福建同安湾潮间带红树林生境与非红树林生境大型底栖动物群落比较

Comparative study of the macrobenthic community in intertidal mangrove and non-mangrove habitats in Tong'an Bay,Fujian Province

底栖动物群落是红树林生态系统多样性研究的重要内容之一。为了解大型底栖动物群落对高有机质含量和富营养的红树林生境的响应,从2006年4月到2007年1月,对福建省同安湾红树林生境和非红树林生境大型底栖动物群落及其时空变化进行了研究。我们在同安湾红树林种植区设置了凤林(FL)和山后亭(XA)两条断面,每条断面在红树林内各设2个取样站(FL1,FL2,XA-A和XA-B),林外各设1个取样站(FL3和XA-C)。底质研究结果显示凤林3个取样站(FL1,FL2和FL3)的有机质含量均超过底质污染评价标准的临界值3.4%,且无论凤林还是山后亭,红树林生境的有机质含量均要高过非红树林生境。共获得大型底栖动物91种,其中在红树林生境内获得77种,高于非红树林生境内获得的67种。红树林生境和非红树林生境的大型底栖动物平均栖息密度分别为4,445.8inds/m2和1,707.2inds/m2,平均生物量分别为51.1g/m2和94.6g/m2。独立样本t-检验结果显示,红树林生境和非红树林生境大型底栖动物平均栖息密度和平均生物量均存在显著差异。研究结果指示红树林生境对于寡毛类生存(如在高耐有机污染中能大量繁殖的沼蚓)有积极作用。但由于邻近的非红树林林生境的水淹时间更长,一些具有移动能力的软体动物和甲壳动物能迁移到更适合生存的非红树林生境中去。其他底质因子如盐度和土壤中值粒径等也会影响大型底栖动物群落变化。

Research on the biodiversity of mangrove ecosystems should include not only the plants but other components,such as the macrobenthos.In order to understand the response of the macrobenthos to a mangrove habitat with high organics and nutrients,we compared the mangrove and non-mangrove macrobenthic communities,and analyzed their spatial-temporal distributions in these two habitats from April 2006 to January 2007 in Tong＇an Bay,Fujian.Six sampling stations were set in Tong＇an Bay,four of them（FL1,FL2,XA-A and XA-B） were in the mangrove habitat,the other two（FL3 and XA-C） were in the non-mangrove habitat.An analysis of sediment properties showed that total organic matter（TOM） of the three sampling stations at Fenglin exceeded the critical threshold,namely 3.4%,and TOM in mangrove stations was higher than in the non-mangrove ones.A total of 91 macrobenthic taxa were obtained from the six sampling stations in Tong＇an Bay,including 77 and 67 taxa from the mangrove and non-mangrove habitats,respectively.Mean macrobenthic densities in the mangrove and non-mangrove habitats were 4,445.8 inds/m^2 and 1,707.2 inds/m^2,respectively.Mean biomasses in the mangrove and non-mangrove habitats were 51.1 g/m^2 and 94.6 g/m^2,respectively.The results of an independent-samples t-test showed that mean density and mean biomass were significantly different in the two habitats.The present study revealed that the mangrove habitat has a positive influence on the Oligochaeta,such as Limnodriloides sp.,that thrives in the high TOM sediments.Because of the shorter inundation period in the mangrove habitat,however,free-living molluscs and crustaceans preferred the non-mangrove habitat.Other sediment properties such as interstitial salinity and median particle diameter also affected the macrobenthic community.