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PubMed2002

[Calculation method of ecological water requirement for forestland and its application to Huang-Huai-Hai region].

The evapotranspiration and soil moisture content of forestland were studied in relation to free growth. It was found that when the soil moisture content was about 45-100% of field capacity and the actual evapotranspiration came up to 60-100% of potential evapotranspiration, the growth of trees could be sustained. On the basis of our research, the grading standard and calculation method of ecological water requirement of forestland were established. Moreover, the ecological water requirement for forestland in Huang-Huai-Hai are was estimated by GIS technology, and its ecological water shortage was compared to its current water consumption. The results indicated of that the annual ecological water requirement of forestland in Huang-Huai-Hai region was 25.6-45.8 billion m3, and its current water consumption was approximately 2.8 billion m3 below the minimum of ecological water requirement, and 8.4 billion m3 below the optimal ecological water requirement.

China↗
PubMed2003

[Preliminary study on ecological footprint in Bashang region of Zhangjiakou city].

The ecological footprint and ecological carrying capacity in Bashang region of Zhangjiakou city were calculated with the statistical data of the region in 1999. Based on calculation, the balance between ecological footprint and ecological carrying capacity was analyzed, and the threshold values of the ecological carrying capacity and population capacity of the region at the current production level were determined. Strategies on reducing ecological deficit in this region were also brought forward.

China↗
PubMed2004

[Sensitivity analysis in ecological modeling].

Sensitivity analysis is used to qualitatively or quantitatively apportion the variation of model output to different source of variation. It is a very useful tool in model parameterization and calibration, and has important ecological significance by identifying the governing factors for a certain ecological process simulated. There are two schools of sensitivity analysis, local sensitivity analysis and global sensitivity analysis. The former examines the local response of the output(s) by varying input parameters one at a time, holding other parameters to a central value; and the latter examines the global response (averaged over the variation of all the parameters) of model output(s) by exploring a finite (or even an infinite) region. Since it is very easy to conduct local sensitivity analysis, it is very popular in ecological models. However, local sensitivity analysis is not computationally effective, because it can only get the sensitivity of a single parameter at a time. It can not take into consideration the effect of interaction of different parameters. Additionally, the value of other parameters will affect the sensitivity of the parameter specified. In view of this, global sensitivity analysis is increasingly preferred to local sensitivity in recent years. However, for most of the ecological modeling study published in Chinese, only local sensitivity analysis is conducted. To provide a toolbox of alternative sensitivity analysis algorithms for ecological model development in future study, we reviewed the main methods of both local sensitivity analysis and global sensitivity analysis, including one at a time method, multivariate regression, Morris' method, Sobol's method, Fourier Amplitude Sensitivity Analysis, and Extended Fourier Amplitude Sensitivity Analysis. Based on the state-of-the-art research on sensitivity analysis, the sensitivity of the interaction between two or more than two model parameters, the sensitivity of common model parameters in a set of models, and the sensitivity analysis in spatially explicit landscape model simulation were identified as the key areas and difficulties of future study on sensitivity analysis in ecological modeling.

Ecology↗
PubMed2004

[A review on disturbance ecology of forest].

More than 80% of terrestrial ecosystems have been influenced by natural disasters, human activities and the combination of both natural and human disturbances. Forest ecosystem, as one of the most important terrestrial ecosystems, has also been disturbed without exception. Under the disturbance from natural disasters and human activities, particularly from the unreasonable activities of human beings, forest decline or forest degradation has become more and more severe. For this reason, sustaining or recovering forest service functions is one of the current purposes for managing forest ecosystems. In recent decades, the studies on disturbed ecosystems have been carried out frequently, especially on their ecological processes and their responses to the disturbances. These studies play a very important role in the projects of natural forest conservation and the construction of ecological environment in China. Based on a wide range of literatures collection on forest disturbance research, this paper discussed the fundamental concepts of disturbance ecology, the relationships between forest management and disturbance, and the study contents of forest disturbance ecology. The major research topics of forest disturbance ecology may include: 1) the basic characteristics of disturbed forests; 2) the processes of natural and human disturbances; 3) the responses of forests ecosystem to the disturbances; 4) the main ecological processes or the consequential results of disturbed forests, including the change of biodiversity, soil nutrient and water cycle, eco-physiology and carbon cycle, regeneration mechanism of disturbed forests and so on; 5) the relationships between disturbances and forest management; and 6) the principles and techniques for the management of disturbed forests. This review may be helpful to the management of disturbed forest ecosystem, and to the projects of natural forest conservation in China.

