Showing papers by "James Cook University published in 2005"

Social-Ecological Resilience to Coastal Disasters

Abstract: Social and ecological vulnerability to disasters and outcomes of any particular extreme event are influenced by buildup or erosion of resilience both before and after disasters occur. Resilient social-ecological systems incorporate diverse mechanisms for living with, and learning from, change and unexpected shocks. Disaster management requires multilevel governance systems that can enhance the capacity to cope with uncertainty and surprise by mobilizing diverse sources of resilience.

Participatory Action Research: Communicative Action and the Public Sphere.

Abstract: [Extract] Participatory action research has an extensive history in many fields of social practice. Our aim in this chapter is to develop the view of participatory action research that has shaped our own theory and practice during recent years.

New paradigms for supporting the resilience of marine ecosystems

Abstract: Resource managers and scientists from disparate disciplines are rising to the challenge of understanding and moderating human impacts on marine ecosystems. Traditional barriers to communication between marine ecologists, fisheries biologists, social scientists and economists are beginning to break down, and the distinction between applied and basic research is fading. These ongoing trends arise, in part, from an increasing awareness of the profound influence of people on the functioning of all marine ecosystems, an increased focus on spatial and temporal scale, and a renewed assessment of the role of biodiversity in the sustainability of ecosystem goods and services upon which human societies depend. Here, we highlight the emergence of a complex systems approach for sustaining and repairing marine ecosystems, linking ecological resilience to governance structures, economics and society.

Developing the Travel Career Approach to Tourist Motivation

Abstract: The purpose of this study lies in the conceptual adjustment of the travel career ladder (TCL) approach to travel motivation. In this context, the study examined the relationship between patterns of travel motivation and travel experience. This research was conducted through two studies: an interview phase to guide the further conceptual development of the travel career approach and a major survey phase for further empirical exploration of the ideas. Overall results suggested that host-site-involvement motivation (e.g., experiencing different cultures) and nature-related motivation (e.g., being close to nature) were more important factors to the more experienced travelers, whereas motivations such as stimulation, personal development, relationship (security), self-actualization, nostalgia, romance, and recognition had a higher priority for the less experienced ones. Importantly, a core of travel motivation factors including escape, relaxation, relationship enhancement, and self-development seem to comprise the central backbone of motivation for all travelers.

Critical science gaps impede use of no-take fishery reserves

Abstract: As well as serving valuable biodiversity conservation roles, functioning no-take fishery reserves protect a portion of the fishery stock as insurance against future overfishing. So long as there is adequate compliance by the fishing community, it is likely that they will also sustain and even enhance fishery yields in the surrounding area. However, there are significant gaps in scientific knowledge that must be filled if no-take reserves are to be used effectively as fishery management tools. Unfortunately, these gaps are being glossed over by some uncritical advocacy. Here, we review the science, identify the most crucial gaps, and suggest ways to fill them, so that a promising management tool can help meet the growing challenges faced by coastal marine fisheries.

Comparing entire colour patterns as birds see them

Abstract: Colour patterns and their visual backgrounds consist of a mosaic of patches that vary in colour, brightness, size, shape and position. Most studies of crypsis, aposematism, sexual selection, or other forms of signalling concentrate on one or two patch classes (colours), either ignoring the rest of the colour pattern, or analysing the patches separately. We summarize methods of comparing colour patterns making use of known properties of bird eyes. The methods are easily modifiable for other animal visual systems. We present a new statistical method to compare entire colour patterns rather than comparing multiple pairs of patches. Unlike previous methods, the new method detects differences in the relationships among the colours, not just differences in colours. We present tests of the method's ability to detect a variety of kinds of differences between natural colour patterns and provide suggestions for analysis.

