A new study finds that the US-Mexico border barrier system restricts wildlife access to water along a stretch of the Rio Grande in southern Texas. A future continuous barrier could eliminate that access entirely in some areas. Researchers modeled how javelina, coyote, and white-tailed deer move across the landscape under three scenarios: no barrier, the current barrier system, and a hypothetical continuous barrier.
The current barrier in the Lower Rio Grande Valley spans about 134 kilometers across 41 separate segments, leaving roughly 40 gaps ranging from 30 meters to nearly 38 kilometers wide. The modeling found that areas next to built barrier sections show reduced wildlife movement toward the river, while the gaps between segments function as corridors that channel movement toward the water.
National Wildlife Refuge lands along the river were found to be especially valuable for wildlife movement, showing both lower movement costs and higher modeled current density than surrounding non-refuge land. However, more than a fifth of the existing gaps were located in areas of medium or low habitat quality, suggesting some passable openings may still carry risk for animals using them.
Under the modeled future scenario, where existing gaps are closed to form a single continuous barrier, wildlife access to water would be lost entirely on the north side of the barrier in those areas. New barrier sections are under construction which means the study's findings likely represent a conservative estimate impact.
The study points to several mitigation options, including habitat restoration near barrier gaps, modified barrier designs that allow smaller species to pass through, and continued land acquisition for conservation corridors connecting existing refuge tracts.
