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Ecological Systems (ecological + system)
Terms modified by Ecological Systems Selected AbstractsThermodynamic optimization of the life cycle of plastics by exergy analysisINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 11 2004J. Dewulf Abstract Decision-makers should strive for an efficient employment of resources for the whole industrial ecological system. The metabolization of resources should be optimized in thermodynamic terms. This contribution presents an effort to use exergy analysis as a quantitative tool in the thermodynamic optimization of the life cycle of plastics. Quantitative results on overall exergetic efficiencies of different industrial metabolic options are presented. Therefore, different waste treatment options of plastics will be considered, taking into account interacting industrial activities, such as virgin plastics production and heat and electricity production starting from natural resources. Copyright © 2004 John Wiley & Sons, Ltd. [source] Using Bayesian inference to understand the allocation of resources between sexual and asexual reproductionJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES C (APPLIED STATISTICS), Issue 2 2009C. Jessica E. Metcalf Summary., We address the problem of Markov chain Monte Carlo analysis of a complex ecological system by using a Bayesian inferential approach. We describe a complete likelihood framework for the life history of the wavyleaf thistle, including missing information and density dependence. We indicate how, to make inference on life history transitions involving both missing information and density dependence, the stochastic models underlying each component can be combined with each other and with priors to obtain expressions that can be directly sampled. This innovation and the principles described could be extended to other species featuring such missing stage information, with potential for improving inference relating to a range of ecological or evolutionary questions. [source] Worms and malaria: noisy nuisances and silent benefitsPARASITE IMMUNOLOGY, Issue 7 2002Mathieu Nacher Summary The burden of malaria mortality has been a major evolutionary influence on human immunity. The selection of the most successful immune responses against malaria has been in populations concomitantly infected by intestinal helminths. Animal models have shown that coinfections with helminths and protozoa in the same host elicit a range of antagonist and synergistic interactions. Recent findings suggest similar interactions take place between helminths, Plasmodium falciparum and humans. However, as the threat of HIV and tuberculosis becomes a major selective force, what used to be a successful ecological system may now prove detrimental. Nevertheless, the understanding of the ecological forces at play may expose new intervention targets for malaria control, and give a new perspective on our shortcomings against the deadliest of human parasites. [source] Ecological network analysis: an application to the evaluation of effects of pesticide use in an agricultural environmentPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 10 2007Peter Andras Abstract Ecological network analysis is used to evaluate the impact of pesticide use on ecological systems in the context of agricultural farmland environments. The aim is to provide support for the design of effective and minimally damaging pest control strategies. The ecological network analysis can identify species that are important to the integrity of the ecological network. The methodology can be used to monitor the impact of shifts in terms of types of pesticide used on the ecological system. The authors' intention is to use this methodology to provide supporting evidence for the UK Voluntary Initiative programme aimed at convincing farmers voluntarily to make improved choices in the use of a wide range of pesticides. Copyright © 2007 Society of Chemical Industry [source] Combined effects of two stressors on Kenyan coral reefs are additive or antagonistic, not synergisticCONSERVATION LETTERS, Issue 2 2010Emily S. Darling Abstract A challenge for conservation science is predicting the impacts of co-occurring human activities on ecological systems. Multiple anthropogenic and natural stressors impact ecosystems globally and are expected to jeopardize their ecological functions and the success of conservation and management initiatives. The possibility that two or more stressors interact synergistically is of particular concern, but such nonadditive effects remain largely unidentified in nature. A long-term data set of hard coral cover from Kenyan reefs was used to examine the independent and interactive effects of two stressors: fishing and a temperature anomaly in 1998 that caused mass coral bleaching and mortality. While both stressors decreased coral cover, fishing by 51% and bleaching by 74%, they did not interact synergistically. Instead, their combined effect was antagonistic or weakly additive. The observed nonsynergistic response may be caused by the presence of one dominant stressor, bleaching, and cotolerance of coral taxa to both bleaching and fishing stressors. Consequently, coral bleaching has been the dominant driver of coral loss on Kenyan reefs and while marine reserves offer many benefits to reef ecosystems, they may not provide corals with a refuge from climate change. [source] Modelling species distributions in Britain: a hierarchical integration of climate and land-cover dataECOGRAPHY, Issue 3 2004Richard G. Pearson A modelling framework for studying the combined effects of climate and land-cover changes on the distribution of species is presented. The model integrates land-cover data into a correlative bioclimatic model in a scale-dependent hierarchical manner, whereby Artificial Neural Networks are used to characterise species' climatic requirements at the European scale and land-cover requirements at the British scale. The model has been tested against an alternative non-hierarchical approach and has been applied to four plant species in Britain: Rhynchospora alba, Erica tetralix, Salix herbacea and Geranium sylvaticum. Predictive performance has been evaluated using Cohen's Kappa statistic and the area under the Receiver Operating Characteristic