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 discrete estimates of leaf age obtained using the traditional approach. Application of the new method offers considerable advantages to examine aspects of seagrass ecology dependent on leaf age. Regression of age-dependent properties of seagrasses such as the leaf surface lost to herbivores or epiphyte load, against the continuous estimates of leaf age estimated with the method proposed allows calculation of important rates for seagrass ecology, such as herbivory rate or epiphyte accrual. The interpolation method to estimate leaf age described provides, therefore, an important tool to assess the ecological implications of seagrass leaf ag.