58 resultados para ecosystem functioning

em Deakin Research Online - Australia


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Animal migrations span the globe, involving immense numbers of individuals from a wide range of taxa. Migrants transport nutrients, energy, and other organisms as they forage and are preyed upon throughout their journeys. These highly predictable, pulsed movements across large spatial scales render migration a potentially powerful yet underappreciated dimension of biodiversity that is intimately embedded within resident communities. We review examples from across the animal kingdom to distill fundamental processes by which migratory animals influence communities and ecosystems, demonstrating that they can uniquely alter energy flow, food-web topology and stability, trophic cascades, and the structure of metacommunities. Given the potential for migration to alter ecological networks worldwide, we suggest an integrative framework through which community dynamics and ecosystem functioning may explicitly consider animal migrations.

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In the search for an integrated understanding of the relationships among productive activities, human well-being, and ecosystem functioning, we evaluated the services delivered by a tropical dry forest (TDF) ecosystem in the Chamela Region, on the Pacific Coast of Mexico. We synthesized information gathered for the past two decades as part of a long-term ecosystem research study and included social data collected in the past four years using the Millennium Ecosystem Assessment (MA) conceptual framework as a guide. Here we identify the four nested spatial scales at which information has been obtained and emphasize one of them through a basin conceptual model. We then articulate the biophysical and socio-economic constraints and drivers determining the delivery of ecosystem services in the Region. We describe the nine most important services, the stakeholders who benefit from those services, and their degree of awareness of such services. We characterize spatial and temporal patterns of the services’ delivery as well as trade-offs among services and stakeholders. Finally, we contrast three alternative future scenarios on the delivery of ecosystem services and human well-being. Biophysical and socioeconomic features of the study site strongly influence human−ecosystem interactions, the ecosystem services delivered, the possible future trajectories of the ecosystem, and the effect on human well-being. We discuss future research approaches that will set the basis for an integrated understanding of human−ecosystem interactions and for constructing sustainable management strategies for the TDF.

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Enhancements are interventions in the life cycle of common-pool aquatic resources. Enhancement technologies include culture-based fisheries, habitat modifications, fertilization, feeding and elimination of predators/competitors. Enhancements are estimated to yield about two million mt per year, mostly from culture-based fisheries in fresh waters where they account for some 20 percent of capture, or 10 percent of combined capture and culture production. Marine enhancements are still at an experimental stage, but some have reached commercial production. Enhancements use limited external feed and energy inputs, and can provide very high returns for labour and capital input. Moreover, enhancement initiatives can facilitate institutional change and a more active management of aquatic resources, leading to increased productivity, conservation and wider social benefits. Enhancements may help to maintain population abundance, community structure and ecosystem functioning in the face of heavy exploitation and/or environmental degradation. Negative environmental impacts may arise from ecological and genetic interactions between enhanced and wild stocks. Many enhancements have not realised their full potential because of a failure to address specific institutional, technological, management and research requirements emanating from two key characteristics. Firstly, enhancement involves investment in common-pool resources and can only be sustained under institutional arrangements that allow regulation of use and a flow of benefits to those who bear the costs of enhancement. Secondly, interventions are limited to certain aspects of the life cycle of stocks, and outcomes are strongly dependent on natural conditions beyond management control. Hence, management must be adapted to local conditions to be effective, and certain conditions may preclude successful enhancement altogether. Governments have a major role to play in facilitating enhancement initiatives through the establishment of conducive institutional arrangements, appropriate research support, and the management of environmental and other impacts on and from enhancements.