Odor/taste integration and the perception of flavor

Abstract: Perceptions of the flavors of foods or beverages reflect information derived from multiple sensory afferents, including gustatory, olfactory, and somatosensory fibers. Although flavor perception therefore arises from the central integration of multiple sensory inputs, it is possible to distinguish the different modalities contributing to flavor, especially when attention is drawn to particular sensory characteristics. Nevertheless, our experiences of the flavor of a food or beverage are also simultaneously of an overall unitary perception. Research aimed at understanding the mechanisms behind this integrated flavor perception is, for the most part, relatively recent. However, psychophysical, neuroimaging and neurophysiological studies on cross-modal sensory interactions involved in flavor perception have started to provide an understanding of the integrated activity of sensory systems that generate such unitary perceptions, and hence the mechanisms by which these signals are "functionally united when anatomically separated". Here we review this recent research on odor/taste integration, and propose a model of flavor processing that depends on prior experience with the particular combination of sensory inputs, temporal and spatial concurrence, and attentional allocation. We propose that flavor perception depends upon neural processes occurring in chemosensory regions of the brain, including the anterior insula, frontal operculum, orbitofrontal cortex and anterior cingulate cortex, as well as upon the interaction of this chemosensory "flavor network" with other heteromodal regions including the posterior parietal cortex and possibly the ventral lateral prefrontal cortex.

Establishing representative no-take areas in the Great Barrier Reef: large-scale implementation of theory on marine protected areas

Abstract: The Great Barrier Reef Marine Park, an area almost the size of Japan, has a new network of no-take areas that significantly improves the protection of biodiversity. The new marine park zoning implements, in a quantitative manner, many of the theoretical design principles discussed in the literature. For example, the new network of no-take areas has at least 20% protection per “bioregion,” minimum levels of protection for all known habitats and special or unique features, and minimum sizes for no-take areas of at least 10 or 20 km across at the smallest diameter. Overall, more than 33% of the Great Barrier Reef Marine Park is now in no-take areas (previously 4.5%). The steps taken leading to this outcome were to clarify to the interested public why the existing level of protection was inadequate; detail the conservation objectives of establishing new no-take areas; work with relevant and independent experts to define, and contribute to, the best scientific process to deliver on the objectives; describe the biodiversity (e.g., map bioregions); define operational principles needed to achieve the objectives; invite community input on all of the above; gather and layer the data gathered in round-table discussions; report the degree of achievement of principles for various options of no-take areas; and determine how to address negative impacts. Some of the key success factors in this case have global relevance and include focusing initial communication on the problem to be addressed; applying the precautionary principle; using independent experts; facilitating input to decision making; conducting extensive and participatory consultation; having an existing marine park that encompassed much of the ecosystem; having legislative power under federal law; developing high-level support; ensuring agency priority and ownership; and being able to address the issue of displaced fishers.

Are U.S. coral reefs on the slippery slope to slime

Abstract: Conservation of U.S. coral reefs has been sidetracked by the partial implementation of management plans without clearly achievable goals. Historical ecology reveals global patterns of coral reef degradation that provide a framework for reversing reef decline with ecologically meaningful metrics for success. The authors of this Policy Forum urge action now to address multiple threats simultaneously, because the harmful effects of stressors like overfishing, pollution, poor land-use practices, and global warming are interdependent. Prompt implementation of proven, practical solutions would lead to both short- and long-term benefits, including the return of keystone species and the economic benefits they entail.

The complex business of survival by aposematism

Abstract: The theory of warning signals dates back to Wallace but is still confusing, controversial and complex. Because predator avoidance of warningly coloured prey (aposematism) is based upon learning and reinforcement, it is difficult to understand how initially rare conspicuous forms subsequently become common. Here, we discuss several possible resolutions to this apparent paradox. Many of these ideas have been largely ignored as a result of implicit assumptions about predator behaviour and assumed lack of variation in the predators, prey and the predation process. Considering the spatial and temporal variation in and mechanisms of behaviour of both predators and prey will make it easier to understand the process and evolution of aposematism.

Understanding the impact of ecotourism resort experiences on tourists' environmental attitudes and behavioural intentions

Abstract: This study explored the conservation benefits of environmental management practices and nature experiences provided at a major Australian ecotourism resort. To achieve this purpose the study investigated changes in tourists' environmental knowledge, awareness, attitudes and behavioural intentions between pre-visit and post-visit stages. Overall, there were few statistically significant differences between the pre-visit and post-visit samples. This study found, however, significant effects of (1) visitor awareness of, and (2) involvement in, the environmental management practices, and (3) participation in nature tour activities on environmental attitudes and behaviours. It is suggested that awareness of in-resort environmental practices and satisfying experiences in ecotourism accommodation may lead to reinforcing visitors' favourable environmental attitudes, thus increasing their interest in further ecotourism experiences. Through these cumulative effects, ecotourism accommodation could achieve its educative goal.

