The last stand: Demographic and population genomic analysis reveals terminal endangerment in tropical timber species Vatica guangxiensis

Abstract

Tropical and subtropical trees provide key ecosystem services but are facing global population decline due to logging, habitat degradation, land conversion, and climate change. Vatica guangxiensis used to be a characteristic timber species of China's tropical forests but is now terminally endangered (280 individuals) and fragmented into three relictual populations in southwest China. Generating genome-wide DNA for ∼82% of all living tree individuals of this species complex, we found evidence for a late Pliocene division into two species-level lineages that have not had gene flow for approximately 3 million years. All three relictual populations exhibited a loss of genetic diversity and recent bottlenecks. In addition, forward simulations indicated a likely population collapse in all three populations within the next century. Our study generates a model framework for the integration of genomic evidence—including evolutionary history, current genetic variation, and future projections—into conservation planning.