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. 采用本地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，修复过程中必须考量大型底栖无脊椎动物（macrofauna）与其潜在食物资源间的营养级互作关系。2. 本研究针对中国南方3个经互花米草清除后修复、且具有不同入侵历史的红树生态系统，探究了其中大型底栖无脊椎动物食性的变化。研究分析了优势大型底栖无脊椎动物及其潜在食物源的碳、氮稳定同位素比值，并计算并比较了各区域采样点间，不同碳源对底栖大型无脊椎动物食性的相对贡献，以及大型底栖无脊椎动物群落的同位素生态位宽度——包括群落的凸壳面积与标准椭圆面积。3. 研究结果显示，3个区域的互花米草群落中，源自互花米草的有机碎屑占优势大型底栖无脊椎动物食物来源的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森林，表明不同消费者类群间存在显著的资源竞争。采用本地红树物种秋茄（Kandelia obovata）替代互花米草，可逆转这些大型底栖无脊椎动物的食性，使其从以互花米草为主导的均质化食性，转变为以藻类为基础的异质化食性。将食物网互作恢复至入侵前状态需耗时数十年之久，即便树龄超过40年的成熟红树林中，大型底栖无脊椎动物的食性仍会受到互花米草衍生有机质的影响。4. 研究总结与应用启示：本研究表明，采用本地红树物种对入侵互花米草开展生态替代，可逐步恢复食物网功能。但该清除与替代手段周期漫长，需投入大量人力与资源。此外，若周边仍有大面积湿地被互花米草占据，本地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海岸生态系统管理的优先事项。