General relationships between consumer dispersal,resource dispersal and metacommunity diversity

One of the central questions of metacommunity theory is how dispersal of organisms affects species diversity. Here, we show that the diversity–dispersal relationship should not be studied in isolation of other abiotic and biotic flows in the metacommunity. We study a mechanistic metacommunity model in which consumer species compete for an abiotic or biotic resource. We consider both consumer species specialised to a habitat patch, and generalist species capable of using the resource throughout the metacommunity. We present analytical results for different limiting values of consumer dispersal and resource dispersal, and complement these results with simulations for intermediate dispersal values. Our analysis reveals generic patterns for the combined effects of consumer and resource dispersal on the metacommunity diversity of consumer species, and shows that hump‐shaped relationships between local diversity and dispersal are not universal. Diversity–dispersal relationships can also be monotonically increasing or multimodal. Our work is a new step towards a general theory of metacommunity diversity integrating dispersal at multiple trophic levels.     

Integrating community assembly and biodiversity to better understand ecosystem function: the Community Assembly and the Functioning of Ecosystems (CAFE) approach

The research of a generation of ecologists was catalysed by the recognition that the number and identity of species in communities influences the functioning of ecosystems. The relationship between biodiversity and ecosystem functioning (BEF) is most often examined by controlling species richness and randomising community composition. In natural systems, biodiversity changes are often part of a bigger community assembly dynamic. Therefore, focusing on community assembly and the functioning of ecosystems (CAFE), by integrating both species richness and composition through species gains, losses and changes in abundance, will better reveal how community changes affect ecosystem function. We synthesise the BEF and CAFE perspectives using an ecological application of the Price equation, which partitions the contributions of richness and composition to function. Using empirical examples, we show how the CAFE approach reveals important contributions of composition to function. These examples show how changes in species richness and composition driven by environmental perturbations can work in concert or antagonistically to influence ecosystem function. Considering how communities change in an integrative fashion, rather than focusing on one axis of community structure at a time, will improve our ability to anticipate and predict changes in ecosystem function.     

Freshwater ecosystem structure–function relationships: from theory to application

1. In this issue we aimed to answer the questions: (i) under what circumstances are functional variables better than structural ones for assessing ecosystem health? and (ii) are there good indicators of change in ecological functioning along perturbation gradients?
2. Of the numerous functional indicators tested in this issue, several show a response to anthropogenic stress and could be included in assessments of ecosystem health and integrity in running waters.
3. In three of eight studies, function showed a stronger response to anthropogenic stress than structure, whereas one study showed a response in structure and not function, and four studies showed responses in both structure and function. Thus structure alone could not detect all types of impairment and functional aspects should also be included and further developed for assessing running-water ecosystem health and integrity. Functional variables may be especially useful in situations where there is a stronger response among organisms not usually included in stream assessment (e.g. fungi and bacteria) than the commonly used invertebrate, macrophytes and fish indicators.
4. Leading research questions related to the use of functional indicators in running waters include: (i) how large is natural and operator-induced variation for functional indicators? (ii) how small of an effect size (delta) can be detected using structural versus functional indicators? and (iii) how do we efficiently improve theories as well as predictive ability for functional measures to assess the effects of anthropogenic stressors?
5. To advance the use of functional indicators in applied running-water studies, we need to supplement the approach of using large-scale datasets and correlation with ecosystem manipulations.     

Meta-ecosystems: a theoretical framework for a spatial ecosystem ecology

This contribution proposes the meta‐ecosystem concept as a natural extension of the metapopulation and metacommunity concepts. A meta‐ecosystem is defined as a set of ecosystems connected by spatial flows of energy, materials and organisms across ecosystem boundaries. This concept provides a powerful theoretical tool to understand the emergent properties that arise from spatial coupling of local ecosystems, such as global source–sink constraints, diversity–productivity patterns, stabilization of ecosystem processes and indirect interactions at landscape or regional scales. The meta‐ecosystem perspective thereby has the potential to integrate the perspectives of community and landscape ecology, to provide novel fundamental insights into the dynamics and functioning of ecosystems from local to global scales, and to increase our ability to predict the consequences of land‐use changes on biodiversity and the provision of ecosystem services to human societies.     

Dispersal-mediated trophic interactions can generate apparent patterns of dispersal limitation in aquatic metacommunities

Dispersal is a major organising force in metacommunities, which may facilitate compositional responses of local communities to environmental change and affect ecosystem function. Organism groups differ widely in their dispersal abilities and their communities are therefore expected to have different adaptive abilities. In mesocosms, we studied the simultaneous compositional response of three plankton communities (zoo-, phyto- and bacterioplankton) to a primary productivity gradient and evaluated how this response was mediated by dispersal intensity. Dispersal enhanced responses in all three planktonic groups, which also affected ecosystem functioning. Yet, variation partitioning analyses indicated that responses in phytoplankton and bacterial communities were not only controlled by dispersal directly but also indirectly through complex trophic interactions. Our results indicate that metacommunity patterns emerging from dispersal can cascade through the food web and generate patterns of apparent dispersal limitation in organisms at other trophic levels.     

