Juan Carlos Bravo | Geology Reports

USGS2022

Spatial models of jaguar energy expenditure in response to border wall construction and remediation

The construction of a wall at the United States-Mexico border is known to impede and deter movement of terrestrial wildlife between the two countries. One such species is the jaguar, in its northernmost range in the borderlands of Arizona and Sonora. We developed an anisotropic cost distance model for jaguar in a binational crossing area of the Madrean Sky Islands at the United States-Mexico border in Southern Arizona as a case study by using previously collected GPS tracking data for jaguars, bioenergetic calculations for pumas, and a digital elevation model. This model describes projected energy expenditure for jaguar to reach key water sources north of the international border. These desert springs and the broader study region provide vital habitat for jaguar conservation and reintroduction efforts in the United States. An emerging impediment to jaguar conservation and reintroduction is border infrastructure including border wall. By comparing walled and un-walled border sections, and three remediation scenarios, we demonstrate that existing border infrastructure significantly increases energy expenditure by jaguars and that some partial remediation scenarios are more beneficial than others. Our results demonstrate opportunities for remediation. Improved understanding of how border infrastructure impacts physiological requirements and resulting impacts to jaguar and other terrestrial wildlife in the United States-Mexico borderlands may inform conservation management.

Arizona↗

USGS2019

A mosaic of land tenure and ownership creates challenges and opportunities for transboundary conservation in the US-Mexico borderlands

In the Madrean Sky Islands of western North America, a mixture of public and private land ownership and tenure creates a complex situation for collaborative efforts in conservation. In this case study, we describe the current ownership and management structures in the US-Mexico borderlands where social, political, and economic conditions create extreme pressures on the environment and challenges for conservation. On the US side of the border, sky island mountain ranges are almost entirely publicly owned and managed by federal, state and tribal organizations that manage and monitor species, habitats, and disturbances including fire. In contrast, public lands are scarce in the adjacent mountain ranges of Mexico, rather, a unique system of private parcels and communal lands make up most of Mexico's Natural Protected Areas. Several of the Protected Area reserves in Mexico form a matrix that serves to connect scattered habitats for jaguars dispersing northward toward public and private reserves in the U.S. from their northernmost breeding areas in Mexico. Despite administrative or jurisdictional boundaries superimposed upon the landscape, we identify two unifying management themes that encourage collaborative management of transboundary landscape processes and habitat connectivity: jaguar conservation and wildfire management. Our case study promotes understanding of conservation challenges as they are perceived and managed in a diversity of settings across the US-Mexico borderlands. Ultimately, recognizing the unique and important contributions of people living and working under different systems of land ownership and tenure will open doors for partnerships in achieving common goals.

Arizona, Baja California, California, Chihuahua, N↗