The Use of Case Studies in Establishing Feasibility for Wetland Restoration

Establishing restoration feasibility is a multifaceted process that requires consideration of the ecological, social, and economic conditions of a given site. Examining completed restoration projects that report successes and failures may enhance this complex decision‐making process. We describe five completed wetland restoration projects and identify commonalities among them to inform the process of establishing feasibility for proposed restoration projects. Most of the case studies identified the need to gather preexisting and historical information, develop scenarios through hydrologic modeling, study the restoration materials, use best professional judgement for unanswered questions, establish multigroup collaboration, gain public support from stakeholders, and monitor postrestoration. We applied these lessons to a study that evaluated the feasibility of restoring Dyke Marsh Preserve, a tidal freshwater marsh in Virginia that the National Park Service is mandated to preserve. We found that the use of case studies substantially increased confidence in the decision‐making process by focusing discussions on the most important ecological, social, and economic aspects of a potential restoration.     

The role of ecological knowledge in explaining biogeography and biodiversity in Amazonia

Biogeographical studies in Amazonia have commonly taken a historical, rather than an ecological approach. General patterns have been sought in the distribution maps of different species, and these have been explained in terms of past or present distribution barriers, especially past climates and large rivers. Implicitly, and often also explicitly, it is assumed that Amazonia is ecologically so uniform that present-day ecological conditions are rather insignificant in determining species distribution patterns and speciation. However, this assumption is more based on the lack of relevant data than on actual observations of environmental uniformity or ecological unspecialization of the species. Recent studies have indeed documented ecological heterogeneity and floristic differences among sites that were previously thought similar. In the absence of direct knowledge of the past, more complete ecological and environmental understanding of the present-day Amazonia are needed for evaluating the relative roles of historical and ecological factors in Amazonian biogeography and biodiversity.     

Nested species interactions promote feasibility over stability during the assembly of a pollinator community

The foundational concepts behind the persistence of ecological communities have been based on two ecological properties: dynamical stability and feasibility. The former is typically regarded as the capacity of a community to return to an original equilibrium state after a perturbation in species abundances and is usually linked to the strength of interspecific interactions. The latter is the capacity to sustain positive abundances on all its constituent species and is linked to both interspecific interactions and species demographic characteristics. Over the last 40 years, theoretical research in ecology has emphasized the search for conditions leading to the dynamical stability of ecological communities, while the conditions leading to feasibility have been overlooked. However, thus far, we have no evidence of whether species interactions are more conditioned by the community''s need to be stable or feasible. Here, we introduce novel quantitative methods and use empirical data to investigate the consequences of species interactions on the dynamical stability and feasibility of mutualistic communities. First, we demonstrate that the more nested the species interactions in a community are, the lower the mutualistic strength that the community can tolerate without losing dynamical stability. Second, we show that high feasibility in a community can be reached either with high mutualistic strength or with highly nested species interactions. Third, we find that during the assembly process of a seasonal pollinator community located at The Zackenberg Research Station (northeastern Greenland), a high feasibility is reached through the nested species interactions established between newcomer and resident species. Our findings imply that nested mutualistic communities promote feasibility over stability, which may suggest that the former can be key for community persistence.     

HIV Treatment as Prevention: The Utility and Limitations of Ecological Observation

Results from several observational studies of HIV-discordant couples and a randomized controlled trial (HIV Prevention Trials Network 052) show that antiretroviral therapy (ART) can greatly reduce heterosexual HIV transmission in stable HIV-discordant couples. However, such data do not prove that ART will reduce HIV incidence at the population level. Observational investigations using ecological measures have been used to support the implementation of HIV treatment for the specific purpose of preventing transmission at the population level. Many of these studies note ecological associations between measures of increased ART uptake and decreased HIV transmission. Given the urgency of implementing HIV prevention measures, ecological studies must de facto be used to inform current strategies. However, the hypothesis that widespread ART can eliminate HIV infection may have raised expectations beyond what we may be able to achieve. Here we review and discuss the construct of the exposure and outcome measures and analysis methods used in ecological studies. By examining the strengths and weaknesses of ecological analyses, we aim to aid understanding of the findings from these studies to inform future policy decisions regarding the use of ART for HIV prevention.     

Identification of Land-Cover Characteristics Using MODIS Time Series Data: An Application in the Yangtze River Estuary

Land-cover characteristics have been considered in many ecological studies. Methods to identify these characteristics by using remotely sensed time series data have previously been proposed. However, these methods often have a mathematical basis, and more effort is required to better illustrate the ecological meanings of land-cover characteristics. In this study, a method for identifying these characteristics was proposed from the ecological perspective of sustained vegetation growth trend. Improvement was also made in parameter extraction, inspired by a method used for determining the hyperspectral red edge position. Five land-cover types were chosen to represent various ecosystem growth patterns and MODIS time series data were adopted for analysis. The results show that the extracted parameters can reflect ecosystem growth patterns and portray ecosystem traits such as vegetation growth strategy and ecosystem growth situations.     

