Beware the Desert Invaders: Border Walls and Buffelgrass

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This is the fourth post in the series Learning from and with Invasive Species: pluralities, refractions, futures, a 4 part series of pieces edited by Estraven Lupino-Smith concerned with how humans choose to relate to species perceived to be “out-of-place” as shaped by ontologies, socioeconomic context, place-based histories, and desires of knowing and belonging to the world. By drawing attention to invasivity as historical production and the fickleness of its adoption, the series takes up discussions around invasion ecology and its relationship to the politics of land, labor, resources, selfhood, and place-making.

Buffelgrass has the potential to turn what maybe attracts you and others to this region–some of the iconic cacti and the biodiversity that surrounds them–into basically an African grassland. It’s a wonderful place in Africa but doesn’t really belong here.

Interview with Debbie Colodner, Dir. Of Conservation Ed. & Science, AZ-Sonora Desert Museum

Organ Pipe Cactus National Monument (OPCNM), part of Hia-Ced O’odham homeland, lies athwart the international boundary between Arizona, United States (US) and Sonora, Mexico. In 2019 and 2020, the Trump administration constructed a 30 mile long by 30 ft tall wall segment through these borderlands as a show of protection against supposed immigrant “invasion” (Trump in Baker, 2019).

Sonoran Desert ecologists beware “Desert Invaders” (Ellis, 2007) of a different ilk: Buffelgrass. Buffelgrass is an introduced plant whose weedy behavior spells disaster for fragile Sonoran Desert Ecosystems. It may stand to reason, then, that “Trump’s Wall” may help control this threat by acting as an impassable membrane, preventing the spread of Buffelgrass from Mexico to the US. Rather than help contain Buffelgrass however, border construction has most likely worsened its spread. Below, I highlight how the twin spread of border walls and Buffelgrass are interwoven with US settler-colonialism which continues to structure life in the borderlands today.

Buffelgrass grows in dense clumps throughout the borderlands. Photograph by U.S. Fish and Wildlife Service/Steve Hillebrand.

The US Department of Agriculture (USDA) first imported Buffelgrass from Kenya to the Americas in the ‘40s (Cox et al., 1988); their aim to control erosion. This was followed by purposefully planting the grass in Northern Mexico (Burquez et al., 1996) and Arizona-Sonora in the 1960s and ‘70s to provide forage for cattle (Burquez and Yetman, 2021). However, the grass was introduced without considering how its anatomy could lead to arrant spread (Cox et al., 1988; Burquez et al., 1996). The seeds’ high wing loads and barbed bristles allow them to move rapidly along disturbed paths like roadways. From there, Buffelgrass penetrates the desert by wind to settle new areas, germinating in disturbed soil and emerging in dense clumps. Its tendency to dry out in droughts and green up quickly after rain allows it to outcompete native plants for resources, “naturally colonizing” Sonoran Desert ecosystems (paraphrasing Burquez, interview with author).

Buffelgrass forms a thick carpet between native Saguaros, dominating this part of the landscape. Source: NPS, U.S. National Park Service, in NPSGallery Digital Asset Management System, Asset ID: 1C4C379E-1DD8-B71B-0BA3E791C1293F66.

Though its rapid, dense growth does make for robust pastoral feed, Buffelgrass greatly increases the probability of wildfires against which native species have negligible protective adaptations (Marshall et al., 2012). Fire can therefore “convert a rich desert ecosystem into a barren Buffelgrass grassland” (AZ-Sonora Desert Museum). Accordingly, US officials now categorize Buffelgrass as a “noxious weed” (USDA, 2014). There, it is subjected to robust eradication efforts including hand-pulling and spraying pesticides. Just a few miles south in Sonora, Mexico however, Buffelgrass is still freely planted as sustenance for cattle. The border is therefore decisive in Buffelgrass management, not only because it helps distinguish where the grass is legal/illegal, but also because it serves as a threshold up to which the US can attempt to eradicate the ecological threat.

Thick carpets of invasive Buffelgrass create the conditions for wildfires that kill native megaflora such as these Joshua trees in the Mojave Desert. NPS Photo published by the U.S. National Park Service in NPSGallery Digital Asset Management System, Asset ID: FC27AAD7-0739-4D8A-0632E2B909F8BD3F.

