43 resultados para Hylodes nasus and site fidelity

em Deakin Research Online - Australia


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Using automated and manual radio-telemetry and resightings of individual colour-ringed birds, we assessed the daily use of space of red knots Calidris canutus canutus at a tropical wintering area along the Sahara coast, the Banc d Arguin in Mauritania. Confirming earlier suggestions, we found that birds were very faithful to their roosts and that the daily foraging range was small; in the course of several winter months birds used an area of only 2 16 km2 of intertidal area. We found no differences between their movements in daylight and at night. Additionally, individuals seem to return to exactly the same locations in subsequent winters. This pattern is very different from red knots wintering in the temperate Wadden Sea. Here, they readily change roost sites and easily cover areas of about 800 km2 in the course of weeks but, just as in Mauritania, no differences between day and night are apparent. In northern Patagonia and north-western Australia, red knots have range sizes closer to those on the Banc d Arguin, but here they do show differences in space use between day and night. Ecological explanations for these contrasting patterns require further comparative data based on in-depth studies on the predictability of the food base and the presence of diurnal and nocturnal predators.

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Wide-ranging marine central place foragers often exhibit foraging site fidelity to oceanographic features over differing spatial scales (i.e., localized coastal upwellings and oceanic fronts). Few studies have tested how the degree of site fidelity to foraging areas varies in relation to the type of ocean features used. In order to determine how foraging site fidelity varied between continental shelf and oceanic foraging habitats, 31 lactating New Zealand fur seals (Arctocephalus australis forsteri1) were satellite tracked over consecutive foraging trips (14–108 d). Thirty-seven foraging trips were recorded from 11 females that foraged on the continental shelf, in a region associated with a coastal upwelling, while 65 foraging trips were recorded from 20 females that foraged in oceanic waters. There were no significant differences in the mean bearings (to maximum distance) of individual's consecutive foraging trips, suggesting individual fidelity to foraging areas. However, overlap in area and time spent in area varied considerably between continental shelf and oceanic foragers. Females that foraged on the continental shelf had significantly greater overlap in consecutive foraging trips when compared to females that foraged in oceanic waters (overlap in 5 × 5 km grid cells visited on consecutive trips 55.9%± 20.4% and 13.4%± 7.6%, respectively). Females that foraged on the continental shelf also spent significantly more time within the same grid cell than females that foraged in oceanic waters (maximum time spent in 5 × 5 km grid cells: 14%± 5% and 4%± 2%, respectively). This comparatively high foraging site fidelity may reflect the concentration of productivity associated with a coastal upwelling system, the Bonney Upwelling. Lower foraging site fidelity recorded by seals that foraged in oceanic waters implies a lower density/larger scale habitat, where prey are more dispersed or less predictable at fine scales, when compared to the continental shelf region.

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Foraging site fidelity has profound consequences for individual fitness, population processes and the effectiveness of species conservation measures. Accordingly, quantifying site fidelity has become increasingly important in animal movement and habitat selection studies. To assess foraging site fidelity in king penguins (Aptenodytes patagonicus) breeding at the Falkland Islands (51.48°S, 57.83°W), we measured overlap in time spent in foraging areas (at a 0.1° × 0.1° grid resolution) between successive foraging trips and foraging route consistency during the crèche period. In total, 30 complete foraging trips from seven king penguins were recorded between April and October 2010. King penguins predominantly foraged on the highly productive Patagonian slope, to the north of the Falkland Islands [median foraging trip distance 213 km (SD = 215 km) and duration 12.8 days (SD = 14.7 days)]. Overlap in time spent in an area on consecutive foraging trips ranged between 2 and 73 % (mean 27 %, SD = 22 %). Bearing during the outbound portion of foraging trips was typically highly repeatable for individual birds, but foraging trip duration and distance were not. Travel during the outbound phase of foraging trips was consistent with the direction of the northward-flowing Falkland Current that may act as a directional cue or facilitate rapid transit to foraging areas. Flexibility in foraging trip distances and durations may be a response to changes in resource availability and changes in the energetic requirements of adults and chicks over an extended breeding cycle.