基于功能与空间格局的区域生态系统保管策略

本研究以位于长江流域的湖北省兴山县为研究区域,着重讨论了基于功能与空间格局的生态系统保育策略,即以改善生态系统功能为评价指标,以调整生态因子的空间格局为手段的生态系统保育策略。根据该县的地理位置,我们以生态系统功能中的水源函养为森林生态系统保育的评价指标。利用基于地理信息系统的水涵养能力。利用生态系统中水涵养能力的空间异质性和变化－位置效应在生态因子改变中的作用,我们提出了“基于空间格局的森林扩展”的策略。将该策略应用于兴山县的生态系统保育,以期达到保育森林与改善水涵养能力的双重目的。本研究为保育,管理和持续利用长江流域和其他遭遇同样问题的区域的生态系统提供了有价值的信息。     

基于生态系统服务功能和生态敏感性的自然生态空间管制分区研究

自然生态空间分区管制是国土空间管制的重要组成部分,也是国内外生态环境研究的热点。针对国内自然生态空间用途管制暂处于试点阶段,有关管制的方法有待进一步探究的情况下,旨在通过江西省自然生态空间管制分区,为实现合理保护自然生态资源,促进自然生态系统健康有序发展提供参考。以江西省为研究对象,借助GIS空间分析技术,通过生态系统服务功能重要性和生态敏感性评价,构建二维关联判断矩阵,进行自然生态空间管制分区,并以此提出相关的管制建议。结果表明:江西省自然生态空间总面积为117924.67 km²,约占全省总面积的70.66%,从空间上可划分为高重要高敏感区、中度重要敏感区和低重要低敏感区3种类型区;其中,高重要高敏感区以生态保护和生态修复为主,实施严格的区域准入措施;中度重要敏感区可依托区域生态资源优势,合理开展以维护、改善生态系统服务功能为主要目的生态经营活动;低重要低敏感区允许在不破坏生态系统结构和功能的前提下,适度开展一定规模的生产建设活动,减少污染排放,增强区域生态功能。全省16个国家自然保护区基本位于高重要高敏感范围内。基于生态系统服务功能与生态敏感性的自然生态空间...     

济南市森林生态系统服务功能的维持机制

森林作为陆地生态系统的重要组成部分,在维持生物多样性、固碳、水源涵养和木材供应等方面起着不可替代的作用。依据《森林生态系统服务功能评估规范》(LY/T1721—2008),以济南市12个林分类型为研究对象,对济南市森林生态系统服务功能维持机制进行研究,得出济南市年森林生态系统涵养水源、保育土壤、固碳释氧、林木积累营养物质、净化大气环境、生物多样性保护的价值为251.80亿元。其中,涵养水源、固碳释氧、生物多样性保护排在前3位;不同林分类型生态系统服务功能价值量中黑杨类和柏类占绝对优势,而泡桐、落叶松和竹林生态系统服务功能较弱;不同林龄生态系统服务功能价值量以中幼龄林为主;济南市森林生态系统服务功能的维持机制,受到森林资源面积、林龄结构、森林起源以及自然保护区建设等诸多因素的影响。     

东江流域森林水源涵养功能空间格局评价

东江流域森林水源涵养功能对于保障流域可持续发展具有重要作用。应用In VEST模型,结合东江流域土地覆盖分类数据、气候数据、土壤数据评估了东江流域森林水源涵养功能的空间分布。结果表明:东江流域森林生态系统水源涵养总量为47.29×10~8m~3,水源涵养功能最高为572.6 mm,平均水源涵养功能为204.15 mm。东江流域森林水源涵养功能在空间上呈现出不同的分布特征,流域内森林水源涵养功能随海拔升高呈现先上升后降低的趋势,在海拔900—1200 m范围,水源涵养功能平均值达到最大值270 mm;流域内森林水源涵养功能随坡度升高呈增加趋势,在坡度大于50°的区域,森林水源涵养功能平均值增加到327.2 mm,高于流域平均水平60%。流域水源涵养功能呈现中游下游上游的空间格局,流域上、中、下游地区的水源涵养总量占流域的比例分别为11%、72%、17%。     

洋河流域土地利用时空变异及其对生态服务功能价值的影响

洋河流域位于我国北方典型的农牧交错地带,是首都重要水源涵养地和生态保护屏障,也是2022年冬奥会举办地之一。对流域土地利用变化及其生态服务功能价值影响的研究可为首都水源保护以及冬奥会场地环境质量的改善提供重要理论依据和决策支持。利用Arc GIS技术分析了洋河流域1990—2013年间的土地遥感数据,估算了这些变化对流域生态服务价值的影响。结果表明:1990—2013年洋河流域林地和未利用地面积呈增加,而水域、草地则呈减少的趋势。由单一土地类型利用动态绝对值说明,除林地以外2000—2013年洋河流域其他土地类型受人类或自然环境变化的影响明显高于1990—2000年。土地转移主要发生在流域西部的兴和县、阳高县、天镇县和下游的张家口市、宣化县和怀来县。近年来流域土地面积变化幅度和变化范围均增加。1990—2013年间洋河流域土地利用的年总生态服务价值经历先增加后减小、总体减少的过程,但林地和未利用地的生态服务价值却一直增加。由于林地面积增加从而导致1990—2013年流域的原材料生产、气候调节、气体调节、生物多样性保护和提供美学景生态功能占年总价值的比值增加。林地、草地和耕地是洋河流域生态服务的主要贡献者,也是生态服务价值变化的敏感因子。     