curve, and a novel approach to identifying thresholds of occurrence which utilises three levels of confidence has been applied. Results demonstrate reasonable to good predictive performance for each species, with the main patterns of distribution simulated at both 10 km and 1 km resolutions. The incorporation of land-cover data was found to significantly improve purely climate-driven predictions for R. alba and E. tetralix, enabling regions with suitable climate but unsuitable land-cover to be identified. The study thus provides an insight into the roles of climate and land-cover as determinants of species' distributions and it is demonstrated that the modelling approach presented can provide a useful framework for making predictions of distributions under scenarios of changing climate and land-cover type. The paper confirms the potential utility of multi-scale approaches for understanding environmental limitations to species' distributions, and demonstrates that the search for environmental correlates with species' distributions must be addressed at an appropriate spatial scale. Our study contributes to the mounting evidence that hierarchical schemes are characteristic of ecological systems. [source] Biological warfare in the garden pond: tadpoles suppress the growth of mosquito larvaeECOLOGICAL ENTOMOLOGY, Issue 1 2003Allie Mokany Abstract. 1. Although tadpoles and mosquito larvae may compete for scarce resources in natural freshwater systems, the mechanisms involved in such competition remain largely unstudied. 2. Replicated artificial ponds were set up to examine the role of pathogenic interference (water-borne growth inhibitors) in two tadpole,mosquito systems from south-eastern Australia. One system comprised taxa that are commonly sympatric in freshwater ponds (tadpoles of Limnodynastes peronii and larvae of Culex quinquefasciatus) while the other comprised species that co-occur in brackish water ponds (tadpoles of Crinia signifera and larvae of Ochlerotatus australis). 3. Water that had previously contained tadpoles suppressed the rates of survival and pupation of mosquito larvae in both systems. Fungicide reduced or eliminated this effect, suggesting that the growth inhibitors may be fungal organisms (possibly the yeast Rhodotorula glutinis) from tadpole faeces. Fungicide also enhanced growth rates of tadpoles. 4. These results suggest that interference competition between tadpoles and mosquito larvae is mediated by other organisms in some ecological systems. [source] The rise of research on futures in ecology: rebalancing scenarios and predictionsECOLOGY LETTERS, Issue 12 2009Audrey Coreau Abstract Concern about the ecological consequences of global change has increasingly stimulated ecologists to examine the futures of ecological systems. Studying futures is not only a crucial element of the interaction between science, management and decision making, but also a critical research challenge per se, especially because futures cannot be observed or experimented on. In addition, researchers can encounter methodological and theoretical difficulties, which make interpretations and predictions problematic. In the literature which deals with futures of ecological systems two main lines of research can be distinguished: a predictive approach, which dominates the literature, can be contrasted with a rarer number of studies that elaborate potential scenarios for ecological systems. Scenario approaches currently concern mainly contacts with stakeholders or decision makers, or the use of climate scenarios to derive projections about ecological futures. We argue that a new direction for ecological futures research could be explored by using ecological scenarios in combination with predictive models to further fundamental ecological research, in addition to enhancing its applied value. Ecology Letters (2009) 12: 1277,1286 [source] Evolution in ecological field experiments: implications for effect sizeECOLOGY LETTERS, Issue 3 2008Sharon Y. Strauss Abstract Rapid evolution in response to strong selection, much of which is human-induced, has been indisputably documented. In this perspective, we suggest that adaptation may influence the effect size of treatments in ecological field experiments and alter our predictions of future dynamics in ecological systems. Field experiments often impose very strong and consistent selection over multiple generations. Focal populations may adapt to these treatments and, in the process, increase or decrease the magnitude of the treatment effect through time. We argue that how effect size changes through time will depend on the evolutionary history of the experimental population, the type of experimental manipulation, and the traits involved in adaptive responses. While no field study has conclusively demonstrated evolution in response to treatments with concomitant changes in ecological effect size, we present several examples that provide strong circumstantial evidence that such effects occur. We conclude with a consideration of the differences between plastic and genetic responses to treatments and discuss future research directions linking adaptation to ecological effect size. [source] Scales of association: hierarchical linear models and the measurement of ecological systemsECOLOGY LETTERS, Issue 6 2007Sean M. McMahon Abstract A fundamental challenge to understanding patterns in ecological systems lies in employing methods that can analyse, test and draw inference from measured associations between variables across scales. Hierarchical linear models (HLM) use advanced estimation algorithms to measure regression relationships and variance,covariance parameters in hierarchically structured data. Although hierarchical models have occasionally been used in the analysis of ecological data, their full potential to describe scales of association, diagnose variance explained, and to partition uncertainty has not been employed. In this paper we argue that the use of the HLM framework can enable significantly improved inference about ecological processes across levels of organization. After briefly describing the principals behind HLM, we give two examples that demonstrate a protocol for building hierarchical models and answering questions about the relationships between variables at multiple scales. The first