Disasters↗
PubMed2006

Population-scale assessment endpoints in ecological risk assessment. Part 1: Reflections of stakeholder values.

The selection of appropriate assessment endpoints is a basic element of an ecological risk assessment, especially at regional or watershed scales. Because ecological services often are tied to specific species, the risk to populations is a critical endpoint and feature of ecological risk assessments. The first item is a discussion of the replacement of population-level risk assessment with the construct of a population-scale assessment endpoint. Next, the criteria that are currently used for assessment endpoints are reviewed and evaluated for utility in an ecological risk assessment. Following this examination, assessment endpoints from a number of regional-scale ecological risk assessments are compared. The outcome of this evaluation is that population-scale assessment endpoints are important expressions of the valued components of ecological structures. Finally, a few recommendations for the selection of assessment endpoints at a population scale are listed.

Animals↗
PubMed1983

Spread of organisms with novel genotypes: thoughts from an ecological perspective.

One category of objection to the release of organisms produced by genetic engineering is based on the fear that such organisms may persist in the environment and damage existing ecosystems. An assessment of environmental risk thus involves an ecological question analogous to the introduction of exotic species which has been known to produce serious ecological disruptions. An investigation of the literature on exotic introductions reveals, however, that foreign species do not invariably produce adverse changes. Ecologists believe that only a fraction of immigrating species actually produces ecological dislocation while the majority probably fail to penetrate existing biotic assemblages. Stressed or simplified environments are, however, more vulnerable to successful invasion. Unfortunately, because very little information has ever been collected to document the number or causes of failed introductions, it is impossible to quantify the probability that any introduced species will or will not cause serious disturbance purely on the basis of historical evidence. The development and spread of genotypes that confer resistance to chemical control agents in insects and microorganisms is also analogous to genetic engineering in that human activity contributes to the spread of new genotypes. In both groups of organisms, resistant genotypes can come to predominate in even geographically widespread populations with great rapidity. Resistance to pesticides in insects is usually found to be determined by single genes. In bacteria, antibiotic resistance genes are usually, if not always, associated with the extrachromosomal genetic elements known as plasmids. Bacteria seem to be able to transmit plasmid-borne genes between species and genera with facility. The ease with which new genes can be inserted into bacteria via plasmid vectors in recombinant technology is thus a two-edged sword. It may be very difficult to keep inserted genes isolated in single bacterial strains. The evaluation of the literature on which this report is based suggests that an ecological approach for risk assessment is appropriate. Microorganisms, for which genetic engineering is of most immediate importance, exhibit the same ecological properties as higher organisms. The proportion of an organism's genome which is novel has no direct correlation with the magnitude of impact such a change may have in economic, medical, or ecological terms. Meaningful probabilities for persistence of engineered organisms in the environment will have to be generated by experiment, probably with model microbial ecosystems.

Animal Population Groups↗
PubMed1995

[Ecological hygiene--a science of global health].

The paper defines ecological hygiene, a science that combines a preventive trend and comprehensive ecological analysis of man-made changes occurring in the biosphere. Ecological hygiene may be regarded as a science of global human health in relation to ecological situations, of modes of its maintenance, promotion, and improvement. As for its application, ecological hygiene may be determined as a complex of medical preventive research subjects whose purpose is to maintain and promote health by preventing diseases and premature aging. To apply this approach, ecological hygiene studies the environment and its influence on the human body, reveals unfavourable environmental factors and defines the maximum acceptable levels of their influence, works out recommendation how to eliminate unfavourable factors and how to rationally apply useful ones.

Ecology↗
PubMed2000

Ecological constraints, life history traits and the evolution of cooperative breeding.

The ecological constraints hypothesis is widely accepted as an explanation for the evolution of delayed dispersal in cooperatively breeding birds. Intraspecific studies offer the strongest support. Observational studies have demonstrated a positive association between the severity of ecological constraints and the prevalence of cooperation, and experimental studies in which constraints on independent breeding were relaxed resulted in helpers moving to adopt the vacant breeding opportunities. However, this hypothesis has proved less successful in explaining why cooperative breeding has evolved in some species or lineages but not in others. Comparative studies have failed to identify ecological factors that differ consistently between cooperative and noncooperative species. The life history hypothesis, which emphasizes the role of life history traits in the evolution of cooperative breeding, offers a solution to this difficulty. A recent analysis showed that low adult mortality and low dispersal predisposed certain lineages to show cooperative behaviour, given the right ecological conditions. This represents an important advance, not least by offering an explanation for the patchy phylogenetic distribution of cooperative breeding. We discuss the complementary nature of these two hypotheses and suggest that rather than regarding life history traits as predisposing and ecological factors as facilitating cooperation, they are more likely to act in concert. While acknowledging that different cooperative systems may be a consequence of different selective pressures, we suggest that to identify the key differences between cooperative and noncooperative species, a broad constraints hypothesis that incorporates ecological and life history traits in a single measure of 'turnover of breeding opportunities' may provide the most promising avenue for future comparative studies. Copyright 2000 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed2001

Developing a spatial framework of common ecological regions for the conterminous United States.

