ESTIMATING LEAF AGE OF THE SEAGRASS POSIDONIA-OCEANICA (L) DELILE USING THE PLASTOCHRONE INTERVAL INDEX

We describe a method to estimate the leaf age of Posidonia oceanica (L .) Delile, which yields continuous estimates compared with the discret e estimates of leaf age obtained using the traditional approach. Appli cation of the new method offers considerable advantages to examine asp ects of seagrass ecology dependent on leaf age. Regression of age-depe ndent properties of seagrasses, such as the leaf surface lost to herbi vores or epiphyte load, against the continuous estimates of leaf age e stimated with the method proposed allows calculation of important rate s for seagrass ecology, such as herbivory rate or epiphyte accrual. Th e interpolation method to estimate leaf age described provides, theref ore, an important tool to assess the ecological implications of seagra ss leaf age.