An Agent Based Model of Post-Disaster Regrowth of Mangrove Forests

Franklin David Ang and James Stephen Mariano

Adviser: Vena Pearl Bongolan, PhD

Abstract

Mangroves are salt-tolerant trees that help protect coastal areas from dangerous water waves and provide livelihood for coastal populations. Individual mangrove species can be very particular about living conditions such as salinity, inundation, pH and oxygen conductivity. Mangrove populations are also vulnerable to natural phenomena, like storm surges and changes in sea level.

This study aims to accurately model the recovery of mangrove populations after being damaged by storms. It adapts Salmo and Juanico's agent-based model for mangrove forest growth to a virtual reconstruction of the Bangrin Marine Protected Area in Pangasinan, Philippines. The virtual environment incorporates two models of Heibeler: Fragmented Habitat to simulate variable inhabitability per unit area, and Block Disturbance to simulate the occurence of storms. The model features planted (Rhizophora mucronata) and native (Avicennia and Sonneratia spp.)

mangrove species, which have di.erent levels of sensitivity and adaptation to environmental factors.

Simulations were run over a span of a hundred years for an approximation of the real-world mangrove plot, plus some possible alternative planting strategies. High seedling mortality and variable tolerance to environmental stressors were shown to be the dominant factors in the mangrove species' survival. Natural mangrove species, with greater tolerance to these stressors, displayed stable population densities in the long term. The R. mucronata populations tended to decline over time.