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Resource pulses are common in various ecosystems and often have large impacts on ecosystem functioning. Many animals hoard food during resource pulses, yet how this behaviour affects pulse diffusion through trophic levels is poorly known because of a lack of individual-based studies. Our objective was to examine how the hoarding behaviour of arctic foxes (Alopex lagopus) preying on a seasonal pulsed resource (goose eggs) was affected by annual and seasonal changes in resource availability. We monitored foraging behaviour of foxes in a greater snow goose (Chen caerulescens atlanticus) colony during 8 nesting seasons that covered 2 lemming cycles. The number of goose eggs taken and cached per hour by foxes declined 6-fold from laying to hatching, while the proportion of eggs cached remained constant. In contrast, the proportion of eggs cached by foxes fluctuated in response to the annual lemming cycle independently of the seasonal pulse of goose eggs. Foxes cached the majority of eggs taken (> 90%) when lemming abundance was high or moderate but only 40% during the low phase of the cycle. This likely occurred because foxes consumed a greater proportion of goose eggs to fulfill their energy requirement at low lemming abundance. Our study clearly illustrates a behavioural mechanism that extends the energetic benefits of a resource pulse. The hoarding behaviour of the main predator enhances the allochthonous nutrients input brought by migrating birds from the south into the arctic terrestrial ecosystem. This could increase average predator density and promote indirect interactions among prey.

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Scientists are increasingly coming to realize that oncogenic phenomena are both frequent and detrimental for animals, and must therefore be taken into account when studying the biology of wildlife species and ecosystem functioning. Here, we argue that several behaviours that are routine in an individual's life can be associated with cancer risks, or conversely prevent/cure malignancies and/or alleviate their detrimental consequences for fitness. Although such behaviours are theoretically expected to be targets for natural selection, little attention has been devoted to explore how they influence animal behaviour. This essay provides a summary of these issues as well as an overview of the possibilities offered by this research topic, including possible applications for cancer prevention and treatments in humans.

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Aim: Globally, urbanization is one of the most widespread, intense and ecologically destructive forms of landscape transformation, and it is often concentrated in coastal areas. Theoretically, species losses attributable to urbanization are predicted not to alter overall ecosystem function if functional redundancy (i.e. replacement of function by alternative species) compensates for such losses. Here, we test this expectation by measuring how coastal urbanization affects scavenger guilds on sandy beaches and whether changes in guild composition result either in an overall loss of scavenging efficiency, or in functional compensation under alternative guild structures, maintaining net ecosystem functioning. Location: Fourteen beaches along the east coast of Australia with variable levels of urbanization. Methods: Scavenging communities and rates of carrion removal were determined using motion-triggered cameras at the beach-dune interface. Results: A substantial shift in the community structure of vertebrate scavengers was associated with gradients in urbanization. Iconic and functionally important raptors declined precipitously in abundance on urban beaches. Importantly, other vertebrates usually associated with urban settings (e.g. dogs, foxes, corvids) did not functionally replace raptors. In areas where < 15% of the abutting land had been developed into urban areas, carcass removal by scavengers was often complete, but always > 70%. Conversely, on beaches bordering coastal cities with < 40% of natural vegetation remaining, two-thirds of fish carcasses remained uneaten by scavengers. Raptors removed 70-100% of all deployed fish carcasses from beaches with < 8% urban land cover, but this number dropped significantly with greater levels of urbanization and was not compensated by other scavenger species in urban settings. Main conclusions: There is limited functional redundancy in vertebrate scavenger communities of sandy beach ecosystems, which impacts the system's capacity to mitigate the ecological consequences of detrimental landscape transformations.

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Ecosystem services are necessary, yet not sufficient for human well-being (however defined). Insufficient access to the ecosystem provisioning service of food is a particularly important factor in the loss of human well-being, but all ecosystem services contribute in some way to well-being. Although perhaps long obvious to ecologists, the links between ecosystems and aspects of human well-being, including health, have been less well understood among the social science community. This situation may now be starting to change, thanks in part to the Millennium Ecosystem Assessment (MA). Causality between ecosystem services and well-being is bidirectional; it is increasingly clear that functioning societies can protect or enhance ecosystem services, and accordingly, that societies with impaired well-being (best documented in the case of chronic diseases such as malaria and HIV/AIDS) can also experience a related decline in ecosystem services.

The future state of human well-being and of ecosystem services is more than the co-evolution of these two fundamental elements. Human well-being also depends, critically, upon the human institutions that govern relationships between human individuals and groups, and also between humans and ecosystem services.

