Jiangsu Key Laboratory for Bioresources of Saline Soils, Jiangsu Provincial Key Laboratory of Coastal Wetland Bioresources and Environmental Protection, Jiangsu Synthetic Innovation Center for Coastal Bio-agriculture, Yancheng Teachers University, 2 South Xiwang Avenue, Yancheng, 224007, China.
Jiangsu Key Laboratory for Bioresources of Saline Soils, Jiangsu Provincial Key Laboratory of Coastal Wetland Bioresources and Environmental Protection, Jiangsu Synthetic Innovation Center for Coastal Bio-agriculture, Yancheng Teachers University, 2 South Xiwang Avenue, Yancheng, 224007, China.
Mar Environ Res. 2020 Apr;156:104862. doi: 10.1016/j.marenvres.2019.104862. Epub 2019 Dec 17.
The exotic species smooth cordgrass (Spartina alterniflora) is recognized as an important invasive species in China, introduced about 40 years ago. The consistent smooth cordgrass invasion significantly modified the coastal ecosystem. Understanding the ecological succession and mechanisms of wetland soil ecosystems is essential for biological conservation after the landscape change resulting from the smooth cordgrass invasion. In this study, five different invasion stages of a 16-year smooth cordgrass invasion sequence were identified in a coastal wetland as no invasion, initial invasion, young invasion, mature invasion, and senescing invasion. The succession of macrofaunal communities and environments were investigated along the gradient of invasion stages. The infauna decreased, and the epifauna increased along the invasion sequence. The significant differences of the communities were detected among the mud flats experiencing different invasion stages. The initial and young invasion stages of smooth cordgrass possibly promote the macrofaunal biodiversity, but biodiversity decreased at mature and senescing invasion stages. The ecological effect of smooth cordgrass invasion on macrofauna depended on the species' traits and the invasion stage. The environmental properties co-varied with invasion stages, and varied significantly among selected habitats. Total organic carbon (TOC), total nitrogen, and the carbon-nitrogen ratio (C/N) strongly related to the smooth cordgrass coverage, stem density, and height. C/N was identified as the key factor for shaping the environment by principal components analysis, and TOC for regulating the macrofaunal community by canonical correspondence analysis. The succession of macrofaunal communities should be considered as a comprehensive response to the variations on environmental properties co-varying with smooth cordgrass invasion in coastal wetlands.
外来物种互花米草（Spartina alterniflora）在中国被认为是一种重要的入侵物种，大约在 40 年前引入。互花米草的持续入侵显著改变了沿海生态系统。了解湿地土壤生态系统的生态演替和机制对于因互花米草入侵导致的景观变化后的生物保护至关重要。在这项研究中，在一个沿海湿地中，确定了互花米草入侵序列的 16 年中五个不同的入侵阶段，包括无入侵、初始入侵、幼龄入侵、成熟入侵和衰老入侵。沿入侵阶段梯度调查了大型动物群落和环境的演替。随着入侵序列的进行，底栖动物减少，而附着动物增加。在经历不同入侵阶段的泥滩之间检测到群落的显著差异。互花米草的初始和幼龄入侵阶段可能会促进大型动物的生物多样性，但在成熟和衰老入侵阶段生物多样性会下降。互花米草入侵对大型动物的生态影响取决于物种的特征和入侵阶段。入侵阶段的环境特性与入侵阶段共同变化，在选定的栖息地之间差异显著。总有机碳（TOC）、总氮和碳氮比（C/N）与互花米草覆盖率、茎密度和高度密切相关。主成分分析确定 C/N 是塑造环境的关键因素，典范对应分析确定 TOC 是调节大型动物群落的关键因素。大型动物群落的演替应被视为对沿海湿地中与互花米草入侵共同变化的环境特性的综合响应。
