Identifying bottlenecks in the life cycle of plants living on cliffs and rocky slopes: Lack of knowledge hinders conservation actions

Long term survival of plant populations relies on successful reproductive cycle to obtain generation turnover. Focusing on plant species of conservation concern, we brought together a group of plant conservationists from different countries to assess whether the already available information on plant reproductive biology and autecology is adequate for identifying which phases of single species life cycle might act as bottleneck. We compiled a list of 80 plant species of conservation concern living on European cliffs and rocky slopes, for which biological and autecological information was collected from scientific literature, technical reports, and expert knowledge. Results have shown that the available information on species reproductive biology and autecology is inadequate to identify bottlenecks in the life cycle of many species and to provide insights for the practical conservation of many more. Available knowledge is mainly referred to the flowering phase, less on seed production and much less on seedling establishment and on cloning. Meanwhile and noteworthy, flowering resulted to be the less critical phase for the fulfilment of the species life cycle. Overall, with this perspective article we aim to encourage a constructive debate among the scientific community members and policymakers to set up novel concerted strategies for the conservation of plant species of conservation concern. The challenge of the discussion is the implementation of the current approach with new biological and ecological information to be exclusively targeted at identifying the constraints that limit the generation turnover and furnishing specific indications for active management.