An improved neutral landscape model for recreating real landscapes and generating landscape series for spatial ecological simulations

Many studies have assessed the effect of landscape patterns on spatial ecological processes by simulating these processes in computer‐generated landscapes with varying composition and configuration. To generate such landscapes, various neutral landscape models have been developed. However, the limited set of landscape‐level pattern variables included in these models is often inadequate to generate landscapes that reflect real landscapes. In order to achieve more flexibility and variability in the generated landscapes patterns, a more complete set of class‐ and patch‐level pattern variables should be implemented in these models. These enhancements have been implemented in Landscape Generator (LG), which is a software that uses optimization algorithms to generate landscapes that match user‐defined target values. Developed for participatory spatial planning at small scale, we enhanced the usability of LG and demonstrated how it can be used for larger scale ecological studies. First, we used LG to recreate landscape patterns from a real landscape (i.e., a mountainous region in Switzerland). Second, we generated landscape series with incrementally changing pattern variables, which could be used in ecological simulation studies. We found that LG was able to recreate landscape patterns that approximate those of real landscapes. Furthermore, we successfully generated landscape series that would not have been possible with traditional neutral landscape models. LG is a promising novel approach for generating neutral landscapes and enables testing of new hypotheses regarding the influence of landscape patterns on ecological processes. LG is freely available online.     

Social feasibility assessments in conservation translocations

Improving the effectiveness of conservation translocations could contribute to reversing global biodiversity loss. Although evaluations of ecological factors affecting translocation outcomes are commonplace, consideration of human social factors remains rare, hindering improvements to this conservation practice. We analysed 550 translocation case studies to explore the inclusion of social factors in project feasibility assessments. Reviewed projects often failed to assess social feasibility, and assessments, where attempted, tended to be narrow in scope. Consequently, challenges such as proactively addressing conflict often remained unaddressed. Insufficient knowledge sharing and prioritisation of ecological feasibility, to the detriment of social feasibility, remain barriers to effective planning. Successful outcomes of translocations are linked to early assessment of social feasibility and to the establishment of long-term commitments between people, places, and partners.     

Ecological vulnerability indicators

Indicators provide easy and quick information on the status or condition of an object of interest and are therefore widely used in policy-making. In recent years, policy interest in vulnerability research has increased and a growing number of studies have been aimed at developing vulnerability indicators. Some of these studies have been done within the social–ecological system (SES) framework, taking into account both social vulnerability and ecological vulnerability. A particular challenged faced, however, is with regard to the incorporation of indicators to capture the latter, especially as the concept of vulnerability as applied in ecology is relatively new and not yet well-explored. This paper expounds on this problem by answering the following questions: (1) How are the concept of vulnerability and thereby ecological vulnerability currently understood? (2) What are the challenges in the development and use of ecological vulnerability indicators? (3) What are the current efforts to overcome these challenges? One insight gathered is that due to the complexity, nonlinearity, and multiplicity of dynamics of natural systems, development of sufficiently general indicators of ecological vulnerability may not be realizable. Rather, ecological vulnerability assessment and the development of indicators thereof, whether done independent of the human system or within the SES, should be conducted at smaller scales and must be context-specific.     

Alpine microorganisms: useful tools for low-temperature bioremediation

Cold environments, including polar and alpine regions, are colonized by a wide diversity of microorganisms able to thrive at low temperatures. There is evidence of a wide range of metabolic activities in alpine cold ecosystems. Like polar microorganisms, alpine microorganisms play a key ecological role in their natural habitats for nutrient cycling, litter degradation, and many other processes. A number of studies have demonstrated the capacity of alpine microorganisms to degrade efficiently a wide range of hydrocarbons, including phenol, phenol-related compounds and petroleum hydrocarbons, and the feasibility of low-temperature bioremediation of European alpine soils by stimulating the degradation capacity of indigenous microorganisms has also been shown.     

Ecological consequences of genetic diversity

Understanding the ecological consequences of biodiversity is a fundamental challenge. Research on a key component of biodiversity, genetic diversity, has traditionally focused on its importance in evolutionary processes, but classical studies in evolutionary biology, agronomy and conservation biology indicate that genetic diversity might also have important ecological effects. Our review of the literature reveals significant effects of genetic diversity on ecological processes such as primary productivity, population recovery from disturbance, interspecific competition, community structure, and fluxes of energy and nutrients. Thus, genetic diversity can have important ecological consequences at the population, community and ecosystem levels, and in some cases the effects are comparable in magnitude to the effects of species diversity. However, it is not clear how widely these results apply in nature, as studies to date have been biased towards manipulations of plant clonal diversity, and little is known about the relative importance of genetic diversity vs. other factors that influence ecological processes of interest. Future studies should focus not only on documenting the presence of genetic diversity effects but also on identifying underlying mechanisms and predicting when such effects are likely to occur in nature.     

