Establishing reference conditions for European streams

The European Water Framework Directive stipulates that Member States have to assess the ecological status of a water body by comparing the present to the expected reference condition. In the AQEM project participating countries used the criteria from the Water Framework Directive to select reference sites for each stream type. The purpose of this study was to evaluate the suitability of these criteria and to validate the reference conditions chosen, by comparing the classification of sites before analysis with the final assessment of the sites using the assessment system which was developed within the AQEM project. Our study showed that not all criteria for reference conditions could be met for all stream types. This implies that `true' reference sites could not be selected for all stream types within the AQEM project. In our study, the differences between ecoregions, countries, and stream types were interpreted in terms of human impact. Validation of reference conditions showed differences between classification of sites as reference sites based on criteria to be used in the field and directly interpreting environmental or biological data and the result of the final assessment system. In some countries it was not possible to select reference conditions, because most of the a priori criteria were met. For example, reference conditions for Dutch stream types were established using historical data and predictions based on data from other geographical regions. Using data from adjacent countries appeared to be a feasible method for establishing reference conditions. Reference sites taken from other geographical areas represented a higher ecological quality than the Dutch sites of good ecological quality. However, metric results showed a large overlap between good and high ecological status. Historical information, on the other hand, was not found to be useful in metric calculations because of the confounding differences in sampling methods. One strong advantage of using historical information is that rare species that are locally extinct but still occur in the same stream type in other geographical areas can be added to the expected reference conditions. When and which methods can be used for establishing reference conditions is illustrated in a decision tree.     

Marine angiosperm indices used to assess ecological status within the Water Framework Directive and South African National Water Act: Learning from differences and common issues

This paper reviews and discusses the methods and metrics used for the assessment of the ecological status of marine angiosperms comparing the European with the South African situation. In Europe salt marsh and seagrasses are an important biological element for establishing the ecological quality status of transitional waters and in South Africa changes over time in the salt marsh and submerged macrophyte habitats (species richness, abundance and community composition) is used nationally to assess the health of estuaries. In Europe several studies have developed metrics that include salt marsh species composition and community structure to assess the ecological quality status. Deviation of taxonomic composition and abundance from a reference situation is investigated. Multi-metric approaches have been shown to provide a more holistic view of the ecological status of the ecosystem. Many indices are highly dependent on historical data to assess the deviation from reference conditions. Within the WFD spirit one widely used approach for salt marsh assessment, the Best’s method, the baseline can be determined based on the first sampling effort, by the largest previously recorded size of the salt marsh or using the “maximum potential size” of the salt marsh from habitat prediction models. In South Africa all habitat below the 5 m contour line is considered estuary habitat and any land occupied here by agricultural or other developments is considered as a loss of habitat from the reference condition. For seagrasses European metrics are based on attributes from the community (e.g., taxonomic composition, epiphytes), the population (e.g., bed extent, shoots density), but also quantified at individual species (e.g., leaves length) or physiological levels (e.g., stable isotopic signatures). Seagrass habitats in South African estuaries are highly dynamic in response to floods and an understanding of this is needed before present ecological status can be assessed.     

Ecological assessment of vegetation from a nature reserve using regional reference data and indicator scores

A method is presented for ecological assessment of botanical sample data from a nature reserve network. The approach uses regional floristic survey data for a specific biotope as a context for spatial and temporal comparison. Assessments are based upon floristic similarity to reference vegetation types and indicator scores that summarise multivariate plant species data in relation to important environmental gradients. The approach was implemented as a software tool using floristic survey data for soligenous mires in a UK region. Plant community monitoring data were assessed against reference communities from this regional baseline to illustrate the potential advantages of the method. These include; (a) allowing links to be made between multivariate plant species data and measurements of environmental drivers, (b) providing realistic assessments of spatial and temporal differences because comparisons are against typical values of indicator scores for the region, (c) providing the scope for setting realistic criteria for vegetation monitoring.     

