底质细化对厦门潮下带文昌鱼栖息地大型底栖动物群落的影响

本文根据2014年至2017年在厦门文昌鱼保护区黄厝、南线十八线、鳄鱼屿和小嶝岛四处潮下带以及参照点白城潮下带获得的大型底栖动物和沉积物粒径数据,探讨底质细化对厦门潮下带文昌鱼栖息地大型底栖动物群落的影响。聚类分析表明个别黏土含量较高的取样站没有发现文昌鱼且大型底栖动物种数少。单因素方差分析表明,厦门潮下带部分大型底栖动物群落参数和优势种数量存在显著差异。底质粒径分析表明, 2017年9月,鳄鱼屿和白城潮下带黏土和粉砂含量高于黄厝、南线十八线和小嶝岛潮下带的黏土和粉砂含量。2016年夏季黄厝、南线十八线潮下带黏土和粉砂含量明显高于2014年夏季的黏土和粉砂含量。相关分析表明,5个大型底栖动物群落参数如物种数、栖息密度、生物量、多样性指数(H′)和丰度指数(d), 7个常见种的栖息密度和生物量与粉砂和黏土含量呈显著正相关,均匀度指数(J)和4种常见种的数量与粉砂和黏土含量无显著相关,白氏文昌鱼(Branchiostoma belcheri)的栖息密度和生物量与粉砂和黏土含量呈显著负相关。上述结果证实,黏土含量增加到15%和粉砂含量增加到60%有利于多数大型底栖动物栖息密度和生物量的增加,但导致白氏文昌鱼栖息密度和生物量的减少,而红角沙蚕(Ceratonereiserythraeenis)、滑指矶沙蚕(Eunice indica)、光滑倍棘蛇尾(Amphioplus laevis)受底质细化的影响较小。

EFFECTS OF SEDIMENT FINING ON BENTHIC MACROFAUNAL COMMUNITY IN SUBTIDAL AMPHIOXUS HABITATS IN XIAMEN

The effects of sediment fining on the benthic macrofaunal community in Xiamen subtidal zone was studied using the data of benthic macrofauna and grain size analyses for five subtidal areas in Xiamen from 2014 to 2017. The Cluster analysis and one-way ANOVA were conducted. Results show that in those stations with higher clay content, no amphioxus fish but few macrobenthic species were found. Significant differences were seen in some community parameters of benthic macrofauna and dominant species. The contents of clay and silt in Eyu Island and Baicheng subtidal areas were higher than those in Huangcuo, Nanxianshibaxian and Xiaodeng Island subtidal areas in September 2017. The contents of clay and silt in Huangcuo and Nanxianshibaxian subtidal areas in the summer 2016 were significantly higher than those in summer 2014. Significantly positive correlations were found not only between the five community parameters of benthic macrofauna such as the species number, density, biomass, diversity index (H''), richness index (d), and silt plus clay contents, but also between the density and biomass of seven dominant species and silt plus clay contents. No significant correlations were observed between evenness index (J) and silt plus clay contents, and between density plus biomass of four dominant species and silt plus clay contents. Significantly negative correlations were revealed between the density plus biomass of Branchiostoma belcheri and silt plus clay contents. The above results confirmed that when silt or clay contents increased up to 15% or 60%, respectively, it favored the increase in density and biomass of most benthic macrofauna, but resulted in the decrease in the density and biomass of B. belcheri; however, those of Ceratonereis erythraeensis, Eunice indica, and Amphioplus laevis were less affected by sediment fining.