Life cycle stages of the amphibian chytrid Batrachochytrium dendrobatidis.

Abstract: An overview of the morphology and life cycle of Batrachochytrium dendrobatidis, the cause of chytridiomycosis of amphibians, is presented. We used a range of methods to examine stages of the life cycle in culture and in frog skin, and to assess ultrastructural pathology in the skin of 2 frogs. Methods included light microscopy, transmission electron microscopy with conventional methods as well as high pressure freezing and freeze substitution, and scanning electron microscopy with critical point drying as well as examination of bulk-frozen and freeze-fractured material. Although chytridiomycosis is an emerging disease, B. dendrobatidis has adaptations that suggest it has long been evolved to live within cells in the dynamic tissue of the stratified epidermis. Sporangia developed at a rate that coincided with the maturation of the cell, and fungal discharge tubes usually opened onto the distal surface of epidermal cells of the stratum corneum. A zone of condensed, fibrillar, host cytoplasm surrounded some sporangia. Hyperkeratosis may be due to (1) a hyperplastic response that leads to an increased turnover of epidermal cells, and (2) premature keratinization and death of infected cells.

Density-dependent spillover from a marine reserve: long-term evidence

Abstract: Spillover, the net export of adult fish, is one mechanism by which no-take marine reserves may eventually have a positive influence on adjacent fisheries. Although evidence for spillover has increased recently, mechanisms inducing movement of adult fish from reserve to fished areas are poorly understood. While density-dependent export is a reasonable expectation, given that density of fish targeted by fisheries should increase over time inside well-protected no-take reserves, no study to date has demonstrated development of the process. This study provides evidence consistent with density-dependent export of a planktivorous reef fish, Naso vlamingii, from a small no-take reserve (protected for 20 years) at Apo Island, Philippines. Mean density of N. vlamingii increased threefold inside the reserve between 1983 and 2003. Density approached an asymptote inside the reserve after 15–20 years of protection. Modal size in the reserve increased from 35 to 45 cm total length (TL) over 20 years of protection. In addition, both density and modal size increased outside the reserve close to (200–300 m), but not farther from (300–500 m), the reserve boundary over the 20 years of reserve protection. Movement of adult N. vlamingii across the boundaries of the reserve was rare. Aggressive interactions among adult N. vlamingii were significantly higher (by 3.7 times) inside than outside the reserve. This suggests that density-dependent interactions were more intense inside the reserve. When interacting adults differed in size, the larger individual usually chased away the smaller one. Furthermore, the mean size of adult fish captured by experimental fishing decreased from 35-cm TL 50– 100 m outside the boundary, to 32-cm TL 250–300 m outside the boundary. This represents some of the best evidence available for density-dependent home-range relocation of fish from a no-take reserve.

The Novel and Endemic Pathogen Hypotheses: Competing Explanations for the Origin of Emerging Infectious Diseases of Wildlife

Abstract: Chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis, is an emerging infectious disease implicated in declines of amphibian populations around the globe. An emerging infectious disease is one that has recently been discovered; has recently increased in incidence, geography, or host range; or is newly evolved. For any given outbreak of an emerging disease, it is therefore possible to state two hypotheses regarding its origin. The novel pathogen hypothesis states that the disease has recently spread into new geographic areas, whereas the endemic pathogen hypothesis suggests that it has been present in the environment but recently has increased in host range or pathogenicity. Distinguishing between these hypotheses is important, because the conservation measures needed to slow or stop the spread of a novel pathogen are likely to differ from those needed to prevent outbreaks of an endemic pathogen. Population genetics may help discriminate among the possible origins of an emerging disease. Current evidence suggests chytridiomycosis may be a novel pathogen being spread worldwide by carriers; until we know how much genetic variation to expect in an endemic strain, however, we cannot yet conclude that B. dendrobatidis is a novel pathogen.

