Population reinforcement - A glimmer of hope for the conservation of the highly endangered Spring Pasque flower (Pulsatilla vernalis)

In this study, we evaluated the reinforcement of Pulsatilla vernalis, a rare and endangered plant species which strongly declined in Central Europe during the last decades. Actually, only nine remnant populations of the Spring Pasque flower still exist. These were subjected to population reinforcement by the governments of the Upper Palatinate and Lower Bavaria in a recovery programme since 1999. Therefore, plants were grown from local seed material and planted out in the respective populations. Here, we investigated the success of this population recovery programme and analysed whether potential bottlenecks during population reinforcement caused by seed collection, germination and plant propagation affected fitness and genetic variation of P. vernalis. For this reason, we compared morphological traits, germination and genetic variation of wild and planted individuals from each population. The total number of individuals rose from 290, when the recovery programme started to 1368 in 2012 (4.7-fold). Wild and planted individuals did not differ in most morphological traits. However, wild individuals were slightly larger than planted ones, due to their higher age. Seeds of P. vernalis germinated well and germination success of wild and planted individuals was comparable. Genetic variation within wild and planted individuals from each population did not differ significantly and we observed in only three populations slight genetic variation between wild and planted individuals. Considering the results of our study, population reinforcement of P. vernalis was a success. Increasing population sizes had no negative impact on fitness and genetic variation. Although reintroduction was recently challenged as a successful tool in plant conservation, population reinforcement is a glimmer of hope for the long-term conservation of this highly endangered species. (C) 2013 Elsevier Ltd. All rights reserved.