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101.
Chris B. Joyce Cristina Vina-Herbon Daniel J. Metcalfe 《Estuarine, Coastal and Shelf Science》2005,65(4):633-644
Coastal water bodies are a heterogeneous resource typified by high spatial and temporal variability and threatened by anthropogenic impacts. This includes saline lagoons, which support a specialist biota and are a priority habitat for nature conservation. This paper describes the biotic variation in coastal water bodies in Sussex, England, in order to characterise the distinctiveness of the saline lagoon community and elucidate environmental factors that determine its distribution. Twenty-eight coastal water bodies were surveyed for their aquatic flora and invertebrate fauna and a suite of exploratory environmental variables compiled. Ordination and cluster analyses were used to examine patterns in community composition and relate these to environmental parameters. Biotic variation in the coastal water body resource was high. Salinity was the main environmental parameter explaining the regional distribution of taxa; freshwater and saline assemblages were evident and related to sea water ingress. Freshwater sites were indicated by the plant Myriophyllum spicatum and gastropod mollusc Lymnaea peregra, while more saline communities supported marine and brackish water taxa, notably a range of chlorophytic algae and the bivalve mollusc Cerastoderma glaucum. Site community differences were also related to bank slope and parameters describing habitat heterogeneity. A saline lagoon community was discerned within the matrix of biotic variation consisting of specialist lagoonal species with associated typically euryhaline taxa. For fauna, the latter were the molluscs Abra tenuis and Hydrobia ulvae, and the crustaceans Corophium volutator and Palaemonetes varians, and for flora they were the algae Ulva lactuca, Chaetomorpha mediterranea, Cladophora spp. and Enteromorpha intestinalis. One non-native polychaete species, Ficopomatus enigmaticus, also strongly influenced community structure within the lagoonal resource. The community was not well defined as specialist and associated taxa were distributed throughout the spectrum of sites surveyed. Implications for the identification and conservation of saline lagoons are discussed. 相似文献
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103.
Distribution and Adaptations of Sea Ice Inhabiting Harpacticoida (Crustacea, Copepoda) of the Weddell Sea (Antarctica) 总被引:5,自引:0,他引:5
Abstract. Seven harpacticoid species were found to be associated with sea ice collected during 5 Antarctic cruises of the RV Polarstern. Their distribution within the fast ice and pack ice zones of the Weddell Sea is presented. Whereas some individuals probably become entrapped into the ice only accidentally, at least 4 species arc genuinely sympagic. These have evolved remarkable adaptations, as evidenced by field and laboratory studies of Dresclieriella glacialis , which is by far the most abundant. Such adaptations include: the ability to penetrate deep into ice; a comparatively high salinity tolerance allowing it to endure large salinity fluctuations associated with ice crystal formation and melting; good swimming ability, necessary both for horizontal dispersal and for a planktonic intermezzo after annual melting of the sea ice. D. glacialis is the first polar non-vertebrate mctazoan to be cultivated through its entire life cycle. Its life history suggests an r-stratcgy; this would be the first indication of such a trait in the polar environment. A new species of Drescheriella , on the other hand, exhibits resting stages (C IV-V) known to date only for Calanoidu but not reported for Harpacticoida. 相似文献
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Abstract. In the Cyclades plateau (Aegean Sea), a qualitative and quantitative analysis of macro-benthic fauna was carried out in 1986. Standard multivariate analysis techniques were applied to both ecological (living benthic fauna) and paleoecological data sets in order to distinguish distribution patterns.
Results showed that caution must prevail in drawing conclusions from a limited data set. The clearest classification was obtained using total living fauna, while the dead molluscan fauna gave a similar pattern; this indicates similar response to the environmental conditions of the area. In the analysis of the living molluscan fauna, the groups failed to show any clusters, probably as an effect of some impoverished sites.
In the two groups delineated, depth seems to be the major factor in the distribution of species.
The fact that two distinct data sets (subfossil assemblages and living communities), when treated separately, produce similar grouping indicates that the subfossil assemblages could be reliably used as a first approach for determination of the living communities' distribution patterns. 相似文献
Results showed that caution must prevail in drawing conclusions from a limited data set. The clearest classification was obtained using total living fauna, while the dead molluscan fauna gave a similar pattern; this indicates similar response to the environmental conditions of the area. In the analysis of the living molluscan fauna, the groups failed to show any clusters, probably as an effect of some impoverished sites.
In the two groups delineated, depth seems to be the major factor in the distribution of species.
The fact that two distinct data sets (subfossil assemblages and living communities), when treated separately, produce similar grouping indicates that the subfossil assemblages could be reliably used as a first approach for determination of the living communities' distribution patterns. 相似文献
108.
The investigation of a limestone cave on the Ryonggok-ri of Sangwon County, North Hwanghae Province, DPRK, has yielded many faunal remains including Late Pleistocene deer, brown bears and horses. Uranium series dating of fossil teeth yielded dates of ~72ka at the base of Layer 2 – the bone-bearing unit – and ~44ka at the top. The rich and diverse mammal remains of Ryonggok Cave No. 1 are indicative of warm and humid temperate conditions during the Late Pleistocene, and reflect the presence of both dense forests and open grassland. In addition, pollen and spores from the site include two families and 24 genera of trees, six families and a genus of grasses and herbs, and two families and six genera of ferns, corroborating the environments inferred from the faunal remains. 相似文献
109.
中国北方著名中、晚侏罗世的燕辽生物群含有丰富的叶肢介动物群。早期燕辽生物群也称为道虎沟生物群,主要产出层位为海房沟组,含有三饰叶肢介动物群,主要分子包括: 海房沟三饰叶肢介(Triglypta haifanggouensis )、滦平三饰叶肢介(T.luanpingensis )和平泉三饰叶肢介(T. pingquanensis )。晚期燕辽生物群又可称为玲珑塔生物群,主要产出层位为髫髻山组,含有丰富的叶肢介化石,主要分子包括: 建昌三饰叶肢介(Triglypta jiancangensis )、玲珑塔辽西叶肢介(Liaoxiestheria linglongtaensis )、大西山玲珑塔叶肢介(Linglongtaestheria daxishanensis )和青龙玲珑塔叶肢介(Linglongtaestheria qinglongensis )。文中总结了北方雕饰叶肢介(Aquilonoglypta )、柴达木叶肢介(Qaidamestheria )和针孔叶肢介(Punctatestheria )的最新研究成果,支持将柴达木叶肢介、辽西叶肢介和玲珑塔叶肢介划归北方雕饰叶肢介科。同时,三饰叶肢介是由针孔叶肢介演化而来,与柴达木叶肢介并无直接演化关系。 相似文献
110.
2010年冬季与2011年春夏季,采用样线法对位于豫鄂交界处的信阳南湾湖鸟类多样性进行调查。结合历史资料,南湾湖共记录到鸟类16目40科110种,其中4目5科9种均为国家重点Ⅱ级保护野生动物;特有种或主要分布在我国的鸟类2目2科2种。留鸟40种,夏候鸟38种,冬候鸟9种,旅鸟23种。古北界鸟类42种,东洋界鸟类35种,广布种33种。研究区具有古北界种与东洋界种混杂的特点,古北界种鸟类占优势,分布型以北方鸟类为主。基于科属水平上的G-F指数计算结果显示,南湾湖的F指数、G指数与F-G指数分别是29.26、4.57、0.84,低于邻近的伏牛山鸟类各指数,显示南湾湖在鸟纲科属水平上与伏牛山鸟类多样性相异,且具有相对较低的鸟类多样性。 相似文献