Ecological limitations to the resilience of coral reefs

The decline of coral reefs has been broadly attributed to human stressors being too strong and pervasive, whereas biological processes that may render coral reefs fragile have been sparsely considered. Here we review several ecological factors that can limit the ability of coral reefs to withstand disturbance. These include: (1) Many species lack the adaptive capacity to cope with the unprecedented disturbances they currently face; (2) human disturbances impact vulnerable life history stages, reducing reproductive output and the supply of recruits essential for recovery; (3) reefs can be vulnerable to the loss of few species, as niche specialization or temporal and spatial segregation makes each species unique (i.e., narrow ecological redundancy); in addition, many foundation species have similar sensitivity to disturbances, suggesting that entire functions can be lost to single disturbances; and (4) feedback loops and extinction vortices may stabilize degraded states or accelerate collapses even if stressors are removed. This review suggests that the degradation of coral reefs is due to not only the severity of human stressors but also the “fragility” of coral reefs. As such, appropriate governance is essential to manage stressors while being inclusive of ecological process and human uses across transnational scales. This is a considerable but necessary upgrade in current management if the integrity, and delivery of goods and services, of coral reefs is to be preserved.     

The niche concept: Suggestions for its use in human ecology

The Hutchinsonian concept of the ecological niche can be made operational for studies in human ecology by defining it in terms of thedistinctive ways of using resources for subsistence that set “cultural species” apart. Subsistence variety, the number of resources used for subsistence, and how much each is depended on are measures of distinctiveness, and the amount of variety present can be defined as thewidth of the ecological niche. The calculation of niche width from subsistence data is discussed, and examples are given from several human groups with reference to total resource variety, resource variety in space, and resource variety in time. The importance of selecting niche dimensions for niche width measurement is stressed, and examples are given of width differences resulting from measuring variety in quantity (biomass or calories) and variety in quality (protein, essential minerals, etc.). Finally, some implications of niche width measurements for human ecology are discussed.     

Forest reconstruction as ecological engineering

Land restoration involves reconstruction of the native biota in a sustainable form. If reconstruction involves deliberate manipulation of biological organisms and the physical-chemical environment to achieve specific human goals, it qualifies as ecological engineering. Restoration which uses natural processes to achieve endpoints which are unpredictable but can be accepted because they are “natural” is not ecological engineering. In Japan a system of forest reconstruction has been developed which is based on knowledge of the potential vegetation of a site, knowledge of the methods of germination and growth of the species which compose the mature vegetation and a method of site preparation and planting. This ecological engineering approach has been used on 285 sites, in a variety of habitats, to form dense stands of vegetation to hide industrial complexes, control visual, noise and chemical pollution, stabilize soil and beaches and provide urban green space. The technique has also been used to restore tropical rain forest.     

An integrative method for delimiting cohesion species: finding the population-species interface in a group of Californian trapdoor spiders with extreme genetic divergence and geographic structuring

Here we present an objective, repeatable approach to delineating species when populations are divergent and highly structured geographically using the Californian trapdoor spider species complex Aptostichus atomarius Simon as a model system. This system is particularly difficult because under strict criteria of geographical concordance coupled with estimates of genetic divergence, an unrealistic number of population lineages would qualify as species (20 to 60). Our novel phylogeographic approach, which is generally applicable but particularly relevant to highly structured systems, uses genealogical exclusivity to establish a topological framework to examine lineages for genetic and ecological exchangeability in an effort to delimit cohesion species. Both qualitative assessments of habitat and niche-based distribution modeling are employed to evaluate selective regime and ecological interchangeability among genetic lineages; adaptive divergence among populations is weighted more heavily than simple geographical concordance. Based on these analyses we conclude that five cohesion species should be recognized, three of which are new to science.     

基于智能体模型的青岛市林地生态格局评价与优化

设计并在GIS平台上开发了基于智能体的生态格局评价模型,以青岛市及周边地区林地为研究对象,分析不同林地空间格局及生态网络保护框架对于物种生存与扩散的影响.结果表明,与现状相比,不同等级的生态网络框架对物种种群数量与物种迁移都有明显提升,且等级越高的生态网络框架提升作用越明显.然而仅仅依靠生态网络框架不足以使研究区域林地系统形成功能上的相互连通,因此,在分析研究区域现状土地利用格局基础上,提出与湿地系统结合,在胶州湾周围及大沽河干流地区增加林地的空间布局.通过模型模拟分析,发现优化后的林地空间格局结合生态网络框架能有效提升林地之间的物种扩散.基于模拟结果,为研究区林地生态格局构建提出如下建议:(1)保证现有的规模较大的林地不被破坏;(2)青岛市中部湿地系统可以作为新增林地的理想区域;(3)生态网络框架可作为青岛市建立城市组团间生态间隔的空间参考.     

