Responses of eastern Chinese coastal salt marshes to sea-level rise combined with vegetative and sedimentary processes.

Zhen-Ming Ge,Heng Wang,Xiao Zhou,Bin Zhao,Xiu-Zhen Li,Hao-Bin Cao,Li-Quan Zhang,Li-Fang Cui,Heli Peltola

doi:10.1038/srep28466

Zhen-Ming Ge, Heng Wang + Show 7 more

Open Access

https://doi.org/10.1038/srep28466

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Abstract

The impacts of sea-level rise (SLR) on coastal ecosystems have attracted worldwide attention in relation to global change. In this study, the salt marsh model for the Yangtze Estuary (SMM-YE, developed in China) and the Sea Level Affecting Marshes Model (SLAMM, developed in the U.S.) were used to simulate the effects of SLR on the coastal salt marshes in eastern China. The changes in the dominant species in the plant community were also considered. Predictions based on the SLAMM indicated a trend of habitat degradation up to 2100; total salt marsh habitat area continued to decline (4–16%) based on the low-level scenario, with greater losses (6–25%) predicted under the high-level scenario. The SMM-YE showed that the salt marshes could be resilient to threats of SLR through the processes of accretion of mudflats, vegetation expansion and sediment trapping by plants. This model predicted that salt marsh areas increased (3–6%) under the low-level scenario. The decrease in the total habitat area with the SMM-YE under the high-level scenario was much lower than the SLAMM prediction. Nevertheless, SLR might negatively affect the salt marsh species that are not adapted to prolonged inundation. An adaptive strategy for responding to changes in sediment resources is necessary in the Yangtze Estuary.

Highlights

Estuary (SMM-YE) was developed to aid in the understanding of the biotic and abiotic factors that regulate the vegetation processes in the salt marshes[16,18]
Response of the salt marshes to sea-level rise (SLR) based on the SMM-YE
With the key vegetative parameters of different salt marsh species in relation to SLR, SMM-YE simulations predicted the response of the salt marsh habitats above 0 m isobaths at CDW (Fig. 4) and JW (Fig. 5) to the present SLR (PSLR) and RCP 8.5 scenarios

Summary

Introduction

Estuary (SMM-YE) was developed to aid in the understanding of the biotic and abiotic factors that regulate the vegetation processes in the salt marshes[16,18]. The model accurately reproduced the spatiotemporal dynamics of the three dominant salt marsh species Spartina alterniflora, Scirpus mariqueter and Phragmites australis in the Yangtze Estuary. In this study, both the SLAMM and the SMM-YE were used to simulate the effects of SLR in the Yangtze Estuary. The aims of this study are 1) to predict how salt marsh habitats in the Yangtze Estuary respond to the different SLR scenarios (the regional scenario and the IPCC scenario) during the 21st century and 2) to assess the combined role of sedimentary accretion and vegetative processes in influencing the further vegetation structure and marsh resilience under SLR. Mitigation measures to threats of SLR are briefly discussed

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