Pollinator Associations of Rare and Endangered Epacris Species (Ericaceae) in Lutruwita/Tasmania: Implications for Conservation

The breeding systems of Lutruwita/Tasmania's threatened Epacris taxa are poorly known. Our main objective was to determine the pollinators of several endemic species and explore for relationships between pollinators, floral morphology, flowering time and habitat. The Epacris have limited variation in floral traits and exhibit generalist floral visitor profiles. No significant relationships were found between the floral visitor profiles and floral attributes, flowering times or habitats. Visitor exclusion trials in three of the Epacris spp. suggest they may be near obligate out‐crossers. In open pollination, up to 30% of capsules had numerous viable seeds. No Epacris were exclusively bee‐, fly‐ or butterfly‐pollinated and for each species, pollen was dispersed by more than one functional group of insects. There was considerable overlap in visitor profiles with flies having the greatest diversity. Reed bees ( Exoneura sp.) and blow flies ( Calliphora spp.) visited all plant species, followed by tachinid flies. Butterflies were recorded from all except E. glabella and E. virgata . The introduced honeybee accounted for over half of all observed visits, while bumblebees were occasional. The fact that rare Epacris use common native insects is arguably positive for their conservation as it buffers against pollinator decline. However, the presence of exotic visitors at their flowers underscores the need to consider the ecological impact of non‐native pollinators in conservation planning. The invasion of Epacris breeding systems by the large super‐generalist social bees is likely to be detrimental in the long term due not only to their efficiency in rapidly depleting nectar and pollen resources but also in their potential to irreversibly alter gene flow in small scattered and rare plant populations.