海南五指山缓步动物物种多样性的初步调查研究

【作者】 王大勇；

【导师】 李晓晨；

【作者基本信息】 陕西师范大学 ， 生态学， 2008， 硕士

【摘要】 缓步动物是一类小型水生多细胞动物,俗称“水熊”,系统分类上为一独立的门,最近分子生物学运用18SrRNA技术的研究表明缓步动物与节肢动物互为姊妹群。缓步动物两侧对称,具有4对肢,肢的末端着生锐爪,成体的体长平均为250-500μm,身体周围需要一层水膜来保持活动状态。它们通常生活在淡水生境、海洋、河流、湖泊沉积物、潮汐带或潮湿苔藓中,绝大多数为陆生种类,生活在潮湿的土壤或落叶中,或生活在苔鲜、地衣、苔类植物以及地毯状显花植物中间。当环境条件发生不适宜的变化时,它们会进入隐生状态,包括低湿隐生、低氧隐生、低温隐生和高压隐生,能够忍受极端低温,甚至一些种类可以生活在绝对温度下,低温隐生使缓步动物在结冰及融化的情况下生存下来,是淡水陆生缓步动物在低温环境下的主要生存策略,桶状的形成在克服低湿环境中发挥作用。2007年3月和5月分别对海南岛五指山及木棉山进行了缓步动物区系调查,分别采集苔藓样本130份和100份,并以海南岛五指山不同海拔的缓步动物群落为研究对象,在海拔600m～1800m之间,设置11个样区,在每个样区随机采集苔藓样本10份,对110份苔藓样本进行缓步动物的提取、鉴定、数量统计,确定其群落组成及个体和物种分布的变化趋势,采用多样性指数来研究缓步动物的物种多样性及变化,利用主成分分析、相似性指数来研究不同海拔缓步动物群落的动态变化规律,并将五指山和太白山的研究结果作对比。研究结果如下:1.对海南岛五指山和木棉山缓步动物区系调查中,共收集缓步动物380个,分别隶属于3目、4科、14属、30种,其中发现新种3个,中国新纪录7个,海南岛新纪录19个。2.五指山不同海拔缓步动物种群密度和物种数,从数值变化上来看是随着海拔的升高呈下降趋势。不同海拔间缓步动物种群密度及物种数与随海拔变化的微环境有关,高海拔出现的高数量是因为高海拔限定了一个适合缓步动物生长的较好环境,同样,在低海拔也会出现同样的情况,只是因地而异。虽然五指山缓步动物的分布随海拔的变化而有所变化,但方差分析显示海拔变化对缓步动物种群密度和物种数影响不显著。多重比较表明较低海拔的种群密度和物种与中、高海拔存在显著差异,而中海拔和高海拔间不存在显著性差异。3.从多样性指数值的变化来看,随着海拔的升高,多样性信息指数总体上呈下降的趋势,优势度指数变化相反。但方差分析表明海拔变化对缓步动物多样性信息指数、均匀度指数和优势度指数的影响均不显著。多重比较表明较低海拔多样性信息指数及均匀度指数与中、高海拔存在显著差异,而中高海拔间不存在显著性差异,优势度指数在各海拔间差异均不显著。4.主成分分析的结果表明:五指山和太白山不同主成分代表种,所处的海拔不同,而同一主成分内的代表物种,所处的海拔相同,说明缓步动物群落是随海拔的变化而变化的,但在太白山南北坡的2500m和2800m均出现了两个主成分,说明能够代表整个缓步动物群落的较多物种处在南北坡的2500m至2800m,此海拔范围具有最高的物种丰富度。5.相似性分析结果表明:五指山缓步动物群落间的相似性,普遍较低,为极不相似或中等不相似;太白山南北坡,相似性也较低,大部分系数仍为极不相似或中等不相似,个别出现中等相似。比较发现太白山缓步动物群落受海拔微环境的影响没有五指山剧烈,缓步动物群落沿海拔的变化比五指山慢。更多还原

【Abstract】 Tardigrades, hydrophilous micrometazoans commonly called "water bears", are generally considered to be an independent phylum. Evidence from recent molecular studies with 18S RNA has shown that tardigrades are a sister group of the arthropods. Tardigrades show bilateral symmetry with four pairs of limbs that usually terminate in claws. Mature adults average 250-500 mm. All active individuals require a film of water around the body. They could be found in permanent freshwater habitats, in sea, river or lake sediment, in littoral zone or in moist mosses. Most tardigrade species are terrestrial, occurring in moist soil and leaf litter, or among mosses, lichens, liverworts, and cushion-shaped flowering plants. Tardigrades can endure extremely low temperatures; some species have even survived absolute zero. A change in environmental conditions can induce the animal to enter a cryptobiosis, which can be anhydrobiosis, anoxybiosis, cryobiosis or osmobiosis. Cryobiosis enables tardigrades to survive freezing and thawing, and is the principal survival strategy of limno-terrestrial tardigrades living in very cold environments. The formation of tuns also plays a role in the dispersal of cryobiotes.Tardigrada fauna has been investigated on Five-Finger Mt and Mumianshan Mt, Hainan Island during March and May of 2007. Tardigrades were collected from eleven sampling sites, the height of which is from 600m to 1800m above the sea level. Ten moss samples were collected within each sampling site. Tardigrades were extracted from a total of 110 samples. All specimens were identified and counted. Species diversity at different altitude was calculated using the diversity index. The community dynamic changing regularity of Tardigrada at different altitude was studied using the Principal Component Analysis and the Similarity index. The community structure of tardigrade on Five-Finger Mt. and Taibai Mt. were compared. The research results are summarized as follows:1. 380 individual tadigrades, belonging to three orders, four families, 14 genera and 30 species including 3 new species, 7 new Chinese record species and 19 new record species for Hainan, were collected on the Five-Finger Mt and Mumianshan Mt.2. Population density and species number mainly decreased with the increase of altitude. Population density and species number at different altitude are related to the microenvironment. The higher number found on higher altitude. The one-way ANOVA showed that the altitude variation has no significant influence on the population density and species diversity. Results from Multiple comparison(LSD) showed that there were significant differences in the population density and species diversity at different altitude.3. Shannon-Wiener index decreased with the increase of altitude, while Simpson index increased with the increase of altitude. However, the one-way ANOVA showed that the altitude variation has no significant influence on Shannon-Wiener index, Pielou index and Simpson index. LSD showed that there were significant differences in the Shannon-Wiener index, Pielou index at different altitude below the medium altitude, but no significant differences above medium and high altitude. The Simpson index has no significant difference at different altitudes.4. The principal component analysis showed that the representative species of different principal component in Five-Finger Mount and Taibai Mount located at different altitude, while the representative species of same principal component located at the same altitude. These reveal that the tardigrada community varies with the change of altitude. Two principal components appear both in 2500m and 2800m in north and south slope of the Taibai Mount, which suggest that the variation of tadigrada community in Taibai Mount can represent the variation of the most tadigrada community, and the tadigrada ranging from 2500m to 2800m has the highest species richness.5. Similarity analysis showed that tardigrada communities on Five-Finger Mt has a low similarity (extremely dissimilarity and medium dissimilarity). And the similarity between south and north slope of Taibai Mt is also low, most of which is extremely dissimilarity and medium dissimilarity. We found that the afflence on tadigrada community of Five-Finger Mt is severer than on the tardigrada community of Taibai Mt, and the variation along the altitude in Taibai Mt is slower than in Five-Finger Mount.更多还原