Integrated Human and Ecological Risk Assessment: A Case Study of Organophosphorous Pesticides in the Environment

This study was chosen as an example of integrated risk assessment because organophosphorous esters (OPs) share exposure characteristics for different species, including human beings and because a common mechanism of action can be identified. The “Framework for the integration of health and ecological risk assessment” is being tested against a deterministic integrated environmental health risk assessment for OPs used in a typical farming community. It is argued that the integrated approach helps both the risk manager and the risk assessor in formulating a more holistic approach toward the risk of the use of OP-esters. It avoids conclusions based on incomplete assessments or on separate assessments. The database available can be expanded and results can be expressed in a more coherent manner. In the integrated exposure assessment of OPs, the risk assessments for human beings and the environment share many communalities with regards to sources and emissions, distribution routes and exposure scenarios. The site of action of OPs, acetylcholinesterase, has been established in a vast array of species, including humans. It follows that in the integrated approach the effects assessment for various species will show communalities in reported effects and standard setting approaches. In the risk characterization, a common set of evidence, common criteria, and common interpretations of those criteria are used to determine the cause of human and ecological effects that co-occur or are apparently associated with exposure to OPs. Results of health and ecological risk assessments are presented in a common format that facilitates comparison of results. It avoids acceptable risk conclusions with regard to the environment, which are unacceptable with regard to human risk and vice versa. Risk managers will be prompted to a more balanced judgement and understanding and acceptance of risk reduction measures will be facilitated.     

Saproxylic hoverflies benefit by modern forest management (Diptera: Syrphidae)

Saproxylic organisms are regarded as threatened in many European countries. Nevertheless, there have been some signals indicating a recent increase of saproxylic hoverflies in the Netherlands. This paper examines the change in occurrence of saproxylic hoverflies compared to other ecological groups of the same family. The trend analysis is based on the database of an extensive recording programme carried out in the Netherlands. The results show an increase in occupied grid cells for a majority of saproxylic species in relation to other ecological groups. This positive trend occurs among all five ecological subcategories of saproxylic hoverflies recognized in this paper. It is suggested that this increase could be attributed to the changes in the Dutch forests during the past 50 years. Important aspects of these changes are: the increase in forest area (including an increase in area of forest with large and very large trees), the increase in age of forests and the changes in forest management in favour of a more natural approach towards dead and ill trees. In the discussion the possible influence of climate change and the method of trend calculation are discussed.     

The ecology of The Netherlands wetlands: characteristics,threats, prospects and perspectives for ecological research

Wetlands are among the worlds' most important, but also most threatened, environmental resources. Wetland losses have been in progress particularly from the industrial revolution onwards, because wetland functions could not successfully compete for space with other land uses. Wetlands became recently foci of conservation efforts because of the increased awareness of their importance in water management and wildlife conservation, and because of the diversity of their habitats. The Netherlands are relatively rich in wetlands: 16% of its' territory is regarded as internationally important wetland and 7% has been registered as such. The major Dutch wetland types are: coastal ecosystems, large riverine systems, base-rich freshwater systems, and nutrient-poor freshwater systems. Most threats to the Dutch wetlands are of man-made origin. They comprise: (1) Changes in hydrology leading to changed discharges, currents and desiccation; (2) Acidification; (3) Eutrophication; and (4) Toxification. Long-term threats are largely climate-change related, and concern temperature rise and the UV-B increase in irradiation. General conservation goals also apply to wetlands but Ramsar-registered wetlands have a special status. Conservation of the Dutch wetlands is difficult, because of the high population density of the country and its inherent threats. However, ecological targets and standards are increasingly set in national Policy Plans and international agreements. Rehabilitation and creation of wetlands is presently widely advocated, and sometimes realised. For ecological research, the sustainability of wetlands should get top priority. Such a research programme would focus on understanding the underlying ecological processes in natural and man-dominated wetland systems to prescribe conservation, rehabilitation and management strategies that would enhance the sustainability of these systems. Within this framework special attention should be directed to studies (1) At the ecosystem level of ecosystem parameters, of which natural oscillations and trends in time, and on which the impact of disturbances are quantified. Particularly these studies, in which often simulation models are used as tools for interpretation, can provide the basis for extrapolations in space and time; (2) On adaptation capacity and mechanisms of (groups of) species to extreme environmental conditions; (3) On (mutual) relationships between plants, animals and microorganisms (e.g. competition, grazing and mineralization); (4) On dispersion between small wetlands. For the contemporary quantitative assessment of the long-term effects of climate changes, the effects of temperature rise and increase in UV-B irradiation on individual species, communities and ecosystems should also be studied.     

