Data from: Persistence of long-distance, insect-mediated pollen movement for a tropical canopy tree species in remnant forest patches in an urban landscape|基因流动数据集|城市化影响数据集

As deforestation and urbanization continue at rapid rates in tropical regions, urban forest patches are essential repositories of biodiversity. However, almost nothing is known about the effects of urbanization on gene flow of forest-dependent tree species. Buildings, roads and other “impervious” substrates considerably constrict the movement of small animals, and for many plant species the restricted movement of seed or pollen dispersers could have far-reaching genetic consequences. In this study, we investigated gene flow in the insect-pollinated, wind-dispersed tropical tree Koompassia malaccensis in and among three remnant forest patches in the urbanized landscape of Singapore. Most mature trees in the study had reproduced; parentage analysis assigned 93% of adults to at least one seedling, which likely contributed to the high allelic richness in the recruit cohort. Spatial genetic structure (SGS) of the recruit and adult cohorts was significant. Supporting this result, parentage analysis showed that 97% of recruits were within 100 m of their mother tree, and there was a high frequency of relatively short distance pollen dispersal (median 143–187 m) — a distance similar to the nearest-neighbour distances (median 105–127 m). Despite these similarities among patches, smaller patches with fewer adults displayed higher self-fertilization. The smallest patch was entirely surrounded by >2.5 km of “impervious” habitat; the SGS in this patch was significantly different from the recruits of the other patches and the adult cohort, with high levels of selfing (30.9%), low within-patch outcrossed parent pairs (n = 7), and the highest pollen and seed extra-patch immigration estimates of the three patches (seed: 2.0–6.7%; pollen 13.8–48.3%). Hence, contrary to our hypothesis, insect-mediated gene flow persists across >2.5 km of urban “impervious” substrate, and several of our results also parallel key findings from insect-pollinated canopy trees sampled in mixed agricultural-forest landscapes.