Restoration of native saltmarshes can reverse arthropod assemblages and trophic interactions changed by a plant invasion

Plant invasions profoundly impact both natural and managed ecosystems, and removal of the invasive plants addresses only part of the problem of restoring impacted areas. The rehabilitation of diverse communities and their ecosystem functions following removal of invasive plants is an important goal of ecological restoration. Arthropod assemblages and trophic interactions are important indicators of the success of restoration, but they have largely been overlooked in saltmarshes. We determined how arthropod assemblages and trophic interactions changed with the invasion of the exotic plant Spartina alterniflora and with the restoration of the native plant Phragmites australis following Spartina removal in a Chinese saltmarsh. We investigated multiple biotic and abiotic variables to gain insight into the factors underlying the changes in arthropod assemblages and trophic structure. We found that although Spartina invasion had changed arthropod diversity, community structure, feeding‐guild composition, and the diets of arthropod natural enemies in the saltmarsh, these changes could be reversed by the restoration of native Phragmites vegetation following removal of the invader. The variation in arthropod assemblages and trophic structure were critically associated with four biotic and abiotic variables (aboveground biomass, plant density, leaf N, and soil salinity). Our findings demonstrate the positive effects of controlling invasive plants on biodiversity and nutrient cycling and provide a foundation for assessing the efficacy of ecological restoration projects in saltmarshes. 土著盐沼恢复能逆转植物入侵所改变的节肢动物群落组合和营养相互作用 植物入侵深刻影响自然和人工生态系统，清除入侵植物只能解决入侵受损区域的部分问题。入侵植物清除后，恢复不同类型生物群落及其生态系统功能是生态恢复的重要目标。节肢动物群落组合和营养相互作用是生态恢复成功的重要标志性指标，但在盐沼恢复中却常常被忽视。本文研究了中国长江口盐沼中外来植物互花米草入侵，以及清除互花米草并恢复土著植物芦苇后，节肢动物群落组合和营养相互作用如何变化。此外，本研究还测定了其他的多种生物、非生物变量，以深入了解影响节肢动物群落和营养结构变化的主导因素。结果发现，虽然互花米草入侵改变了盐沼节肢动物的多样性、群落结构、取食功能群组成和天敌食性，但这些变化可在入侵植物清除并恢复芦苇植被后而发生恢复性逆转。节肢动物群落组合和营养结构的变化主要与4个生物、非生物变量(地上生物量、植株密度、叶片氮含量和土壤盐度)密切相关。这些结果表明，治理入侵植物并恢复土著植被对盐沼生物多样性和营养循环具有积极作用。本研究可为盐沼生态修复工程的效益评估提供科学依据。