23 resultados para 770103 Weather

em Deakin Research Online - Australia


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Previous studies of the remarkable seasonal colour changes of Blue Lake, Mount Gambier, South Australia have speculated on the roles of weather and solar elevation in this phenomenon. In this study the influence of weather and solar elevation on apparent colour is examined. Solar elevation and some weather variables were found to have a statistically significant influence, particularly when Blue Lake is undergoing transition from its blue to grey stage. However, the proportion of the overall variation in colour explained by solar elevation and weather was only 16%, so it is concluded that in-lake properties are probably the main determinants of colour.

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These photographs on paper are about the fragility and sense of impermanence of the world. So it goes. Some are taken from a great distance around the spaces of cities, revisiting again and again the detritus of habitation or the shape and punctuation of nature or details of figures in close-up.

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Bird song is generally regarded as a sexually selected trait, and may represent a reliable handicap signal under at least certain conditions. Females may use the degree of male song production as a reliable cue to male condition or territory quality. We investigated the effect of supplementary feeding on song output in the migratory Australian reed warbler Acrocephalus australis. We experimentally increased the food availability on alternate days, and recorded several weather variables. We measured song rate and song length independently. Supplementary fed birds sang more on feeding days than on non-feeding days, while control birds did not show this effect. Song output was not significantly associated with any of the weather variables examined. Our results indicate that singing has the potential to serve as a reliable handicap signal to territorial food availability irrespective of the prevailing weather conditions. We discuss the role of energetic constraints and behavioural flexibility on the signaling function of song.

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Context : Designing an appropriate survey protocol requires understanding of how capture rates of target species may be influenced by factors other than on-ground abundance, such as weather conditions or seasonality. This is particularly relevant for ectotherms such as reptiles, as activity can be affected by environmental conditions such as ambient temperature.
Aims : The present study examines factors affecting capture success of reptiles in semi-arid environments of southern Australia, and addresses the following two main questions: (1) what is the influence of weather and seasonal factors on capture rates of reptiles, and (2) what are the implications for developing an effective protocol for reptile surveys?
Methods : We surveyed reptiles using pitfall traps in spring and summer of 2006/07 and 2007/08 at sites (n = 280) throughout the Murray Mallee region of south-eastern Australia. We used mixed-effect regression models to investigate the influence of seasonal and weather-related variables on species’ capture success.
Key results : Total captures of reptiles, and the likelihood of capture of 15 reptile species, increased with rising daily temperature. Greater numbers of individual species were captured during spring than in summer, even though temperatures were cooler. This probably reflects greater levels of activity associated with breeding. Several species were more likely to be captured when maximum or minimum daily temperatures exceeded a certain level (e.g. Lerista labialis, Delma australis, Nephrurus levis). Other factors, such as rainfall and moon phase, also influenced capture success of some species.
Conclusions : Surveys for reptiles in semi-arid environments are likely to capture the greatest diversity of species on warm days in late spring months, although surveys on hot days in summer will enhance detection of particular species (e.g. Morethia boulengeri, Varanus gouldii). We recommend trapping during periods with maximum temperatures exceeding 25–30C and minimum overnight temperatures of 15C. Finally, trapping during rainfall and full-moon events will maximise chances of encountering species sensitive to these variables (blind snakes and geckoes).
Implications : Selecting the most favourable seasonal and weather conditions will help ensure that reptile surveys maximise the likelihood of capturing the greatest diversity of reptiles, while minimising trap-effort required.

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A sound effect of a foggy and stormy ambiance at sea with a distant fog horn.

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Events happening in one season can affect life-history traits at (the) subsequent season(s) by carry-over effects. Wintering conditions are known to affect breeding success, but few studies have investigated carry-over effects on survival. The Eurasian oystercatcher Haematopus ostralegus is a coastal wader with sedentary populations at temperate sites and migratory populations in northern breeding grounds of Europe. We pooled continental European ringing-recovery datasets from 1975 to 2000 to estimate winter and summer survival rates of migrant and resident populations and to investigate long-term effects of winter habitat changes. During mild climatic periods, adults of both migratory and resident populations exhibited survival rates 2% lower in summer than in winter. Severe winters reduced survival rates (down to 25% reduction) and were often followed by a decline in survival during the following summer, via short-term carry-over effects. Habitat changes in the Dutch wintering grounds caused a reduction in food stocks, leading to reduced survival rates, particularly in young birds. Therefore, wintering habitat changes resulted in long-term (>10 years) 8.7 and 9.4% decrease in adult annual survival of migrant and resident populations respectively. Studying the impact of carry-over effects is crucial for understanding the life history of migratory birds and the development of conservation measures.

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The Intergovernmental Panel on Climate Change and the McKinsey Greenhouse Gas abatement studies have highlighted reduction of building energy consumption as a primary cost-effective element in the abatement of Global Warming. Nevertheless, the energy investigation in most of our existing building stock remains at a novice level at best. Building sub-metering, by which we mean any secondary, hourly, metering (after the main) of various circuits, provides substantial information on when and where energy is used in specific buildings. Furthermore, combining this information with external weather data provides information beyond basic metering results. This paper discusses three case studies and explains how sub-metering, augmented by external solar and temperature data, benefits energy management and identified problems. It explains how different methods of analysing energy usage allowed: justifiable sizing of a solar photovoltaic system, with a calculated Cooling Degree Unit, identified the absence of savings from a proprietary chiller controller, and the energy variation due to user schedules and external conditions indicated anomalies in energy use. The advantages of wireless access are noted. Extracting information in graphical formats suggests better strategies to understand and control energy use.

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The Australian coast is rich in history and is scattered with coastal settlements amongst a contrasting landscape with infinite visual and ecological diversity. These attributes provide the opportunity to create sustainable and resilient settlements, linking the wholeness of a place to the foundation of living in harmony with nature. On the contrary the coastal regions of Australia are facing dynamic changes of population growth including the looming impact of a changing climate. Acknowledging these challenges, the Australian Government highlighted that one of the key requirements for a sustainable future is to establish sustainable settlements that are resilient against the impacts of climate change. Recent government studies and reports highlighted various possible impacts to the Australian coast and regional settlements due to sea level rise with associated coastal recession, extreme weather events, flooding, and prolonged heat waves. Various adaptation frameworks are proposed to deal with this issue, but very few consider the relationship between ecological systems and human built environments. The resilience planning of settlements must consider the co-evolution of human and nature under future climate effects. This paper is thus seeking answers to the question: How can the theoretical principles of Design with Nature (McHarg, 1967) and The Nature of Order (Alexander, 1980) provide for input to a adaptation model for settlements along the coast? Reflecting on a literature review of these two well established theories, the author select key principles from both as input to a ecological design based adaptation model for coastal settlements, which establishes a system of unfolding steps to create sustainable communities that connect with the landscape, and are resilient against future impacts of change.