In 1996, nine federal agencies with mandates to inventory and manage the nation's land, water, and biological resources signed a memorandum of understanding entitled "Developing a Spatial Framework of Ecological Units of The United States." This spatial framework is the basis for interagency coordination and collaboration in the development of ecosystem management strategies. One of the objectives in this memorandum is the development of a map of common ecological regions for the conterminous United States. The regions defined in the spatial framework will be areas within which biotic, abiotic, terrestrial, and aquatic capacities and potentials are similar. The agencies agreed to begin by exploring areas of agreement and disagreement in three federal natural-resource spatial frameworks--Major Land Resource Areas of the US Department of Agriculture (USDA) Natural Resources Conservation Service, National Hierarchy of Ecological Units of the USDA Forest Service, and Level III Ecoregions of the US Environmental Protection Agency. The explicit intention is that the framework will foster an ecological understanding of the landscape, rather than an understanding based on a single resource, single discipline, or single agency perspective. This paper describes the origin, capabilities, and limitations of three major federal agency frameworks and suggests why a common ecological framework is desirable. The scientific and programmatic benefits of common ecological regions are described, and a proposed process for development of the common framework is presented.

Conservation of Natural Resources↗
PubMed1997

SPECIAL SECTION: Perspectives of the Scientific Community on the Status of Ecological Risk Assessment

/ Views from a wide variety of practicing environmental professionals on the current status of ecological risk assessment (ERA) indicate consensus and divergence of opinion on the utility and practice of risk assessment. Central to the debate were the issues of whether ERA appropriately incorporates ecological and scientific principle into its conceptual paradigm. Advocates argue that ERA effectively does both, noting that much of the fault detractors find with the process has more to do with its practice than its purpose. Critics argue that failure to validate ERA predictions and the tendency to over-simplify ecological principles compromise the integrity of ERA and may lead to misleading advice on the appropriate responses to environmental problems. All authors felt that many improvements could be made, including validation, better definition of the ecological questions and boundaries of ERA, improved harmonization of selected methods, and improvements in the knowledge base. Despite identified deficiencies, most authors felt that ERA was a useful process undergoing evolutionary changes that will inevitably determine the range of environmental problems to which it can be appropriately applied. The views expressed give ERA a cautious vote of approval and highlight many of the critical strengths and weaknesses in one of our most important environmental assessment tools.KEY WORDS: Ecological risk assessment; Ecology; Probability

Journal Article↗
PubMed2005

Ecological risk assessment for aquatic species exposed to contaminants in Keelung River, Taiwan.

An ecological risk assessment was conducted for Keelung River in northern Taiwan. The objective of this study was to assess the risk to fish, aquatic insects, and benthic macroinvertebrates associated with chemical-of-potential-concern (COPC) in the river and to rank ecological risk for these chemicals. The protection of at least 95% of the species 90% of the time from acute and chronic COPC exposures was the defined assessment endpoint. Nine inorganic and organic contaminants were selected to evaluate the impact to aquatic community in the Keelung River. The quotient method served as screen level estimation of risk. The Aquatic Ecological Risk Assessment model was used to analyze exposure and ecological effects and to estimate community level risk. The logarithmic regression model between probability and lethal concentration was established. The combined risks of multiple chemicals were evaluated under assumption of additive risk. The results indicated that zinc and copper pose higher risk among metals. Ammonia, copper, and zinc posed virtually all of the risk, while organic COPCs posed a negligible risk. Potential ecological risk from ammonia exposure was greatest. The probability of more than 5% of the species being affected by acute or chronic toxicity of COPCs is about 100%. In average (50% of the time), 99% of the species would be affected by acute toxicity of COPCs, and about all the species would be affected by chronic toxicity of COPCs. Uncertainties in this assessment were associated with variability in ecosystem stressors, exposure data, ecological effect data, and risk characterization.

Ammonia↗
PubMed2006

An ecologically based examination of barriers to physical activity in students from grade seven through first-year university.

