王 琰,童春富

华东师范大学河口海岸学国家重点实验室, 上海 200062

长江口芦苇和互花米草盐沼湿地蟹类洞穴分布特征及主要影响因子

王 琰,童春富*

华东师范大学河口海岸学国家重点实验室, 上海 200062

蟹类洞穴是蟹类在潮间带盐沼生存、繁衍的特征性结构,具有重要的生态功能。洞穴分布特征及其影响因子的分析,是深入探讨蟹类及其洞穴的生态系统功能的重要基础。2015年10月,在崇明北滩单一芦苇(Phragmitesaustralis)群落,单一互花米草(Spartinaalterniflora)群落和芦苇-互花米草混合群落3种典型生境中,对蟹类洞穴的分布特征及其相关的大型底栖动物、植被、沉积物等的特征参数进行了调研与分析。结果表明,生境类型差异对蟹类洞穴分布特征及相关生境因子具有重要影响。蟹类洞穴的分布密度和开口直径在不同生境间存在显著差异(P<0.05),且单一芦苇群落生境内洞穴密度要显著高于单一互花米草群落生境(P<0.05),洞穴开口直径在单一互花米草生境要显著高于单一芦苇生境(P<0.05)；大型底栖动物生物量、密度、植物地下部分生物量在不同生境间差异不显著(P>0.05),而植株密度、活植株高度、植物地上部分生物量以及沉积物含水率、pH、氧化还原电位在不同生境间存在显著差异(P<0.05)。沉积物中值粒径,总氮含量和总碳含量在不同生境间的差异随深度不同会发生变化。不同生境主要生境因子的差异是导致蟹类洞穴分布特征不同的根本原因；蟹类洞穴分布特征受多个生境因子的综合作用。筛选的生境因子的组合虽然与洞穴分布特征具有显著相关性,但相关系数较小。未来研究中需要拓展生境因子涵盖范围,加强多因子综合作用分析。

长江口；盐沼湿地；蟹类；洞穴分布；影响因子

Abstract： Crab burrows have a unique structure, which is essential for ecosystem functions and for the survival and reproduction of crabs in tidal salt marshes. Studies on the distribution characteristics of the burrows, and corresponding factors that influence such features, provide an important basis to reveal the ecosystem functions of crabs and their burrows. In October 2015, we conducted surveys on crab burrows in three typical salt marsh habitats in the northern tidal flat of Chongming Island in the Yangtze estuary, including thePhragmitesaustralishabitat,Spartinaalterniflorahabitat, andP.australis-S.alternifloramixed habitat. In each habitat, the characteristics of crab burrows and related factors, including macrobenthos, vegetation, and sediment, were surveyed. The results indicated that the type of the habitat influenced the crab burrow distributions and their related factors. Burrow densities and opening diameters were significantly different among the different habitats (P< 0.05). The burrow density inP.australishabitat was significantly higher than that inS.alterniflorahabitat (P< 0.05), whereas the burrow opening diameter inS.alterniflorahabitat was significantly greater than that inP.australishabitat (P< 0.05). There was no significant difference in biomass and density of macrobenthos, and belowground biomass of plants among the different habitats (P> 0.05). However, there were significant differences in shoot density, height, aboveground biomass of the vegetation, as well as water content, pH, and oxidation-reduction potential of the sediment among the different habitats (P< 0.05). The differences among the habitats in the total carbon content, total nitrogen content, and median particle diameter of the sediments varied with depth. The different combinations of habitat factors resulted in a variation in the distribution characteristics of crab burrows. In the present study, although the combination of several selected factors was significantly correlated with the crab burrow distribution characteristics, the coefficient was relatively low. Therefore, there could be other factors that were not included in the surveys that also affected burrow distribution characteristics. Further study should extend the scope of the factors and strengthen the comprehensive analysis.

KeyWords: Yangtze estuary; salt marsh; crabs; burrow distribution; influencing factors

盐沼湿地是河口海岸地区分布最广的生态系统类型之一,具有生物栖息地、营养物质过滤器,固碳等多种重要的生态系统服务功能[1- 3]。以蟹类为代表的潮间带掘穴生物是盐沼湿地重要的生物扰动者[4]、物质搬运者[5]、生态系统工程师(Ecosystem Engineer)[6- 7],其掘穴行为及洞穴特征是当前盐沼湿地生态学研究的重要内容[8- 11]。

蟹类洞穴是蟹类在潮间带盐沼中的特征性结构,对蟹类的生存、繁衍都有着极其重要的意义[12]。……