Pollen thieves: Reproductive interference in Australian alpine angiosperm communities by invasive Taraxacum officinale

Abstract

Flowering plants must vie with their peers to attract and reward animal pollinators in order to maximise the amount of conspecific pollen transferred to their ovules, and thus the number of their future offspring.  When a flowering plant is introduced into a stable community, it can engage in reproductive interference by limiting the amount of conspecific pollen received by native plants, leading to potential shifts in native plant abundance and diversity.  In the Australian Snowy Mountains, invasive Taraxacum officinale (L.) Weber ex F.H. Wigg has been found to be limiting pollen transferred to native species by competing for pollinators and creating a potential pollen cross-contamination risk.  T. officinale pollen was found on 31% of pollinators carrying native pollen, and on a further 12% of pollinators exclusively.  It was particularly attractive to Coleoptera, 75% of which were found to be carrying T. officinale pollen, putting native plants that rely on the order’s services at risk of pollen limitation.  Furthermore, T. officinale produced proportionally more florets than any other native or invasive plant species across four transects.  With climate change likely to boost abundance of the already formidable weed, more research into the scale of its impact on the vulnerable Australian alpine flora communities is needed.