Competition, predation, and density-dependent mortality in demersal marine fishes

Abstract: The relative roles of competition and predation in demographic density dependence are poorly known. A tractable experimental design to determine such effects and their interactions for demersal (seafloor oriented) fishes and similar sedentary species is cross-factoring multiple densities of new recruits with the presence and absence of predators. This design allows one to distinguish between density-dependent mortality due to competition alone, predation alone, or an interaction between the two, especially when supplemental field observations are available. To date, 14 species of marine fish have been examined with some variant of this design, and for 12 species predation was demonstrated to be the sole or major cause of density dependence. However, as competition may be slow acting relative to predation, the importance of competition can be underestimated in short-term experiments. On the Great Barrier Reef, we conducted a long-term field experiment in which multiple densities of new recruits of a planktivorous damselfish were cross-factored with the presence or absence of resident piscivorous fish on patch reefs. During the first 10 months, no density-dependent mortality was detected, regardless of whether resident predators were present or absent. By the end of the experiment at 17 months, per capita mortality was strongly density dependent and highly compensatory in both predator treatments; all reefs ultimately supported nearly the same adult density regardless of experimental treatment. Examination of treatment effect sizes suggested that competition was the main source of density-dependent mortality, with predation being merely a proximate agent of death. We hypothesize that predators were ineffective in this system compared with similar studies elsewhere because prey density was low relative to ample prey refuges provided by highly complex corals. Combined with previous studies, these findings indicate that density-dependent mortality in demersal marine fishes is often caused by interplay of predation and competition, whose roles may be altered by variation in habitat complexity and larval supply. These conclusions are relevant to marine fisheries models, which typically assume that density dependence is due solely to intraspecific competition.

Potential causes and life-history consequences of sexual size dimorphism in mammals

Abstract: 1. Male-biased sexual size dimorphism (SSD) in mammals has been explained by sexual selection favouring large, competitive males. However, new research has identified other potential factors leading to SSD. The aim of this review is to evaluate current research on the causes of SSD in mammals and to investigate some consequences of SSD, including costs to the larger sex and sexual segregation. 2. While larger males appear to gain reproductive benefits from their size, studies have also identified alternative mating strategies, unexpected variance in mating success and found no clear relationship between degree of polygyny and dimorphism. This implies that sexual selection is unlikely to be the single selective force directing SSD. 3. Latitude seems to influence SSD primarily through variation in overall body size and seasonal food availability, which affect potential for polygyny. Likewise, population density influences resource availability and evidence suggests that food scarcity differentially constrains the growth of the sexes. Diverging growth patterns between the sexes appear to be the primary physiological mechanism leading to SSD. 4. Female-biased dimorphism is most adequately explained by reduced male–male competition resulting in a decrease in male size. Female–female competition for dominance and resources, including mates, may also select for increased female size. 5. Most studies found that sexual segregation arises through asynchrony of activity budgets between the sexes. The larger sex can suffer sex-biased mortality through increased parasite load, selective predation and the difficulty associated with sustaining a larger body size under conditions of resource scarcity. 6. None of the variables considered here appears to contribute a disproportionate amount to SSD in mammals. Several promising avenues of research are currently overlooked and long-term studies, which have previously been biased toward ungulates, should be carried out on a variety of taxa.

Neoproterozoic cap carbonates: a critical appraisal of existing models and the plumeworld hypothesis

