7 resultados para Coral reefs and islands

em Deakin Research Online - Australia


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There are three key drivers of the biodiversity crisis: (1) the well known existing threats to biodiversity such as habitat loss, invasive pest species and resource exploitation; (2) direct effects of climate-change, such as on coastal and high elevation communities and coral reefs; and (3) the interaction between existing threats and climate-change. The third driver is set to accelerate the biodiversity crisis beyond the impacts of the first and second drivers in isolation. In this review we assess these interactions, and suggest the policy and management responses that are needed to minimise their impacts. Renewed management and policy action that address known threats to biodiversity could substantially diminish the impacts of future climate-change. An appropriate response to climate-change will include a reduction of land clearing, increased habitat restoration using indigenous species, a reduction in the number of exotic species transported between continents or between major regions of endemism, and a reduction in the unsustainable use of natural resources. Achieving these measures requires substantial reform of international, national and regional policy, and the development of new or more effective alliances between scientists, government agencies, non-government organisations and land managers. Furthermore, new management practices and policy are needed that consider shifts in the geographic range of species, and that are responsive to new information acquired from improved research and monitoring programs. The interactions of climate-change with existing threats to biodiversity have the potential to drive many species to extinction, but there is much that can be done now to reduce this risk.

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Coral reefs face a crisis due to local and global anthropogenic stressors. A large proportion of the ~50% coral loss on the Great Barrier Reef has been attributed to outbreaks of the crown-of-thorns-seastar (COTS). A widely assumed cause of primary COTS outbreaks is increased larval survivorship due to higher food availability, linked with anthropogenic runoff . Our experiment using a range of algal food concentrations at three temperatures representing present day average and predicted future increases, demonstrated a strong influence of food concentration on development is modulated by temperature. A 2°C increase in temperature led to a 4.2–4.9 times (at Day 10) or 1.2–1.8 times (Day 17) increase in late development larvae. A model indicated that food was the main driver, but that temperature was an important modulator of development. For instance, at 5000 cells ml−1 food, a 2°C increase may shorten developmental time by 30% and may increase the probability of survival by 240%. The main contribution of temperature is to ‘push’ well-fed larvae faster to settlement. We conclude that warmer sea temperature is an important co-factor promoting COTS outbreaks.

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The system described in the part of the coral fossils collected from Xainza area, northern Lower Devonian Dahl East group. Wrinkles coral genera and 5 species (including a new species Hunanaxonia xizangensis sp nov.) And two undetermined species; bedplate coral-shaped coral 4 4 species, including two new species the (Pachycanalicula sparcula sp nov. Paraheliolites zakangensis sp nov.) these coral fossil discovery will help to further understanding of the Early Devonian corals fauna symbiotic combination, evolution, and coral paleobiogeographic flora.

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Population outbreaks of adult Acanthaster planci cause significant reductions in coral cover and reduce the resilience of coral reefs, but little is known about the behaviour and food preference of juvenile A. planci. In 2014, food preferences and feeding rates of recently settled (<1 year) juvenile A. planci were tested and determined at the National Sea Simulator facilities of the Australian Institute of Marine Science. Juveniles were offered eight species of coral (Acropora formosa, A. millepora, A. tenuis, Pavona cactus, Echinopora lamellosa, Pocillopora damicornis, Stylophora pistillata and Porites lutea), known to be either consumed or avoided by adult sea stars, in a multiple-choice and a no-choice experiment. In the multiple-choice experiment, a preference for A. tenuis was detected, while S. pistillata, E. lamellosa and P. lutea were avoided. The no-choice experiment showed that the avoidance of these species was not influenced by the presence of other coral species, the exception being E. lamellosa, which was only consumed when no other choice was offered. Interestingly, all juveniles consuming E. lamellosa died post-predation. The study suggests that as A. planci matures it feeds on a wider range of species, even those which would have been lethal to them if consumed as a juvenile.

