Temperature impact on reproduction and development of congener copepod populations

The goal of this study was to relate the temperature response of all developmental stages and reproductive biology of two congener copepod pairs inhabiting different biogeographic regions to their geographic distribution patterns. Survival of adult females and egg production, embryonic development and hatching success of the genera Centropages and Temora from two stations, in the North Sea and the Mediterranean, were studied in laboratory experiments in a temperature range from 2 to 35 °C. Postembryonic development was determined from cohorts raised at temperatures between 10 and 20 °C with surplus food. Tolerance limits and optima of female survival, reproduction and development distinguished the northern species Centropages hamatus and Temora longicornis from the southern T. stylifera, while C. typicus, which is found in both regions, was intermediate. Thus, thermal preferences could in part explain distribution patterns of these species. While C. hamatus and the two Temora species showed distinct temperature ranges, C. typicus was able to tolerate different temperature conditions, resulting in its wide distribution range from the subarctic to the tropics. However, the thermal range of a species did not necessarily correlate with the optimal temperatures in the experiments. Optima of egg production and stage development were surprisingly low in T. stylifera, which has a mere southern distribution.     

The effects of grazing on the distribution and composition of low-shore algal communities on the central coast of Portugal and on the southern coast of Britain

A red algal turf is often found just below the barnacle/limpet zone of many European shores, especially on steep shores of moderate exposure. The hypothesis that grazing by limpets determines the upper limit of distribution of this red algal turf was tested on moderately exposed shores in Portugal and Britain. We also aimed to assess whether the grazing effect is modified at various spatial scales. Grazers were excluded by fences, with half-fenced and unfenced controls. Exclusion plots were rapidly colonised by green ephemeral algae in the months immediately after the beginning of the experiment (summer); these algae were later replaced by perennial algae. The percentage cover of turf-forming macroalgae showed a significant increase at both locations. The upper limit of distribution extended more than 50 cm on most of the shores studied. In contrast, control and half-fenced plots remained devoid of algae. After 2 years, ungrazed plots were mainly colonised by a red algal turf (e.g. Caulacanthus ustulatus, Gelidium spp., Laurencia pinnatifida) in Portugal, while canopy cover (Fucus serratus and Himanthalia elongata) dominated in Britain in marked contrast to the grazed plots. Physical factors acting at both local and geographical scales may explain these differences. However, although physical factors probably have an important influence on the identity, size and abundance of sublittoral fringe macroalgae, grazers play a major role in directly setting their upper limits. The effect of grazing by limpets was not consistent for all of the morphological algal groups and spatial scales considered in the present study. The effect of grazing on the cover of turf algae varied between Portugal and Britain (location scale), while effects on ephemeral and canopy algal cover varied at the shore scale within location.     

山茶科濒危植物猪血木的生态与繁殖特性

在广东省阳春市八甲镇地区发现濒危和特有植物猪血木（Euryodendron excelsum)80余株个体及其自然居群,通过其生境条件,分布格局,群落组成,物候,种子散布和种子萌发实验等研究。结果显示该植物生长繁殖正常;其种子散布以黄臀鹎（Pycnonotus xanthorrhous)等鸟类散布为主,但鸟类消化处理不是其种子萌发的必要条件,湿度保持是其种子保持活力的重要条件;其种子无休眠期,同时探讨了该植物的濒危状况的原因。提出了相应的保护建议和方案。     

4 689例血培养病原菌的临床分布与种类分析

目的：了解本院血培养病原菌的检出种类及在临床各科的分布。方法：应用Bact/Alert-120全自动血培养仅对4689例血标本进行培养,标本检出病原菌按常规鉴定并分类统计。结果：检出有临床意义病原菌355株,其中肠杆菌科和葡萄球菌属的细菌为主要病原菌（35.5%和27.3%)。以2000年全年标本统计,阳性率12.5%,假阳性率0.4%。以内科,外科,儿科,传染科,血液科,新生儿科等为病区统计,病原菌种类分布有明显不同,此外,病原菌种类不同,其阳性报告时间不同。结论：应用全自动血培养仪可以缩短阳性检出时间,了解病原菌在临床各科的分布特点,有利于医师对败血症诊治,及时准确地选择药物。     

Recruitment in Dentaria bulbifera; the roles of dispersal,habitat quality and mollusc herbivory

Abstract. We investigated the effects of dispersal limitation, diaspore density, soil chemistry, disturbance and mollusc herbivory on the abundance and distribution of the perennial forest herb Dentaria bulbifera (Brassicaceae). After experimental sowing of bulbils in originally empty patches, juveniles of Dentaria emerged in 83% of plots. The seventh year after sowing, plants still persisted and were reproducing in several plots, demonstrating that the species is dispersal‐limited. However, long‐term survival of transplants was higher at sites where Dentaria occurred naturally, and this difference increased with time after sowing. Thus, the importance of local factors may only be expressed fully several years after colonisation. Differences in soil chemistry and disturbance treatment were not associated with differences in patch suitability. Removal of molluscs, however, significantly increased recruitment, and the effects of a single molluscicide treatment persisted after four years. We conclude that dispersal is not the only limitation to the distribution of Dentaria, and that local factors, such as mollusc herbivory, are also crucial.     

