Mangrove Mortality: Analyses of Natural and Anthropic Causes and their Effects on Forest Dynamics

Abstract

Lopes, D.M.S.; Chaves, F.O., and Tognella, M.M.P., 2020. Mangrove mortality: Analysis of natural and anthropic causes and their effects on forest dynamics. In: Malvarez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 102-107. Coconut Creek (Florida), ISSN 0749-0208.Located in the north coast of Espirito Santo State, Brazil, mangrove forests are associated with estuarine systems of variable flow, changing according to the climate regime of their origin. The complexity of this ecosystem is also a function of different factors, such as the physiography, the geology of the coastal plain and pollution. Natural and anthropogenic stressors can drain energy by removing structures and restricting the development, which causes variation in the number of dead individuals. In this study is reported the dynamics of the Barra Nova mangroves (in of Espirito Santo) through forest mortality investigations, either for natural or anthropic reasons. At total, eleven phytosociological data collection stations were performed along the estuary. Structural development showed an average height ranging from 3.41 to 16.69 m, average DBH of 2.69 to 21.68 cm, and trunk density of 853 to 6,360 ha-1. Measurements of the salinity of water in the estuary ranged from 25 to 68. A large number of dead and cut trunks occurred in most stations, with the highest percentage of dead basal area (84.18 %) occurring in the station 1. Four stations harbored more than 50 % of dead basal area. Overall, the structural values were extremely variable. Although sufficiently anthropized and submitted to natural environmental changes, the results obtained here show normal and no-massive mangrove mortality, which indicate a good structural development in the analyzed areas when compared to other mangrove forests. Finally, the information about the mortality rates and processes presented in this study are helpful tools to detect pressures on ecosystems, contributing to the knowledge and protection of these natural systems.