Encouraging news for in situ conservation: Translocation of salamander larvae has limited impacts on their skin microbiota.

Abstract

The key role of symbiotic skin bacteria communities in amphibian resistance to emerging pathogens is well recognized, but factors leading to their dysbiosis are not fully understood. In particular, the potential effects of population translocations on the composition and diversity of hosts' skin microbiota have received little attention, although such transfers are widely carried out as a strategy for amphibian conservation. To characterize the potential reorganization of the microbiota over such a sudden environmental change, we conducted a common-garden experiment simulating reciprocal translocations of yellow-spotted salamander larvae across three lakes. We sequenced skin microbiota samples collected before and 15 days after the transfer. Using a database of antifungal isolates, we identified symbionts with known function against the pathogen Batrachochytrium dendrobatidis, a major driver of amphibian declines. Our results indicate an important reorganization of bacterial assemblages throughout ontogeny, with strong changes in composition, diversity and structure of the skin microbiota in both control and translocated individuals over the 15 days of monitoring. Unexpectedly, the diversity and community structure of the microbiota were not significantly affected by the translocation event, thus suggesting a strong resilience of skin bacterial communities to environmental change-at least across the time-window studied here. A few phylotypes were more abundant in the microbiota of translocated larvae, but no differences were found among pathogen-inhibiting symbionts. Taken together, our results support amphibian translocations as a promising strategy for this endangered animal class, with limited impact on their skin microbiota.