Data from: Exchanging genes within a city: Analysis of pollen flow patterns in a narrow endemic plant species threatened by urbanisation

Disruption of gene flow following anthropogenic fragmentation of natural
habitat has been investigated in many species; however,
fragmentation-induced effects on endemic plants that rely on
species-specific invertebrate pollinators are still unclear. While
honeybees can forage over long distances, many native bees with small body
size are unable to extend their foraging range and overcome man-made
infrastructure, making habitat fragmentation the largest threat to such
systems. In many long-lived plants, the time since fragmentation has not
been long enough for detectable changes in the genetic composition of
standing populations, and changes in dispersal patterns observed in seeds
may provide insights into the future impact of habitat changes. Using
paternity assignment analysis, we characterised the plant mating system
and changes in dispersal patterns across multiple fragmented and
non-fragmented populations. Results showed that while pollen could travel
unimpeded through unfragmented bushland, fragments separated by built-up
areas resulted in complete isolation, with no pollen immigration. Native
pollinators appeared unable to maintain an adequate inter-population
pollen flow in heavily fragmented landscapes. This reduction in
contemporary gene flow may reduce the ability of small populations to
recover lost genetic variation through connection with larger remnants,
with impacts on the future persistence of threatened species that rely on
species-specific pollinators. Our study highlights the importance of
understanding species-specific life history and ecological traits when
planning conservation actions, such as translocations and reintroductions,
in order to maintain, or increase, adequate population size to sustain
genetic diversity and mating systems within populations.