Ecologue

What is Biodiversity?

Biodiversity is the variety of life on Earth. A single species is insignificant in the sense that it is one of billions, but it is actually of supreme importance, due to the interdependence of all life. We call this interdependence of life and its physical environment an ecosystem. An ecosystem can range anywhere in scale from a single tree, to the Earth itself. The removal of one species from the Earth’s ecosystem has a ripple effect on all other life forms, including humans. For example, coral reefs and mangrove swamps provide protection for organisms that live on coasts (including humans), so if we lost these components of biological diversity, thousands of organisms would face direct consequences, likely leading to a cascading loss of biodiversity. Professor David MacDonald of Oxford University puts it simply: “Without biodiversity, there is no future for humanity.”

Border Wall Severs Ancient Ecological Ties

Dr. William Ripple, professor of ecology at OSU, is one of 16 co-authors from the US and Mexico, who recently published a paper that outlines the wall’s impact on biodiversity. Some of North America’s most biologically diverse regions lay along the 3200-kilometer US-Mexico border, where fence and wall construction are already underway. The sections of wall constructed thus far are “reducing the area, quality, and connectivity of plant and animal habitats.” In addition to this direct ecological impact, the wall will reverse over a century of multinational conservation investment.

The Real ID Act gives the Department of Homeland Security (DHS) authority to bypass laws, such as the Endangered Species Act (ESA) and the National Environmental Policy Act (NEPA), on the basis that they slow construction. The laws would delay construction, but for necessary reasons: environmental impact analysis, development of less-damaging alternative strategies, post construction environmental monitoring, mitigation, public input, and pursuit of legal remedies.

The US-Mexico border spans six eco-regions: California Coastal, the Sonoran Desert, the Madrean Archipelago, the Chihuahuan Desert, the Southern Texas Plains, and the Western Gulf Coastal Plain. Vegetation types in these eco-regions include desert scrub, temperate forests and woodlands, semi-desert and plains grasslands, subtropical scrub-lands, freshwater wetlands, and salt marshes. These regions support considerable biodiversity; the border divides the geographic ranges of 1506 native plant and animal species, including 62 species listed as Critically Endangered, Endangered, or Vulnerable by the International Union for Conservation of Nature (IUCN).

Construction of the wall and associated infrastructure destroys or damages natural vegetation, kills animals directly or through habitat loss, fragments habitats, erodes soils, changes wildfire behavior, and alters hydro-logical processes. The wall physically prevents animals from accessing food, water, mates, and other resources that they require. A continuous border wall would disconnect over 34% of US non-flying native species (346) from over 50% of their range, which is south of the border wall. If isolated by a wall, 17% of the 346 species, including jaguar and ocelot, would have residual US populations covering less than 20,000 square kilometers, elevating their risk of complete removal from the US.  

Additional Information

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Peters, et al. “Nature Divided, Scientists United: US–Mexico Border Wall Threatens Biodiversity and Binational Conservation | BioScience | Oxford Academic.” OUP Academic, Oxford University Press, 24 July 2018, academic.oup.com/bioscience/advance-article/doi/10.1093/biosci/biy063/5057517.