Imprints of Land Use History on the Cutaneous Microbiota of Mexican Cloud Forest Salamanders

The cloud forest harbors the highest amphibian diversity in Mexico, particularly among plethodontid salamanders. However, the expansion of agricultural and cattle ranching activities has significantly impacted this ecosystem and their native species. Beyond direct effects on cloud forest-dwelling species, effects of land-use change on free-living and salamander skin associated bacterial assemblages are underexplored in the cloud forest and in plethodontid salamanders specifically. This study examines how historical land-use changes may influence environmental and salamander skin bacterial communities, focusing on two types of previous land-use and six sympatric plethodontid salamanders from the cloud forest. Furthermore, we explored the presence of the pathogenic fungus Batrachochytrium dendrobatidis (Bd), due to its potential interaction with salamander skin bacterial communities. We found that skin bacterial communities varied with land-use history: in habitats formerly used for agriculture salamanders exhibited higher bacterial diversity, and communities' dispersion varied depending on the previous land-use. We found a very low Bd prevalence throughout the study area. Our findings suggest that bacterial communities associated with the skin of plethodontid salamanders may be influenced by land-use history in cloud forest fragments.