Responses of an endemic species (Roscoea humeana) in the Hengduan Mountains to climate change

Abstract

Aim: Adaptation, migration and extinction of species is closely associated with climate changes and shape the distribution of biodiversity. The adaptive responses of species in the biodiversity hotspot, the Hengduan Mountains, to climate change remain poorly understood. Location: The Hengduan Mountains, southeast of the Qinghai-Tibet Plateau. Methods: The principles of phylogeography and landscape genomics were applied to the endemic species Roscoea humeana in the Hengduan Mountains by genotyping by sequencing data. A total of 5,902 single-nucleotide polymorphisms were used to analyse the genetic structure/diversity and changes in effective population size over time. Species distribution modelling, principal component analysis and gradient forest analysis were used to explore associations between climate change and genetic variation. Results: The population size of R. humeana rapidly increased after the Last Glacial Maximum. The contribution of climate to genetic variation was greater than that of geography. Precipitation during the warmest season played a pivotal role in the adaptation to climate changes. Loci associated with drought tolerance and anti-ultraviolet radiation were identified, suggesting local adaptation of R. humeana to alpine environments. Main conclusions: These results suggest that the current genetic structure and diversity of R. humeana were shaped by Quaternary climate fluctuations and persistence of microrefugia in the Hengduan Mountains. The results further suggest that R. humeana can survive in future refugia within the area where the warmest quarter precipitation is higher than 560 mm, and local adaptation to drought tolerance may be beneficial for its acclimation to future climate changes.