Strong seedling recruitment does not limit mangrove vulnerability to harvest
Ecological studies on the impacts of timber harvesting contributed to inform sustainablemanagement strategies of tropical forests. However, these studies rely strongly on twomajor assumptions: (i) strong seedlings recruitment predispose for positive population dynamics, and (ii)more adult trees is a guarantee for a strong reproductive capability of the population. These assumptions are applied without accounting for the life history of the harvested species. Here, we revisit these assumptions in light of the life history theory, which predicts different responses of shortand long-lived species to perturbation.Wepredict that harvesting adults, rather than reducing seedling recruitment of longlived species, would have greater impact on population dynamics.We tested our prediction on three mangrove species in SouthAfrica. First, we reconstructed the projectionmatrices for threemangrove species in theMngazana Estuary of EasternCape province of SouthAfrica. Next, we simulated a range of harvest intensities for different life stages and explored howharvesting influences population dynamics. Finally, we examined the age-specificmortality trajectories for all three species.We found that populations of all three species were closer to their stable stage distribution. Contrary to popular belief, we found that changes in seedling recruitment will haveminimal effects onmangrove longtermpopulation dynamics, afinding consistent with the life history theory. However, contrary to expectation, simulating harvest of adults hadminimal effect on population dynamics. This is due to low reproductive values for these late stages. Our analysis of age-specificmortality trajectories further provided evidence for positive senescence particularly forAvicenniawhichwas the least resilient to harvest. Ourfindings cast doubt on the traditional forestmanagement strategies that rely strongly on seedling density as ametric of sustainability and forbid unquestionably harvesting large individuals. We call for cautionwhile generalizing forestmanagement strategies irrespective of the life history of the species at hand.