Data from: Genetic connectivity of the moth pollinated tree Glionnetia sericea in a highly fragmented habitat

Long-distance gene flow is thought to be one prerequisite for the
persistence of plant species in fragmented environments. Human influences
have led to severe fragmentation of native habitats in the Seychelles
islands, with many species surviving only in small and isolated
populations. The endangered Seychelles endemic tree Glionnetia sericea is
restricted to altitudes between 450 m and 900 m where the native forest
vegetation has been largely lost and replaced with exotic invasives over
the last 200 years. This study explores the genetic and ecological
consequences of population fragmentation in this species by analysing
patterns of genetic diversity in a sample of adults, juveniles and seeds,
and by using controlled pollination experiments. Our results show no
decrease in genetic diversity and no increase in genetic structuring from
adult to juvenile cohorts. Despite significant inbreeding in some
populations, there is no evidence of higher inbreeding in juvenile cohorts
relative to adults. A Bayesian structure analysis and a tentative
paternity analysis indicate extensive historical and contemporary gene
flow among remnant populations. Pollination experiments and a paternity
analysis show that Glionnetia sericea is self-compatible. Nevertheless,
outcrossing is present with 7% of mating events resulting from pollen
transfer between populations. Artificial pollination provided no evidence
for pollen limitation in isolated populations. The highly mobile and
specialized hawkmoth pollinators (Agrius convolvuli and Cenophodes tamsi;
Sphingidae) appear to promote extensive gene flow, thus mitigating the
potential negative ecological and genetic effects of habitat fragmentation
in this species. We conclude that contemporary gene flow is sufficient to
maintain genetic connectivity in this rare and restricted Seychelles
endemic, in contrast to other island endemic tree species with limited
contemporary gene flow.