Data for: Elevated inbreeding in Heliconia tortuosa is determined by tropical forest stand age, isolation, and loss of hummingbird functional diversity

Forest conversion and habitat loss are major threats to biological
diversity.  Forest regeneration can mitigate the negative effects
of old growth forest loss on species diversity, but less is known about
the extent to which forest loss reduces genetic diversity in remnant
populations and whether secondary forests play a role in the maintenance
of genetic diversity. We quantified genetic diversity in a tropical
hummingbird-pollinated understory herb, Heliconia tortuosa, across a
landscape mosaic of primary and secondary forest regrowth. Using
microsatellite genotypes from >850 adult and juvenile plants within
33 forest patches and extensive bird surveys, we examined the effect of
contemporary and historical landscape features including forest age
(primary vs. secondary forest), stand isolation, and pollinator
assemblages on genetic diversity and levels of inbreeding in H. tortuosa.
We found that inbreeding was up to 3x higher in secondary forest, and this
effect was amplified with reductions in primary forest in the surrounding
landscape through reduced observed heterozygosity in isolated fragments.
Inbreeding in forest patches was negatively correlated with the local
frequency of specialist long-distance foraging traplining hummingbirds.
Traplining hummingbirds therefore appear to facilitate mating among
unrelated plants - an inference we tested using empirically parameterized
simulations. Higher levels of inbreeding in H. tortuosa are therefore
associated with reduced functional diversity of hummingbirds in secondary
forests and forest patches isolated from primary forests. Our findings
suggest a cryptic consequence of primary forest loss and secondary forest
regeneration through the disruption of mutualistic interactions resulting
in the erosion of genetic diversity in a common understory plant.