Data from: Restoration of native mangrove wetlands can reverse diet shifts of benthic macrofauna caused by invasive cordgrass

1. Ecological replacement using native mangrove species combined with physical treatments has become an effective method in controling the spread of invasive Spartina alterniflora. To re-establish ecosystem functions, trophic interactions between macrofauna and their potential food resources must be considered during the restoration process. 2. Here we examined the changes in the diets of macrofauna in three restored mangrove ecosystems with different invasion histories following the removal of S. alterniflora in southern China. Carbon and nitrogen stable isotope ratios for dominant macrofauna, as well as their potential food sources, were analyzed. The relative contributions of the different carbon sources to the diets of benthic macrofauna and isotopic niche width, including convex hull areas and standard ellipse areas of the macrofaunal community, were then calculated and compared among sampling sites in each region. 3. Our results indicated that Spartina-derived detritus contributed to >80% of the food sources of dominant macrofauna in the S. alterniflora communities in all three regions. S. alterniflora communities had lower convex hull areas and standard ellipse areas than natural mangrove forests, indicating significant resource competition among different consumer populations. Replacing S. alterniflora with the native mangrove species Kandelia obovata could reverse the diets of these macrofaunal species, resulting in a shift from homogeneous Spartina-dominated diets to more heterogeneous algae-based diets. It could take several decades to restore food web interactions to a pre-impacted state. Even the diets of macrofauna in mature mangrove (>40 years) remained affected by the Spartina-derived organic matter. 4. Synthesis and applications: Our study revealed that the ecological replacement of invasive Spartina alterniflora using native mangrove species could restore food web function gradually. However, this removal and replacement approach is a long process and requires significant manpower and resources. Furthermore, the native ecosystem will continue to be influenced by the cordgrass as long as large areas of wetland nearby are occupied by S. alterniflora. Consequently, preventing the colonization of S. alterniflora should be a priority for coastal ecosystem management in southern China.1. 采用本土红树植物结合物理修复手段开展生态替代，已成为防控入侵物种互花米草（Spartina alterniflora）扩散的有效手段。为重建生态系统功能，修复过程中必须考虑大型底栖动物与其潜在食物资源之间的营养级相互作用。2. 本研究针对中国南方地区互花米草清除后的3个具有不同入侵历史的修复红树林生态系统，探究了其大型底栖动物的食性变化。研究分析了优势大型底栖动物及其潜在食物源的碳、氮稳定同位素比值，随后计算并对比了各区域采样点中，底栖大型动物食性的不同碳源相对贡献占比，以及大型底栖动物群落的同位素生态位宽度（包括凸壳面积与标准椭圆面积）。3. 研究结果显示，在所有3个区域的互花米草群落中，源自互花米草的碎屑占优势大型底栖动物食物来源的80%以上。互花米草群落的凸壳面积与标准椭圆面积均低于天然红树林，表明不同消费者类群间存在显著的资源竞争。采用本土红树植物秋茄（Kandelia obovata）替代互花米草，可逆转这些大型底栖动物的食性，使其从以互花米草为主导的同质化食性，转变为以藻类为主的异质化食性。将食物网相互作用恢复至受干扰前的状态可能需要数十年时间，即便树龄超40年的成熟红树林内的大型底栖动物食性，仍会受到互花米草来源有机质的影响。4. 综合与应用：本研究表明，采用本土红树植物开展生态替代以防控入侵互花米草，可逐步恢复食物网功能。但该清除与替代方案属于长期过程，需投入大量人力与资源。此外，若周边大片湿地仍被互花米草占据，本土生态系统将持续受到该入侵植物的影响。因此，防控互花米草定植应成为中国南方沿海生态系统管理的优先事项。