Isthmus Railway Wildlife Crossing Concerns

Oaxaca, Mexico — Despite being a biological corridor and habitat for species such as the jaguar, tapir, spider monkey, and ocelote, the Isthmus of Tehuantepec Railway (FIT) lacks infrastructure for the safe crossing of wildlife.

Along the 133 kilometers of the Isthmus of Tehuantepec Railway, there will be only one wildlife crossing.

Located at kilometer 223+380, between Chivela and Lagunas, Oaxaca, this work does not respond to an environmental initiative of the project, but to a condition imposed by the Ministry of Environment and Natural Resources (Semarnat) to authorize the railway construction.

The FIT itself acknowledges this in the Technical Annex of contract FIT-GARMOP-SZ-26-2024 for the service to carry out the executive project of the wildlife crossing, a copy of which is held by EL UNIVERSAL.

The document specifies that the ministry conditioned the environmental authorization of the project on the adaptation of drainage works that function as wildlife crossings, a rule that the railway has complied with, so far, with this single construction.

The measure was established in the Eighth Condition of the environmental impact resolution issued by the General Directorate of Environmental Impact and Risk (DGIRA), which orders the Isthmus of Tehuantepec Railway to present a monitoring program and adapt underpasses and overpasses for wildlife to protect species such as the jaguar, ocelote, tapir, yaguarundí, white-lipped peccary, and spider monkey, common in the region.

The environmental resolution, issued on July 19, 2019, with official letter SGPA/DGIRA/DG/05602, obliged the FIT to apply mitigation measures and hire a company specialized in environmental management to ensure compliance with the provisions imposed by the Ministry of Environment.

Some of these species, such as the jaguar (Panthera onca), tapir (Tapirus bairdii), and ocelote (Leopardus pardalis), are listed as endangered in NOM-059-SEMARNAT-2010.

The technical document acknowledges that the railway line—132.8 kilometers between Medias Aguas, Veracruz, and La Mata, Oaxaca—does not have equivalent infrastructure for the crossing of wildlife.

Based on an observation study carried out in the area by the Unit for Environmental and Ecological Monitoring and Protection (USPAE) and the Institute of Ecology (Inecol), the FIT reported that along this section, animals continue to move along the right of way, in areas close to rural settlements and fragmented vegetation.

This analysis, prepared with the support of project staff as part of the Environmental Surveillance Plan approved by Semarnat, also evidences the lack of effective ecological connectivity measures between the patches of jungle and scrub surrounding the line.

For this reason, the Technical Annex concludes that the construction of the wildlife crossing, which is actually the extension of a culvert, in Chivela–Lagunas is necessary to maintain the flow of organisms and avoid the fragmentation of wild populations only in that area.

The total cost of the work is 11 million 714 thousand 524 pesos, as indicated by the details of the items of contracts FIT-GARMOP-OP-Z-39-2024, with a total cost of 10 million 131 thousand 959 pesos, and FIT-GARMOP-SZ-26-2024, for one million 582 thousand 565 pesos, signed with the companies Imeval de Occidente S.A. de C.V. and Grupo Consultor y Construcciones S.A. de C.V.

Regarding the composition of the wildlife crossing, the Technical Annex that brings together the catalog of concepts of contract FIT-GARMOP-OP-Z-39-2024 corresponding to the construction of the culvert extension for the Wildlife Underpass (PIF) details that it has extensions of containment walls built with braza stone, bat shelters, and a causeway for wildlife movement with ramps.

The Isthmus of Tehuantepec is one of the regions with the greatest biological diversity in the country due to its location between the ecosystems of the Gulf and the Pacific.

According to the National Commission for the Knowledge and Use of Biodiversity (Conabio), this area concentrates low jungles, tropical forests, and scrublands that serve as a natural corridor for mammals, reptiles, and birds at risk.

Research from the Institute of Ecology (Inecol) and the Institute of Biology of UNAM indicates that “the Isthmus concentrates 10% of the national biodiversity and functions as a biological bridge between the north and Central America, where populations of jaguar, tapir, spider monkey, and ocelote converge, species that depend on the continuity of the habitat to move and reproduce.”

Additionally, the Institute of Ecology has recorded in the region more than 746 species of vascular plants, belonging to 458 genera and 119 families.