生态补偿的机理与准则

分析国内外生态补偿实践和理论研究的基础上,从可持续发展角度探讨生态补偿的基本内涵;通过对生态系统自组织与反馈、恢复机制的剖析,提出了生态补偿应遵循的基本准则;结合国情,探讨了生态补偿亟待解决的实践困惑和应对策略。     

Global patterns of terrestrial assemblage turnover within and among land uses

Land use has large effects on the diversity of ecological assemblages. Differences among land uses in the diversity of local assemblages (alpha diversity) have been quantified at a global scale. Effects on the turnover of species composition between locations (beta diversity) are less clear, with previous studies focusing on particular regions or groups of species. Using a global database on the composition of ecological assemblages in different land uses, we test for differences in the between‐site turnover of species composition, within and among land‐use types. Overall, we show a strong impact of land use on assemblage composition. While we find that compositional turnover within land uses does not differ strongly among land uses, human land uses and secondary vegetation in an early stage of recovery are poor at retaining the species that characterise primary vegetation. The dissimilarity of assemblages in human‐impacted habitats compared with primary vegetation was more pronounced in the tropical than temperate realm. An exploratory analysis suggests that this geographic difference might be caused primarily by differences in climate seasonality and in the numbers of species sampled. Taken together the results suggest that, while small‐scale beta diversity within land uses is not strongly impacted by land‐use type, compositional turnover between land uses is substantial. Therefore, land‐use change will lead to profound changes in the structure of ecological assemblages.     

The Shifting of Ecological Restoration Benchmarks and Their Social Impacts: Digging Deeper into Pleistocene Re‐wilding

Current and projected rates of species loss prompt us to look for innovative conservation efforts. One such proposal is that large areas of North America be re‐wilded with old world species that descended from Pleistocene mega‐fauna. We argue that this approach overlooks many important ecological, evolutionary, cultural, and economic issues and detracts from conservation efforts by adding another arbitrary restoration benchmark. Our objectives are to specifically address the shifting benchmark for ecological restoration, explore the social dimensions of Pleistocene re‐wilding, which have been largely overlooked, and discuss why we think Pleistocene re‐wilding is not a proactive approach for conservation. This is not intended as a critique of innovative approaches. Instead it is an argument that human and ecological factors need to be considered in depth before any restoration initiative can be practically implemented. Proactive approaches should consider historical conditions while managing based on the present, should plan for the future, and should allow adaptation to changing conditions. We support the strategy to restore ecological interactions using species that coevolved with these interactions, bearing in mind the complexities of the socio‐ecological dimensions of any management action.     

