Niche Evolution and Conservation of a Chinese Endemic Genus Sinojackia (Styracaceae)

Climate change and human activities are expected to have a profound impact on the distribution of species, especially for narrowly distributed species. <i>Sinojackia</i> is endemically distributed in China, and all species are listed under Chinese protected wild species. Here, we reconstructed the phylogeny and estimated the divergence time of <i>Sinojackia</i> based on whole plastomes, conducted the niche evolution, and predicted the potential habitat area of <i>Sinojackia</i> from the LGM to the future. Our results strongly supported the monophyly of <i>Sinojackia</i> based on whole plastomes. This genus originated in the middle Miocene and diversified since the late Miocene. The aridity index was the highest significant factor for its niche evolution, and the niche evolution rate increased slowly since its divergence. The precipitation of the warmest quarter was a main environmental variable affecting the distribution of <i>Sinojackia</i> in the LGM, while the human footprint is the main variable in the near-current era and 2081-2100. Compared to the current distribution of <i>Sinojackia</i>, the highly suitable distribution area contracted in the LGM, but expanded during 2081-2100. This study provides potential areas for the in situ conservation of <i>Sinojackia</i>.