PURPOSE: The first purpose was to identify barriers to physical activity that students in grade seven through first-year university experienced. A second purpose was to classify barriers using an ecological framework and to examine the pattern of barrier categories (i.e., intrapersonal, interpersonal, institutional, community, public policy, and physical environmental) and specific barrier types as grade increased. The use of an ecological model addressed limitations in prior research revolving around the identification of salient barriers in a manner that makes the design of effective interventions difficult. METHODS: Participants in grades 7-8 (n = 35), 9-10 (n = 67), 11-12 (n = 80), and the freshmen year of university (n = 109) listed barriers to physical activity on an open-ended measure. RESULTS: Findings revealed a trend for the average number of barriers reported per student to increase as grade in school increased. First-year university students reported significantly more barriers than all other grade groupings. The frequency of barriers reported within the ecological categories was dependent on the specific grade groupings. Further, within each ecological category, distinct barriers were reported across the different grade groupings. CONCLUSIONS: Findings highlight the utility of using an ecological model to categorize barriers, rather than simply classifying barriers as internal or external to an individual, as done in prior research. Understanding the pattern of ecologically based barrier categories and specific types of barriers will help to inform the content of future research and interventions designed to alleviate salient barriers to physical activity.

Adolescent↗
PubMed2004

Transients: the key to long-term ecological understanding?

Ecological theory has been dominated by a focus on long-term or asymptotic behavior as a way to understand natural systems. Yet experiments are done on much shorter timescales, and the relevant timescales for ecological systems can also be relatively short. Thus, there is a mismatch between the timescales of most experiments and the timescales of many theoretical investigations. However, recent work has emphasized the importance of transient dynamics rather than long-term behavior in ecological systems, enabling the examination of forces that allow coexistence on ecological timescales. Through an examination of what leads to transients in ecological systems, a deeper appreciation of the forces leading to persistence or coexistence in ecological systems emerges, as well as a general understanding of how population levels can change through time.

Journal Article↗
PubMed2003

Lutzomyia vectors for cutaneous leishmaniasis in Southern Brazil: ecological niche models, predicted geographic distributions, and climate change effects.

Geographic and ecological distributions of three Lutzomyia sand flies that are cutaneous leishmaniasis vectors in South America were analysed using ecological niche modelling. This new tool provides a large-scale perspective on species' geographic distributions, ecological and historical factors determining them, and their potential for change with expected environmental changes. As a first step, the ability of this technique to predict geographic distributions of the three species was tested statistically using two subsampling techniques: a random-selection technique that simulates 50% data density, and a quadrant-based technique that challenges the method to predict into broad unsampled regions. Predictivity under both test schemes was highly statistically significant. Visualisation of ecological niches provided insights into the ecological basis for distributional differences among species. Projections of potential geographic distributions across scenarios of global climate change suggested that only Lutzomyia whitmani is likely to be experiencing dramatic improvements in conditions in south-eastern Brazil, where cutaneous leishmaniasis appears to be re-emerging; Lutzomyia intermedia and Lutzomyia migonei may be seeing more subtle improvements in climatic conditions, but the implications are not straightforward. More generally, this technique offers the possibility of new views into the distributional ecology of disease, vector, and reservoir species.

Algorithms↗
PubMed1999

Ergonomic evaluation of an ecological interface and a profilogram display for hemodynamic monitoring.

OBJECTIVE: Comprehensive monitoring of the patient state and subsequent decision making is an essential part of the task of an anaesthetist. The physicians' decision making process is based upon a concept of partly abstract physiologic parameters such as depth of anaesthesia or contractility. This concept is derived from the measured parameters given on todays' trend displays in addition to context information available for the anaesthetist. We investigated two alternative approaches of display design for hemodynamic monitoring: 1) integrated displays based on ecological interface design, and 2) profilogram displays based on intelligent alarms. METHOD: To evaluate differences in decision making, the two displays and a trend display were compared in an experimental set-up with computer simulated vital parameter curves. From a start state with random parameter deviations from the ideal state, subjects had to achieve the ideal circulatory performance as fast as possible by manipulating vasomotor tone, heart rate, blood volume and contractility. To analyse subjects' decision making process, eye-tracking, event-logging, and the method of think aloud protocols were used. Twenty anaesthesiologists performed 113 experiments (approximately 2 with each display). RESULTS: The anaesthetists failed to achieve the task in 37% using the trend display, in 19% using the profilogram display, and in 13% using the ecological interface. Hence, a safer task solution was possible with the ecological interface and the profilogram display but at the expense of various performance parameters such as higher trial time, more interactions with the simulated system, and more frequent eye movements. In contrast to the trend display and the profilogram display, where anaesthetists were mainly focussed on controlling the left atrial pressure, such an behaviour was less observed with the ecological interface. CONCLUSION: Our results have shown that subjects came to more effective solutions with the traditional trend display. The main reason for this result may be their years of experience with this kind of display type. Regarding safe and goal-intended decision finding, the results are encouraging for further experiments with redesigned ecological displays. But these displays ought to have smoother changes with respect to the traditional trend displays. Furthermore, new experiments have to be performed under real or fairly real (e.g. together with an anaesthesia simulator) conditions to underline the positive results for ecological interfaces.

