The interplay between flowering timing and environmental constraints affects the functional strategies in central Apennine grasslands

The timing of flowering is an important component of community assembly. Indeed flowering phenology affects the composition of plant communities through its effect on species interactions. Moreover, flower production is resource-intensive, which might tend to favour reproduction during times of low environmental stress. Nevertheless, if flowering time is critical to competition for resources or avoidance of stress, it could be considered a part of a larger plant strategy that incorporates other functional traits. Actually it was stated that in grasslands of central Apennines, dominant species tend to bloom in the central phases of the growing season, when no stress acts in the system, day-length and light intensity allow a high rate of photosynthesis, and a long time is available for seed maturation. These species do not need functional strategies allowing fast pre-emption of the canopy or tolerance to stresses. Instead, subordinate and accidental species have functional strategies that allow them to flower before or after the dominant ones or to share the same period through a different type of space occupation. Moreover the functional set underlying the flowering pattern of subordinate and accidental species has a dual ecological meaning. It limits competition with dominant species and enables tolerance to environmental stresses, which change throughout the growing season (i.e. low soil temperature in spring and water shortage in summer). Also invasion of pastures by tall grasses owing to the management cessation affects the flowering-related functional pattern in that during the central and late phases of the growing season (when invasive tall grasses are growing and blooming), flowering species of abandoned meadows are marked by a set of traits devoted to stress tolerance or underlying a long reproductive cycle. It is possible to argue that the comprehension of the changes in the flowering-related functional pattern in abandoned pastures may help to explain the ecosystem functional response to the cessation of anthropogenic disturbance.