Population dynamics of Aster pyrenaeus Desf., a threatened species of temperate forest edges: A view of meso- and micro-scales

The effect of forest edges on population viability is one of the most unexplored aspects of plant conservation, and questions arise as to the most adequate management model for preserving species in these habitats. Here, we investigate the population dynamics of a high-priority species (Aster pyrenaeus) related to temperate forest edges in northern Spain. One isolated population was monitored during a 6-year period to analyse its response to habitat configuration at different scales. The effect of the sun-shade gradient was tested at the micro-scale using vegetation cover classes, and stochastic simulations were conducted at the meso-scale using spatially explicit models. At the micro-scale, monitored individuals were preferably located in sunny and semi-shady habitats, where population growth was greater. Species presence at the meso-scale was restricted to mixed shady vegetation, showing a null extinction risk in all the tested scenarios but a high probability of decline under past land use. The studied population seems to have persisted on historical remnants with habitat heterogeneity, supporting the hypothesis that the species has its proper ecological niche in grassland–forest edges. We conclude that the conservation management of plant populations dependent on forest edges should consider the maintenance of heterogeneous habitats.