May 20, 2019
Mae Lacey

When you think of the U.S.-Mexico border, a myriad of “hot-button” issues may go through your head. Ethical dilemmas, immigration policy and border security are just a few. There is a torrent of conversation on these issues here in Washington, D.C., but one issue that isn’t discussed as widely is the impact on wildlife and biodiversity. Add to the chaos the seemingly constant changes in the location and types of border wall the current administration proposes to construct. Can you keep up?

Border wall comparison Matt Clark/Defenders

Here in the Center for Conservation Innovation (CCI) at Defenders of Wildlife, we strive to stay on top of the latest data, methods, and literature on all things wildlife-related. None of these topics has been as nebulous as the U.S.-Mexico border wall in my time as CCI’s GIS and Technical Computing Associate. The Department of Homeland Security (DHS) frequently releases documents with updates to sections of border that they either plan to explore for possible construction in the future (waived) or sections they have already approved to begin construction (proposed) (much of this unchecked damage can be credited to the REAL ID Act of 2006). These documents can be released quietly, often sneaking by the public eye if not closely monitored. Even while writing this blog post, I received an email with a newly released DHS document indicating they will soon begin construction in a region containing important wildlife corridors… Of course, the DHS did not tell us this outright. We were only able to confirm this direct threat to important wildlife habitat after taking the time to interpret the DHS’ written descriptions of where this construction will be located.

Waiver update 2019

The process of interpreting DHS documents is complicated by their vague descriptions of where the latest sections of waived or proposed border wall are located. At times this can be straightforward: some documents will provide start and end coordinates that you can clearly mark on a map. However, the exact path the wall will follow as it runs from coordinate A to coordinate B is left up to the mapmaker. In other cases, the DHS doesn’t even provide us the luxury of exact start and end coordinates. Rather, the DHS will describe sections of waived or proposed border wall construction as “starting at approximately one (1) mile west of Border Monument 20 and extending east to Border Monument 9,” for example (see full document here).

You might imagine that a border monument would make a good geographic marker for the DHS to use in their descriptions. However, there isn’t even a standard, publicly available dataset on the exact locations of all the border monuments. Many people aren’t aware the border monuments even exist (read more about them here)! We were lucky enough to connect with an artist, David Taylor, who put together a photographic portfolio of all 276 Border Monuments. Throughout this process he also collected the geographic coordinates of each border monument, which he shared with Defenders to use in mapping waived and proposed border wall relative to border monument locations. While we were lucky that David’s artwork provided this data, in an ideal world we should be able to clearly map the border based on the information provided in these government documents alone. The use of vague descriptions and poorly known landmarks all contribute to the ways in which the DHS has complicated the process of determining where a wall is being built at any given time. Misinformation (or a total lack of information) on the location of potential border wall construction can have profound impacts on the ground. Some examples include knowing whether or not critical wildlife habitat is threatened by wall construction or deciding where to focus conservation efforts for a species whose dispersal pathways may be under siege.

Border wall corridors infographic

Organizations that rely on this information to map out new border wall locations are struggling to keep up with the number and frequency of updates, especially given such vague descriptions. Since the DHS isn’t providing clear maps to accompany these written documents, it becomes difficult to know which maps are most accurate and up to date. This can complicate decision making for organizations that rely on comprehensive border maps for conservation management decisions. For example, one map may claim a section is comprised of vehicle fencing that may be about eight feet tall when it is in fact 30-foot bollard wall. This can have dramatically different impacts on the landscape and local wildlife such as the endangered Quino checkerspot butterfly that rarely flies more than 15 feet high. Whether a section of wall is eight feet versus 30 feet tall could determine whether the Quino checkerspot butterfly can disperse across the border or not (ABC News). 

Quino checkerspot butterfly

In an effort to minimize these and other discrepancies and combat the DHS’s lack of clarity, CCI is working to put together a standard dataset of waived, proposed, and existing border wall. This standard dataset takes into account DHS document descriptions and maps produced by other professionals who specialize in this topic such as Dr. Kenneth Madsen at Ohio State (check out his work here). We are also accepting feedback from border wall specialists at Defenders and our colleagues at other organizations who are uniquely familiar with the borderlands. We believe that putting together a more complete, accurate, and up-to-date spatial dataset on the border can help Defenders and other organizations better monitor border wall developments. Such information is critical in determining where to focus wildlife conservation efforts on the ground in this ever-changing field. 


So where is the U.S.-Mexico border wall being built right now, and what exactly is it made of? The answer may differ depending on who you ask. Nonetheless, I remain optimistic that through our efforts compiling a standard (and regularly updated) spatial dataset, we can continue to have these conversations and begin making sense of the chaos that surrounds the U.S.-Mexico border wall. CCI is certainly putting in our best effort to keep up with the border wall, nebulous as it may be. We hope that in doing so we can best inform conservation management practices on the border and hone our efforts in protecting critical wildlife corridors and habitat that exist along this magnificent and biodiverse region. 


Mae Lacey headshot

Mae Lacey

GIS and Technical Computing Associate
As the GIS and Technical Computing Associate, Mae Lacey provides full-service mapping support and basic geospatial analysis support for Defenders staff nationwide and in collaborative work with external organizations.

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