Three New Species of Thraulodes (Ephemeroptera: Leptophlebiidae: Atalophlebiinae) from Venezuela

Three new species of Thraulodes from Venezuela are described. One species is known from male and female imagines, and the other two only from male imagines. With this, the known Thraulodes species for Venezuela are four. A key for the male imagines of the known species of Thraulodes from Venezuela is provided.     

Birds at a Southern California beach: seasonality, habitat use and disturbance by human activity

Use of a Santa Barbara beach by people and birds varied in both time and space. There were 100 birds, 18 people and 2 dogs per kilometer. Bird density varied primarily with the season and tide while human activity varied most between weekend and weekday. Bird distributions along the beach were determined mainly by habitat type (particularly a lagoon and exposed rocky intertidal areas) For crows and western gulls, there was some evidence that access to urban refuse increased abundance. Interactions between birds and people often caused birds to move or fly away, particularly when people were within 20 m. During a short observation period, 10% of humans and 39% of dogs disturbed birds. More than 70% of birds flew when disturbed. Bird species varied in the frequency that they were disturbed, partially because a few bird species foraged on the upper beach where contact with people was less frequent. Most disturbances occurred low on the beach. Although disturbances caused birds to move away from humans, most displacement was short enough that variation in human activity did not alter large-scale patterns of beach use by the birds. Birds were less reactive to humans (but not dogs) when beach activity was low.     

Habituation and habitat changes can moderate the impacts of human disturbance on shorebird breeding performance

Disturbance by humans is widely expected to reduce the reproductive fitness of nesting birds if disturbance reduces nest attentiveness, and unattended eggs experience increased risk of predation or exposure to potentially lethal temperature extremes. Yet, relatively few studies have examined the physiological or behavioural mechanisms whereby disturbance influences reproductive fitness, or the extent to which the costs of disturbance may be reduced through habituation. We compared the behavioural responses, egg temperatures and reproductive success of shore-nesting white-fronted plovers Charadrius marginatus to disturbance at two breeding sites experiencing low versus high human recreational activity, respectively. Daytime nest attentiveness decreased with increasing experimental disturbance at both sites, but this relationship differed between sites; for any given level of disturbance, incubating birds at the more disturbed site had greater nest attentiveness. They achieved this through habituation, allowing a closer human approach before leaving the nest, and returning to the nest faster after a disturbance event. Despite lower average daytime nest attentiveness at the more disturbed site, incubation temperatures did not differ significantly between sites. Nest mortality, mostly by natural mammalian and corvid predators, was significantly lower at the site experiencing high recreational activity. However, chick mortality was significantly greater at the more disturbed site, most likely because of predation by domestic dogs. Chick mortality may have been increased by the habitation of chicks, whose escape responses were much reduced at the more disturbed site. Nonetheless, annual fecundity was substantially higher at the more disturbed site, showing that the overall reproductive fitness of wild birds is not always compromised by human disturbance and urbanization.     

Seasonal variations in nematode assemblages on an Australian temperate ocean beach; the effect of heavy seas and unusually high tides

Free-living nematodes inhabiting a sandy beach exposed to strong ocean waves were sampled at bimonthly intervals for two years. Six 1.3-litre core samples were taken on each occasion down to a depth of 60 cm. The numbers of each species and their status as juveniles, males and females (with or without eggs) was recorded. In the common species all these stages occur throughout the year, but the population increases in the warmer months of the year and falls to a much lower level in winter. Most species are dispersed throughout the sand to a depth of at least 60 cm, but several species where almost always found below the water table at about 60 cm. The faunal composition of the nematode assemblages changed significantly from month to month. Additional samples were taken to monitor the effects of very strong waves coupled with a very high tide which remodelled the beach. The nematode fauna was partially reconstituted by this event. It is concluded that the intertidal beach fauna is a dynamic extension of the near shore sub-littoral nematode fauna.     