example employs maximum likelihood methods to construct a two-level linear model predicting herbivore damage to a perennial plant at the individual- and patch-scale; the second example uses Bayesian estimation techniques to develop a three-level logistic model of plant flowering probability across individual plants, microsites and populations. HLM model development and diagnostics illustrate the importance of incorporating scale when modelling associations in ecological systems and offer a sophisticated yet accessible method for studies of populations, communities and ecosystems. We suggest that a greater coupling of hierarchical study designs and hierarchical analysis will yield significant insights on how ecological processes operate across scales. [source] Strategies of family farms to strengthen their resilienceENVIRONMENTAL POLICY AND GOVERNANCE, Issue 4 2010Ika Darnhofer Abstract Resilience thinking offers a framework to emphasize dynamics and interdependencies across time, space and domains. It is based on understanding social,ecological systems as complex, and future developments as unpredictable, thus emphasizing adaptive approaches to management. In this paper the four clusters of factors that have been identified as building resilience in large-scale social,ecological systems are applied at the farm level. Suggestions on how these factors could be operationalized at the farm level are derived from workshops held with family farmers in Austria. The results show that farmers understand change as unpredictable and unfolding, have a number of strategies to ensure the flexibility and adaptability of their farm and build extensive networks to diversify information and income sources. However, these strategies, while ensuring adaptability and transformability, compete for scarce resources. The farmers thus face trade-offs between strategies that ensure the adaptive capacity of their farm over the long term and those ensuring profitability over the short term. Copyright © 2010 John Wiley & Sons, Ltd and ERP Environment. [source] Governing long-term social,ecological change: what can the adaptive management and transition management approaches learn from each other?ENVIRONMENTAL POLICY AND GOVERNANCE, Issue 1 2009Timothy J. Foxon Abstract Maintaining social welfare and opportunity in the face of severe ecological pressures requires frameworks for managing and governing long-term social,ecological change. In this paper we analyse two recent frameworks, adaptive management and transition management, outlining what they could learn from each other. Though usually applied in different domains, the two conceptual frameworks aim to integrate bottom-up and top-down approaches, and share a focus on the ability of systems to learn and develop adaptive capacity whilst facing external shocks and long-term pressures. Both also emphasize learning from experimentation in complex systems, but transition management focuses more on the ability to steer long-term changes in system functions, whilst adaptive management emphasizes the maintenance of system functions in the face of external change. The combination of iterative learning and stakeholder participation from adaptive management has the potential to incorporate vital feedbacks into transition management, which in turn offers a longer-term perspective from which to learn about and manage socio-technical and social,ecological change. It is argued that by combining insights from both frameworks it may be possible to foster more robust and resilient governance of social,ecological systems than could be achieved by either approach alone. The paper concludes by critically reflecting upon the challenges and benefits of combining elements of each approach, as has been attempted in the methodology of a research project investigating social,ecological change in UK uplands. Copyright © 2009 John Wiley & Sons, Ltd and ERP Environment. [source] A test of the community conditioning hypothesis: Persistence of effects in model ecological structures dosed with the jet fuel jp-8ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2000Wayne G. Landis Abstract The foundation of the community conditioning hypothesis, the persistence of effects, was tested in a series of microcosm experiments. Experiments were conducted with the water-soluble fraction of the turbine fuel JP-8 using the standard protocols for the standardized aquatic microcosm (SAM). A repeat trial was conducted using the SAM protocol but with a 126-d test period, twice the standard duration. The results were examined using a variety of conventional univariate, multivariate, and graphical techniques. The principal conclusions were as follows. Effects are persistent in these model ecological systems long after the degradation of the toxicant. Patterns of impacts are detectable at concentrations 15 times lower than an experimentally derived single-species EC50. The replicate experiments are not replicable in the specific, but the broad pattern of the disruption of algal- herbivore dynamics followed by more subtle effects are consistently repeated. The durability of the indirect effects and therefore the information about historical events appears to be a consistent feature of these microcosm systems. The identity of the treatment groups persists. The critical features of the community conditioning hypothesis,persistence of information within ecologicalsystems and the reappearance of patterns and therefore the nonequilibrium dynamics,are again confirmed. The implications of these findings for environmental toxicology, monitoring, and ecological risk assessment are discussed. [source] Links between Community Violence and the Family System: Evidence from Children's Feelings of Relatedness and Perceptions of Parent Behavior,FAMILY PROCESS, Issue 3 2002Michael Lynch Ph.D. In this study, we examined some of the ways in which broader ecological systems may influence the organization of behavior within the family system. Specifically, links between exposure to community violence and children's relationships with maternal caregivers were investigated in a sample of 127 urban children between the ages of 7 and 13 years. Children were asked to indicate whether they had been exposed to a wide variety of violent events. In addition, their feelings of