Reproductive system of the critically endangered taxon Gentianella praecox subsp. bohemica

Gentianella praecox subsp. bohemica is a critically endangered taxon endemic to the Bohemian Massif and very dependent on appropriate management. We found that it is also very dependent on pollinator services, as the probability of autonomous selfing is low. Both hand-selfing and outcrossing resulted in similar seed production. Three out of four of the populations studied appeared to be pollen limited. The most frequent visitors and effective pollinators were bumblebees. However, we found that the different species of bumblebee differed greatly in their efficiency as pollinators due to differences in their behaviour. In contrast to other bumblebees, Bombus wurflenii, which nearly always robbed nectar through a hole in the corolla tube and only accidentally touched the reproductive organs, was an inefficient pollinator. Other important pollinators of G. praecox subsp. bohemica were honeybees (in lowland areas) and hoverflies. This study indicates that management for conservation should focus not only on creating gaps to improve the germination of G. praecox subsp. bohemica and reduce competition from other species, but also on improving conditions for pollinators. Hand pollination may be necessary to increase survival in populations that are close to extinction.