Data from: Invasion status and phylogenetic relatedness predict cost of heterospecific pollen receipt: implications for native biodiversity decline

Understanding the mechanisms by which invasive species affect native
plants is a central challenge. Invasive plants have been shown to reduce
pollinator visitation to natives and increase pollen quantity limitation.
However, visitation and conspecific pollen delivery are only two
components of the pollination process; post-pollination interactions on
the stigma (heterospecific pollen [HP] receipt) could intensify
pre-pollination responses to invasion. Here we used meta-analysis to test
the hypotheses that invasive plants are more detrimental as HP donors than
natives ones, and that HP donors that are closely related to the
recipients have stronger effects on fruit and seed production compared to
distantly related ones. Invasive HP donors reduced fruit and seed
production of recipients to a greater degree than native ones, and this
was more intense for HP donors closely related to natives. Related donors
were more detrimental overall. Synthesis: These results suggest that the
total effect of invasive plants on native plant reproductive success could
be greater than what is inferred from visitation and conspecific pollen
transfer alone. Furthermore, these results indicate that invasive species
can reduce reproductive success of native species even if pollinator
visitation rates remain unaltered. Thus, we highlight the need to evaluate
pre- and post-pollination processes in order to fully understand the
potential effects of invasive species on the reproductive success and
maintenance of native plant populations.