Low microbiome diversity in threatened amphibians from two biodiversity hotspots.

Microbial diversity positively influences community resilience of the host microbiome. However, extinction risk factors such as habitat specialization, narrow environmental tolerances, and exposure to anthropogenic disturbance may homogenize host-associated microbial communities critical for stress responses including disease defense. In a dataset containing 43 threatened and 90 non-threatened amphibian species across two biodiversity hotspots (Brazil's Atlantic Forest and Madagascar), we found that threatened host species carried lower skin bacterial diversity, after accounting for key environmental and host factors. The consistency of our findings across continents suggests the broad scale at which low bacteriome diversity may compromise pathogen defenses in species already burdened with the threat of extinction.

Herpetofauna from an Atlantic Forest fragment in São Paulo, Brazil

Habitat loss via urbanization is a cause of decline for reptile and amphibian species around the world. The Atlantic Forest is the second largest rainforest of South America and holds one of the most extraordinary herpetofauna in the world, even after decades of fragmentation. The Parque Estadual das Fontes do Ipiranga (PEFI) is one of the most important remnants of Atlantic Forest inside the city of São Paulo (Brazil), but its herpetofauna richness has not been studied. Between 2011 and 2014, we carried out a herpetofaunal inventory in the PEFI and made notes on habitat use by using pitfall traps with drift fences combined with acoustic and visual encounter surveys. We also collected data from opportunistic encounters and historical information from scientific collections. We found that the PEFI harbors 22 native species of anurans, 24 native species of reptiles, and three exotic species of reptiles. Also, through surveying scientific collections, we found three species of amphibians and one of the snakes that were detected in the past but were not detected during our survey. The composition of amphibian species in the PEFI is similar to proximal small urban and periurban Atlantic Forest fragments, but its species richness is higher than these fragments even when compared to areas with similar or larger size. In conclusion, the highly urban PEFI supports considerable herpetofaunal diversity in comparison with other regional areas and our data reinforce the necessity of conserving this and other urban forest fragments through strategic management across the Atlantic Forest.