Buffelgrass’s varying legal status across the border shows how belonging and unbelonging—indeed the unfixed category of “nature” itself—are socially produced, geographically and historically contingent categories. As stated above, Buffelgrass was once not only legal in the US but purposely cultivated by US agencies to feed a growing cattle population. This cattle industry also begot the introduction of barbed wire fences, which transformed and divided the borderlands (Razac, 2000). The spread of Buffelgrass and the extension of border fences are therefore intimately intertwined. They were both imported in part to stabilize the cattle industry, itself a vehicle for violently settling Native land and displacing Indigenous peoples along the American-Mexican frontier.

The first federal border fence built between Arizona-Sonora (1949) was constructed in Organ Pipe. It was a cooperation between the National Parks Service, the Bureau of Animal Industry, and the International Boundary and Water Commission to control cattle (for which Buffelgrass was later introduced) from grazing and supposedly spreading disease into the park (Piekielek, 2016). The monument makes up just one part of Hia-Ced O’odham ancestral territory which spans both the US and Mexico sides of the border (Bell et al., 1980). When NPS installed the cattle-wire fence, they did not include a gate at Quitobaquito springs (sacred site to the Hia-Ced O’odham, also known as ‘A’al Waippea). The Orozcos, Hia-Ced O’odham then living at ‘A’al Waippea, were impeded from routing water and tending land on the other side of the fence (Piekielek, 2016). The cattle-wire fence and the border it hardened were just some of the settler-colonial infrastructures contributing to a state of diaspora in which the Hia-Ced O’odham survive today (see Martínez, 2013; Hia-Ced Hemajkam, LLC).

Imperialism sometimes functions ecologically (Crosby, 1986). Kyle P. Whyte conceptualizes settler-colonialism as a form of ecological domination “that violently disrupts human relationships with the environment” (Whyte, 2018: 125). The introduction of non-native plants (like Buffelgrass), animals, and their associated corrals, aids settler colonial expansion by transforming ecologies in ways that sever Indigenous relationships with land. In this context, the spread of Buffelgrass and “The Wall” are related ecological developments of settler-colonial dispossession. To use Whyte’s phrasing, they “loop” from the past through the present (2018: 125). Indeed, the cattle wire fence that originally delimited Organ Pipe in 1949 was not fully replaced until Trump’s wall construction in 2019. That construction involved desecrating land along Quitobaquito springs without consulting the Hia-Ced O’odham (Martínez, 2020; Christina C. Bell Andrews, Hia-Ced Hemajkam Chairwoman, interview with author).

Since it offers a material barrier between where Buffelgrass is controlled and uncontrolled, some have suggested that Trump’s wall could help prevent the spread of Buffelgrass internationally. In my interview with Rijk Morawe, Chief of Natural and Cultural Resources Management at Organ Pipe Cactus National Monument, he implied that Buffelgrass is spread by people moving through the park (a migration pattern itself shaped by tactical infrastructure that funnels migration through remote areas like Organ Pipe):

We being a border park next to Mexico they don’t have the same constraints and restrictions that we have and so it is problematic. Especially around the village of Sonoita and when we have vehicles on our side that get the seed into them or whatever they can transport the seed and if we have people that are moving through the landscape, those folks can capture the seed and it can be transported through the landscape as well, so it’s a big issue for us.

Rijk Morawe, Chief of Natural and Cultural Resources Management at Organ Pipe Cactus National Monument

Morawe suggested that despite the negative environmental impacts of “The Wall” (including habitat fragmentation, erosion, groundwater draining, bulldozing of vegetation, and more) it could provide one ecological upside. That is, its barriers may keep human migration and Border Patrol activity closer to the boundary (Morawe, interview with author), preventing Buffelgrass seeds from spreading inland. The notion that the border wall may lessen the spread of Buffelgrass has also been shared by others, though in overtly racist ways. In these cases, the ecological is the stage upon which race and nationhood is performed (see Sundberg & Kaserman, 2007).

A screenshot of a quotation by biologist Sue Rutman in Saxon Burns, “Stopping the Spread” in Tucson Weekly.
A screenshot of a tweet by Southern Arizona Cattlemen erroneously connecting the spread of buffelgrass to the movement of “illegal” immigrants.

Despite speculation that Trump walls could help contain Buffelgrass, border construction has most likely worsened the spread. This is because border wall segments are flanked by border roads, disturbed pathways along which construction and Border Patrol vehicles ferry Buffelgrass along the boundary. From there, as I wrote above, the seeds’ nimble structures allow them to travel inland by wind. The extent to which wall infrastructure threatens Buffelgrass suppression is evidenced by the comments on DHS’s proposed environmental remediation plan for Tucson sector wall segments (U.S. Customs and Border Protection, 2022). Over one third of those comments demand treatment for invasive species like Buffelgrass (USCBP, 2022). Treatments could include monitoring programs and Border Patrol agents regularly washing their tire treads.