The scenarios working group of the MA found that human well-being is highest in the Global Orchestration scenario, which assumes the fastest evolution of beneficial institutions, and is lowest in the Order from Strength scenario. Human well-being was found to be intermediate in the other two scenarios (Adapting Mosaic and Techno-Garden) even though these scenarios share a much greater recognition of the importance of ecosystem services to human well-being.

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■ Human well-being has several key components: the basic material needs for a good life, freedom and choice, health, good social relations, and personal security. Well-being exists on a continuum with poverty, which has been defined as"pronounced deprivation in well-being."
■ How well-being and ill-being, or poverty, are expressed and experienced is context- and situation-dependent, reflecting local social and personal factors such as geography, ecology, age, gender,and culture.These concepts are complex and value-laden.
Ecosystems are essential for human well-being through their provisioning, regulating, cultural, and supporting services. Evidence in recent decades of escalating human impacts. on ecological systems worldwide raises concerns about the consequences of ecosystem changes for human well-being.
■ Human well-being can be enhanced through sustainable human interaction with ecosystems with the support of appropriate instruments, institutions, organizations, and technology. creation of these through participation and transparency may contribute to people's freedoms and choices and to increased economic, social,and ecological security.
■ Some believe that the problems from the depletion and degradation of ecological capital can be largely overcome by the substitution of physical and human capital. Others believe that there are more significant limits to such substitutions.The scope for substitutions varies by socioeconomic status.
■ We identify direct and indirect pathways between ecosystem change and human well-being,whether it be positive or negative.lndirect effects are characterized by more complex webs of causation, involving social, economic, and political threads. Threshold points exist beyond which rapid changes to human well-being can occur.
■ Indigent poorly resourced, and otherwise disadvantaged communities are generally the most vulnerable to adverse ecosystem change. Spirals, both positive and negative, can occur for any population, but the poor are more vulnerable.      
Functioning institutions are vital to enable equitable access to ecosystem services. lnstitutions sometimes fail or remain undeveloped because of powerful individuals or groups. Bodies that mediate the distribution of goods and services may also be appropriated for the benefit of powerful minorities.
■ For poor people, the greatest gains in well-being will occur through more equitable and secure access to ecosystem services. In the long run, the rich can contribute greatly to human well-being by reducing their substantial impacts on ecosystems and by facilitating greater access to ecosystem services by the poor.
■ We argue ecological security warrants recognition as a sixth freedom of equal weight with participative freedom, economic   facilities, social opportunities, transparency guarantees, and protective security.

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The aim of this study was to investigate age, menopausal status, and the male partner's sexual function on the sexual function of the menopausal woman. Sexual functioning of 304 women (120 premenopausal, 76 perimenopausal, 108 postmenopausal) aged between 35 and 65 years from a community sample was investigated. Multiple regression analyses found that sexual satisfaction within the relationship was better predicted by age group than by menopausal status. Younger women were more likely to be satisfied with their sexual relationship than older women. Age group was also a better predictor than menopausal status of current frequency of intercourse, with younger women being likely to have more frequent intercourse than older women. Whether a female respondent had experienced a sexual dysfunction was better predicted by menopausal status than by age. Women who were menopausal were more likely to report a sexual problem such as lack of sexual interest, poor lubrication, and failure to have an orgasm. However, age group appeared to be a better predictor of whether the male partner had experienced a sexual dysfunction. Older men were more likely to have experienced failure to have an erection, for example. The findings of this study indicate that age and the sexual function of the partner are important factors to take into consideration when investigating the sexual function of the menopausal woman.

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Objective: This study was designed to investigate the role of depression, anxiety, and fatigue in Chronic Fatigue Syndrome (CFS) sufferers' objective and subjective cognitive performance. Methods: Twenty-three CFS sufferers and 23 healthy control participants were compared on objective and subjective assessments of cognitive performance. Depression, anxiety, and fatigue were also evaluated. Results: CFS sufferers did not demonstrate any impairment in objective cognitive functioning compared to the control group, and objective performance was not related to their higher levels of depression or their level of fatigue. Depression scores only accounted for a small amount of the variance in CFS sufferers' lower subjective assessment of their cognitive performance compared to control participants. There were no differences between the groups on anxiety scores. Conclusion: The results are discussed in terms of the heterogeneity of the CFS population and the complex interaction of symptomatological factors that characterise CFS.

