互花米草入侵对广西北海光滩大型底栖动物群落的影响

Impact of Spartina alterniflora on Benthic Macro-Invertebrate Communities in Beihai's Coastal Flat,Guangxi Zhuang Autonomous Region

为探讨互花米草入侵对广西北部湾光滩的生态影响,于2012年7月—2013年9月对北海市青山头地区的互花米草群丛和光滩2种生境分别连续进行5次大型底栖动物群落采样,分析不同采样时间和生境下大型底栖动物的物种组成、生物量、总栖息密度、群落生物多样性、群落结构等群落特征.结果表明:1该区域内大型底栖动物共15种,隶属于4门5纲11科,其中中国绿螂(Glauconome chinensis)占互花米草群丛大型底栖动物个体总数的86.7%,为绝对优势物种;短指和尚蟹(Mictyris brevidactylus)为光滩的优势物种.2双因素方差分析(two-way ANOVA)结果显示,互花米草入侵光滩后大型底栖动物物种数量显著增加,并且互花米草群丛中中国绿螂个体数量的剧增也显著增加了大型底栖动物的生物量和总栖息密度,而采样时间对大型底栖动物物种数、生物量和总栖息密度的影响不显著;不同生境和采样时间均未对大型底栖动物的多样性指数产生显著影响.3非度量多维度分析(non-metric multidimensional scaling,NMDS)结果表明,互花米草群丛与光滩的大型底栖动物物种群落相似度较高,但与2012年10月相比,2013年9月互花米草和光滩大型底栖动物群落相似度降低,因此可能随着互花米草入侵时间的增加,其对大型底栖动物群落的影响也不同.

Research on the ecological impacts of Spartina alterniflora invasion was conducted by comparing the benthic macro-invertebrate communities in S.alterniflora salt marsh and bare flat habitat in Qingshantou Estuary,Beihai City,Guangxi Zhuang Autonomous Region.The results showed that： 1） Fifteen macro-invertebrate species,belonging to Arthropoda,Mollusca,Annelida and Sipuncula,were collected in the two types of habitat from July 2012 to September 2013,in order to determine responses of macro-invertebrate communities in species composition,biomass,density and diversity towards altered living habitats induced by S.alterniflora invasion.Glauconome chinensis was the predominant species in the salt marsh,occupying 86.7% of the entire macro-invertebrate species population.Mictyris brevidactylus was the dominant species in the bare flat.2） Based on two-way analysis of variance（ ANOVA）,the macro-invertebrate species population size increased with the invasion of S.alterniflora.Particularly,the population size of G.chinensis boomed,which was one of the causes of increasing macro-invertebrate species density and biomass under the invaded habitat.No distinguished difference of the Margalef,Shannon-Wiener,Simpson richness and evenness of macro-invertebrates was found across temporal and spatial scales.3） Non-metric multidimensional scaling analysis showed that the community structure of macro-invertebrates in S.alterniflora habitat was similar to that of bare flat habitat in the different sampling times,though the similarity in fall 2013 was reduced compared to the fall from the previous year.The impacts of S.alterniflora on macro-invertebrate community might vary in futurescenarios with longer invasion of S.alterniflora.In conclusion,the invasion of S.alterniflora increased the biomass,density and population size of macro-invertebrates in bare flats in Qingshantou Estuary,but it did not affect their diversity or the community structure.