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The aim of this study was to test the hypotheses of faunistic mixing. Various different mechanisms of the mixture of zooplanktonic
organisms may exist in the transition zones. The distribution of planktonic gastropods of the order Thecosomata, which show
a high fidelity to the water masses, was analysed. The study area comprises the southern part of the Brazil Current, the Brazil-Malvinas
Confluence Zone, the Brazil Current Front, the Subtropical Front, the South Atlantic Current and the southern Benguela Current.
The Subtropical Front presents sectors with contrasting dynamic characteristics which allow us to test hypotheses about the
mechanisms generating faunistic mixture on a mesoscale. The evidence presented in the present study suggests that at least
two mechanisms of faunistic mixture exist in the Subtropical Front. One is passive, resulting from environmental mixture in
very dynamic front areas, where eddies are formed. The other mechanism occurs when the water column is vertically stratified.
This mechanism depends on the migratory behaviour of the zooplankters and requires that there is stable stratification, that
the depth of layers does not exceed the migratory capacity of the larger individuals and that the species can survive the
physicochemical gradient.
Received: 30 September 1998 / Accepted: 9 May 1999 相似文献
2.
Petra Quillfeldt Javier Martínez Janos Hennicke Katrin Ludynia Anja Gladbach Juan F. Masello Samuel Riou Santiago Merino 《Die Naturwissenschaften》2010,97(9):809-817
Whereas some bird species are heavily affected by blood parasites in the wild, others reportedly are not. Seabirds, in particular,
are often free from blood parasites, even in the presence of potential vectors. By means of polymerase chain reaction, we
amplified a DNA fragment from the cytochrome b gene to detect parasites of the genera Plasmodium, Leucocytozoon, and Haemoproteus in 14 seabird species, ranging from Antarctica to the tropical Indian Ocean. We did not detect parasites in 11 of these species,
including one Antarctic, four subantarctic, two temperate, and four tropical species. On the other hand, two subantarctic
species, thin-billed prions Pachyptila belcheri and dolphin gulls Larus scoresbii, were found infected. One of 28 thin-billed prions had a Plasmodium infection whose DNA sequence was identical to lineage P22 of Plasmodium relictum, and one of 20 dolphin gulls was infected with a Haemoproteus lineage which appears phylogenetically clustered with parasites species isolated from passeriform birds such as Haemoproteus lanii, Haemoproteus magnus, Haemoproteus fringillae, Haemoproteus sylvae, Haemoproteus payevskyi, and Haemoproteus belopolskyi. In addition, we found a high parasite prevalence in a single tropical species, the Christmas Island frigatebird Fregata andrewsi, where 56% of sampled adults were infected with Haemoproteus. The latter formed a monophyletic group that includes a Haemoproteus line from Eastern Asian black-tailed gulls Larus crassirostris. Our results are in agreement with those showing that (a) seabirds are poor in hemosporidians and (b) latitude could be a
determining factor to predict the presence of hemosporidians in birds. However, further studies should explore the relative
importance of extrinsic and intrinsic factors on parasite prevalence, in particular using phylogenetically controlled comparative
analyses, systematic sampling and screening of vectors, and within-species comparisons. 相似文献
3.
Glucocorticosteroids (GCs) of the hypothalam–pituitary–adrenal axis play a role in association with both stressful events
and daily life processes. However, relatively little is known about the role of GCs in relation to daily and seasonal life
processes in animals in the wild. In this paper, we present data on basal levels of plasma corticosterone CORT in chicks of
a pelagic seabird, the thin-billed prion, Pachyptila belcheri, during two predictable changes in demands, the daily activity pattern and the preparation for fledging. By comparing chicks
fed recently with unfed chicks, we test how GC levels are modified according to nutritional condition. In accordance with
their nocturnal feeding rhythm, chicks had a clear daily rhythm with increased CORT secretion at night, but CORT levels during
the active phase were also highly elevated in unfed chicks compared with fed chicks. Close to fledging, chicks rapidly increased
basal CORT levels, and again unfed chicks had higher levels than fed chicks, although the age effect here was stronger than
the effect of recent feeding. The present data thus support the hypothesis that GC levels are adjusted to life stages with
predictable changes in demands, but food availability and/or internal energy stores also affect the level to which GCs increase. 相似文献
4.
