# Ecophysiological Suitability of Batrachochytrium dendrobatidis in Mexico

## TL;DR

This study predicts where a deadly frog fungus will thrive in Mexico, showing it favors mountainous regions and how climate change may reduce its spread.

## Contribution

A novel ecophysiological suitability index for Batrachochytrium dendrobatidis integrating temperature parameters and climate change projections.

## Key findings

- Bd suitability is highest in central Mexican mountainous regions and lowest in coastal and lowland areas.
- By 2050 and 2070, climate change scenarios predict reduced Bd suitability across most of Mexico.
- Over half of state natural protected areas have high suitability for Bd, threatening endemic amphibians in mountain habitats.

## Abstract

Batrachochytrium dendrobatidis (Bd) is a fungal pathogen responsible for amphibian population declines worldwide. In Mexico, understanding the potential distribution of Bd is crucial for conservation. Here, we developed an ecophysiological suitability index that integrates five key physiological parameters related to temperature. The environmental variables from WorldClim v2.1 were used to derive spatial representations of Bd’s thermal responses. A multicriteria evaluation combined these parameters into an ecophysiological suitability index. This index was projected to 2050 and 2070 under two contrasting climate change scenarios. We also analyzed the overlap between Bd’s suitability, natural protected areas (NPAs), and endemic amphibian geographic distributions to assess conservation implications. Our results indicate that Bd suitability is highest in the mountainous regions of central Mexico and declines significantly in coastal and lowland areas. By 2050 and 2070, both climate change scenarios predict reduced suitability across most of Mexico. Thirty-five percent of federal NPAs and 53% of state NPAs had high suitability for Bd. Endemic amphibians inhabiting mountains face greater suitability for Bd in their habitats. Our findings highlight the utility of mechanistic models for predicting pathogen distributions under environmental constraints. This approach provides actionable insights for prioritizing conservation efforts, including habitat management and amphibian population monitoring.

The online version contains supplementary material available at 10.1007/s10393-025-01734-w.