Distribution of bathyal meiofauna in the region of the Subtropical Front, Chatham Rise, south-west Pacific

Metazoan meiofauna was sampled along a temperate latitude transect (41-47°S 178°30′E) across the Chatham Rise, south-west Pacific, from water depths of 350-2600 m on three occasions (austral autumn 1997, spring 1997, summer 2000). Samples were collected using a multicorer and extracted on a 63-μm mesh. Meiofaunal density and biomass were negatively correlated with water depth, median grain-size and sediment calcium carbonate content, and positively correlated with sediment chlorophyll a. There were no significant relationships between meiofaunal abundance and biomass and measures of sediment organic matter and bacterial productivity and biomass, except in summer when bacterial and meiofaunal biomass were positively correlated. Vertical penetration of meiofauna into the sediment was related to sediment organic matter and sediment chloroplastic pigments. Variation in meiofaunal abundance at different spatial scales was examined at two sites: at 450 and 2300 m on the northern slope of the rise. At both sites, variation between subcores of a multicore (< 10-cm scale) was lower than that of multicores within a deployment (< 1-m scale). However, whilst the highest variance component at the shallow site was for multicores within a deployment, it was between multicore deployments (< 1-km scale) for the deep site. Meiofaunal density and biomass were generally higher on the southern slope of the rise than on the northern slope, a trend probably attributable to high productivity of the overlying Subtropical Front and the flux of more nutritious organic material to the sea floor.     

厦门凤林红树林湿地大型底栖动物群落

为摸清厦门集美凤林红树林湿地的大型底栖动物群落结构及其多样性现状,2002年1、4、7和10月在厦门集美凤林红树林区进行大型底栖动物调查,4个季度共获得大型底栖动物42种。生物量优势种是软体动物门的珠带拟蟹守螺(Cerithideacingulata)和节肢动物门的弧边招潮(Ucaarcuata)。密度优势种是软体动物门的短拟沼螺(Assimineabrevicula)和环节动物门的沼蚓(Limnodriloidessp.)。集美凤林红树林区大型底栖动物年平均密度和年平均生物量分别为1,990ind./m2和139.0g/m2。密度的季节变化是:1月>4月>10月>7月,生物量的季节变化是1月>10月>4月>7月。聚类分析和数量分布表明,优势种珠带拟蟹守螺、短拟沼螺、弧边招潮和沼蚓的季节变化各不相同。与2002年10月深圳湾福田红树林区大型底栖动物群落的物种多样性指数平均值(0.56)比较,厦门凤林红树林区的平均值较高(2.66)。文中分析了影响大型底栖动物多样性的环境因素。     

Cytotaxonomic observations on some Hymenophyllaceae from the New Hebrides, Fiji and New Caledonia

Seventy-two chromosome counts representing 36 species are recorded with taxonomic notes and discussed in relation to the classifications of the family proposed by Copeland and Morton. A comparison of the available cytological data with the two classifications raises problems of a different nature with respect to the proposed subdivisions of the hymenophylloid and trichomanoid species. Many of the hymenophylloid taxa are cytologically heterogeneous, and it is suggested that morphological reassessment of cytologically authenticated material may lead to a more satisfactory grouping of these species. In contrast most of the trichomanoid taxa are confirmed by the cytological data; but at the same time there is considerable cytological uniformity among the numerous small genera recognized by Copeland. The cytological pattern of the subgenera in Morton's classification indicates how an improved classification of these species, recognizing fewer genera, might eventually be achieved.     

Genetic variation in Lumnitzera racemosa, a mangrove species from the Indo-West Pacific

The genetic structure of 18 populations of Lumnitzera racemosa from the Indo-West Pacific, including South China, Malay Peninsula, Sri Lanka, and North Australia, was assessed by inter simple sequence repeat (ISSR) markers. Our results showed a relatively high level of genetic variation at the species level (P = 87.04%, H_e = 0.260). The value of G_st was 0.642, suggesting significant genetic differentiation among populations. At the population level, however, genetic diversity was low (P = 32.17%, H_e = 0.097). When populations were grouped according to geographic regions, i.e., South China Sea, the East Indian Ocean, and North Australia, it was inferred from AMOVA that more than half the total variation (55.37%) was accounted for by differentiation between regions. A UPGMA dendrogram based on genetic distance also revealed a deep split between populations from these regions, indicating that Malay Peninsula and the Indonesia archipelago may play an important part on the genetic differentiation in L. racemosa. The high degree of population differentiation between regions and low genetic variation within populations recorded here highlights the need for appropriate conservation measures for this species, both in terms of incorporating further populations into protected areas, and the restoration strategies for separate regions.     

Plant species and community responses to sand burial on the machair of the Outer Hebrides,Scotland

Question: Is there a critical depth of burial by sand beyond which species and communities fail to recover, and does repeated incremental burial have a greater impact than a single large deposition? Location: The machair on the calcareous sand dunes on South Uist, in the Outer Hebrides of Scotland, UK. Methods: Eight turves were collected from each of four machair sub‐community types. After acclimatization in an unheated polythene tunnel, they were buried with sterilized machair shell sand, either by one single burial to 5 cm or by five applications of 1 cm of sand at approximately seven‐week intervals. Species response was recorded on five occasions. Results: Within machair sub‐communities, burial by sand reduced the abundance (local rooted frequency) of plants more than it reduced species richness. Intermittent burial was more damaging than a single burial event. Those species with the highest pre‐burial frequencies tended to dominate recovery in the sub‐community as a whole. Species occurring across all four sub‐community types exhibited varying responses to community burial between the differing types. Samples from slack sub‐communities had distinctly different response characteristics from those of foredunes and unploughed and three‐year fallow dune grassland. Conclusions: The perennial life‐form of many machair species has been evolutionarily selected for and dominates throughout the machair habitat. Account needs to be taken of competitive interaction between species in relation to burial response. The results of the investigation show that the hypotheses of Gilbertson et al. and Kent et al. on ‘machair stratification’ require refinement in that frequency of shallow burial can be as important as overall burial depth.     

