Short-term effects of a tilling-based Spartina alterniflora removal project on intertidal macrobenthic communities

Coastal wetland ecosystem has been severely threatened by Spartina alterniflora, and eradicating this invasive plant is considered an effective approach to facilitating ecological restoration. Macrobenthos are widely considered as biological indicators for evaluating the intertidal ecological functions due to their low mobility and high sensitivity to habitat changes. Existing studies have mainly concentrated on evaluating macrobenthic community recovery over long temporal scales, while the short-term ecological consequences of S. alterniflora removal have received relatively little attention. Accordingly, we conducted a field-based study along the Jiangsu coast and assessed the short-term effects of a tilling-based S. alterniflora removal approach on intertidal macrobenthic communities using generalized linear mixed models (GLMMs) and piecewise structural equation modeling (SEM). Analyses of community structure showed that S. alterniflora removal significantly reduced species richness, abundance and Margalef index of macrobenthic communities in the study area, and compressed available habitat within sediments, resulting in macrobenthic vertical distributions being restricted to surface layers. The SEM results revealed that direct physical disturbance was the primary driver of short-term macrobenthic community decline. This was reflected in a pronounced direct negative effect of S. alterniflora removal on epifaunal taxa, as well as removal-induced habitat alterations that constrained the recolonization of infauna and mobile faun taxa. Overall, these short-term macrobenthic responses represent an essential component of the ecological consequences of S. alterniflora management in intertidal ecosystems and provide a basis for comprehensive ecological assessment and subsequent restoration decision-making.