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We translocated five colonies of the highly social and co-operatively breeding Black-eared Miner Manorina melanotis, an endangered Australian honeyeater. Two colonies were released immediately (hard release) and two colonies were housed in aviaries for up to a week on-site and then supplied with food for a further week following release (soft release). A fifth colony was released using a combination of methods. All four hard and soft released colonies contained dependent fledglings at the time of release. This appears to be the first translocation of a co-operative species where intact colonies containing multiple breeding females, each with a suite of helpers have been translocated successfully. Both hard and soft release treatments appeared equally successful during an initial monitoring period of up to two months. All four colonies maintained social cohesion, and displayed high levels of survival and site fidelity. Both hard release and one soft release colony attempted to breed within 600 m of their release site within eight weeks of release. The other soft release colony bred 12 months later. We believe the inclusion of dependent young in each translocated colony provided a focus for translocated colonies that promoted site faithfulness and colony cohesion. Results of long-term monitoring remain inconclusive and it is recommended that monitoring be repeated during several future breeding events. Given our findings, we recommend that when translocating highly social species every effort is made to translocate the entire group, hard release techniques be applied and stimuli that enhance group cohesion and site faithfulness (the presence of dependent young) be exploited.

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Objectives: To compare the skeletal benefits associated with gymnastics between ulna and radius.
Methods: 19 retired artistic gymnasts, aged 18-36 years, were compared to 24 sedentary women. Bone mineral content (BMC), total and cortical bone area (ToA, CoA), trabecular and cortical volumetric density (TrD, CoD) and cortical thickness (CoTh) were measured by pQCT at the 4% and 66% forearm.
Results: At the 4% site, BMC and ToA were more than twice greater at the radius than ulna whereas at the 66% site, BMC, ToA, CoA, CoTh and SSIpol were 20 to 51% greater at the ulna than radius in both groups (p<0.0001). At the 4% site, the skeletal benefits in BMC of the retired gymnasts over the non-gymnasts were 1.9 times greater at the radius than ulna (p<0.001), with enlarged bone size at the distal radius only. In contrast, the skeletal benefits at the 66% site were twice greater at the ulna than radius for BMC and CoA (p<0.01).
Conclusion: Whereas the skeletal benefits associated with long-term gymnastics were greater at the radius than ulna in the distal forearm, the reverse was found in the proximal forearm, suggesting both bones should be analysed when investigating forearm strength.

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An approach to achieving the ambitious goal of cost effectively extending the safe operation life of energy pipelines to, for instance, 100 years is the application of structural health monitoring and life prediction tools that are able to provide long-term remnant pipeline life prediction and in-situ pipeline condition monitoring. A critical step in pipeline structural health monitoring is the enhancement of technological capabilities that are required for quantifying the effects of key factors influencing buried pipeline corrosion and environmentally assisted materials degradation, and the development of condition monitoring technologies that are able to provide in-situ monitoring and site-specific warning of pipeline damage. This paper provides an overview of our current research aimed at developing new sensors for monitoring, categorising and quantifying the level and nature of external pipeline and coating damages under the combined effects of various inter-related variables and processes such as localised corrosion, coating damage and disbondment, cathodic shielding. The concept of in-situ monitoring and site-specific warning of pipeline corrosion is illustrated by a case of monitoring localised corrosion under disbonded coatings using a new corrosion monitoring probe. A basic principle that underpins the use of sensors to monitor localised corrosion has been presented: Localised corrosion and coating failure are not an accidental occurrence, it occurs as the result of fundamental thermodynamic instability of a metal exposed to a specific environment. Therefore corrosion and coating disbondment occurring on a pipeline will also occur on a sensor made of the same material and exposed to the same pipeline condition. Although the exact location of localised corrosion or coating disbondment could be difficult to pinpoint along the length of a buried pipeline, the ‘worst-case scenario’ and high risk pipeline sections and sites are predictable. Sensors can be embedded at these strategic sites to collect data that contain ‘predictor features’ signifying the occurrence of localised corrosion, CP failure, coating disbondment and degradation. Information from these sensors will enable pipeline owners to prioritise site survey and inspection operations, and to develop maintenance strategy to manage aged pipelines, rather than replace them.

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This research investigated links between the occurrence of endangered southern right whales and characteristics of their habitat. Habitat selection is based on physical environmental features, with important roles for social cues and site fidelity. This complex interaction of factors affects spatial recovery capacity and presents challenges for conservation management.