Adult↗
PubMed2002

Genetic, ecological, and behavioural divergence between two sibling snapping shrimp species (Crustacea: Decapoda: Alpheus).

Examination of genetic and ecological relationships within sibling species complexes can provide insights into species diversity and speciation processes. Alpheus angulatus and A. armillatus, two snapping shrimp species with overlapping ranges in the north-western Atlantic, are similar in morphology, exploit similar ecological niches and appear to represent recently diverged sibling species. We examined phylogenetic and ecological relationships between these two species with: (i) sequence data from two mitochondrial genes (16S rRNA and COI); (ii) data on potential differences in microhabitat distribution for A. armillatus and A. angulatus; and (iii) data from laboratory experiments on the level of reproductive isolation between the two species. DNA sequence data suggest A. armillatus and A. angulatus are sister species that diverged subsequent to the close of the Isthmus of Panama, and that haplotype diversity is lower in A. armillatus than in A. angulatus. Both species are distantly related to A. heterochaelis and A. estuariensis, two species with which A. angulatus shares some similarities in coloration. Ecological data on the distribution of A. angulatus and A. armillatus from two locations revealed differences in distribution of the two species between habitat patches, with each patch dominated by one or the other species. However, there was no apparent difference in distribution of the two species within habitat patches with respect to microhabitat location. Ecological data also revealed that heterospecific individuals often occur in close proximity (i.e. within metres or centimetres) where sympatric. Behavioural data indicated that these species are reproductively isolated, which is consistent with speciation in transient allopatry followed by post-divergence secondary contact. Our data further resolve taxonomic confusion between the sibling species, A. armillatus and A. angulatus, and suggest that sympatry in areas of range overlap and exploitation of similar ecological niches by these two recently diverged species have selected for high levels of behavioural incompatibility.

Animals↗
PubMed2005

The injury iceberg: an ecological approach to planning sustainable community safety interventions.

ISSUE ADDRESSED: A systematic ecological framework in which to design sustainable, community-based, safety promotion interventions is presented. METHOD: A literature review was undertaken of English-language articles addressing the topics of 'ecological injury prevention or safety promotion', 'ecological health promotion', 'sustainable economic, health or ecological systems' and 'steady state', with 143 articles retrieved and reviewed. RESULTS: Injury prevention is a biomedical construct, in which injury is perceived to be a physical event resulting from the sudden release of environmental energy producing tissue damage in an individual. This reductionist perspective overlooks the importance of psychological and sociological determinants of injury. Safety has physical, psychological and sociological dimensions. It is inherently an ecological concept. Interventions aiming to achieve long-term improvements in community safety must seek to develop sustainable safety promoting characteristics within the target community. CONCLUSION: To reduce a community's risk of injury and sustain this lowered risk, the community 'ecological system' must have access to the resources necessary to maintain the desired outcome and the ability to mobilise these resources.

Accident Prevention↗
PubMed2001

The social ecology of the co-occurrence of substance use and early coitus among poor, urban black female adolescents.

Currently, the profession of social work has proclaimed the need for an empirical research agenda to broaden its knowledge base. The profession's positivists rightly argue that a sound knowledge base is derived from rigorous scientific empirical methods. Unquestionably, the profession's unique contribution to the study of human development has been its emphasis on environmental effects and individual adaptation. Presently, social scientists embrace an ecological perspective when studying how social environmental effects are mediated. As researchers shift to a social ecological perspective, an empirical contextual model will allow the study of racial/ethnic differences in the incidence of adolescent problem behaviors (Stevens, 1998). An examination of the social ecology of poor, urban black female adolescents was undertaken to examine claims of the co-occurrence of early coitus and substance use, behaviors evident in black adolescents. An ecological framework operationalized by the constructs structural strain, kinscriptions, and community bridging is used to explicate how coital behavior among black females may not co-occur with drug use. The article's exegesis is directed by four postulates that help clarify the relationship of social ecology to the linkage of early coital behavior and substance use. The article concludes with adolescent narratives that illumine the cogency of the ecological analysis.

Adolescent↗