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Social entrepreneurs formally or informally generate community associations and networking that produces social outcomes. Social entrepreneurship is a relatively new and poorly understood concept. Policy promotes generating community activity, particularly in rural areas, for health and social benefits and ‘community resilience’. Rural health professionals might be well placed to generate community activity due to their status and networks. This exploratory study, conducted in rural Tasmania and the Highlands and Islands of Scotland considered whether rural health professionals act as social entrepreneurs. We investigated activities generated and processes of production. Thirty-eight interviews were conducted with general practitioners, community nurses, primary healthcare managers and allied health professionals living and working rurally. Interviewees were self-selecting responders to an invitation for rural health professionals who were ‘formally or informally generating community associations or networking that produced social outcomes’. We found that rural health professionals initiated many community activities with social outcomes, most related to health. Their identification of opportunities related to knowledge of health needs and examples of initiatives seen elsewhere. Health professionals described ready access to useful people and financial resources. In building activities, health professionals could simultaneously utilise skills and knowledge from professional, community member and personal dimensions. Outcomes included social and health benefits, personal ‘buzz’ and community capacity. Health professionals' actions could be described as social entrepreneurship: identifying opportunities, utilising resources and making ‘deals’. They also align with community development. Health professionals use contextual knowledge to envisage and grow activities, indicating that, as social entrepreneurs, they do not explicitly choose a social mission, rather they act within their known world-view. Policymakers could consider ways to engage rural health professionals as social entrepreneurs, in helping to produce resilient communities.

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Pittosporum undulatum Vent. (Sweet Pittosporum) is a densely foliaged tall shrub or small tree, native to the wet forests of south east Australia, This species now functions as a serious environmental weed in a range of habitats in Australia and on other continents and islands throughout the temperate, sub-tropical and tropical zones. This study investigated some of the ecological causes and consequences of P. undulatum invasion across a range of habitat types in south east Australia. Key aspects of P. undulatum biology and ecology investigated in the current study include; patterns of morphological variation across the range of habitats occupied (as a measure of the species’ plasticity), dispersal ecology and seed germinability, population structure and spatial pattern, community relationships and the ecological impacts of invasion. Phenotypic plasticity is considerable in P. undulatum. No clear patterns of geographic variation emerged from a study of leaf morphological attributes across the current range of this species on mainland south east Australia. The pattern of morphological variation is particularly complex in Victoria, where the invasion of this species is most advanced. The species’ adaptability to a range of environments and environmental conditions will likely promote further range expansion. The abundant winter fruit crop produced by functionally female P. undulatum plants attracts a suite of generalist opportunistic frugivores, which feed on P. undulatum fruits and seeds at various stages of fruit dehiscence, thereby enhancing dispersal opportunities for this species. P. undulatum seed collected from natural and invasive populations, at two stages of fruit maturity and from the scats and pellets of dispersal agents, displayed high germinability. European Blackbirds and Pied Currawongs are implicated as the main avian dispersal agents of P undulatum in south east Australia. The broader ecological implications of developing relationships between invasive fleshy-fruited bird-dispersed plant species and adaptive frugivores are likely to be considerable. The distribution of P. undulatutn seedlings was significantly negatively correlated with adult conspecifics and significantly positively correlated with trees and shrubs of other genera. This pattern reflects the importance of both firugivorous dispersal agents and the species’ germination and establishment requirements, in shaping the contagious distribution pattern typical of this species. These analyses suggest that recruitment opportunities for conspecific seedlings are limited beneath the canopy of adult conspecifics. Densities of P. undulatum were on average, 2.7 times higher in invaded populations, compared to the natural populations sampled. A male-bias was evident in all populations and no relationships between reproductive activity and the density of seedlings and juveniles were evident. Invading populations of P. undulatum impose substantial changes on ecosystem-level properties and functions. Mean species richness and cover-abundance declined notably once P. undulatum cover-abundance exceeded 20% at the invaded sites and 60% at the natural sites sampled. The natural communities sampled displayed comparatively greater resilience to the competitive effects of P. undulatum, but community attributes were affected at high densities and cover-abundance of this species. The cover-abundance of herbs and grasses declined most substantially with increasing P. undulatum at invaded sites, whereas, at the natural sites sampled, the species’ structural analogues appeared to be most affected by increasing P. undulatum cover-abundance. This study has demonstrated that the ecological consequences of P. undulatum population expansion are substantial and contribute to changes in the composition and successional trajectory of affected communities. These processes ultimately lead to the loss and simplification of biodiversity values and the homogenisation of affected habitats. P. undulatum has the potential to emerge as one of south east Australia's most serious environmental weed species.

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Using the archaeological displays at the Museum of Scotland in Edinburgh, this paper examines the exhibition as a site of identity creation through the negotiations between categories of same and Other. Through an analysis of the poetics of display, the paper argues that the exhibition constructs a particular relationship between the Celtic Fringe and Scottish National identity that draws upon the historical discourses of the Highlands and Islands of Scotland as a place and a time 'apart'. This will be shown to have implications for the display of archaeological material in museums but also for contemporary understandings of Scottish National identity.