relatedness and separation anxiety, and their perceptions of maternal behavior were assessed. It was expected that exposure to community violence would be associated with feeling less secure with caregivers. Consistent with predictions from ecological-transactional theory, data supported this hypothesis. Children who reported that they had been exposed to high levels of community violence also indicated that they felt less positive affect when with their caregiver, were dissatisfied with how close they felt to her, felt more separation anxiety, and reported more negative maternal behavior than children exposed to less violence. Findings are discussed in terms of how violence may affect the family system and the protective function of human attachment. [source] Genetic immunity and influenza pandemicsFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 1 2006Sergey N. Rumyantsev Abstract In addition to the great number of publications focused on the leading role of virus mutations and reassortment in the origin of pandemic influenza, general opinion emphasizes the victim side of the epidemic process. Based on the analysis and integration of relevant ecological, epidemiological, clinical, genetic and experimental data, the present article is focused on the evolution of ,virus , victim' ecological systems resulting in the formation of innate (i.e. genetic, constitutional) immunity in the involved species and populations. This kind of immunity functions today as the greatest natural barrier to the pandemic spread of influenza among humans and ecologically related kinds of animals. Global influenza pandemics can arise when the worldwide population contains at least a minimum number of people susceptible to a known or mutant influenza virus. Special attention is paid in this article to individual tests for the presence of this barrier, including the implications of specific findings for public health policy. Such tests could be based on in vitro observation of the action of relevant virus strains on primary cell cultures or on their cellular or molecular components extracted from individuals. The resources of the Human Genome Project should also be utilized. [source] Trends in water quality and discharge confound long-term warming effects on river macroinvertebratesFRESHWATER BIOLOGY, Issue 2 2009ISABELLE DURANCE Summary 1.,Climate-change effects on rivers and streams might interact with other pressures, such as pollution, but long-term investigations are scarce. We assessed trends among macroinvertebrates in 50 southern English streams in relation to temperature, discharge and water quality over 18 years (1989,2007). 2.,Long-term records, coupled with estimates from inter-site calibrations of 3,4 years, showed that mean stream temperatures in the study area had increased by 2.1,2.9 °C in winter and 1.1,1.5 °C in summer over the 26 year period from 1980 to 2006, with trends in winter strongest. 3.,While invertebrate assemblages in surface-fed streams were constant, those in chalk-streams changed significantly during 1989,2007. Invertebrate trends correlated significantly with temperature, but effects were spurious because (i) assemblages gained taxa typical of faster flow or well-oxygenated conditions, contrary to expectations from warming; (ii) more invertebrate families increased in abundance than declined and (iii) concomitant changes in water quality (e.g. declining orthophosphate, ammonia and biochemical oxygen demand), or at some sites changes in discharge, explained more variation in invertebrate abundance and composition than did temperature. 4.,These patterns were reconfirmed in both group- and site-specific analyses. 5.,We conclude that recent winter-biased warming in southern English chalk-streams has been insufficient to affect invertebrates negatively over a period of improving water quality. This implies that positive management can minimize some climate-change impacts on stream ecosystems. Chalk-stream invertebrates are sensitive, nevertheless, to variations in discharge, and detectable changes could occur if climate change alters flow pattern. 6.,Because climatic trends now characterize many inter-annual time-series, we caution other investigators to examine whether putative effects on ecological systems are real or linked spuriously to other causes of change. [source] Regional Planning in Queensland's Rangelands: Challenges and Prospects for Biodiversity ConservationGEOGRAPHICAL RESEARCH, Issue 1 2007CLIVE A. MCALPINE Abstract In Australia, the Commonwealth and State governments are increasingly devolving natural resource management (NRM) responsibilities to regional bodies. This move has led to the development of regional NRM plans. Native vegetation and biodiversity conservation, along with soil, pasture and water resources, are key components of the regional NRM plans in Queensland's extensive rangelands. This paper outlines and applies a set of criteria for evaluating the native vegetation and biodiversity content of accredited regional NRM plans for Queensland's rangelands. The evaluation showed considerable variation in the comprehensiveness of the information and knowledge base and management action targets among plans, including the poor articulation of impacts of excessive grazing pressure on biodiversity. The NRM plans lacked effective integration of natural resource, native vegetation and biodiversity conservation targets and actions. Several regions had too many biodiversity targets, many of which were poorly integrated. This is symptomatic of a limited understanding of rangelands as ecological systems and the lack of an integrated planning framework. We conclude regional NRM planning is not a ,silver bullet' for biodiversity conservation in the rangelands, but rather, it is the beginning of a long road to address complex, multi-scale problems at a regional level. [source] Understanding Dryland Landscape Dynamics: Do Biological Crusts Hold the Key?GEOGRAPHY COMPASS (ELECTRONIC), Issue 3 2008Heather A. Viles Understanding landscape dynamics in arid and semi-arid areas is becoming increasingly important, as global change threatens to upset linked ecological and geomorphological systems with potentially serous impacts on livelihoods and environments. Biological crusts (composed of lichens, algae, fungi and