ABSTRACT Questions The loss of semi‐natural grasslands due to land‐use changes has accelerated secondary succession, in a process known as woody plant encroachment (WPE). In recent decades, the implications of this phenomenon have begun to be studied more intensively; however, the effects on plant functional diversity and strategies have not received the same level of attention. In this study, we evaluated how the functional traits and functional diversity of plant communities change along a gradient of WPE. We also analysed how ecological and disturbance indicators vary with increasing cover of encroaching species. Location Sub‐Mediterranean calcareous grasslands in the northern Iberian Peninsula. Methods We surveyed 144 plots distributed across four study sites and along a gradient of woody cover. Species‐level trait and ecological and disturbance indicator values were compiled from published databases and combined with plot‐level cover to calculate community‐weighted means (CWMs) and functional diversity indices. Study site and encroachment effects were evaluated using multivariate (PERMANOVA) and mixed‐effects modelling approaches. Results Community functional composition shifted along the encroachment gradient, from grasslands characterised by hemicryptophytes, short‐distance dispersal and wind pollination to more encroached communities associated with taller life forms (phanerophytes and chamaephytes), longer dispersal distances and greater entomophily. Functional dispersion increased with encroachment, particularly beyond around 30% woody cover. Ecological indicator values indicated progressively moister, shadier and more acidic conditions with increasing shrub cover, accompanied by lower disturbance frequency. Encroachment effects were strongly site‐dependent, as supported by a significant study site (SITE) and woody plant encroachment level (LEVEL) interaction in multivariate trait space (PERMANOVA) and by frequent SITE × LEVEL effects across response variables. Conclusion Woody encroachment is associated with consistent community‐level functional and ecological shifts, but the magnitude and direction of these changes depend strongly on study site (local context). Integrating trait‐based metrics with ecological and disturbance indicators helps interpret grassland–shrubland transitions and supports site‐specific management of semi‐natural grasslands undergoing WPE.
Sánchez-Carmona et al. (Fri,) studied this question.