Petra Quillfeldt Christian C. Voigt Juan F. Masello 《Behavioral ecology and sociobiology》2010,64(7):1157-1164
Pelagic seabird populations can use several discrete wintering areas, but it is unknown if individuals use the same wintering
area year after year. This would have consequences for their population genetic structure and conservation. We here study
the faithfulness of individuals to a moulting area within and among years in a small pelagic seabird, the Thin-billed prion,
which moult their primary feathers during the early part of the non-breeding period. According to stable carbon isotope ratios
(δ13C) of these feathers, 90% of Thin-billed prions moult in Antarctic and 10% in South American waters. Repeated samples from
individuals in 2 or 3 years indicated that several birds changed between Antarctic and South American moulting areas or vice
versa. However, individuals moulting in an area in one year were more likely to do so again. Four out of five adults maintained
highly conserved δ13C over the extended moulting period. One bird, however, had systematic changes in δ13C indicating latitudinal movements between the two areas during moult. Thus, the present data show that this seabird species
has a highly flexible migratory strategy, not only at the population level, but also at the individual level, enabling these
seabirds to exploit a highly unpredictable environment. 相似文献
5.
Petra Quillfeldt Leandro Bugoni Rona A. R. McGill Juan F. Masello Robert W. Furness 《Marine Biology》2008,155(6):593-598
Stable isotopes of growing feathers and blood both represent assimilated diet, and both tissues are used to study the diet
and foraging distribution of marine and terrestrial birds. Although most studies have assumed that both tissues represent
a difference of one trophic level to diet, the enrichment factors of blood and feathers may differ, especially where endogenous
reserves are used as precursors during feather synthesis. In this study, we compare carbon and nitrogen stable isotopes of
blood and simultaneously growing feathers of five species of Procellariiformes, representing five genera, different geographical
regions and different life stages (chicks and adults). In all species, feathers were enriched in 15N and 13C compared with blood. Isotopic values of carbon and nitrogen were correlated in different tissues growing simultaneously
for most species analyzed, suggesting that mathematical corrections could be used to compare different tissues. Our results
imply that more care needs to be taken when comparing stable isotope signatures across studies assuming different tissues
are equivalent indicators of trophic ecology. 相似文献
6.
AL Heffernan K English LML Toms AM Calafat L Valentin-Blasini P Hobson S Broomhall RS Ware P Jagals PD Sly JF Mueller 《Environmental science and pollution research international》2016,23(23):23436-23448
A range of pesticides are available in Australia for use in agricultural and domestic settings to control pests, including organophosphate and pyrethroid insecticides, herbicides, and insect repellents, such as N,N-diethyl-meta-toluamide (DEET). The aim of this study was to provide a cost-effective preliminary assessment of background exposure to a range of pesticides among a convenience sample of Australian residents. De-identified urine specimens stratified by age and sex were obtained from a community-based pathology laboratory and pooled (n = 24 pools of 100 specimens). Concentrations of urinary pesticide biomarkers were quantified using solid-phase extraction coupled with isotope dilution high-performance liquid chromatography–tandem mass spectrometry. Geometric mean biomarker concentrations ranged from <0.1 to 36.8 ng/mL for organophosphate insecticides, <0.1 to 5.5 ng/mL for pyrethroid insecticides, and <0.1 to 8.51 ng/mL for all other biomarkers with the exception of the DEET metabolite 3-diethylcarbamoyl benzoic acid (4.23 to 850 ng/mL). We observed no association between age and concentration for most biomarkers measured but noted a “U-shaped” trend for five organophosphate metabolites, with the highest concentrations observed in the youngest and oldest age strata, perhaps related to age-specific differences in behavior or physiology. The fact that concentrations of specific and non-specific metabolites of the organophosphate insecticide chlorpyrifos were higher than reported in USA and Canada may relate to differences in registered applications among countries. Additional biomonitoring programs of the general population and focusing on vulnerable populations would improve the exposure assessment and the monitoring of temporal exposure trends as usage patterns of pesticide products in Australia change over time. 相似文献
7.
Petra Quillfeldt Juan F. Masello Paul Brickle Dominik Martin-Creuzburg 《Marine Biology》2011,158(8):1805-1813
In diet analyses of seabirds, fatty acid signatures (FAS) can be used to overcome biases due to differential digestion of
prey and enable the analysis of very digested diet samples. We applied FAS analysis to stomach contents of a small sub-Antarctic
seabird, the Thin-billed Prion Pachyptila belcheri, which feeds mainly on squid during incubation and on crustacea during chick rearing. This seasonal dietary switch of Thin-billed
prions was reflected in differences in FAS in regurgitates, as were inter-annual differences in diet composition. A discriminant
function analysis correctly classified 93.4% of cases with respect to year (2006–2008) and stage of the breeding cycle (incubation
versus chick rearing). The dominant types of crustacea in the diet of Thin-billed prions (amphipods Themisto gaudichaudii, euphausiids, decapods Munida gregaria, and calanoid copepods) were distinguished well by characteristic FAS patterns. However, the FAS of the two main types of
prey by volume, amphipods T. gaudichaudii and squid Gonatus antarcticus, were similar to each other. Although FAS were successfully applied in the analysis of prey in stomach contents of prions,
FAS of some prey species were similar and may not be distinguishable from each other if used in quantitative diet analyses. 相似文献
8.