bacteria) cover many rock, soil and sediment surfaces in arid and semi-arid areas and provide a key to understanding future dryland landscape dynamics. Such crusts have been found to play a number of key geomorphic and ecological roles, and are identified as important ecosystem engineers and biogeomorphological agents that could be used in environmental restoration. However, they have also been reported to be highly fragile and susceptible to disturbance, and damage to them may result in non-linear consequences for linked dryland geomorphological and ecological systems. This paper outlines the current state of knowledge on biological crusts in arid and semi-arid areas and calls for increased collaboration between geomorphologists and ecologists and better links between studies of biological crusts on rock and soil surfaces. [source] Exploitation and habitat degradation as agents of change within coral reef fish communitiesGLOBAL CHANGE BIOLOGY, Issue 12 2008S. K. WILSON Abstract Over-exploitation and habitat degradation are the two major drivers of global environmental change and are responsible for local extinctions and declining ecosystem services. Here we compare the top-down effect of exploitation by fishing with the bottom-up influence of habitat loss on fish communities in the most diverse of ecological systems, coral reefs. Using a combination of multivariate techniques and path analyses, we illustrate that the relative importance of coral cover and fishing in controlling fish abundance on remote Fijian reefs varies between species and functional groups. A decline in branching Acropora coral is strongly associated with a decline in abundance of coral-feeding species, and a decrease in coral-associated habitat complexity, which has indirectly contributed to reduced abundance of small-bodied damselfish. In contrast, reduced fishing pressure, brought about by declining human populations and a shift to alternate livelihoods, is associated with increased abundance of some piscivores and fisheries target species. However, availability of prey is controlled by coral-associated habitat complexity and appears to be a more important driver of total piscivore abundance compared with fishing pressure. Effects of both fishing and coral loss are stronger on individual species than functional groups, as variation in the relative importance of fishing or coral loss among species within the same functional group attenuated the impact of either of these potential drivers at the functional level. Overall, fishing continues to have an influence on Fijian fish communities; however, habitat loss is currently the overriding agent of change. The importance of coral loss mediated by climate change is expected to have an increasing contribution to fish community dynamics, particularly in remote locations or where the influence of fishing is waning. [source] Anthropogenic and climatic impacts on surface pollen assemblages along a precipitation gradient in north-eastern ChinaGLOBAL ECOLOGY, Issue 5 2010Yun Zhang ABSTRACT Aim, To understand the scenarios of ,anthropogenic biomes' that integrate human and ecological systems, we need to explore the impacts of climate and human disturbance on vegetation in the past and present. Interactions among surface pollen, modern vegetation and human activities along climate and land-use gradients are tested to evaluate the natural and anthropogenic forces shaping the modern vegetation, and hence to aid the reconstruction of vegetation and climate in the past. This in turn will help with future predictions. Location, The North-east China Transect (NECT) in north-eastern China. Methods, We analysed 33 surface pollen samples and 213 quadrats across four vegetation zones along the moisture/land-use gradients of the NECT. Detrended correspondence analysis (DCA) and redundancy analysis (RDA) of 52 pollen taxa and three environmental variables were used to distinguish anthropogenic and climatic factors that affect surface pollen assemblages along the NECT. Results, The 33 surface samples are divided into four pollen zones (forest, meadow steppe, typical steppe and desert steppe) corresponding to major vegetation types in the NECT. Variations in pollen ratios of fern/herb (F/H), Artemisia/Chenopodiaceae (A/C) and arboreal pollen/non-arboreal pollen (AP/NAP) represent the vegetation and precipitation gradient along the NECT. DCA and RDA analyses suggest that surface pollen assemblages are significantly influenced by the precipitation gradient. Changes in the abundance of Chenopodiaceae pollen are related to both human activities and precipitation. Main conclusions, Surface pollen assemblages, fossil pollen records, archaeological evidence and historical documents in northern China show that a large increase of Chenopodiaceae pollen indicates human-caused vegetation degradation in sandy habitats. The A/C ratio is a good indicator of climatic aridity, but should be used in conjunction with multiple proxies of human activities and climate change in the pollen-based reconstruction of anthropogenic biomes. [source] Short-term transformation of matrix into hospitable habitat facilitates gene flow and mitigates fragmentationJOURNAL OF ANIMAL ECOLOGY, Issue 6 2007NIELS BLAUM Summary 1Habitat fragmentation has major implications for demography and genetic structure of natural plant and animal populations as small and isolated populations are more prone to extinction. Therefore, many recent studies focus on spatial fragmentation. 2However, the temporal configuration of suitable habitat may also influence dispersal and gene flow in fragmented landscapes. We hypothesize that short-term switching of inhospitable matrix areas into suitable habitat can mitigate effects of spatial fragmentation in natural and seminatural ecosystems. 3To test our hypothesis, we investigated the hairy-footed gerbil (Gerbillurus paeba, Smith 1836), a ground-dwelling rodent, in fragmented Kalahari savannah areas. Here, rare events of high above mean annual rainfall suggest short-term matrix suitability. 4During the field survey in ,matrix' areas in the Kalahari (shrub encroachment by heavy grazing) we never observed the hairy-footed gerbil in years of average rainfall, but observed mass occurrences of this species during rare events of exceptionally high rainfall. 