大叶藤黄叶片角质层的酶分离技术

角质层运输特征的研究在生态学、环境和农用化学等方面都具有非常重要的意义 ,完好地分离角质层是进行这方面研究的前提。本文以生长在西双版纳热带雨林中的大叶藤黄为材料 ,探讨了角质层的酶分离技术。结果表明 ,30℃时用 2 % (w/v) ,pH 3 0的果胶酶和纤维素酶溶液浸泡大叶藤黄叶圆片 9h ,叶圆片边缘角质层分离 ,浸泡 5d可分离到完整的角质层 ,角质层在硼酸盐缓冲液 (0 0 1mol·L-1,pH 9 0 )中充分浸泡数日去除石炭酸 ,空气中干燥 ,室温下于聚乙烯的盒子保存备用     

A limits-oriented approach to evolutionary ecology

Evolutionary ecology focuses on optimal traits to provide a mechanistic understanding of ecological patterns. For some issues, however, It might be a mismatch to marry optimality and ecology. Given that many ecological questions involve limits (to species distributions and abundances; to species diversity), it might be useful to focus on `limiting traits' rather than optimal traits; that is, to understand ecological limits it might be useful to identify the things that organisms do poorly, and to study constraints on the evolution of these limiting traits. While a limiting-traits approach has a long history in ecology, relatively few studies have fully applied the approach, and some ecological issues have only recently been examined from this view.     

Molecular biomarkers for chronological age in animal ecology

The chronological age of an individual animal predicts many of its biological characteristics, and these in turn influence population‐level ecological processes. Animal age information can therefore be valuable in ecological research, but many species have no external features that allow age to be reliably determined. Molecular age biomarkers provide a potential solution to this problem. Research in this area of molecular ecology has so far focused on a limited range of age biomarkers. The most commonly tested molecular age biomarker is change in average telomere length, which predicts age well in a small number of species and tissues, but performs poorly in many other situations. Epigenetic regulation of gene expression has recently been shown to cause age‐related modifications to DNA and to cause changes in abundance of several RNA types throughout animal lifespans. Age biomarkers based on these epigenetic changes, and other new DNA‐based assays, have already been applied to model organisms, humans and a limited number of wild animals. There is clear potential to apply these marker types more widely in ecological studies. For many species, these new approaches will produce age estimates where this was previously impractical. They will also enable age information to be gathered in cross‐sectional studies and expand the range of demographic characteristics that can be quantified with molecular methods. We describe the range of molecular age biomarkers that have been investigated to date and suggest approaches for developing the newer marker types as age assays in nonmodel animal species.     

Ecological consequences of interactions between ants and honeydew-producing insects

Interactions between ants and honeydew-producing hemipteran insects are abundant and widespread in arthropod food webs, yet their ecological consequences are very poorly known. Ant-hemipteran interactions have potentially broad ecological effects, because the presence of honeydew-producing hemipterans dramatically alters the abundance and predatory behaviour of ants on plants. We review several studies that investigate the consequences of ant-hemipteran interactions as 'keystone interactions' on arthropod communities and their host plants. Ant-hemipteran interactions have mostly negative effects on the local abundance and species richness of several guilds of herbivores and predators. In contrast, out of the 30 studies that document the effects of ant-hemipteran interactions on plants, the majority (73%) shows that plants actually benefit indirectly from these interactions. In these studies, increased predation or harassment of other, more damaging, herbivores by hemipteran-tending ants resulted in decreased plant damage and/or increased plant growth and reproduction. The ecological consequences of mutualistic interactions between honeydew-producing hemipterans and invasive ants relative to native ants have rarely been studied, but they may be of particular importance owing to the greater abundance, aggressiveness and extreme omnivory of invasive ants. We argue that ant-hemipteran interactions are largely overlooked and underappreciated interspecific interactions that have strong and pervasive effects on the communities in which they are embedded.     

