Data from: Persistence of long-distance, insect-mediated pollen movement for a tropical canopy tree species in remnant forest patches in an urban landscape

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 gene flow of forest-dependent tree
species in urban landscapes. 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. We genotyped the vast majority of adults (N=179) and a large
number of recruits (N=2103) with 8 highly polymorphic microsatellite
markers. Spatial genetic structure of the recruit and adult cohorts was
significant, showing routine gene dispersal distances of ~100–400 m.
Parentage analysis showed that 97% of recruits were within 100 m of their
mother tree, and a high frequency of relatively short-distance pollen
dispersal (median ~143–187 m). Despite routine seed and pollen dispersal
distances of within a few hundred meters, interpatch gene flow occurred
between all patches and was dominated by pollen movement: parentage
analysis showed 76 pollen versus 2 seed interpatch dispersal events, and
the seedling neighborhood model estimated ~1–6% seed immigration and
~21–46% pollen immigration rates, depending on patch. In addition, the
smallest patch (containing five adult K. malaccensis trees) was entirely
surrounded by >2.5 km of ‘impervious’ substrate, yet had the
highest proportional pollen and seed immigration estimates of any patch.
Hence, contrary to our hypothesis, insect-mediated gene flow persisted
across an urban landscape, and several of our results also parallel key
findings from insect-pollinated canopy trees sampled in mixed
agricultural–forest landscapes.