5In a second step, we developed an agent-based model simulating subpopulations in two neighbouring habitats and the separating matrix. Our mechanistic model reproduces the mass occurrences as observed in the field and thus suggests the possibly underlying processes. In particular, the temporary improvement in matrix quality allows reproduction in the matrix, thereby causing a substantial increase in population size. 6The model demonstrates further how the environmental trigger (rainfall) impacts genetic connectivity of two separated subpopulations. We identified seasonality as a driver of fragmentation but stochasticity leading to higher connectivity. 7We found that our concept of temporal fragmentation can be applied to numerous other fragmented populations in various ecological systems and provide examples from recent literature. We conclude that temporal aspects of fragmentation must be considered in both ecological research and conservation management. [source] Priority research areas for ecosystem services in a changing worldJOURNAL OF APPLIED ECOLOGY, Issue 6 2009Emily Nicholson Summary 1.,Ecosystem services are the benefits humans obtain from ecosystems. The importance of research into ecosystem services has been widely recognized, and rapid progress is being made. However, the prevailing approach to quantifying ecosystem services is still based on static analyses and single services, ignoring system dynamics, uncertainty and feedbacks. This is not only partly due to a lack of mechanistic understanding of processes and a dearth of empirical data, but also due to a failure to engage fully with the interdisciplinarity of the problem. 2.,We argue that there is a tendency to ignore the feedbacks between and within both social and ecological systems, and a lack of explicit consideration of uncertainty. Metrics need to be developed that can predict thresholds, which requires strong linkages to underlying processes, while the development of policy for management of ecosystem services needs to be based on a broader understanding of value and drivers of human well-being. 3.,We highlight the complexities, gaps in current knowledge and research, and the potentially promising avenues for future investigation in four priority research areas: agendas, processes, metrics and uncertainty. 4.,Synthesis and applications. The research interest in the field of ecosystem services is rapidly expanding, and can contribute significantly to the sustainable management of natural resources. However, a narrow disciplinary approach, or an approach which does not consider feedbacks within and between ecological and social systems, has the potential to produce dangerously misleading policy recommendations. In contrast, if we explicitly acknowledge and address uncertainties and complexities in the provision of ecosystem services, progress may appear slower but our models will be substantially more robust and informative about the effects of environmental change. [source] Testing the use of interviews as a tool for monitoring trends in the harvesting of wild speciesJOURNAL OF APPLIED ECOLOGY, Issue 4 2008Julia P. G. Jones Summary 1Many aspects of human behaviour impact on ecological systems. Ecologists therefore need information on changes in these behaviours and are increasingly using methods more familiar to social scientists. 2Understanding patterns of wildlife harvesting is important for assessing the sustainability of harvests. Interviews are commonly used in which informants are asked to summarize their activities over a period of time. However, few studies have investigated the reliability of such data, the usefulness of interviews for monitoring trends, and how their information content can be maximized. 3We carried out rapid assessment interviews with villagers in Madagascar about the quantity, timing and spatial patterns of crayfish Astacoides granulimanus and firewood collection. We compared the results with information from daily interviews with the same informants. We used mixed models to investigate how accurately people reported their activities in the rapid assessment interviews, and estimated the probability of detecting a change in harvesting from two such interviews using a Bayesian approach. 4The interviews provided reliable information on quantities, effort, and the spatial pattern of harvesting. Simulations suggested the interviews would detect changes in catches and harvesting effort with reasonable power; for example, a 20% change in the amount of time spent crayfish harvesting could be detected with 90% power. Power is higher when the same informants are questioned in repeat interviews. 5Synthesis and applications. Ecologists are increasingly using social techniques and it is vital that they are subject to rigorous testing to ensure robustness in trend detection. This study suggests that interviews can be used to monitor changes in harvesting patterns by resource users, but whether the power is adequate will depend on the needs of the study. To maximize the power of interviews, informants should be interviewed independently and the same informants interviewed in subsequent years. [source] Large-scale processes in ecology and hydrologyJOURNAL OF APPLIED ECOLOGY, Issue 2000R.W.G. Caldow 1. Several papers published in the 1980s stressed the importance of scaling issues, the inter-relatedness of patterns and processes at different scales of time and space, to our understanding of ecological systems. Scaling issues are of major theoretical interest and increasingly are of considerable applied importance. 2. In recognition of this, the Natural Environment Research Council, in partnership with the Scottish Executive Rural Affairs Department, funded a Thematic Programme entitled ,Large-scale Processes in Ecology and Hydrology'. The principal aim of this Programme was to integrate recent major developments in information resources and technologies with current theory in order to improve understanding of large-scale patterns and processes and their relationship to patterns and processes at smaller scales. 3. The Thematic Programme, which ran from 1995 until 1999, funded six research projects that have generated a large body of published papers. This volume, dedicated to the findings of the Programme, brings together outputs from all six projects with the aim of ensuring a rapid and widespread dissemination of the Programme's findings. A brief résumé of each of the papers is presented. 