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Australasian gannets (Morus serrator) breed in the cool temperate waters of south-eastern Australia and also at several localities around New Zealand, where they are a major marine predator feeding on commercially-exploited pelagic fish. This study investigated the foraging behaviour and habitat utilization of gannets at Pope’s Eye Marine Reserve during the 2005-2005 breeding period using GPS-depth-loggers. GPS data were recorded for a total of 45 foraging trips from 20 individuals. Gannets were found to forage at average maximum distances of 52.7 km (± 29.6 km) from the colony, with total foraging path lengths of 177.1 km (± 93.4 km) and foraging trip durations of 16.5 h (± 9.9 h). During foraging trips gannets spent on average 31.5% (± 11.4) of the time flying at an average flight speed of 47.3 km h-1 (± 2.9 km h-1). Gannets made an average of 39.8 (± 35.2) dives per trip and 3.8 (± 5.6) dives per daylight hour. Dives had an average depth of 3.5 m (± 1.1 m) and a mean maximum depth of 7.0 m (± 3.0 m), lasting for a mean dive duration of 5.3 sec (± 1.3 sec). Gannets foraged predominantly in shallow coastal waters and there was some evidence for foraging site fidelity. Considerable individual variation in foraging strategies was also observed. The results highlight the potential of GPS technology to reveal the fine-scale foraging behaviour of marine predators, thereby improving our understanding the interaction between marine predator populations, commercially exploited fish stocks and the marine environment.

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Inhibitors of insulin-regulated aminopeptidase (IRAP) improve memory and are being developed as a novel treatment for memory loss. In this study, the binding of a class of these inhibitors to human IRAP was investigated using molecular docking and site-directed mutagenesis. Four benzopyran-based IRAP inhibitors with different affinities were docked into a homology model of the catalytic site of IRAP. Two 4-pyridinyl derivatives orient with the benzopyran oxygen interacting with the Zn2+ ion and a direct parallel ring-stack interaction between the benzopyran rings and Phe544. In contrast, the two 4-quinolinyl derivatives orient in a different manner, interacting with the Zn2+ ion via the quinoline nitrogen, and Phe544 contributes an edge-face hydrophobic stacking point with the benzopyran moiety. Mutagenic replacement of Phe544 with alanine, isoleucine, or valine resulted in either complete loss of catalytic activity or altered hydrolysis velocity that was substrate-dependent. Phe544 is also important for inhibitor binding, because these mutations altered the Ki in some cases, and docking of the inhibitors into the corresponding Phe544 mutant models revealed how the interaction might be disturbed. These findings demonstrate a key role of Phe544 in the binding of the benzopyran IRAP inhibitors and for optimal positioning of enzyme substrates during catalysis.

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Although marine protected areas (MPAs) are a common conservation strategy, these areas are often designed with little prior knowledge of the spatial behaviour of the species they are designed to protect. Currently, the Coral Sea area and its seamounts (north-east Australia) are under review to determine if MPAs are warranted. The protection of sharks at these seamounts should be an integral component of conservation plans. Therefore, knowledge on the spatial ecology of sharks at the Coral Sea seamounts is essential for the appropriate implementation of management and conservation plans. Acoustic telemetry was used to determine residency, site fidelity and spatial use of three shark species at Osprey Reef: whitetip reef sharks Triaenodon obesus, grey reef sharks Carcharhinus amblyrhynchos and silvertip sharks Carcharhinus albimarginatus. Most individuals showed year round residency at Osprey Reef, although five of the 49 individuals tagged moved to the neighbouring Shark Reef (∼14 km away) and one grey reef shark completed a round trip of ∼250 km to the Great Barrier Reef. Additionally, individuals of white tip and grey reef sharks showed strong site fidelity to the areas they were tagged, and there was low spatial overlap between groups of sharks tagged at different locations. Spatial use at Osprey Reef by adult sharks is generally restricted to the north-west corner. The high residency and limited spatial use of Osprey Reef suggests that reef sharks would be highly vulnerable to targeted fishing pressure and that MPAs incorporating no-take of sharks would be effective in protecting reef shark populations at Osprey and Shark Reef.

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The movements of 8 green turtles Chelonia mydas in Brazilian coastal waters were tracked using transmitters linked to the Argos system for periods of between 1 and 197 d. These were the first tracking data gathered on juveniles of this species in this important foraging ground. Information was integrated with that collected over a decade using traditional flipper-tagging methods at the same site. Both satellite telemetry and flipper tagging suggested that turtles undertook 1 of 3 general patterns of behaviour: pronounced long range movements (>100 km), moderate range movements (<100 km) or extended residence very close to the capture/release site. There seemed to be a general tendency for the turtles recaptured/tracked further afield to have been among the larger turtles captured. Satellite tracking of 5 turtles which moved from the release site showed that they moved through coastal waters; a factor which is likely to predispose migrating turtles to incidental capture as a result of the prevailing fishing methods in the region. The movements of the 3 turtles who travelled less than 100 km from the release site challenge previous ideas relating to home range in green turtles feeding in sea grass pastures. We hypothesise that there may be a fundamental difference in the pattern of habitat utilisation by larger green turtles depending on whether they are feeding on seagrass or macroalgae. Extended tracking of 2 small turtles which stayed near the release point showed that small juvenile turtles, whilst in residence in a particular feeding ground, can also exhibit high levels of site-fidelity with home ranges of the order of several square kilometers.

