Application of a Coupled Vegetation Competition and Groundwater Simulation Model to Study Effects of Sea Level Rise and Storm Surges on Coastal Vegetation

Su Teh,Jiang Jiang,Thomas Smith,Hock Koh,Donald Deangelis,Leonard Pearlstine,Michael Turtora

doi:10.3390/jmse3041149

Abstract

Global climate change poses challenges to areas such as low-lying coastal zones, where sea level rise (SLR) and storm-surge overwash events can have long-term effects on vegetation and on soil and groundwater salinities, posing risks of habitat loss critical to native species. An early warning system is urgently needed to predict and prepare for the consequences of these climate-related impacts on both the short-term dynamics of salinity in the soil and groundwater and the long-term effects on vegetation. For this purpose, the U.S. Geological Survey’s spatially explicit model of vegetation community dynamics along coastal salinity gradients (MANHAM) is integrated into the USGS groundwater model (SUTRA) to create a coupled hydrology–salinity–vegetation model, MANTRA. In MANTRA, the uptake of water by plants is modeled as a fluid mass sink term. Groundwater salinity, water saturation and vegetation biomass determine the water available for plant transpiration. Formulations and assumptions used in the coupled model are presented. MANTRA is calibrated with salinity data and vegetation pattern for a coastal area of Florida Everglades vulnerable to storm surges. A possible regime shift at that site is investigated by simulating the vegetation responses to climate variability and disturbances, including SLR and storm surges based on empirical information.

Highlights

Sea Level Rise (SLR) is one of the most significant predicted consequences of global climate change and has the potential for severe effects on the vegetation of low-lying coastal areas and islands [1]
By combining MANHAM with Saturated–Unsaturated TRAnsport (SUTRA), forming MANTRA (MANhamsuTRA), we provide an integrated model that simulates the possible effects of gradual sea level rise (SLR), as well as both short- and long-term effects of a single or a sequence of overwash events on a coastal area or small island, containing zones of glycophytic and halophytic vegetation
Scenario 3 consisted of a storm surge in which only moderate damage was done to the hardwood hammock vegetation, reducing the initial vegetation by one-half

Summary

Introduction

Sea Level Rise (SLR) is one of the most significant predicted consequences of global climate change and has the potential for severe effects on the vegetation of low-lying coastal areas and islands [1]. Rising sea level will mean higher storm surges [2], even if the frequencies do not change. The immediate effect will be on the freshwater lenses that sit on top of saline groundwater in these areas. Such effects on available fresh water may have negative consequences for the ecological and human populations of coastal areas and, islands, as they depend critically on fresh water stored in the lenses [3,4,5]. In southern Florida, USA, the beneficial effects of increased freshwater flow resulting from the Comprehensive Everglades

Methods

Results

Discussion

Conclusion