4. The papers in this volume cover a wide variety of subjects ranging from ions to the flora and fauna of the United Kingdom. Nonetheless, each study has sought in various ways to quantify observed spatio-temporal patterns at a range of scales, to determine whether those patterns are consistent across scales and to identify the interactions between small-scale patterns and processes and those at larger scales. The importance of the spatial and temporal scales at which studies are conducted, the key role played by dispersal in spatial population dynamics, and the diversity of ways in which large-scale patterns and processes relate to those at smaller scales are highlighted in many of the papers. 4. All of the papers presented here have direct relevance to applied issues. These issues are diverse and include the control of invasive alien species, the conservation of declining, threatened or endangered species, the development of survey techniques, strategies for farmland, woodland and forestry management, and the assessment of pollution sensitivity. Thus, the Thematic Programme has addressed issues of considerable theoretical interest and has at the same time generated results and predictive models that are of considerable practical and policy relevance. [source] Facilitation in the conceptual melting potJOURNAL OF ECOLOGY, Issue 6 2009Rob W. Brooker Summary 1. Here we present an introduction to this issue's Special Feature arising from the British Ecological Society Symposium: Facilitation in Plant Communities (20,22 April 2009). 2. Papers in the Special Feature demonstrate the benefits that arise from cross-system application of general concepts, for example, the well-known stress gradient hypothesis. Such comparisons challenge our definition of facilitation, as well as our pre-conceptions on the nature of intermediary organisms. 3. We suggest that under some circumstances a clear definition of the two-way nature of interactions is essential, e.g. when considering the evolutionary implications of facilitation. In other cases, however, we can perhaps be more relaxed, e.g. when facilitation is a component of conservation ecology. 4.Synthesis. Overall we believe that establishing facilitation as an independent concept has driven substantial progress towards a clearer understanding of how ecological systems work. Through the links established by work such as that presented in this Special Feature, we believe this field will continue to make rapid progress and aid ecological understanding in general. [source] Ecosystem science and human,environment interactions in the Hawaiian archipelagoJOURNAL OF ECOLOGY, Issue 3 2006PETER VITOUSEK Summary 1Tansley's ecosystem concept remains a vital framework for ecological research in part because the approach facilitates interdisciplinary analyses of ecological systems. 2Features of the Hawaiian Islands , particularly the nearly orthogonal variation in many of the factors that control variation among ecosystems elsewhere , make the archipelago a useful model system for interdisciplinary research designed to understand fundamental controls on the state and dynamics of ecosystems, and their consequences for human societies. 3Analyses of rain forest sites arrayed on a substrate age gradient from c. 300 years to over 4 million years across the Hawaiian archipelago demonstrate that the sources of calcium and other essential cations shift from > 80% rock-derived in young sites to > 80% derived from marine aerosol on substrates older than 100 000 years. Rock-derived phosphorus is retained longer within ecosystems, but eventually long-distance transport of continental dust from Asia becomes the most important source of phosphorus. 4A biogeochemical feedback from low nutrient availability to efficient resource use by trees to slow decomposition and nutrient regeneration accentuates the geochemically driven pattern of low phosphorus availability and phosphorus limitation to net primary productivity in the oldest site. 5Variations in ecosystem biogeochemistry across the archipelago shaped the development and sustainability of Polynesian agricultural systems in the millennium between their discovery of Hawai'i and contact by Europeans. Irrigated pondfields were largely confined to stream valleys on the older islands, while rain-fed dryland systems occupied a narrow zone of fertile, well-watered soils on the younger islands. 6The ecosystem approach often represents the most appropriate level of organization for analyses of human influences on ecological systems; it can play a central role in the design and analysis of alternative agricultural, industrial and residential systems that could reduce the human footprint on the Earth. [source] Experimentally testing the role of foundation species in forests: the Harvard Forest Hemlock Removal ExperimentMETHODS IN ECOLOGY AND EVOLUTION, Issue 2 2010Aaron M. Ellison Summary 1.,Problem statement, Foundation species define and structure ecological systems. In forests around the world, foundation tree species are declining due to overexploitation, pests and pathogens. Eastern hemlock (Tsuga canadensis), a foundation tree species in eastern North America, is threatened by an exotic insect, the hemlock woolly adelgid (Adelges tsugae). The loss of hemlock is hypothesized to result in dramatic changes in assemblages of associated species with cascading impacts on food webs and fluxes of energy and nutrients. We describe the setting, design and analytical framework of the Harvard Forest Hemlock Removal Experiment (HF-HeRE), a multi-hectare, long-term experiment that overcomes many of the major logistical and analytical challenges of studying system-wide consequences of foundation species loss. 2.,Study design, HF-HeRE is a replicated and blocked Before-After-Control-Impact experiment that includes two hemlock removal treatments: girdling all hemlocks to simulate death by adelgid and logging all hemlocks >20 cm diameter and other merchantable trees to simulate pre-emptive salvage operations. These treatments are paired with two control treatments: hemlock controls that are beginning to be infested in 2010 by the adelgid and hardwood controls that represent future conditions of most hemlock stands in eastern North America. 