Anticipating the potential impacts of Batrachochytrium salamandrivorans on Neotropical salamander diversity

Abstract

Emergent infectious disease caused by the fungal pathogens Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal) represents one of the major causes of biodiversity loss in amphibians. While Bd has affected amphibians worldwide, Bsal remains restricted to Asia and Europe, but also could be a major threat for salamanders in the Western hemisphere, including the 320 bolitoglossine species described. Here, we predict the suitable areas for Bsal in the Neotropics and assess its potential impact on bolitoglossine diversity. For this, we determined the geographic patterns of taxonomic, phylogenetic, and functional diversity for bolitoglossines and modeled the potential distribution of Bsal in the Neotropics. We identified which species and regions could be at risk from an eventual introduction of Bsal in the region, quantified the degree of overlap between regions of high diversity and the suitable conditions for the pathogen, and considered species IUCN Red List status, and geographic range size. We found that regions of high taxonomic, phylogenetic, and functional diversity are concentrated in the Trans‐Mexican Volcanic Belt, Sierra Madre Oriental, the southern portion of Sierra Madre del Sur and the mountains of Oaxaca in México, as well as the Chiapan‐Guatemalan highlands, and the Cordilleras of Costa Rica and Panama. Alarmingly, the regions of high diversity for bolitoglossines and over 75% of the ranges of the more threatened species could be affected by Bsal. Given the unknown vulnerability of these species, we strongly recommend measures to avoid the introduction of Bsal in the continent. Abstract in Spanish is available with online material.

The fungal pathogen Batrachochytrium salamandrivorans is not detected in wild and captive amphibians from Mexico

“… (A) Map of amphibian richness in Mexico constructed using amphibian distribution maps of the IUCN (2022) . (B) Map of Bsal habitat suitability obtained from García-Rodríguez et al (2022) and categorized following Basanta, Rebollar & Parra-Olea (2019) . Circles represent sampled sites for wild amphibians, and the white square represents the sample site for captive amphibians.…”

“…We also revised the risk category according to the IUCN ( IUCN, 2022 ) for all amphibian species analyzed. Additionally, we estimated the potential risk of Bsal on each sampled site by extracting the Bsal suitability values from the model obtained in García-Rodríguez et al (2022) using QGIS v3.8.3 ( http://www.qgis.org ). Because the logistic output of the suitability map of Bsal ranges from 0 to 1, with 0 indicating unsuitable habitat and 1 indicating the highest suitability, we also categorized them into four categories of suitability (not suitable, low suitability, moderate suitability, high suitability) according to Basanta, Rebollar & Parra-Olea (2019) .…”

“…It is highly likely that the potential introduction of Bsal to Mexico would represent a serious threat to local and global amphibian diversity. Previous studies have predicted that regions of Mexico such as the Trans Mexican Volcanic Belt, Sierra Madre del Sur, Sierra Madre Oriental, and Northern Oaxaca are places that could become highly suitable for Bsal ( Basanta, Rebollar & Parra-Olea, 2019 ; García-Rodríguez et al, 2022 ). These studies also have found that the potential suitable habitat areas for Bsal corresponded to areas of high salamander diversity, increasing the risk of Bsal -vulnerable species losses in case the pathogen arrives ( Basanta, Rebollar & Parra-Olea, 2019 ; García-Rodríguez et al, 2022 ).…”

“…Previous studies have predicted that regions of Mexico such as the Trans Mexican Volcanic Belt, Sierra Madre del Sur, Sierra Madre Oriental, and Northern Oaxaca are places that could become highly suitable for Bsal ( Basanta, Rebollar & Parra-Olea, 2019 ; García-Rodríguez et al, 2022 ). These studies also have found that the potential suitable habitat areas for Bsal corresponded to areas of high salamander diversity, increasing the risk of Bsal -vulnerable species losses in case the pathogen arrives ( Basanta, Rebollar & Parra-Olea, 2019 ; García-Rodríguez et al, 2022 ). Thus, Bsal surveillance directed to areas of high suitability for Bsal and high amphibian diversity could be a good strategy to take immediate conservation actions.…”

“…In this study, our main goal was to survey wild and captive amphibian populations in Mexico to search for the presence of Bsal . We sampled amphibians from different sites across the country with variable degrees of amphibian diversity and Bsal habitat suitability areas based on previous studies ( Basanta, Rebollar & Parra-Olea, 2019 ; García-Rodríguez et al, 2022 ). This information could be informative for future surveillance efforts in areas of potential risk and identify new areas where pathogen arrival may be more likely to occur in Mexico.…”