Abstract: Evidence for glaciation during the mid-late Neoproterozoic is widespread on Earth, reflecting three or more ice ages between 730 Ma and 580 Ma. Of these, the late Neoproterozoic Marinoan glaciation of approximately 635 Ma stands out because of its ubiquitous association with a characteristic, microcrystalline cap dolostone that drapes glacially influenced rock units worldwide. The Marinoan glaciation is also peculiar in that evidence for low altitude glaciation at equatorial latitudes is compelling. Three models have been proposed linking abrupt deglaciation with this global carbonate precipitation event: (i) overturn of an anoxic deep ocean; (ii) catastrophically accelerated rates of chemical weathering because of supergreenhouse conditions following global glaciation (Snowball Earth Hypothesis); and (iii) massive release of carbonate alkalinity from destabilized methane clathrates. All three models invoke extreme alkalinity fluxes into seawater during deglaciation but none explains how such alkalinity excess from point sources could be distributed homogeneously around the globe. In addition, none explains the consistent sequence of precipitation events observed within cap carbonate successions, specifically: (i) the global blanketing of carbonate powder in shallow marine environments during deglaciation; (ii) widespread and disruptive precipitation of dolomite cement; followed by (iii) localized barite precipitation and seafloor cementation by aragonite. The conceptual model presented here proposes that low latitude deglaciation was so massive and abrupt that the resultant meltwater plume could extend worldwide, physically separating the surface and deep ocean reservoirs for ≥103 years. It is proposed that cap dolostones formed primarily by microbially mediated precipitation of carbonate whitings during algal blooms within this low salinity plumeworld rather than by abiotic precipitation from normal salinity seawater. Many of the disruption features that are characteristic of cap dolostones can be explained by microbially mediated, early diagenetic dolomitization and cementation. The re-initiation of whole ocean circulation degassed CO2 into the atmosphere in areas of upwelling, triggering localized, abiotic CaCO3 precipitation in the form of aragonite fans that overlie cap dolostones in NW Canada and Namibia. The highly oxygenated shallow marine environments of the glacial and post-glacial Neoproterozoic world provided consistently favourable conditions for the evolutionary development of animals and other oxygenophiles.

Ecology of chytridiomycosis in rainforest stream frog assemblages of tropical Queensland.

Abstract: In the wet tropics of Queensland, Australia, eight species of stream-dwelling frogs have experienced population declines. Some declines were associated with an emerging infectious disease of amphibians (chytridiomycosis) caused by the fungus Batrachochytrium dendrobatidis. We examined the spatial and temporal pattern of infection prevalence in a sample of frog populations. Infected adults and tadpoles of all species were found, and infections occurred at every site. Infection prevalence varied among species and was always < 10.0% in adults but ranged from 0.75 to 76.0% in tadpoles. In this system tadpoles and adults of some species may act as disease reservoirs, experiencing avirulent infections, whereas other hosts (declining species) experience virulent infections. Infection prevalence was higher during the cool, dry winter season (May to September) and at high elevations (600–800 m), suggesting regulation by environmental conditions, including temperature and precipitation. We found no relationships between infection prevalence and mean body condition, fluctuating asymmetry of hind limbs, population density, or the presence of metamorphosing tadpoles and juvenile frogs. Although it is not certain whether chytridiomycosis was responsible for past frog population declines in the wet tropics of Queensland, the pathogen is now endemic. Our data indicate that at the landscape level, environmental conditions have strong effects on host-pathogen dynamics. These effects interact with species-specific behavior or immune function and may be important underlying determinants of chytridiomycosis epizootics and emergence.

Animal visual systems and the evolution of color patterns: sensory processing illuminates signal evolution

Abstract: Animal color pattern phenotypes evolve rapidly. What influences their evolution? Because color patterns are used in communication, selection for signal efficacy, relative to the intended receiver's visual system, may explain and predict the direction of evolution. We investigated this in bowerbirds, whose color patterns consist of plumage, bower structure, and ornaments and whose visual displays are presented under predictable visual conditions. We used data on avian vision, environmental conditions, color pattern properties, and an estimate of the bowerbird phylogeny to test hypotheses about evolutionary effects of visual processing. Different components of the color pattern evolve differently. Plumage sexual dimorphism increased and then decreased, while overall (plumage plus bower) visual contrast increased. The use of bowers allows relative crypsis of the bird but increased efficacy of the signal as a whole. Ornaments do not elaborate existing plumage features but instead are innovations (new color schemes) that increase signal efficacy. Isolation between species could be facilitated by plumage but not ornaments, because we observed character displacement only in plumage. Bowerbird color pattern evolution is at least partially predictable from the function of the visual system and from knowledge of different functions of different components of the color patterns. This provides clues to how more constrained visual signaling systems may evolve.