The tri‐trophic niche concept and adaptive radiation of phytophagous insects

A conceptual divide exists between ecological and evolutionary approaches to understanding adaptive radiation, although the phenomenon is inherently both ecological and evolutionary. This divide is evident in studies of phytophagous insects, a highly diverse group that has been frequently investigated with the implicit or explicit goal of understanding its diversity. Whereas ecological studies of phytophagous insects increasingly recognize the importance of tri‐trophic interactions as determinants of niche dimensions such as host‐plant associations, evolutionary studies typically neglect the third trophic level. Here we attempt to reconcile ecological and evolutionary approaches through the concept of the ecological niche. We specifically present a tri‐trophic niche concept as a foil to the traditional bi‐trophic niche concept for phytophagous insects. We argue that these niche concepts have different implications for understanding herbivore community structure, population divergence, and evolutionary diversification. To this end, we offer contrasting empirical predictions of bi‐ and tri‐trophic niche concepts for patterns of community structure, the process of population divergence, and patterns of evolutionary diversification of phytophagous insects.     

全球长期城市生态研究中的社会经济要素:指标、数据与应用前景

社会经济要素作为城市生态系统的重要组成部分,能够反映居民特征、衡量居民福祉,是城市生态研究中不可或缺的内容。然而,在城市生态研究中合理、有效利用社会经济要素的规范和框架尚未得到充分研究。城市生态研究中常用的社会经济指标包括哪些？社会经济指标的常见数据源有哪些？社会经济要素可协助回答哪些方面的科学问题？为回答上述问题,本文综述了全球范围内11个长期城市生态研究站点开展的系统性调查和案例研究,总结社会经济指标的内容、数据来源,以及这些研究的议题。结果表明：常用社会经济指标可分为人口基本信息、认知和意愿、行为三类,前两者在城市生态研究中的应用已较为普遍。数据的主要来源包括政府部门提供的统计资料或普查数据、商业数据,以及研究人员开展的独立调查。在城市生态研究中纳入社会经济要素有助于分析社会与环境的相互关系,进而揭示城市系统中人与自然的耦合效应。近年来,我国城市生态研究快速发展,但研究中欠缺对社会经济要素的考虑与利用,可能会逐渐偏离国际上城市生态学的主流研究方向。社会经济数据获取困难是当前研究者面临的重大挑战,同时也存在一些机遇能够促进我国城市生态研究纳入社会经济要素,例如利用新兴数据和大数据手段、构建统一的指标框架和数据共享机制,以及充分了解和利用政府公开的统计数据。     

无人机遥感技术在景观生态学中的应用

野外数据的获取是生态学研究的挑战之一,而通过遥感技术能够实现对地球表面的多面立体观测,获取丰富多样的空间信息数据,开展从微观到宏观不同尺度上的景观单元(包括物种、种群、群落、生态系统等)的空间关系研究。传统卫星遥感影像受空间和时间分辨率的限制,难以满足局域尺度或者时间序列上的景观空间生态学研究需求。无人机遥感技术为生态学研究的野外数据获取提供了一种新方法,以其灵活、高效、简便等特点弥补了传统卫星遥感的空间分辨率低、重访周期长、云雾影响等方面的不足,在景观空间生态学研究中受到越来越多的关注。简要介绍无人机类型及其搭载常见的传感器类型,分别从不同尺度的景观单元,即物种、种群、群落以及生态系统水平上探讨其应用进展,并指出当前无人机技术在景观生态学研究中存在的挑战与困难,同时展望了未来可能的研究热点,以期对今后无人机遥感技术在景观生态学领域的应用研究有所启发。     

A Recipe for Unconventional Evenness Measures

The degree to which abundances are evenly divided among the species of a given community is a basic property of any biological community. Several evenness indices have thus far been proposed in ecological literature. However, despite their vast potential applicability in ecological research, none seems to be generally preferred. In this paper, I first summarize the basic requirements that evenness measures should meet to adequately behave in ecological studies. Then, I discuss the major drawbacks of these requirements and propose an alternative family of measures that are based on the notion of specificity used in fuzzy set theory for measuring the uncertainty associated with a fuzzy set.     

Metacommunity speciation models and their implications for diversification theory

The emergence of new frameworks combining evolutionary and ecological dynamics in communities opens new perspectives on the study of speciation. By acknowledging the relative contribution of local and regional dynamics in shaping the complexity of ecological communities, metacommunity theory sheds a new light on the mechanisms underlying the emergence of species. Three integrative frameworks have been proposed, involving neutral dynamics, niche theory, and life history trade‐offs respectively. Here, we review these frameworks of metacommunity theory to emphasise that: (1) studies on speciation and community ecology have converged towards similar general principles by acknowledging the central role of dispersal in metacommunities dynamics, (2) considering the conditions of emergence and maintenance of new species in communities has given rise to new models of speciation embedded in the metacommunity theory, (3) studies of diversification have shifted from relating phylogenetic patterns to landscapes spatial and ecological characteristics towards integrative approaches that explicitly consider speciation in a mechanistic ecological framework. We highlight several challenges, in particular the need for a better integration of the eco‐evolutionary consequences of dispersal and the need to increase our understanding on the relative rates of evolutionary and ecological changes in communities.