Impact ofSpartina alternifloraon benthic macro-invertebrates communities on mangrove wetland in Xicungang Estuary, Guangxi

Abstract

In order to assess the ecological impacts of Spartina alterniflora on mangrove ecosystems, we investigated macro-invertebrate communities in S. alterniflora wetlands and a mangrove wetland between October 2012 and September 2013, in the Xicungang estuary, Guangxi Zhuang Autonomous Region. The species composition, biomass and diversity of macro-invertebrates were compared at different times between the mangrove habitat and S. alterniflora community. Sixteen species from Arthropoda, Mollusca, Annelida, Cnidadia and Sipuncula were collected from the two habitats. Twelve species were found in mangrove wetlands whereas 10 species were found in S. alterniflora wetlands. Perhaps due to the invasion of S. alterniflora, Glauconome chinensis became the predominant species, leading to a greater macro-invertebrate biomass in S. 第 5 期 赵彩云等: 广西北海西村港互花米草对红树林湿地大型底栖动物群落的影响 631 alterniflora wetlands than in mangrove wetland. On the other hand, the Margalef, Shannon-Wiener index, Simpson and Pieous diversity indices of macro-invertebrates were lower in S. alterniflora habitat than in mangrove habitat. Two-way ANOVA was used to analyze the effect of sampling periods and habitats on the number of species, biomass and diversity indices of macro-invertebrates. Our results showed that ShannonWiener index and Simpson diversity indices differed between the two habitats, the Margalef and Pieous diversity indices differed among sampling periods, number of species and biomass were affected by both habitats and sampling periods. Based on multiple linear regression analyses, macro-invertebrate biomass was related to the density of S. alterniflora, and Shannon-Wiener, Simpson diversity and species richness of macro-invertebrates were all related with the height of S. alterniflora. According to our NMDS (non-metric multidimensional scaling) analysis, macro-invertebrate communities in S. alterniflora habitat mainly differed from those of mangrove habitats due to sampling periods. In conclusion, the invasion of S. alterniflora in mangrove wetlands in Xicungang estuary increased the biomass of macro-invertebrates, while decreased the diversity of them, and also changed the community structure of macro-invertebrate assemblages. Key word: macro-invertebrates, Spartina alterniflora, community structure, biodiversity biological invasion 红树林是最具特色的湿地生态系统, 在我国主 要分布于广西、广东、海南、台湾、福建和浙江南 部沿岸(吴培强等, 2013)。我国拥有丰富的红树林资 源, 在历史上面积曾达到250,000 ha, 由于围海造 地、改造盐田、围海养殖等不合理的开发利用, 严 重破坏了红树林资源, 到2010年, 我国红树林已经 锐减到24,578.2 ha(吴培强等, 2013)。 此外, 外来入侵物种也危害着红树林生态系统 的安全, 如互花米草(Spartina alterniflora)、薇甘菊 (Mikania micrantha)、无瓣海桑(Sonneratia apwtala)、 大米草(Spartina anglica)、凤眼莲(Eichhornia crassipes)、马樱丹(Lantana camara)等(周青青等, 2010), 其中互花米草近年来在我国沿海大面积暴发, 不断 侵占红树林生存空间, 对我国红树林湿地生态系统 构成了威胁。广西壮族自治区拥有丰富的红树林资 源, 为保滩护岸, 北海市于1979年在山口镇山角海 面和党江镇沙冲船厂海滩首次引进互花米草, 由于 其繁殖速度快, 迅速在海滩上滋生蔓延, 成为当地 典型的外来入侵物种(覃盈盈和梁士楚, 2008), 与红 树林争夺资源, 威胁着红树林生态系统。