3.,Ongoing measurements and monitoring, Ongoing long-term measurements to quantify the magnitude and direction of forest ecosystem change as hemlock declines include: air and soil temperature, light availability, leaf area and canopy closure; changes in species composition and abundance of the soil seed-bank, understorey vegetation, and soil-dwelling invertebrates; dynamics of coarse woody debris; soil nitrogen availability and net nitrogen mineralization; and soil carbon flux. Short-term or one-time-only measurements include initial tree ages, hemlock-decomposing fungi, wood-boring beetles and throughfall chemistry. Additional within-plot, replicated experiments include effects of ants and litter-dwelling microarthoropods on ecosystem functioning, and responses of salamanders to canopy change. 4.,Future directions and collaborations, HF-HeRE is part of an evolving network of retrospective studies, natural experiments, large manipulations and modelling efforts focused on identifying and understanding the role of single foundation species on ecological processes and dynamics. We invite colleagues from around the world who are interested in exploring complementary questions to take advantage of the HF-HeRE research infrastructure. [source] Using limiting factors analysis to overcome the problem of long time horizonsNEW DIRECTIONS FOR EVALUATION, Issue 122 2009Raymond Gullison In recent years, donors to biodiversity conservation projects have sought greater accountability, using professional evaluators to help assess the degree to which grantees are achieving conservation objectives. One of the most formidable challenges evaluators face is the time required both for ecological systems to respond to management interventions and over which grantees must maintain their biodiversity conservation gains. The authors present a simple methodology, called limiting factors analysis, which was developed during the course of evaluating several large portfolios of conservation projects. The method is a practical basis for rapidly assessing whether current conditions are likely to prevent grantees from achieving their long-term objectives. Use of the methodology is illustrated with examples from recent evaluations of the Andes Amazon Initiative and the Columbia Basin Water Transactions Program. © Wiley Periodicals, Inc. [source] Ngongas and ecology: on having a worldviewOIKOS, Issue 1 2001Joel S. Brown Ngongas provide a metaphor for some of the opportunities and challenges facing the science of ecology and evolution. Ngongas, the traditional healers of the Shona culture, Zimbabwe, fail in the delivery of quality health by today's standards. Their outdated worldview makes most health related issues seem more complicated and more multi-factorial than when viewed through the worldviews of modern medicine. With the wrong worldview, one can work very hard, be very bright and dedicated, and still be ineffective. With the right worldview, one can work much less hard and still be extremely effective. As ecologists, we should be opinionated and possess clearly articulated worldviews for filtering and interpreting information. As ecologists we are also a bit like ngongas , we often fail to provide answers for society's ecological questions and problems, and we excuse ourselves with a belief that ecological systems are too complex and have too many factors. Unlike ngongas, this invites us to pay a lot of attention to promoting and assessing competing worldviews. We should be open-minded to the anomalies in our worldview and the successes of alternative viewpoints. As an admitted ecological ngonga, I discuss the worldview I use in my own research: the Optimization Research Program, a Darwinian research program that uses game theory to conceptualize and understand ecological systems. I use it illustrate how worldviews can synthesize disparate ideas. (I use kin selection and reciprocal altruism as examples.) I use it to show how new ideas and predictions can be generated. (I use root competition in plants and the possibility that increased crop yield may be forthcoming from knowledge of this game.) [source] The method of synthesis in ecologyOIKOS, Issue 1 2001E. David Ford Synthesis of results from different investigations is an important activity for ecologists but when compared with analysis the method of synthesis has received little attention. Ecologists usually proceed intuitively and this can lead to a problem in defining differences between the syntheses made by different scientists. It also leads to criticism from scientists favoring analytical approaches that the construction of general theory is an activity that does not follow the scientific method. We outline a methodology for scientific inference about integrative concepts and the syntheses made in constructing them and illustrate how this can be applied in the development of general theory from investigations into particular ecological systems. The objective is to construct a causal scientific explanation. This has four characteristics. (1) It defines causal and/or organizational processes that describe how systems function. (2) These processes are consistent , under the same conditions they will produce the same effect. (3) A causal scientific explanation provides general information about events of a similar kind. (4) When experiments are possible then a designed manipulation will produce a predictable response. The essential characteristic of making synthesis to construct a causal scientific explanation is that it is progressive and we judge progress made by assessing the coherence of the explanation using six criteria: acceptability of individual propositions including that they have been tested with data, consistency of concept definitions, consistency in the type of concepts used in making the explanation, that ad hoc propositions are not used, that there is economy in the number of propositions used, that the explanation applies to broad questions. We illustrate development of a causal scientific explanation for the concept of long-lived pioneer tree species, show how the coherence of this explanation can be assessed, and how it could be improved. [source] | ||||||||||||||||||||||||||||||||||||||||