Lost paradise-anthropogenic pressure alters microbial functional diversity in an endangered endemic toad-habitat system.

Tourism-driven human activity is increasingly disrupting fragile and once-pristine ecosystems worldwide, as evidenced by coral reef degradation in the Great Barrier Reef, vegetation loss in the Himalayas, and, as demonstrated in this study, microbial shifts in isolated highland habitats such as tepui summits. Integrating field-based ecological, microbiological, and conservation perspectives, this study provides novel insights into how anthropogenic disturbance-particularly tourism-affects microbial functional diversity across interconnected environmental (soil) and host-associated (amphibian skin and faeces) compartments in a globally unique and poorly studied highland ecosystem, the summit of Roraima-tepui in Venezuela. Our results provide clear evidence that anthropogenic disturbance on the summit of Roraima-tepui reduces microbial functional diversity-by 59% in soil and by 21% and 14% in the skin and faecal microbiomes of the (near)endemic toad Oreophrynella quelchii, respectively-compared to pristine sites. Our findings raise significant concern, as alterations in microbial composition and functions could disrupt host immunity and disease resistance in this unique, insular, and ecologically fragile ecosystem, particularly given the recent detection of anthropogenic pathogen incursion in amphibian communities. Our results stress the need to better understand the link between the observed shift in the skin microbiome's functional profiles in O. quelchii at summit sites most impacted by tourism and the recent emergence of the fungal pathogen Batrachochytrium dendrobatidis in the same environmental context. Our findings underscore the urgent need to mitigate human-induced pressures threatening the ecological integrity of the summit of Roraima-tepui, one of the world's most fragile and irreplaceable montane habitats.