Evaluating the Long-Term Effect of Successful Translocation on the Genetic Diversity of Romer's Tree Frog (Liuixalus romeri) in Hong Kong: Small Steps Lead to Giant Leaps

The Hong Kong International Airport was built by reclaiming land from the ocean and flattening Chek Lap Kok Island. Among the species inhabiting the island was the endangered Liuixalus. Due to imminent airport construction, this population was translocated to eight sites where the species was not previously found in Hong Kong. Subsequent population monitoring found that three were unsuccessful, and five are were successful. Our study aims to 1) provide a detailed translocation history of L. romeri , 2) evaluate the long-term effect that translocation had on L. romeri genetic diversity and 3) identify the environmental variables that promoted translocation success. We performed double digestion RAD sequencing for 61 individuals from 16 localities (8 native, 8 translocation). We found that each native island represents a genetically independent cluster, and the translocation sites are not significantly different from each other. We extracted environmental data (NDVI, slope and bioclimatic variables) from the localities of successful and unsuccessful translocation sites, and all Hong Kong sites with L. romeri records in four 5-year time intervals. Only the slope was significantly different between successful and unsuccessful translocation sites, and that the precipitation and the temperature were significantly different between sites and across the four 5-year time intervals. By estimating the genetic diversity of L. romeri post-translocation and accounting for the environment suitability, we provide information to help manage the conservation efforts for this species, as well as contribute to the general understanding of the impact of translocations.