射阳河口互花米草入侵对大型底栖动物群落的影响

2008年11月至2009年10月,在盐城自然保护区射阳河口滩涂分别于潮间带、潮上带和潮沟中设置互花米草区与非米草区2类对照样地(共6类生境),按月份取样来研究大型底栖动物群落特征的差异,探讨互花米草入侵对底栖动物的影响。共发现大型底栖动物22种,隶属3门4纲17科,其中软体动物13种,节肢动物6种,环节动物3种。米草区和非米草区的物种组成不同,各生境在不同月份大型底栖动物的物种数、密度、生物量和Shannon-Wiener多样性指数均在不断波动,在潮间带上述指标均为In>Ig,潮上带除密度外均为Sn>Sg,潮沟边滩除个别月份外均为Cg>Cn;3类互花米草生境中大型底栖动物群落各项指标月间变动趋势基本一致(仅个别月份例外),均表现为Cg>Sg>Ig,互花米草生境存在共同的优势种,但数量有一定的差异。分别对潮间带、潮上带和潮沟中互花米草区与非米草区2类对照样地的物种数、密度、生物量以及Shannon-Weiner多样性指数H’进行生境-月份间无重复双因素方差分析,结果显示潮间带2类对照样地各项指标在生境间差异均极显著,月份间差异均不显著;潮上带2类对照样地各项指标生境间存在极其显著的差异(除密度外),月份间差异显著(除多样性外);潮沟2类对照样地生境间差异显著(除生物量外),月份间差异均显著。研究结果表明不同生境中的互花米草对底栖动物的影响不甚相同:潮间带互花米草的入侵降低了大型底栖动物的物种数、密度、生物量和多样性;潮沟米草的入侵提高了大型底栖动物的物种数、密度和多样性;而潮上带米草入侵对大型底栖动物的各指标影响不一。

EFFECT OF SPARTINA ALTERNIFLORA INVASION ON THE MACROBENTHIC COMMUNITY IN THE SHEYANG ESTUARY

The macrobenthic community from Nov.2008 to Oct.2009 was studied monthly in order to know the effect of Spartina alterniflora invasion on them in Sheyang estuary,Yancheng Nature Reserve.Six habitats were selected for the macrobenthic sampling including two contrast teams(area with Spartina alterniflora and area without Spartina alterniflora) in intertidal flat,supralittoral zone and creek.Total of 22 species of macrobenthic were found,including 17 families,4 classes and 3 phyla which were mollusks(13 species),crustaceans(6 species) and polychaetes(3 species).The compositions of species between 2 contrast teams of each group were no different,the number of species,density,biomass and biodiversity indices varied continuously among all months in different habitats,all the indices in the habitat with Spartina alterniflora(Ig) were lower than naked tidal without vegetable(In) in the intertidal flat;all except for density were lower in the habitat with Spartina alterniflora(Sg) than the naked tidal without vegetable(Sn) in the supralittoral zone;all the indices at the bank of creek with Spartina alterniflora(Cg) were bigger than the bank of creek without vegetable(only few months was different)(Cn);and the trend to fluctuate of density,biomass,and Shannon-Wiener biodiversity index was uniform approximately among 3 Spartina alterniflora habitats(only few months was different),namely Cg>Sg>Ig(only few months was different).The dominant species were the same among 3 Spartina alterniflora habitats,but the numbers were different.A two-factors ANOVA was used to analyze the effect of months and habitats on the number of species,the density,biomass of and the Shannon-Weiner H’index between 2 contrast teams of each group.Which revealed all the indices had extremely distinct difference between 2 habitats in the intertidal flats,but had not distinct difference among months;all indices had extremely distinct differences between 2 habitats(not including density) in the supralittoral zone,had distinct difference among months except for diversity;all the indices had distinct differences except for biomass between 2 habitats of creek,but all indices had distinct differences among months.In conclusion,the effect of Spartina alterniflora from different habitats was different: either reduced the number of species,density,biomass,and biodiversity in intertidal flats or enhanced these indices except for biomass in creek,however,the effect of Spartina alterniflora invasion on all indices was inconsistent in supralittoral zone.