Impact of miniature geolocation loggers on a small petrel, the thin-billed prion Pachyptila belcheri
Petra Quillfeldt Rona A. R. McGill Robert W. Furness Erich M?stl Katrin Ludynia Juan F. Masello 《Marine Biology》2012,159(8):1809-1816
Effects of deployment of miniaturised transmitters and loggers have been studied mainly in diving seabirds such as penguins, and less so in flying seabirds. However, some studies of albatrosses and petrels recorded extended trip durations and elevated rates of nest desertion following device attachment, especially if transmitter loads exceeded 3 % of adult mass. Studies have usually compared performance parameters such as trip duration, meal mass, breeding success or rate of return in the next season between birds with devices and controls. We here examined the effects of geolocator loggers (Global Location Sensing, (GLS)) on thin-billed prions Pachyptila belcheri (130 g), by comparing performance parameters and additionally eco-physiological parameters. GLS weighed ca. 1 % of the body mass, and were fixed on leg rings, which may influence the flight efficiency by creating an asymmetric load. We found no differences in the performance parameters, either in the season of attachment or the season following recovery. Similar stable isotope ratios in adult blood and feather samples further indicated that the foraging ecology was not influenced. However, after 1 year of logger deployment, adults differed in their hormonal response to stress: while baseline corticosterone levels were not influenced, corticosterone levels in response to handling were elevated. Moreover, increased heterophil/lymphocyte ratios and a decreased tail growth in winter suggest that carrying the GLS was energetically costly, and adults adapted physiologically to the higher work load, while keeping up a normal breeding performance. 相似文献
9.
Petra Quillfeldt Andreas Michalik Gritta Veit-Köhler Ian J. Strange Juan F. Masello 《Marine Biology》2010,157(9):2043-2050
Central place foragers are constrained in their foraging distribution by the necessity to return to their nest site at regular
intervals. In many petrels that feed on patchily distributed prey from the sea surface over large foraging areas, alternating
long and short foraging trips are used to balance the demands of the chick with the requirements of maintaining adult body
condition. When the local conditions are favourable for prey density and quality, adults should be able to reduce the number
of long foraging trips. We studied the flexibility in foraging trip lengths of a small pelagic petrel, the thin-billed prion
Pachyptila belcheri, over three breeding seasons with increasingly favourable, cold-water conditions. During a warm-water influx in February
2006, chicks were fed less frequently and adults carried out foraging trips of up to 8 days. When conditions became more favourable
with colder water temperatures in 2007 and 2008, thin-billed prions decreased trip lengths, more often attended their chick
every day, and long foraging trips of six to eight days were not registered during 2008. Chick growth rates mirrored this,
as chicks grew poorly during 2006, intermediate during 2007 and best during 2008. Thin-billed prions preyed mainly on squid
during incubation and mainly on amphipods and euphausiids during chick-rearing. In the poorest season only, the diet was substantially
supplemented with very small copepods. Together, the present results indicate that during warm-water conditions, thin-billed
prions had difficulties in finding sufficient squid, amphipods or euphausiids and were forced to switch to lower trophic level
prey, which they had to search for over large ocean areas. 相似文献
10.
Petra Quillfeldt Inga Träger Kate Griffiths Katherine L. Buchanan Juan F. Masello 《Behavioral ecology and sociobiology》2007,61(5):793-800
Mass differences between the sexes of dimorphic bird species often appear early in the nestling development. But how do adults know how much to feed a chick in a sexually dimorphic species? Do chicks of the heavier sex beg more? We studied begging in Cory’s shearwaters Calonectris diomedea, a species with heavier adult and juvenile males than females. We found that begging rates and call numbers were not different between male and female chicks, but parameters of begging intensity differed between the sexes in their relationship to chick body condition. For the same body condition, males had significantly higher begging call numbers and rates. Acoustical parameters, which were analysed semi-automatically, included the lengths of call and silence intervals, the minimum, mean and maximum frequency in a call and the number of frequency peaks within a call. We found no consistent differences of acoustic begging call elements between the sexes. Male and female chicks did not differ in the levels of the steroid hormones testosterone or corticosterone in the second quarter of the nestling period, and the mechanism leading to sex-related differences in begging rates for a given body condition remains unknown. 相似文献
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