Mountain caves of the central region of Veracruz: A vertebrate biodiversity reservoir in a Neotropical hotspot

contains a high percentage of unique species [1,3], especially in the case of reptiles and amphibians. Birds and mammals were the groups that shared the most species between karst and volcanic caves. The mountain region of central Veracruz, Mexico hosts a large system of karst and volcanic caves that are unexplored. If we consider the number of unexplored caves present in this region (approximately 53), the vertebrate diversity found in this study is likely to represent a fraction of the total diversity that these subterranean ecosystems can contain. Future studies should focus on assessing vertebrate diversity in other unexplored caves of the region. Human disturbances, such as land-use change, directly affect subterranean biodiversity [69–71]. Many vertebrates that inhabit caves are especially adapted to these environments and may be highly vulnerable to human disturbances [67], particularly those that cannot move large distances such reptiles and amphibians. For example, the loss of vegetation may result in environmental degradation, especially of small, shallow caves. In this context, in the last twenty years, the conversion of forests into cattle pastures and agricultural fields has been the main land use pressure on the natural forests of central Veracruz [24], which affects the forests around caves. Considering these threats, it is becoming increasingly important to carry out conservation actions to protect subterranean environments [71,72], since the species that inhabit them, many of which are endemic, are vulnerable to human disturbances.

Protecting cave ecosystems and the vertebrates that rely on them is essential for preserving biodiversity and preventing the loss of unique species and ecological functions [73]. Our results confirm the presence of vertebrates native to Mexico listed in some risk category in the Official Mexican Standard NOM-059-SEMARNAT-2010. Four amphibians, five reptiles, 22 birds, and one mammal are found in special protection categories, two mammals, nine birds, two reptiles, and one amphibian are listed as threatened, and one bird and one mammal are listed as endangered. Conservation efforts aimed at preserving these cave ecosystems are essen- tial for the protection of vertebrate biodiversity. We suggest including the caves of the central region of Veracruz in the conservation agenda of local governments and communities. Com- munity-based conservation can help ensure the presence of vertebrate species in the caves of this region. Given that this system of karst and volcanic caves is located in the transition belt between the Nearctic and Neotropical regions, it may favor a greater diversity of vertebrates and other life forms, especially of poorly studied groups such as invertebrates. Many cave ecosystems support diverse communities of invertebrates, such as cave-adapted insects and crustaceans [68]. These invertebrates serve as a food source for vertebrates, contributing to the overall bio- diversity within caves [68]. Future studies focusing on the evaluation of invertebrate diversity can provide complementary information about the importance of these organisms for the eco-

logical functions and maintenance of vertebrate food webs in the caves of this region. Supporting information S1 Table. Vertebrate species recorded in karst and volcanic caves at different altitudinal zone of the central region of Veracruz, Mexico. (DOCX) Acknowledgments A.H.L. thanks CONAHCYT for the scholarship granted. Thanks to the ejidal commissioners of each locality for facilitating access to underground entrances. Special thanks to the speleolo- gists from the Exploration Clubs Mexico A.C. (Memo, Abraham, Rober, Lucy, Lico, Edgar, PLOS ONE Vertebrates in caves of Neotropical hotspot PLOS ONE | https://doi.org/10.1371/journal.pone.0306105 August 9, 2024 15 / 19