【作者】 张尽函；

【导师】 王瑁；

【作者基本信息】 厦门大学 ， 动物学， 2008， 硕士

【摘要】 本文调查了海南东寨港角果木林、白骨壤林、红海榄林和海莲+木榄林林内、林外共八个地点蟹的种类、生物量及其季节变化，并通过红树植物叶片、沉积物和蟹的δ¹³C、δ¹⁵N值，分析了不同生境内沉积物的组成和蟹的食物来源。在采样地点共发现蟹类5科18种，以招潮蟹和相手蟹为主。招潮蟹主要分布在林外光滩，相手蟹主要分布在红树林中。长足长方蟹也是常见种之一，既可分布在林外光滩又可分布在林内。红树林林外滩涂蟹类生物量无显著差异。角果木林内蟹类生物量最低（25．24g／m²），林外光滩蟹类生物量（105．13g／m²）显著大于林内；红海榄林内蟹类生物量最高（166．73g／m²），林外光滩（89．28g／m²）显著低于林内；白骨壤林内（102．57g／m²）和海莲+木榄林内（104．94g／m²）蟹类生物量居中，且林内、林外蟹类生物量没有显著差异。红树林林外滩涂蟹生物量雨季大于旱季；而林内蟹生物量雨季小于旱季。由于种类和环境条件的不同，红树植物δ¹³C、δ¹⁵N值存在差异。角果木和白骨壤有较高的δ¹³C值，约为-28．1到-25．2‰，而红海榄（-30．8-27．8‰）和海莲的δ¹³C（-32．5--28．9‰）较低。按δ¹⁵N值大小排列，角果木（3．8‰）<海莲（5．0‰）<红海榄（6．3‰）<白骨壤（7．7‰）。角果木林内沉积物δ¹³C值略高于角果木叶片δ¹³C值，红海榄林内沉积物δ¹³C值与红海榄叶片δ¹³C值都极为接近，白骨壤林内以及海莲+木榄林内沉积物δ¹³C值分别比白骨壤叶片和海莲叶片δ¹³C值高2．0‰左右。角果木、白骨壤和海莲+木榄林内、林外沉积物δ¹³C值没有差别，而红海榄林外沉积物δ¹³C值约比林内高出3．0‰。根据沉积物和红树植物δ¹³C值可知不同地点沉积物组成不同。红树林林内沉积物δ¹³C值均有雨季低于旱季的趋势。角果木、红海榄、海莲+木榄林外滩涂沉积物δ¹³C值却是雨季高于旱季。白骨壤林外沉积物δ¹³C值仍然是雨季低于旱季。红树林区沉积物δ¹³C存在雨旱季的变化，跟凋落物和微藻的贡献的改变有关。蟹在不同地点的食物组成存在差别。白骨壤林内蟹的主要食物来源是白骨壤叶片和沉积物，它们的贡献分别为26．7％和73．3％；角果木、红海榄林内蟹主要以大型藻类和沉积物为食；海莲+木榄林内蟹主要是以微藻为食。角果木林外和海莲+木榄林外的蟹主要以大型藻类为食；白骨壤和红海榄林外可能主要以微藻为食。更多还原

【Abstract】 This study was designed to understand how the habitat heterogeneity of mangroves influence crabs’ species, biomass and food composition. The study was carried out in Dongzhai Bay, Hainan, China. Four mangrove forests were chosen, including three monospecific forests dominated by Ceriops tagal, Avicennia marina, and .Rhizophora stylosa, respectively, and a mixed forests dominated by Bruguiera sexangula and Bruguiera gymnorrhiza. A pair sites was selected for each forests, One site was established inside the forest, and the other was on the mudflat near the forest. Species and biomass of crabs were investigated, andδ¹³C、δ¹⁵N values of mangrove leaves, sediments and muscle tissues of crabs were determined seasonally through2007 April to 2008, January.In Dongzhai Bay, 18 species of crabs belong to 5 Families were recorded during out investigation. Fiddler crabs and Sesarminae crabs were two major subfamilies. Most Fiddler crabs live on mudflat and Sesarminae crabs prefer inhabiting under canopy. Metaplax longipes （Grapsidae） was also a common species in the area, and distributed both on mudflat and under canopy. There were no significant differences in what among the four sites on mudflat near the forests. The biomass of crabs （25.24g/m²） inside the C. tagal forest was the lowest, significantly lower than that on the mudflat near the forest（105.13g/m²）; the highest （166.73g/m²） was inside the R. stylosa forest, remarkably higher than that on the mudflat near the forest（89.28g/m²）. The biomass of crabs in A. marina （102.57g/m²） is similar to that in B. sexangula + B. gymnorrhiza mixed forest （104.94g/m²）, and there were no significant differences of biomass of crabs between the sites in the two forests and on the mudflat close to them. The biomasses of crabs in the four sites on mudflat were higher in wet season than in dry season, but reverse trend was found in forests.There were significant differences in theδ¹³C、δ¹⁵N values among mangrove species. Theδ¹³C values of C. tagal and A. marina were higher （-28.1 to -25.2‰）, and that of R. stylosa and B. sexangula were lower（-30.7 to -27.8‰）.δ¹⁵N values the four mangrove species can be listed as: C. tagal （3.8‰） < B. sexangula （5.0‰） < R. stylosa （6.3‰） < A. marina （7.7‰）.δ¹³C values of C. tagal, B. sexangula and R. stylosa were higher in wet season than in dry season, butδ¹³C value of A. marina have inversed trend. However,δ¹⁵N values had no significant seasonal changes.Sedimentδ¹³C value in C. tagal forest was lower than C. tagal leafδ¹³C value. Sedimentδ¹³C value in R. stylosa forest was similar to R. stylosa leaves. The sediments in A. marina forest and B. sexangula + B. gymnorrhiza forest were about 2.0‰¹³C enriched than mangrove leaves, repectively. Sedimentδ¹³C values on mudflat near C. tagal, A. marina and B. sexangula + B. gymnorrhiza forests were similar to that in forests, but the sedimentδ¹³C value on mudflat near R. stylosa forest was about 3.0‰higher than that in the forest. Based on the analysis onδ¹³C values of the sediments and mangroves, we found that the sediments in different mangrove forests had different major contributions. The sedimentδ¹³C values in the four forests in wet season were lower than in dry season. The sedimentδ¹³C values on mudflat near C. tagal, R. stylosa and B. sexangula + B. gymnorrhiza forests were higher in wet season than in dry season. While, both sedimentδ¹³C values in A. marina forest and on the mudflat nearby were lower in wet season than in dry season. These seasonal changes were influenced by the changes of relative contribution of mangrove litters and microalgae.Based on analysis onδ¹³C、δ¹⁵N values of crab muscle tissues, we found differences in diets of crabs in different sites. Crabs in A. marina forest may mainly eat mangrove leaf litters and sediments, we estimated that the contributions were 26.7% and 73.3%, respectively. The major food for crabs in C. tagal and R. stylosa forests was probably macroalgae and sediments. Microalgae was possibly the major food of crabs in B. sexangula + B. gymnorrhiza forest. Crabs on mudflat near C. tagal and B. sexangula + B. gymnorrhiza forests may mainly eat macroalgae. Crabs on mudflat near A. marina and R. stylosa forests may mainly eat microalgae.更多还原