101 resultados para Ephemeral habitats
Resumo:
As the world’s rural populations continue to migrate from farmland to sprawling cities, transport networks form an impenetrable maze within which monocultures of urban form erupt from the spaces in‐between. These urban monocultures are as problematic to human activity in cities as cropping monocultures are to ecosystems in regional landscapes. In China, the speed of urbanisation is exacerbating the production of mono‐functional private and public spaces. Edges are tightly controlled. Barriers and management practices at these boundaries are discouraging the formation of new synergistic relationships, critical in the long‐term stability of ecosystems that host urban habitats. Some urban planners, engineers, urban designers, architects and landscape architects have recognised these shortcomings in contemporary Chinese cities. The ideology of sustainability, while critically debated, is bringing together thinking people in these and other professions under the umbrella of an ecological ethic. This essay aims to apply landscape ecology theory, a conceptual framework used by many professionals involved in land development processes, to a concept being developed by BAU International called Networks Cities: a city with its various land uses arranged in nets of continuity, adjacency, and superposition. It will consider six lesser‐known concepts in relation to creating enhanced human activity along (un)structured edges between proposed nets and suggest new frontiers that might be challenged in an eco‐city. Ecological theory suggests that sustaining biodiversity in regions and landscapes depends on habitat distribution patterns. Flora and fauna biologists have long studied edge habitats and have been confounded by the paradox that maximising the breadth of edges is detrimental to specialist species but favourable to generalist species. Generalist species of plants and animals tolerate frequent change in the landscape, frequenting two or more habitats for their survival. Specialist species are less tolerant of change, having specific habitat requirements during their life cycle. Protecting species richness then may be at odds with increasing mixed habitats or mixed‐use zones that are dynamic places where diverse activities occur. Forman (1995) in his book Land Mosaics however argues that these two objectives of land use management are entirely compatible. He postulates that an edge may be comprised of many small patches, corridors or convoluting boundaries of large patches. Many ecocentrists now consider humans to be just another species inhabiting the ecological environments of our cities. Hence habitat distribution theory may be useful in planning and designing better human habitats in a rapidly urbanising context like China. In less‐constructed environments, boundaries and edges provide important opportunities for the movement of multi‐habitat species into, along and from adjacent land use areas. For instance, invasive plants may escape into a national park from domestic gardens while wildlife may forage on garden plants in adjoining residential areas. It is at these interfaces that human interactions too flow backward and forward between land types. Spray applications of substances by farmers on cropland may disturb neighbouring homeowners while suburban residents may help themselves to farm produce on neighbouring orchards. Edge environments are some of the most dynamic and contested spaces in the landscape. Since most of us require access to at least two or three habitats diurnally, weekly, monthly or seasonally, their proximity to each other becomes critical in our attempts to improve the sustainability of our cities.
Resumo:
We examined the abundance and distribution of neutrophilic, microaerophilic Fe(II)-oxidizing bacteria (FeOB) in aquatic habitats of a highly weathered, subtropical coastal catchment where Fe biogeochemistry is of environmental significance. Laboratory cultivation and microscopy indicated that stalked Gallionella and sheathed Leptothrix-like FeOB were present in microbial mats associated with a circumneutral-pH, groundwater seep and streambank surface sediment,whereas unicellular FeOB werewidespread in surface and subsurface waters, including a seep, shallow stream and estuary-adjacent groundwater. Direct Gallionella-specificPCR detected dominant bacterial members related to Sideroxydans paludicola (95% sequence identity, SI) and Gallionella capsiferriformans (96% SI) in the seep microbialmat. TGGE analysis indicated that themost common FeOB in water enrichment cultures were related to S. lithotrophicus (96% SI). The ubiquity of FeOB in Poona catchment aquatic habitats suggests bacterial Fe(II) oxidation is integral to catchment Fe biogeochemistry.
Resumo:
While the Ramsar Convention for the Protection of Wetlands of International Importance was the first habitat-based treaty, much of the recent focus of international attention in the area of freshwater has been on the regulation of watercourses. Attention is only beginning to be given to the interconnectedness of freshwater, habitats and ecosystems. This chapter explores and analyses the context, structure and substantive rules for the couservation and managemet of freshwater, habitats and ecosystems across the complex range of multilateral environmental agreements.
