Pure, shared, and coupling effects of climate change and sea level rise on the future distribution of Spartina alterniflora along the Chinese coast

AIM: Global change seriously threatens the salt marsh ecosystem, while it remains unclear how S. will respond to climate change and sea level rise. Here, we investigated interactions among variables and identified the impacts of climate change, sea level rise, and their interactions on the distribution of Spartina alterniflora. LOCATION: Northern Chinese coast and Southern Chinese coast. TAXON: Spartina alterniflora Loisel. METHODS: With global sensitivity analysis, we determined interactions among variables and their relative importance to the distribution of S. alterniflora. Integrating the Venn's four‐set diagram, we built ecological niche models under current and three future scenarios to identify pure, shared, and coupling effects of climate change and sea level rise on the distribution of S. alterniflora. RESULTS: Mean diurnal range (Bio02) and Elevation were the two most critical variables controlling the distribution of S. alterniflora on the Chinese coast, and interactions among variables of the northern coast were much greater than that of the southern coast. Habitats change was mainly caused by pure effects of climate change, except habitats reduction on the southern coast. Pure effects of sea level rise were low, but it can influence habitats change through shared and coupling effects from complex interactions with climate change. Interactions of climate change and sea level rise can drive habitats change, and the changed habitats caused by shared and coupling effects were mainly distributed the areas near the landward side. MAIN CONCLUSIONS: Our research suggests paying attention to interactions among variables when calculating the relative importance of explanatory variables. Identifying pure, shared, and coupling effects of climate change and sea level rise for the distribution of S. alterniflora will provide scientific references for assessing the risk of similar coastal species.