Improved surveillance for early detection of a potential invasive species: the alien Rose-ringed parakeet <Emphasis Type="Italic">Psittacula krameri</Emphasis> in Australia

The Rose-ringed parakeet Psittacula krameri is the most widely introduced parrot in the world, and is an important agricultural pest and competitor with native wildlife. In Australia, it is classified as an ‘extreme threat’, yet captive individuals frequently escape into the wild. The distribution and frequency of incursions are currently unknown, as are the potential impacts of the species in Australia. This lack of critical ecological information greatly limits effective biosecurity surveillance and decision-making efforts. We compiled a unique dataset, which combined passive surveillance sources from government and online resources, for all available information on parakeet detections at-large in Australia. We investigated whether geographic variables successfully predicted parakeet incursions, and used species distribution models to assess the potential distribution and economic impacts on agricultural assets. We recorded 864 incursions for the period 1999–2013; mostly escaped birds reported to missing animal websites. Escapes were reported most frequently within, or around, large cities. Incursions were best predicted by factors related to human presence and activity, such as global human footprint and intensive land uses. We recommend surveillance of high (predicted) establishment areas adjacent to cities where a feral parakeet population could most affect horticultural production. Novel passive surveillance datasets combined with species distribution models can be used to identify the regions where potential invasive species are most likely to establish. Subsequently, active surveillance can be targeted to the areas of highest predicted potential risk. We recommend an integrated approach that includes outreach programs involving local communities, as well as traditional biosecurity surveillance, for detecting new incursions.     

Evaluating the ecological status of rivers using an index of ecological distance: An application to diatom communities

Community structure changes with pollution or stress. In the Water Framework Directive, high ecological status through biological parameters is defined as a slight or minor deviation from the reference community, while the good status is defined as a small deviation.To assess the importance of this deviation, and then to measure the degradation of ecological status along a river, an index based on the concept of “ecological distance” between species was created and called ecological distance index (EDI). It was tested on diatom data from a pilot watershed (the Garonne river basin, South-West France).The results show a good correlation between the EDI and the IPS (Indice de Pollusensibilité Spécifique – specific pollusensitivity index – a diatom-based biotic index) ecological ratios, which means first that the EDI is a valuable indicator of ecological status, and that it can account for ecoregional specificities. This index can be applied to any communities (macro-invertebrates, fish, etc.), since: (i) typical reference communities are found for each river type; (ii) species are characterised then ranked by pollution sensitivity values.     

Restoration for multiple use

Management of restored ecosystems for multiple use is a modern necessity given a growing human population and dwindling supplies of ecosystem goods and services. Multiple use management refers to managing resources simultaneously for sustainable output of many goods and services. Within any restoration, thoughtful planning and early stakeholder engagement can help harmonize seemingly competing multiple uses. Although the field of ecological restoration is young and there are few long‐term lessons to draw from, we can infer from ecological theory that maximization of native biodiversity can impart resilience in the restored ecosystem and can buffer against the stress of multiple use management. Restoration for multiple use should be accompanied with an acknowledgment that humility is required and monitoring is needed to keep the restored ecosystem on an acceptable trajectory. The field of ecological restoration was founded upon the notion that ecosystems would be restored for ethical reasons, but modern realities have necessitated a more utilitarian approach to restoration that requires restoring ecosystems for multiple uses. This reality represents a grand challenge for the next generation of restoration ecologists.     

Assessement and management of environmental quality conditions in marine sandy beaches for its sustainable use—Virtues of the population based approach

Sandy beaches constitute high natural value ecosystems which have been worldwide a target for growing human activities and ensuing pressures in the last decades, which caused ecological damages on these environments and led to its environmental quality decline. However, little is known about the responses of these ecosystems to distinct stressors and pressures, and holistic and integrated coastal management actions that protect beach environments and their ecological processes are yet to be developed. The aim of this viewpoint article is to present and discuss the utility of using a population approach to macrofaunal key species as a helpful tool for the assessment, management, and sustainable use of sandy beaches. The role of macrofaunal key species as indicators of environmental changes and of ecological quality condition is discussed and illustrated by some practical examples from the literature. The population is presented as a highly relevant ecological unit in management and one of the easiest ones to use, responding more rapidly to disturbances in the ecosystem than the most complex units. In this context, bio-ecology and population dynamics models are presented as tools and their potential, to improve the way we assess and manage ecological quality conditions of beach ecosystems aiming at its sustainable use, are discussed. Also, the advantages and drawbacks of the use of these tools in the population approach are evaluated. Monitoring, assessment and management practices focusing on beach key species bio-ecology as ecological indicator hold large potential in nowadays fast changing scenario, and should be encouraged as a function of their identifiable responses to manmade and natural disturbances.