Estimates of biomass in a temperate mangrove community

Above and below ground biomass of Avicennia marina (Forsk.) Vierh. was studied in a mangrove community near Sydney, Australia. Data were obtained for seedlings (0–80 cm) and established trees (≥ 200 cm) growing in two nearby sites. Estimates were made of total mangrove biomass and its components: roots and pneumatophores; trunks and branches: leaves and petioles. The sites studied differed in average tree size (277 kg v. 97 kg) and in seedling biomass (0.12 km m^-2 v. 0.02 kg m^-2) but not in total biomass (29.2 kg m^-2 v. 27.3 kg m^-2). The partitioning of biomass of Avicennia marina in this temperate mangrove community was similar to that of Rhizophora mangle in a tropical mangrove community.     

Aeolid opisthobranch molluscs (Glaucidae) from the Indian Ocean and the south-west Pacific

Eight aeolid opisthobranch molluscs of the subfamilies Facelininae, Favorininae, and Herviellinae are reported from Tanzanian waters, and two species from Northwestern India. New records from Queensland, Australia greatly extend the range of two species reported from Tanzania. Phidiana militaris (Alder & Hancock) and P. indica (Bergh) are shown to be distinct and a species from New Zealand, originally identified as P. militaris , is shown to be new. P. bourailli (Risbec), previously reported only from New Caledonia, is described from Tanzania, as is a new species of Phidiana. Favorinus japonicus Baba is reported from Tanzania, the first published record outside Japan, a new species of Godiva is described from Tanzania and Queensland, and three new species of Sakuraeolis are described, one from India and two from Tanzania. A new species of Herviella is described from Tanzania.     

湛江特呈岛红树植物群落结构特征

2008年6月,采用样方调查法对湛江特呈岛红树植物群落结构及白骨壤(Avicennia marina)的种群特征进行了全面调查.结果表明:该地区红树林是白骨壤纯林以及白骨壤为主,有红海榄(Rhizophora stylosa)、木榄(Bruguieragymnorrhiza)和桐花树(Aegiceras corniculatum)的混交林.白骨壤在潮滩上连续分布,红海榄、木榄和桐花树生长于近陆林缘及潮滩的中部,物种多样性指数由陆缘向海缘呈降低趋势.通过分析白骨壤种群的株高、地径在潮滩上的变化规律得出年幼的个体聚集于近陆林缘,近海林缘较少.白骨壤种群的年龄结构为增长型,但是根据生境条件及白骨壤种群在海滩上的分布格局,分析得出该红树林资源处于退化的状态.     

Terrestrial vertebrates of the New Hebrides: origin and distribution.

The known terrestrial vertebrate fauna of the New Hebrides consists of 16 species of mammals (excluding feral domestic stock), 61 species of resident land- and freshwater birds, 20 species of reptiles and one amphibian. Of these, three, five, four and one species respectively have apparently been introduced by man. The non-introduced fauna is clearly Indo-Australian in origin, but some species have an exclusively Pacific island distribution and others (two bats, seven birds, and four lizards) are endemic. On the six islands visited 95 out of the possible 98 vertebrate species occur. Santo, the largest and most northerly island, supports the richest fauna. The comparative impoverishment of more southerly islands is not directly attributable to the progressive increase in isolation and distance from presumptive source area, nor to decrease in island area or maximum height.     

Spatial variability of mangrove fish assemblage composition in the tropical eastern Pacific Ocean

Mangroves in the tropical eastern Pacific (TEP) constitute a dominant coastal ecosystem that harbours diverse and economically important fish assemblages. We describe here regional scale patterns in the composition of this poorly documented mangrove ichthyofauna. A review of available studies (including own data) from five countries covering the entire region was performed. Species abundance distribution curves were constructed and compared among studies. Relative abundance data of fish species and families were analysed with classification and ordination techniques. Common species and families responsible for differences among localities were identified. Overall, 315 fish species associated to mangroves of the TEP were identified. Fifteen fish families accounted for 80 % or more of the relative abundance of all studies. Despite the use of different sampling techniques, common features arose for most of the mangrove fish assemblages. Clupeidae were numerically dominant throughout the region, while Gerreidae were particularly dominant in the northern mangroves. The catch mass contributions of families from studies where these data were available indicated a dominance of Ariidae, Centropomidae, Lutjanidae and Tetraodontidae. A relatively uniform composition at the family (and sometimes species) level supports recent claims to merge the Panamic with the Mexican province in the TEP according to the distribution of the shore fish fauna. Similarities found with other estuarine-mangrove ichthyofaunas in the Neotropics may be related to the connectedness of these regions in past geological times. Quantitative assessments of mangrove fish communities in four areas of the TEP would improve further zoogeographic analyses and facilitate the development of conservation strategies.     

Host-specificity amongst arthropods ectoparasitic upon mammals and birds in the New Hebrides

• 1 Examination of 606 mammals of seventeen species and 959 birds of thirty-three species yielded sixty-three species or species groups of ectoparasitic arthropod. These included eighteen species of Acari, twenty-five species or species groups of Phthiraptera, eighteen species of Diptera Pupipara, and two species of Siphonaptera. These are listed with their hosts and island localities, and host associations noted.
• 2 Host specificity amongst ectoparasitic insects is discussed, and the insects classified into four groups of decreasing specificity.
• 3 Several broad factors likely to encourage specificity are noted, and it is concluded that the wide diversity of specificity observed is caused by complex interaction of these factors.