Life Stage-Specific Genetic Diversity and Landscape Characteristics Collectively Influence Genetic Recovery in Pometia pinnata Population 生活史阶段特异的遗传多样性与景观特征对番龙眼种群遗传恢复的协同影响

Abstract

Understanding the genetic structure of tree populations is crucial for forest conservation and management. This study investigates Pometia pinnata, an ecologically significant dominant tree species in Xishuangbanna, China. We hypothesized that historical colonization patterns and complex topography have shaped the genetic structure of the current population, with species diversity and density acting as barriers to gene flow. We sampled 988 P. pinnata individuals across a topographically complex 20 ha plot with varying elevations (821.4–1043 m a.s.l.). Using nine microsatellite loci, we genotyped individuals and categorized them into life stages based on diameter at breast height classes: Adult, Sapling I, Sapling II, and Seedlings. We excluded two microsatellites that deviated from the Hardy–Weinberg Equilibrium and analyzed the genetic structure, parentage/offspring relationships, demographic history, and associations with ecological characteristics, such as species diversity, species density, and topography. The demographic history indicated that adults in the valley are a potential source for the entire population, as confirmed by bottleneck events observed during early restoration. Despite this, a panmictic structure and wide gene flow were detected, suggesting multiple progeny sources. Inbreeding was observed to increase in seedlings. Species diversity and density showed a positive correlation with genetic distance in adults, while topographic features influenced genetic structure differently across life stages. The genetic landscape of P. pinnata reflects a complex interplay of ecological and historical factors rather than a single barrier to gene flow. Forest conservation strategies should focus on maintaining landscape-level gene flow to preserve genetic diversity, ensuring the long-term adaptive potential of forest populations, and mitigating the impacts of habitat loss due to anthropogenic activity.