Abstract
Long-term monitoring is a crucial tool for anticipating population collapse, which is particularly important in the case of priority species (rare, endangered or threatened). The 'Adopt a plant' programme was launched in 2013 as a collaborative network for monitoring plant populations in a heterogeneous landscape in northeastern Spain. Coordinated by scientists, participants (volunteers and rangers) estimate population sizes, record disturbances and follow rigorous sampling methods to track plant abundance year after year. This information allows us to estimate the long-term trend and temporal variation of nearly 300 populations. Regardless of the method used, we produce standardised indices of abundance change and, interestingly, stability resulted to be the dominant trend, particularly for priority species. Such information is crucial for reporting the conservation status of threatened plants and plants of Community interest (Habitats Directive). Our unexpected finding also highlights the importance of collecting large-scale information in order to refine conservation priorities and achieve a more comprehensive assessment of the vulnerability of the flora.