The case of Buffelgrass highlights how walls supposedly installed to defend against invasion so often exacerbate the violences surrounding illegalized (more-than-human-)migration. In this case, Trump border wall segments worsen the Buffelgrass issue by forging disturbed pathways upon which Border Patrol and construction vehicles transmit seeds.

US-Mexico border wall construction did not cause the Buffelgrass concern. Nor is Buffelgrass spread the reason wall segments were installed. But they are both interconnected functions of a settler colonial structure that continues to shape borderlands life. With US environmentalism’s own fraught relationship with racism and Native genocide, environmentalists concerned with justice in the borderlands must center an anticolonial approach in their Buffelgrass response. As I have discussed above, border walls beget environmental, imperial, and racial violence. They cannot be re-framed as tools for conserving land which, naturally, contains no bounds.

Works Cited

Arizona-Sonora Desert Museum. Save Our Saguaros: Beat Back Buffelgrass. Arizona-Sonora Desert Museum.

Baker, P. (2019, Feb 15). Trump Declares a National Emergency and Provokes a Constitutional Clash. New York Times.

Bell, F., Anderson, K.M., and Stewart, Y.G. (1980). The Quitobaquito Cemetery and Its History. U.S. Department of the Interior National Park Service.

Burquez, A., Martínez-Yrízar, A., Miller M., Rojas, K.,Quintana, M.A., and Yetman. D. (1996). Mexican grasslands and the changing aridlands of Mexico: an overview and a case study in northwestern Mexico. In B. Tellman, DM Finch, C. Edminster, and R. Hamre (Eds.) The future of arid grasslands: identifying issues, seeking solutions (pp. 21-32). Fort Collins: Forest Service United States Department of Agriculture.

Yetman, D., Búrquez, A., Sanderson, M., and Hultine, K. (2020). The saguaro cactus: a natural history. Southwest Center.

Cox, J.R., Martin-R, M.H., Ibarra-F, F.A., Fourie, J.H., Rethman, N.F.G., and Wilcox, D.G. (1988) The Influence of Climate and Soils on the Distribution of Four African Grasses. Journal of Range Management, 41(2), 127-139.

Crosby, A.W. (1986) Ecological imperialism: the biological expansion of Europe, 900-1900. Cambridge University Press.

U.S. Customs and Border Protection. (2022). Tucson Sector Border Barrier Remediation Plan

DoD 284 Funded Projects Stakeholder Feedback Report.

Ellis, Tim. “Desert enemy No.1: Buffelgrass.” Arizona Daily Star, July 12, 2007.

Hia-Ced Hemajkam. The Mission and Vision of the Hia-Ced Hemajkam. Hia-Ced Hemajkam, LLC.

Marshall, V. M., M. M. Lewis, and B. Ostendorf. (2012). Buffel grass (Cenchrus ciliaris) as an invader and threat to biodiversity in arid environments: a review. Journal of Arid Environments, 78, 1-12.

Martínez, D. (2013). “Hiding in the shadows of history: revitalizing Hia-Ced O’odham peoplehood.” Journal of the Southwest: 131-173.

Martínez, D. (2020). Trump’s Wall Would Destroy the Hia Ced O’odham Tribe’s History. The Copper Courier,

Piekielek, J. (2016). Creating a Park, Building a Border: The Establishment of Organ Pipe Cactus National Monument and the Solidification of the US-Mexico Border. Journal of the Southwest, 1-27.

Razac, O. 2000. Barbed Wire: A political history. The New Press: New York.

Sundberg, J., and Kaserman, B. (2007). Cactus carvings and desert defecations: embodying representations of border crossings in protected areas on the Mexico-US border. Environment and Planning D: Society and Space, 25(4), 727-744.

United States Department of Agriculture. (2014). Field Guide for Managing Buffelgrass in the Southwest.

Whyte, K.P. (2018). Settler Colonialism, Ecology, and Environmental Justice. Environment and Society: Advances in Research, 9(1), 125-144.

Feature Image: Saguaro cactuses and native shrubs pepper the landscape of Organ Pipe Cactus National Monument, Arizona USA. Photograph by Carol Highsmith from the Carol M. Highsmith Archive, Library of Congress, Prints and Photographs Division.
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Gabrielle Wolf

Gabrielle Wolf is a geographer. Her graduate research involves counter-mapping Trump border wall segments with a coalition of activist-scientists, and analyzing the border barriers’ reciprocal influences with cross-border ecological communities in Arizona-Sonora.

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