Resumo:
In ecosystems driven by water availability, plant community dynamics depend on complex interactions between vegetation, hydrology, and human water resources use. Along ephemeral rivers—where water availability is erratic—vegetation and people are particularly vulnerable to changes in each other's water use. Sensible management requires that water supply be maintained for people, while preserving ecosystem health. Meeting such requirements is challenging because of the unpredictable water availability. We applied information gap decision theory to an ecohydrological system model of the Kuiseb River environment in Namibia. Our aim was to identify the robustness of ecosystem and water management strategies to uncertainties in future flood regimes along ephemeral rivers. We evaluated the trade-offs between alternative performance criteria and their robustness to uncertainty to account for both (i) human demands for water supply and (ii) reducing the risk of species extinction caused by water mining. Increasing uncertainty of flood regime parameters reduced the performance under both objectives. Remarkably, the ecological objective (species coexistence) was more sensitive to uncertainty than the water supply objective. However, within each objective, the relative performance of different management strategies was insensitive to uncertainty. The ‘best’ management strategy was one that is tuned to the competitive species interactions in the Kuiseb environment. It regulates the biomass of the strongest competitor and, thus, at the same time decreases transpiration, thereby increasing groundwater storage and reducing pressure on less dominant species. This robust mutually acceptable strategy enables species persistence without markedly reducing the water supply for humans. This study emphasises the utility of ecohydrological models for resource management of water-controlled ecosystems. Although trade-offs were identified between alternative performance criteria and their robustness to uncertain future flood regimes, management strategies were identified that help to secure an ecologically sustainable water supply.
Resumo:
While they are among the most ecologically important animals within forest ecosystems, little is known about how bats respond to habitat loss and fragmentation. The threatened lesser short-tailed bat (Mystacina tuberculata), considered to be an obligate deep-forest species, is one of only 2 extant land mammals endemic to New Zealand; it plays a number of important roles within native forests, including pollination and seed dispersal, and rarely occurs in modified forests. We used radiotelemetry to study the movements, roosting behavior, and habitat use of M. tuberculata within a fragmented landscape comprised of 3 main habitat types: open space (harvested forest and pastoral land), native forests, and exotic pine plantations. We found that the bats had smaller home-range areas and travelled shorter nightly distances than populations investigated previously from contiguous native forest. Furthermore, M. tuberculata occupied all 3 habitat types, with native forest being preferred overall. However, individual variation in habitat selection was high, with some bats preferring exotic plantation and open space over native forest. Roosting patterns were similar to those previously observed in contiguous forest; individual bats often switched between communal and solitary roosts. Our findings indicate that M. tuberculata exhibit some degree of behavioral plasticity that allows them to adapt to different landscape mosaics and exploit alternative habitats. To our knowledge, this is the first such documentation of plasticity in habitat use for a bat species believed to be an obligate forest-dweller.
Resumo:
Acoustic recordings play an increasingly important role in monitoring terrestrial environments. However, due to rapid advances in technology, ecologists are accumulating more audio than they can listen to. Our approach to this big-data challenge is to visualize the content of long-duration audio recordings by calculating acoustic indices. These are statistics which describe the temporal-spectral distribution of acoustic energy and reflect content of ecological interest. We combine spectral indices to produce false-color spectrogram images. These not only reveal acoustic content but also facilitate navigation. An additional analytic challenge is to find appropriate descriptors to summarize the content of 24-hour recordings, so that it becomes possible to monitor long-term changes in the acoustic environment at a single location and to compare the acoustic environments of different locations. We describe a 24-hour ‘acoustic-fingerprint’ which shows some preliminary promise.
Resumo:
A significant gap in the tourism and travel literature exists in the area of tourism destination branding. Although brands have been used as sources of differentiation in consumer goods markets for over a century, academic research attention towards destination branding has only been reported since the late 1990s. Three important components of the brand construct are brand identity, brand position and brand image. While interest in applications of brand theory to practise in tourism is increasing, there is a paucity of published research in the literature to guide destination marketing organisations (DMOs). In particular there have been few reported analyses of destination brand positioning slogans. The focus of this paper is on destination brand position slogans, which represent the interface between brand identity and brand image. Part of a wider investigation of DMO slogans worldwide, and in keeping with the conference location, the paper focuses on analysis of slogans used by New Zealand RTOs. The slogans are examined in terms of the extent to which they have been limited to ephemeral indifference. In other words, have they stood the test of time and do they effectively differentiate through a meaningful proposition? Analysis of the slogans indicates very few could be characterised as memorably distinctive. This reflects the complexity involved in capturing the essence of a multi-attributed destination in a succinct and focused positioning slogan, in a way that is both meaningful to the target audience and effectively differentiates the destination from competitors offering the same benefits.