Agroforestry Tree Products (AFTPs): Targeting Poverty Reduction and Enhanced Livelihoods

Abstract: Agroforestry tree domestication emerged as a farmer-driven, market-led process in the early 1990s and became an international initiative. A participatory approach now supplements the more traditional aspects of tree improvement, and is seen as an important strategy towards the Millennium Development Goals of eradicating poverty and hunger, promoting social equity and environmental sustainability. Considerable progress has been made towards the domestication of indigenous fruits and nuts in many villages in Cameroon and Nigeria. Vegetatively-propagated cultivars based on a sound knowledge of ‘ideotypes’ derived from an understanding of the tree-to-tree variation in many commercially important traits are being developed by farmers. These are being integrated into polycultural farming systems, especially the cocoa agroforests. Markets for Agroforestry Tree Products (AFTPs) are crucial for the adoption of agroforestry on a scale to have meaningful economic, social and environmental impacts. Important lessons ...

Dietary overlap among coral-feeding butterflyfishes (Chaetodontidae) at Lizard Island, northern Great Barrier Reef

Abstract: This study documented the range of corals, and other prey types, consumed by 20 species of butterflyfishes, which co-occur at Lizard Island, northern Great Barrier Reef, Australia. Six species (Chaetodon aureofasciatus, C. baronessa, C. lunulatus, C. plebius, C. rainfordi and C. trifascialis) fed almost exclusively on scleractinian corals, and a further eight species (C. citrinellus, C. kleinii, C. lunula, C. melannotus, C. rafflesi, C. speculum, C. ulietensis, and C. unimaculatus) took a significant proportion of their bites from corals. The other six species (C. auriga, C. ephippium, C. lineolatus, C. semeion, C. vagabundus, and Chelmon rostratus) rarely consumed coral, but fed on small discrete prey items from non-coral substrates. Coral-feeding butterflyfishes consumed a wide range of corals. Chaetodon lunulatus, for example, consumed 51 coral species from 24 different genera. However, there was up to 72% dietary overlap between coral-feeding butterflyfishes, with 11/14 species feeding predominantly on Acropora hyacinthus or Pocillopora damicornis. The most specialised corallivore, C. trifascialis, took 88% of bites from A. hyacinthus. Chaetodon trifascialis defend territories encompassing one or more colonies of A. hyacinthus, and may have prevented other species such as C. lunulatus from feeding even more extensively on this coral. This study has shown that coexistence of coral-feeding butterflyfishes occurs despite an apparent lack of partitioning of prey resources. While different coral-feeding butterflyfishes were more or less selective in their use of different coral prey, virtually all species fed predominantly on A. hyacinthus or P. damicornis.

Virulence of the amphibian chytrid fungus Batrachochytrium dendrobatidis varies with the strain

Abstract: Although mortality in 3 groups of 15 green tree frogs Litoria caerulea exposed to 3 isolates of Batrachochytrium dendrobatidis was 100%, time to death varied with isolate, highlighting the importance of strain and/or passage history in pathogenicity studies and possibly in the epidemiology of chytridiomycosis. A standard naming scheme for isolates of B. dendrobatidis is proposed.

Food webs in tropical Australian streams: shredders are not scarce

Abstract: 1. Macroinvertebrates were collected in dry and wet seasons from riffles and pools in two streams in tropical north Queensland. Total biomass, abundance and species richness were higher in riffles than in pools but did not differ between streams or seasons. 2. Gut contents of all species were identified. Cluster analysis based on gut contents identified five dietary groups: I, generalist collectors; II, generalist shredders and generalist predators; III, generalist scrapers; IV, specialist shredders; and V, specialist predators. Species were allocated to functional feeding groups (FFGs) based on these dietary groups. 3. Many species were generalist in their diets, but specialist predators and shredders were particularly prominent components of the invertebrate assemblages in terms of biomass and species richness. 4. Community composition (proportions of biomass, abundance and species richness of the different FFGs) varied between habitat types, but not between streams or seasons, although differences between riffles and pools varied with season. 5. Comparison of the fauna of 20 streams showed that our study sites were similar to, or not atypical of, low-order streams in the Queensland wet tropics.