Uso do modelo Delft3D no estudo da dispersão de propágulos de mangue no estuário do Rio Pacoti

Abstract

Understanding the influence of the physical factors in the distribution of mangroves propagules help the comprehension of the mangroves distribution and its vulnerability through natural and anthropic modifications in the environment. At this study will be used Delft3D-PART particles model to simulate the influence of the physical factors in the dispersion of mangroves propagules in Pacoti’s river estuary for the species Avicennia germinans and Avicennia schaueriana, described as Avicennia spp., Laguncularia Racemosa and Rizophora Mangle. The hydrodynamic scenario used are three: 1- tidal forced, 2- tidal forced and fluvial discharge and 3- tidal forced, fluvial discharge and wind. Each one of the scenarios have 45 simulation days, where the propagules will be released in the day sixteen and its path followed until the final simulation. The forced scenario just for tidal had withheld 75% of the propagules within the estuary. The capture near the mangrove increases the possibility of establish through proximity of favorable areas to mainly implantation to the species L. racemosa and R. mangle occasioned by its capacity of sink for establishing while Avicennia spp. need to be free of tidal effects to establishing. In the scenario forced by tidal and fluvial discharge until the third day, about 90% of all species propagules had left the estuary, revealing the function of the discharge as transporting propagules to the shelf. At the shelf area after discharge influence cease the dispersion is tidal dominated. In the scenario forced by tidal, fluvial discharge and wind had output more than 90% of the propagules in the estuary until the seventh day. In the estuary exit, the wind forced the propagules of all species to more time in the estuary. In the external area of the river, the wind divert all the path to west, parallel to the shoreline. The transport of all propagules to west direction open connectivity of the studied species propagules with dispersion mangrove areas to west of pacoti’s river. In a general mode the tidal is the mainly factor to the propagules dispersion within the estuary. The discharge is the transport factor the the shelf and the wind is the factor that directs the dispersion at the external area of the estuary.