Coastal Marsh Vulnerability to Sea-Level Rise Is Exacerbated by Plant Species Invasion

Area of Science:

• Ecology
• Geomorphology
• Coastal Science

Background:

• Coastal salt marshes provide vital ecosystem services but face degradation from rising sea levels.
• Biogeomorphic feedbacks are key to salt marsh adaptation, but invasive species impacts are poorly understood.

Purpose of the Study:

• To investigate the geomorphological effects of Spartina alterniflora invasion versus native Suaeda salsa in Chinese coastal marshes.
• To assess the influence of different sea-level rise and tidal scenarios on these impacts.

Main Methods:

• Utilized a coupled biogeomorphic model to simulate marsh geomorphology.
• Compared the effects of Spartina alterniflora invasion and native Suaeda salsa.
• Analyzed various sea-level rise and tidal conditions.

Main Results:

• Spartina alterniflora invasion promoted a "levee-basin" geomorphological structure at landscape and local scales.
• Invaded marshes developed significant depressions, especially in basin areas under microtidal conditions, increasing vulnerability.
• Spartina alterniflora proliferation led to the displacement of native Suaeda salsa.

Conclusions:

• Invasive Spartina alterniflora can degrade salt marsh structure and reduce resilience to sea-level rise.
• Controlling plant invasions is essential for preserving coastal ecosystem integrity and function.