States, as well as the wetter environment of the Eastern US and the drier environments of the West, which results in an unusually high amount of biodiversity.1  There are three refuge complexes in the Rio Grande Valley: The Lower Rio Grande Valley National Wildlife Refuge, Laguna Atascosa National Wildlife Refuge, and Santa Ana Wildlife Refuge.  Between the three, there are 429 species of birds, 44 species of mammals, 115 species of reptiles and amphibians, 31 species of fish, 300 species of butterflies , and 100 species of dragonflies and damselflies.  Eighty-five of these species are currently on the endangered, rare, or threatened species list.2  The area is one of the top birdwatching spots in the country, and plays host to at least half of the butterfly species seen in the United States.3  There are currently fewer than 50 Texas ocelots left in the region,4 and I once saw a jaguarundi there on an elementary school field trip.5

All of this is under threat from a proposed 74 mile long section of the border wall proposed by the Trump administration.  Say what you will about the border wall: racist, waste of money, economic effect on nearby communities, or maybe you're for it; regardless, one of the things that isn't being discussed enough is the ecological impact.

The current proposal for the border wall cuts through three miles of the Santa Ana Wildlife Refuge and an undetermined length of the National Butterfly Center.6
Advocates in this area are looking to other parts of the country and are understandably concerned: for the San Diego portion of the wall, the Department of Homeland Security waived 32 different laws, including the Clean Air Act, Clean Water Act, Solid Waste Disposal Act, a variety of wildlife protection acts, and, ironically enough, the Eagle Protection Act. among others.  Those are just the environmental laws: waivers have also been granted for archaeology laws, antiquities laws, and several laws involving the Native American community.7. Things that we've known were problems for decades, that we've been trying to fix for decades, are now back on the table for border regions.  But what exactly does that mean ecologically for these regions?

We have some idea, because there have been intermittent segments of a border fence in the Rio Grande Valley since 2008.  A study done after these first segments were built came to the conclusions that fences and walls resulted in groups of animals not being as freely connected to mate and interact with others of their species, which, in turn, reduces the population size.8  The same study reported that border barriers have reduced the range for some species by as much as 75%, which means more competition for resources, less to go around, and forcing species into areas where they haven't been seen before (or forcing higher numbers), where the resources available might not be what they need or are used to.  

Rice University professor Scott Egan agreed with these findings.  In an interview with Click2Houston, he emphasized the effects of a population bottleneck that would reduce the number of individuals in a species and risk cutting a single species into isolated populations, as well as the genetic effects and overall weakening of the population caused by the inbreeding resulting from less interconnectivity. He also made the addition of the disruption not just of local populations, but of migratory patterns of animals all along the border.  Disrupting migration patters wouldn't just affect the migratory animals; it would also have potentially disasterous consequences for the plants that rely on those animals for pollination.  On a longer term migratory scale, more and more species are shifting their location distributions northward in response to global warming.  If species are limited by a barrier, they could essentially end up trapped in areas with no resources or inappropriate climates.9

The ecological effects of the border wall are not just limited to impacting fauna.  The majority of the US-Mexico border is a river, and large sections of the US-Mexico border wall are being built in floodplains.  Those familiar with the area have indicated that some of the proposed wall in the Rio Grande Valley is actually on a sandbar.10  During times of heavy rain, a solid barrier in a floodplain will basically become a dam, preventing the flow of water on both sides of the river.  Indeed, this has already happened in Arizona, with two deaths in Nogales, AZ and millions of dollars of damage in multiple floods over the past ten years, primarily due to debris collecting the border wall and having nowhere to go.11  Almost 200 miles away, in a separate incident, the Organ Pipe Cactus National Monument was damaged in a similar flood.12  Intense flooding can not only threaten human lives and damage property, but can result in tainted water supplies, contaminating and spreading contaminated sediment, damaging agricultural, and losses of both plants and animals.  

The final ecological impact I'll briefly mention is the disruption of the actual process of building the wall.  Construction means construction crews, construction equipment, and construction access.  Animals tend to shy away from areas with loud noises and lots of people and development, even if they've been living in the region for decades.  An immediate outcome of building a border wall is likely to be disrupting populations of animals as they leave the area to find safe places.  Cutting down and trampling plants is also pretty much inevitable in the construction process. 

I focused a lot on the Rio Grande Valley in this post, but these issues apply to the entire length of the border wall.  In the Rio Grande Valley specifically though, sections of the wall will go directly through Santa Ana Wildlife Refuge, wreaking environmental havoc on an area specifically set aside to protect species from the effects of urban development.  If the border wall doesn't end kill these animals, the irony certainly will.  For those in Texas, there are protests happening often and campaigns to contact legislatures that you can be a part of.  For those not in Texas, share this article so people know what's going on and how damaging it is.  If you'd like to keep up with these efforts, "Like" the Facebook page for Save Santa Ana Wildlife Refuge.  And, as always, follow me on Twitter @reviewer3blog for science articles, gifs, and retweets of The Atlantic's Ed Yong in between blog posts.  


  1. Thank you for sharing this and educationing me on how much more critical than I originally thought or knew. I will share and hope others will take the time to read is urgent information.

  2. I will share this article also. So many don't understand what is at stake.

  3. These studies always produce them the same scenario, and it's a very biased one. We humans are always quick to jump on the ecological band wagon and tend to do so without looking at the whole from all sides. We don't want to give up anything, we just want to spew our opinion. The wildlife in these areas have been adjusting for 1000's of years, as have we.

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