On the use of reconstructive aging techniques for assessing seagrass demography:a critique of the model test of Jensen et al. (1996)

Abstract

The paper by Jensen et al. (1996) reports an attempt to test the predictive abilities of a population model based on the use of reconstructive techniques (Duarte et al. 1994). The population model that was tested utilizes the age distributions of individual seagrass short-shoots collected at least once per year, from which annual gross shoot recruitment rates (Rgrass yr-1 = lnN;-ln1Vi>t• where Nt is the total number of shoots and N;> 1 is the number of shoots older than a year) and instantaneous mortality rates [ l\lf, derived from the number of shoots in consecutive cohorts and estimated by fitting the equation N(t) = N(O) e·•Vft to observed data, where. N(t) is the number of shoots at time t, N(O) represents the number of shoots at t = 0, if t = 1 yr then