淫羊藿属(小檗科)花瓣的演化和地理分布格局的研究

淫羊藿属的种数与60年前大不相同,现在已知约有50种。该属种类间断地分布于日本至北非 的阿尔及利亚之间的广大地区,这一分布格局表明了该属的古老性质。它们在欧亚大陆的分布极不均 匀,约有80％的种类产于中国中部至东南部,而且根据花瓣的演化分析结果表明,只有中国的淫羊藿属 植物具有连续不断的演化过程。由此可见,中国中部至东南部成为北半球淫羊藿属植物的汇集中心是 有充分根据的。淫羊藿属种类基本上是林地草本植物,常生于水青冈林下,为林下草本层的优势种,而 且该属的分布格局与第三纪植物属——水青冈属在欧亚大陆的分布格局极为相似,说明淫羊藿属植物 在早第三纪时期已广泛分布于北半球。中新世时期由于中亚地区气候变干,加之印度板块向欧亚大陆 俯冲并引起喜马拉雅山脉隆起,致使中亚地区进一步干旱,水青冈属和淫羊霍属植物随之消失,进而导致其东亚—地中海、西亚间断分布格局的形成。     

Benthic fauna in tropical tidal flats of Hinchinbrook Channel, NE Australia: diversity, abundance and their spatial and temporal variation

A survey of the benthic infauna (macro- and mesofauna) in tidalflats of Hinchinbrook Channel, north-east Australia, was carried out toassess the species diversity and individual abundances as well as theirtemporalvariations. Two sites were surveyed at five occassions from November 1988 toOctober 1991. In addition, spatial distributions over the intertidal gradientwere investigated once in May 1990. During the entire survey, over 200 specieswere recorded, with 53 species found on average at each sampling occassion.Species densities ranged from 4.0 to 8.2 species 177cm^–2 for macrofauna and from 4.1 to 11.8 species10 cm^–2 for mesofauna, but varied little betweensites. The average infaunal diversity (H') was 2.53. Individual abundancesreached median values of 14.0 individuals 177cm^–2for macrofauna and 14.5 individuals 10 cm^–2 formesofauna. Changes in total abundances were not related to season andinconsistent at the two study sites, with significantly higher abundancesoccurring either at site A or B on single sampling dates. Transects sampled inMay 1990 showed varying species compositions and abundances in the upper, midand lower intertidal, but no defined benthic communities were revealed bymultivariate analyses. Temporal variations in the benthic assemblages of thetwotidal flats in Hinchinbrook Channel were higher than variations between sites,with a separation of assemblages before and after 1989. Problems to assess andinterpret temporal changes in species rich tropical benthic communities arediscussed.     

Hydrozoan and protozoan epibionts on two decapod species, Liocarcinus depurator (Linnaeus, 1758) and Pilumnus hirtellus (Linnaeus, 1761), from Scotland

Crabs of the species Liocarcinus depurator and Pilumnus hirtellus, collected on the west coast of Scotland, showed hydrozoan and protozoan epibionts. The epibionts of Liocarcinus depurator were the protozoan Ephelota plana and the hydrozoans Clytia gracilis and Leuckartiara sp. The epibionts of Pilumnus hirtellus were the protozoans E. plana and Zoothamnium sp. For Liocarcinus depurator the number of Ephelota per crab fluctuated between 0 and 47 and the greatest number of suctorians were located on the chelipeds, carapace and anterior pereiopods. The hydrozoans, for Liocarcinus depurator, showed densities of 0-20 (Clytia gracilis on the second pereiopod) and 0-507 individuals per crab (Leuckartiara sp., principally on chelipeds, carapace and the fourth right pereiopod). For Pilumnus hirtellus, Ephelota plana showed densities between 3 and 56 individuals per crab, the greatest number of suctorians being located on the same areas as on Liocarcinus depurator. There was a density of 10-69 individuals per crab of Zoothamnium sp. on Pilumnus hirtellus (located on the carapace). Ephelota plana has not been observed previously as an epibiont on crustacea, nor had Zoothamnium sp. as an epibiont on Pilumnus hirtellus. Both hydrozoans, Leukartiara and Clytia, have not been previously described as epibionts on Liocarcinus depurator. Data about the morphological characteristics and distribution of these epibionts are included.     

On the Estimation of Heritability from Unbalanced Data

The distribution and moments, of ANOVA estimator of heritability are given under unbalanced random model. These expressions are used to investigate the effect of unbalancedness on the bias and variance/MSE of the estimator and also the validity of certain approximations for its variance, numerically. The computed results reveal that the unbalancedness increases both the bias and variance/MSE of the estimator and the Smith-approximation for the variance of the estimator provides better accuracy.