Resumo:
This paper reports on progress in developing new design and measurement concepts, and translating these concepts into practical applications. This research addresses gaps in ‘best practice’ green building, and is aimed ultimately at replacing green buildings with sustainable urban environments. Building on the author’s previously articulated concepts of Design for Eco-services and Positive Development, this research will demonstrate how to eco-retrofit cities so that they reverse the negative impacts of past design and generate net positive ecological impacts, at no extra cost. In contrast to ‘restorative’ design,this means increasing ecological carrying capacity and natural and social capital through built environment design. Some exemplars for facilitating Positive development will be presented in this talk,such as Green Scaffolding for retrofits, and Green Space Walls for new construction. These structures have been designed to grow and change over time, be easily deconstructed, and entail little waste. The frames support mini-ecospheres that provide a wide range of ecosystem services and biodiversity habitats, as well as heating, cooling and ventilating. In combination, the modules serve to improve human and environmental health. Current work is focused on developing a range of such space frame walls, optimised through an innovative marriage of eco-logical design and virtual modelling.
Resumo:
We introduce a formal model for certificateless authenticated key exchange (CL-AKE) protocols. Contrary to what might be expected, we show that the natural combination of an ID-based AKE protocol with a public key based AKE protocol cannot provide strong security. We provide the first one-round CL-AKE scheme proven secure in the random oracle model. We introduce two variants of the Diffie-Hellman trapdoor the introduced by \cite{DBLP:conf/eurocrypt/CashKS08}. The proposed key agreement scheme is secure as long as each party has at least one uncompromised secret. Thus, our scheme is secure even if the key generation centre learns the ephemeral secrets of both parties.
Resumo:
This practice-led research was initiated in response to a series of violent encounters that occurred between my fragile installations and viewers. The central focus of this study was to recuperate my installation practice in the wake of such events. This led to the development of a ‘responsive practice’ methodology, which reframed the installation process through an ethical lens developed from Emmanuel Levinas’ ethical phenomenology. The central propositions of this research are the reconceptualisation of ‘violent encounters’ in terms of difference whereby I accept viewers responses, even those which are violent, destructive or damaging, and secondly that the process operates as a generative excess for practice through which recuperative strategies can be found and implemented. By re-examining this process as it unfolded in the three phases of the practical component, I developed strategies whereby violated, destroyed or damaged works could be recuperated through the processes of reconfiguration, reparation and regeneration. Therefore my installations embody and articulate vulnerability but also demonstrate resilience and renewal.
Resumo:
Physiological responses to environmental stress are increasingly well studied in scleractinian corals. This work reports a new stress-related skeletal structure we term clypeotheca. Clypeotheca was observed in several livecollected common reef-building coral genera and a two to three kya subfossil specimen from Heron Reef, Great Barrier Reef and consists of an epitheca-like skeletal wall that seals over the surface of parts of the corallum in areas of stress or damage. It appears to form from a coordinated process wherein neighboring polyps and adjoining coenosarc seal themselves off from the surrounding environment as they contract and die. Clypeotheca forms from inward skeletal centripetal growth at the edges of corallites and by the merging of flange-like outgrowths that surround individual spines over the surface of the coenosteum. Microstructurally, the merged flanges are similar to upsidedown dissepiments and true epitheca. Clypeotheca is interpreted primarily as a response to stress that may help protect the colony from invasion of unhealthy tissues by parasites or disease by retracting tissues in areas that have become unhealthy for the polyps. Identification of skeletal responses of corals to environmental stress may enable the frequency of certain types of environmental stress to be documented in past environments. Such data may be important for understanding the nature of reef dynamics through intervals of climate change and for monitoring the effects of possible anthropogenic stress in modern coral reef habitats.