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A diagnosis of cancer is a very stressful event for the patients and their families. Patients, partners and other family members can suffer from clinical levels of depression and severe levels of anxiety and stress reactions. The similarity in levels of distress between patients and partners and patients and offspring suggests that there are common factors that impact on families' distress levels. The current study examined levels of depression and anxiety in newly diagnosed adult patients (n = 48) and their adult relatives (n = 99). Family functioning and patients' illness characteristics were identified as factors that might impact on families' depression and anxiety. Results from multilevel models indicated that family functioning was important. Families that were able to act openly, express feelings directly, and solve problems effectively had lower levels of depression. Direct communication of information within the family was associated with lower levels of anxiety. Aside from differences anxiety due to cancer type, patients' illness characteristics appear to be risk factors in patients' but not relatives' depression and anxiety. The results from the current study suggest that researchers and clinicians need to be family-focused as cancer affects the whole family, not just the patient.

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Relationship and sexual satisfaction among people with multiple sclerosis (MS) has received little research attention. This article reports on a longitudinal investigation of the impact of coping style and illness-related variables among people with MS and the general population on sexual and relationship functioning. Both men (n = 120) and women (n= 201) with MS and men (n = 79) and women (n = 160) from the general population participated in the study at two points in time, 6 months apart. People with MS experienced lower levels of sexual activity, sexual satisfaction, and relationship satisfaction and higher levels of sexual dysfunction. Generally speaking, the time 1 levels of the health and coping variables explained little of the variance in the time 2 sexual and relationship variables. However, sexual activity at time 1 contributed significant unique variance to relationship satisfaction at time 2 for MS men, and coping strategies at time I contributed to relationship satisfaction among general population women at time 2. Furthermore, for those respondents who had been diagnosed with MS for less than 7 years, levels of sexual activity at time 2 were predicted by levels of sexual and relationship satisfaction, as well as levels of sexual activity at time 1. These results suggest that strategies used to cope with illness may not play a major role in sexual and relationship satisfaction. However, an examination of these strategies over a longer time frame is needed.

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Few studies have compared sexual behaviours among adolescents with high-functioning autism (HFA) and typical populations, and indicated whether specialized education is required. We hypothesized that adolescents with HFA would (1) display poorer social behaviours; (2) engage in fewer behaviours related to privacy and have poorer knowledge regarding privacy issues; (3) have less sex education; and (4) display more inappropriate sexual behaviours; and that (5) parental concerns would be greater for the HFA sample. Parents of typical adolescents (n = 50) and adolescents with HFA (n = 23) were surveyed with a Sexual Behaviour Scale (SBS) developed by the authors, with domains corresponding to the hypotheses. The HFA and typical groups were found to be significantly different on all five domains. However, following covariation with age and level of social behaviour, it was found that only parental concerns about their child distinguished between typical adolescents and those with HFA. Specialized sex education programmes with a social interaction emphasis should be considered for this group.


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A survey of parents/caregivers of a child with an autism spectrum disorder (ASD) was conducted to examine the relationship between ASD characteristics, family functioning and coping strategies. Having a child with ASD places considerable stress on the family. Primary caregivers of a child with ASD from a regional and rural area in Victoria, Australia (N = 53) were surveyed concerning their child with ASD, family functioning (adaptability and cohesion), marital satisfaction, self-esteem and coping strategies. Results suggest that these caregivers had healthy self-esteem, although they reported somewhat lower marital happiness, family cohesion and family adaptability than did norm groups. Coping strategies were not significant predictors of these outcome variables. Results highlight the need for support programmes to target family and relationship variables as well as ASD children and their behaviours, in order to sustain the family unit and improve quality of life for parents and caregivers as well as those children.