The amphibian skin-microbiome is a component influencing host health that may provide resistance to pathogens, such as the fungal pathogen Batrachochytrium dendrobatis (Bd), the likely agent of amphibian population declines. Alteration of the microbiome associated with unfavorable environmental changes produced by anthropogenic activities may make the host more susceptible to pathogens. Some amphibians thought to be “extinct” have been rediscovered years/decades after population declines in the late 1980s probably due to evolved resistance to Bd and are now threatened by anthropogenic land-use changes. We previously detected that these survivor species possess a dynamic skin-microbiome with putative Bd-inhibitory bacteria. However, the way that habitat disturbance influences their skin-microbiome is unknown. We studied the influence of habitat disturbance on the skin-microbiome as well as the putative Bd-inhibitory bacteria of Lithobates vibicarius, an amphibian surviving after its presumed extinction. We hypothesized that skin-microbiome and putative Bd-inhibitory bacteria from host skin differ between undisturbed- and disturbed-habitats. We analyzed the skin-microbiome from adults (68 individuals) of L. vibicarius across distinct sites (undisturbed sites = 3, disturbed sites = 3) in the Juan Castro Blanco National Park, Costa Rica. We used 16S rRNA amplicon-sequencing to analyze the diversity patterns of the skin-microbiome.
Results/Conclusions
We found that cutaneous bacterial communities of adults differed between undisturbed and disturbed habitats. The adults from disturbed habitats exhibited greater bacterial community dispersion than those from undisturbed habitats. These findings support the microbial “Anna Karenina principle”, in which disturbance is hypothesized to cause greater dysbiosis in communities that can impact host health. Greater variation in individual profiles may be due to the presence of environmental stressors at disturbed habitats (e.g., livestock grazing, agriculture activities, and loss of natural forest coverage) that alter a stable state of the microbiome that can impact host health. Putative Bd-inhibitory bacterial community followed the same pattern as the entire bacterial community across habitat types. Adults from the disturbed habitats showed a higher richness of Bd-inhibitory bacteria and a greater number of these bacteria with high relative abundance than those from the undisturbed habitats. Our results provide insights into the influence of human-modified landscapes on the skin-microbiome and health of Bd-survivors.