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Aim: To quantify bird responses to a large unplanned fire, taking into consideration landscape-level fire severity and extent, pre-fire site detection frequency and environmental gradients. Location: South-eastern Australia. Methods: A major wildfire in 2009 coincided with a long-term study of birds and provided a rare opportunity to quantify bird responses to wildfire. Using hierarchical Bayesian analysis, we modelled bird species richness and the detection frequency of individual species in response to a suite of explanatory variables, including (1) landscape-level fire severity and extent (2) pre-fire detection frequency, (3) site-level vegetation density and (4) environmental variables (e.g. elevation and topography). Results: Landscape-level fire severity had strong effects on bird species richness and the detection frequency of the majority of bird species. These effects varied markedly between species; most responded negatively to amount of severely burned forest in the landscape, one negatively to the amount of moderately burned forest and one responded negatively to the total area of burned forest. Only one species - the Flame Robin - responded positively to the amount of burned forest. Relationships with landscape-scale fire extent changed over time for one species - the Brown Thornbill - with initially depressed rates of detection recovering after just 2 years. The majority of species were significantly more likely to be detected in burned areas if they have been recorded there prior to the fire. Main conclusions: Birds responded strongly to the severity and spatial extent of fire. They also exhibited strong site fidelity even after severe wildfire which causes profound changes in vegetation cover - a response likely influenced by environmental features such as elevation and topography.

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Objective:

To survey prevocational doctors working in Australian hospitals on aspects of postgraduate learning.
Participants and setting:

470 prevocational doctors in 36 health services in Australia, August 2003 to October 2004.
Design:

Cross-sectional cohort survey with a mix of ordinal multicategory questions and free text.
Main outcome measures:

Perceived preparedness for aspects of clinical practice; perceptions of the quantity and usefulness of current teaching and learning methods and desired future exposure to learning methods.
Results:

64% (299/467) of responding doctors felt generally prepared for their job, 91% (425/469) felt prepared for dealing with patients, and 70% (325/467) for dealing with relatives. A minority felt prepared for medicolegal problems (23%, 106/468), clinical emergencies (31%, 146/469), choosing a career (40%, 188/468), or performing procedures (45%, 213/469). Adequate contact with registrars was reported by 90% (418/465) and adequate contact with consultants by 56% (257/466); 20% (94/467) reported exposure to clinical skills training and 11% (38/356) to high-fidelity simulation. Informal registrar contact was described as useful or very useful by 94% (433/463), and high-fidelity simulation by 83% (179/216). Most prevocational doctors would prefer more formal instruction from their registrars (84%, 383/456) and consultants (81%, 362/447); 84% (265/316) want increased exposure to high-fidelity simulation and 81% (283/350) to professional college tutorials.
Conclusion:

Our findings should assist planning and development of training programs for prevocational doctors in Australian hospitals.

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Nearly all discourses on migration (to my knowledge) emphasise that the migrant is not so much a traveller, but a figure oriented towards settlement and a particular destination. Discourses on migration have attended more to the process and site of ‘arrival’, and few studies have focused on the process and site of ‘departure’. However, central to the thesis of this paper would be the testimony of two migrant houses – one in the city of  immigration (Melbourne, Australia), and the other in the village of emigration (Zavoj in Macedonia). The focus will be on the Zavoj house as a significant house, a house that points to a thesis about how architecture makes explicit other processes of migration, namely that of ‘return’. Here there are several intertwined communities and nations, and also different notions of community and nation. It has been noted that ‘diaspora’ is constituted through longer distances, severe separation, and a taboo on return. And yet implicit in many more ‘autobiographical’ accounts is that one only leaves with a promise to return. The conflict and question of ‘return’ is at the centre of the migrant’s imaginary. A study of the two houses of migration implicates a set of networks, forces, relations, circumscribing a much larger global geopolitical and cultural field that questions our understandings of diaspora, the currency of transnationalism, the binary structure of dwelling/travelling, and the fabric and fabrication of community. But the study goes inwards and underneath as well through the figure of the migrant, the figure through which the two migrant houses are deeply associated. The paper will explore the subjective nature of the thesis, the idea of a ‘migrant house’ as an imaginary architecture, a psychic geography, an imaginary community and sense of nationhood.