2,158 research outputs found

    Germination responses of a dry sclerophyll forest soil-stored seedbank to fire related cues

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    Fire is an integral component of many ecosystems worldwide. Many plant species require fire-related cues, primarily heat and smoke, to trigger germination. Despite the importance of this process, the responses of many Australian species to these cues are unknown. Without this knowledge fire management strategies may be developed that are inappropriate for individual species and vegetation communities. In this study we examined the responses of a dry sclerophyll forest seed bank to heat and smoke germination cues. Analysis was possible for 48 taxa within the soil seedbank with 34 of these showing a response to one or both of the germination cues. 10 species responded to the heat treatment, 11 species responded to the smoke treatment and 13 species responded to both the heat and smoke treatments. Germination cues acted independently for all species considered. Results in this study were consistent with published reports for most species, although some differences were seen at the species and genus level. The study highlights the importance of fire-related cues in enhancing germination of a large proportion of the species occurring in dry sclerophyll forests

    Sum-dominant sets and restricted-sum-dominant sets in finite abelian groups

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    Into the firing line: civilian ingress during the 2013 Red October bushfires, Australia

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    A major issue for bushfire management arises when residents decide to leave a safe area and enter the fire zone to rescue or defend their property, pets, loved ones or other assets. Here, we use statistical and narrative analyses of data from an online survey and semi-structured interviews with residents affected by the 2013 Red October bushfires in New South Wales, Australia. The survey results revealed that of the 58 % of respondents who were not at home at the time the threat became apparent, 65 % indicated that they attempted to get home prior to the arrival of the fire front. In doing so, many endangered themselves, their family, friends and emergency services personnel. This paper discusses the shortcomings of bushfire survival plans and official risk communication, which do not cater well for household units that are divided or unattended when a bushfire starts. Findings suggest that to enhance bushfire safety and preparedness, emergency managers should acknowledge and speak more directly to the specific constraints to action for particular social groups at the wildland-urban interface, including families with school-age children, commuters and absentee landholders

    Rapid mortality transition of Pacific Islands in the 19th century

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    The depopulation of Pacific islands during the 16th to 19th centuries is a striking example of historical mass mortality due to infectious disease. Pacific Island populations have not been subject to such cataclysmic infectious disease mortality since. Here we explore the processes which could have given rise to this shift in infectious disease mortality patterns. We show, using mathematical models, that the population dynamics exhibited by Pacific Island populations are unlikely to be the result of Darwinian evolution. We propose that extreme mortality during first-contact epidemics is a function of epidemiological isolation, not a lack of previous selection. If, as pathogens become established in populations, extreme mortality is rapidly suppressed by herd immunity, Pacific Island population mortality patterns can be explained with no need to invoke genetic change. We discuss the mechanisms by which this could occur, including (i) a link between the proportion of the population transmitting infectious agents and case-fatality rates, and (ii) the course of infection with pathogens such as measles and smallpox being more severe in adults than in children. Overall, we consider the present-day risk of mass mortality from newly emerging infectious diseases is unlikely to be greater on Pacific islands than in other geographical areas

    Modelling the response of surface fuel to climate change across south-eastern Australia: consequences for future fire regimes

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    Geophysical Research Abstracts of EGU General Assembly 2014, held 27 April - 2 May, 2014 in Vienna, Austria
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