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The dancing doctorate is an interrogative endeavour which can but nurture the art form and forge a beneficial dynamism between those who seek and those who assess the emerging knowledges of dance’. (Vincs, 2009) From 2006-2008 three dance academics from Perth, Brisbane and Melbourne undertook a research project entitled Dancing between Diversity and Consistency: Refining Assessment in Postgraduate Degrees in Dance, funded by the ALTC Priority Projects Program. Although assessment rather than supervision was the primary focus of this research, interviews with 40 examiner/supervisors, 7 research deans and 32 candidates across Australia and across the creative arts, primarily in dance, provide an insight into what might be considered best practice in preparing students for higher research degrees, and the challenges that embodied and experiential knowledges present for supervision. The study also gained the industry perspectives of dance professionals in a series of national forums in 5 cities, based around the value of higher degrees in dance. The qualitative data gathered from these two primary sources was coded and analysed using the NVivo system. Further perspectives were drawn from international consultant and dance researcher Susan Melrose, as well as recent publications in the field. Dance is a young addition to academia and consequently there tends to be a close liaison between the academy and the industry, with a relational fluidity that is both beneficial and problematic. This partially explains why dance research higher degrees are predominantly practice-led (or multi-modal, referring to those theses where practice comprises the substantial examinable component). As a physical, embodied art form, dance engages with the contested territory of legitimising alternative forms of knowledge that do not sit comfortably with accepted norms of research. In supporting research students engaged with dance practice, supervisors traverse the tricky terrain of balancing university academic requirements with studies that are emergent, not only in the practice and attendant theory but in their methodologies and open-ended outcomes; and in an art form in which originality and new knowledge also arises from collaborative creative processes. Formal supervisor accreditation through training is now mandatory in most Australian universities, but it tends to be generic and not address supervisory specificity. This paper offers the kind of alternative proposed by Edwards (2002) that improving postgraduate supervision will be effective if supervisors are empowered to generate their own standards and share best practice; in this case, in ways appropriate to the needs of their discipline and alternative modes of thesis presentation. In order to frame the qualities and processes conducive to this goal, this paper will draw on both the experiences of interviewees and on philosophical premises which underpin the research findings of our study. These include the ongoing challenge of dissolving the binary oppositions of theory and practice, especially in creative arts practice where theory resides in and emerges from the doing as much as in articulating reflection about the doing through what Melrose (2003) terms ‘mixed mode disciplinary practices’. In guiding practitioners through research higher degrees, how do supervisors deal with not only different forms of knowledge but indeed differing modes of knowledge? How can they navigate tensions that occur between the ‘incompatible competencies’ (Candlin, 2000) of the ‘spectating’ academic experts with their ‘irrepressible drive ... to inscribe, interpret, and hence to practise temporal closure’, and practitioner experts who create emergent works of ‘residual unfinishedness’ (Melrose 2006) which are not only embodied but ephemeral, as in the case of live performance?
Resumo:
The black rat (Rattus rattus) has been shown to be the primary species responsible for causing significant crop losses within the Australian macadamia industry. This species success within macadamia orchards is directly related to the flexibility expressed in its foraging behaviour. In this paper a conceptual foraging model is presented which proposes that the utilisation of resources by rodents within various components of the system is related not only to their relative abundance, but also to predator avoidance behaviour. Nut removal from high predation risk habitats during periods of low resource abundance in low risk compartments of the system is considered an essential behaviour that allows high rodent densities to be maintained throughout the year.
Resumo:
This practice-led research project examines some of the factors and issues facing artists working in the public domain who wish to engage with the community as audience. Using the methodology of action research, the three major creative projects in this study use art as a socio-political tool with the aim of providing an effective vehicle for broadening awareness, understanding forms of social protest and increasing tolerance for diversity. The three projects: Floodline November 7, 2004, Look in, Look out, and The Urban Terrorist Project, dealt with issues of marginalisation of communities, audiences and graffiti artists respectively. The artist/researcher is outlined as both creator and collaborator in the work. Processes included ephemeral elements, such as temporary installation and performance, as well as interactive elements that encouraged direct audience involvement as part of the work. In addition to the roles of creator and collaborator, both of which included audience as well as artist, the presence of an outside entity was evident. Whether local, legal authorities or prevailing attitudes, outside entities had an unavoidable impact on the processes and outcomes of the work. Each project elicited a range of responses from their respective audiences; however, the overarching concept of reciprocity was seen to be the crucial factor in conception, artistic methods and outcomes.