浙江乐清湾湿地水鸟资源及其多样性特征

乐清湾是我国具有重要意义的海湾之一。作者于1997、1999和2003年对乐清湾水鸟的分布、数量和多样性特征进行了研究,共观察到54种水鸟,隶属4目7科24属。其中湾口的水鸟物种数、个体数量、多样性指数、均匀度指数以及涉禽所占比例均为最高,湾底次之,湾中部最低。影响这一区域鸟类分布和多样性的因素包括不同区域的滩涂宽度、水动力条件以及有效潮上坪面积等。乐清湾冬季水鸟的物种数呈逐年下降趋势,但年间差异均不显著。除2003年分布于湾底的水鸟个体数量比1999年有所增加外,其他区域都呈逐年下降的趋势,但只有湾口2003年和1997年间的差异显著。鸟类多样性指数和均匀度指数均呈下降趋势,说明适宜水鸟栖息的整体资源环境正逐渐退化,这可能与围垦等人为干扰因素有关。     

Perturbation,Restoration and Seeking Ecological Sustainability in Australian Flowing Waters

It is now accepted that most of the rivers and streams of Australia have been degraded to varying extents by European settlement. The scale and level of this degradation have been documented by State and Federal government authorities. To halt and reverse the degradation in the next two decades, it is crucial that the conservation and restoration of streams, rivers, riparian zones, and catchments become paramount in land and water management. Effective stream restoration requires a coordinated effort at the catchment level rather than at the level of many individual local sites. Monitoring, including the gathering of before-restoration data, and the setting of feasibly-attainable goals are key components of effective restoration. In planning projects and setting goals, it needs to be recognized that some goals may only be attained in the long-term. Large-scale restoration projects will require partnerships to be formed between resource managers and scientists, with other stakeholders possibly involved. Selected projects could be adaptively managed with the emphasis on gaining scientific knowledge on the effects of management interventions.     

Discovery of Maritrema obstipum (Digenea: Microphallidae) from migratory birds in Korea

Adults of Maritrema obstipum (Digenea: Microphallidae) were found in the intestines of 4 species of migratory birds, including the sanderling (Crocethia alba), Kentish plover (Charadrius alexandrines), Mongolian plover (Charadrius mongolus), and red-necked stint (Calidris ruficollis), collected from Yubu Island, Chungcheongnam-do, Korea. The worms of were 451 × 265 μm in size, and were easily identifiable as Maritrema species by the presence of the cirrus sac, and the ring-like distribution of the vitellaria. More specifically, the ejaculatory duct curved posteromedially, and the 2 parts of vitelline follicles were found to be distinct at the posterior end. The eggs were brown-colored, and 19.8 × 12.3 μm in size. All these findings implicated M. obstipum as the pertinent species of the worms. Beside these, adult worms of Gynaecotyla squatarolae, Parvatrema duboisi, and Acanthoparyphium sp. were also discovered. This is the first report establishing migratory birds as the natural definitive hosts for M. obstipum.     

Diets of hooded seals (Cystophora cristata) in coastal waters and drift ice waters along the east coast of Greenland

To provide data on the diets of hooded seals (Cystophora cristata) in the Greenland Sea, seals were collected for scientific purposes on expeditions conducted in the pack ice belt east of Greenland in September/October 1999, 2002 and 2003 (autumn), July/August in 2000 (summer), and February/March in 2001 and 2002 (winter). The results from analyses of stomach and intestinal contents from captured seals revealed that their diet was comprised of relatively few prey taxa. The squid Gonatus fabricii and polar cod (Boreogadus saida) were particularly important, whereas capelin (Mallotus villosus) and sand eels (Ammodytes spp.) occasionally contributed more. These four prey items constituted 60-97% of the diet biomass. Gonatus fabricii was the most important food item in autumn and winter, whereas polar cod dominated the summer diet, with important contributions from G. fabricii and sand eels. The latter was only observed on the hooded seal menu during the summer period, whereas polar cod, which was an important component during the autumn survey, was almost absent from the winter samples. During the latter survey, capelin also contributed to the hooded seal diet. Samples obtained from hooded seals in more coastal waters indicated a more varied diet based on fish such as polar cod, redfish (Sebastes sp.) and Greenland halibut (Reinhardtius hippoglossoides).     

Association in Long-Evans hooded rats of red cell 2,3-diphosphoglycerate levels with hemoglobin types

Two sublines of commercially available Long-Evans hooded rats have been developed by genetic selection. These sublines have widely differing levels of erythrocyte 2,3-diphosphoglycerate (DPG) due to different alleles at a single genetic locus. In the present work, it is shown that rats from the commercial population are also polymorphic at a hemoglobin locus, probably involving two alleles of the ^III-globin chain locus. Particular hemoglobin types have been found to be strongly associated with certain DPG types, not only in the high-DPG and low-DPG lines but also in the commercial population. Two explanations for this association are considered. One is a single-locus hypothesis, with hemoglobin allelic variation causing DPG variation, and the other is a two-locus hypothesis, with marked linkage disequilibrium.This work was supported by a Michigan Heart Association Grant, by the Meyers Foundation, and by NIH Training Grant (5 T01-GM-0071).