Long‐term temporal and spatial trends in eutrophication status of the Baltic Sea

Much of the Baltic Sea is currently classified as ‘affected by eutrophication’. The causes for this are twofold. First, current levels of nutrient inputs (nitrogen and phosphorus) from human activities exceed the natural processing capacity with an accumulation of nutrients in the Baltic Sea over the last 50–100 years. Secondly, the Baltic Sea is naturally susceptible to nutrient enrichment due to a combination of long retention times and stratification restricting ventilation of deep waters. Here, based on a unique data set collated from research activities and long‐term monitoring programs, we report on the temporal and spatial trends of eutrophication status for the open Baltic Sea over a 112‐year period using the HELCOM Eutrophication Assessment Tool (HEAT 3.0). Further, we analyse variation in the confidence of the eutrophication status assessment based on a systematic quantitative approach using coefficients of variation in the observations. The classifications in our assessment indicate that the first signs of eutrophication emerged in the mid‐1950s and the central parts of the Baltic Sea changed from being unaffected by eutrophication to being affected. We document improvements in eutrophication status that are direct consequences of long‐term efforts to reduce the inputs of nutrients. The reductions in both nitrogen and phosphorus loads have led to large‐scale alleviation of eutrophication and to a healthier Baltic Sea. Reduced confidence in our assessment is seen more recently due to reductions in the scope of monitoring programs. Our study sets a baseline for implementation of the ecosystem‐based management strategies and policies currently in place including the EU Marine Strategy Framework Directives and the HELCOM Baltic Sea Action Plan.     

Searching for effective indicators of ecosystem function in urban streams: assessing cellulose decomposition potential

1. Urbanisation and landuse changes threaten the ecological integrity of rivers and streams globally. A major challenge in such impacted environments is to develop functional indicators for use by waterway managers. We first reviewed cellulose decomposition potential (CDP) as one such indicator, and here present current understanding and highlight the knowledge gaps which hinder its widespread incorporation into programmes monitoring stream health. In a field study, we also evaluated two differing cellulose materials (Shirley soil burial test material and unbleached calico) and measurement techniques. 2. We also investigated the effects of urbanisation and riparian cover on CDP as a standardised indicator of ecosystem function. Cotton fabrics were deployed in paired open and closed reaches across six stream catchments varying in degree of urbanisation (in south‐eastern Australia). After 7, 14 and 21 days materials were retrieved and their decomposition assessed in conjunction with a number of physicochemical variables. 3. We observed a strong positive relationship between the decomposition of Shirley and calico materials, thus indicating unbleached calico is an effective substitute for Shirley test cloth, which is no longer available. 4. Across sites, CDP was positively correlated with ammonium concentrations and also, to a lesser extent, with filterable reactive phosphorus and sediment silt and clay content/carbon availability. Despite these relationships, cellulose decomposition was not correlated with urbanisation or riparian cover. 5. Cellulose decomposition is a simple, rapid and sensitive functional indicator of water quality and associated anthropogenic landuse changes and is thus a valuable tool for monitoring stream health.     

水源涵养型国家重点生态功能区生态系统服务功能评估

为评估“十二五”以来国家重点生态功能区转移支付政策的阶段性实施效果,以水源涵养类型国家重点生态功能区为对象,基于水量平衡法,利用2011年和2019年土地覆被数据,并结合气象数据,分析了水源涵养型国家重点生态功能区2011年和2019年水源涵养功能、生态系统面积、生态系统质量状况及其变化情况。研究结果表明,自2011年转移支付政策实施以来：1)全国水源涵养型重点生态功能区内的水源涵养能力呈现从西北部到东南部逐渐增加的空间分布趋势,2019年全国水源涵养型重点生态功能区水源涵养能力较2011年显著增加。2)全国水源涵养型重点生态功能区森林面积有所增加,湿地得到有效恢复。3)全国水源涵养重点生态功能区内生态系统质量提高,平均植被覆盖度有所增加,呈现东北部及中南部高,西北部低的分布趋势。总体来看,转移支付政策的实施对全国水源涵养重点生态功能区森林、草地生态系统水源涵养功能的提升发挥了积极作用,基本上达到了转移支付政策预期的阶段性目标。     

Greater than the sum of the parts: how the species composition in different forest strata influence ecosystem function

The mechanisms underpinning forest biodiversity‐ecosystem function relationships remain unresolved. Yet, in heterogeneous forests, ecosystem function of different strata could be associated with traits or evolutionary relationships differently. Here, we integrate phylogenies and traits to evaluate the effects of elevational diversity on above‐ground biomass across forest strata and spatial scales. Community‐weighted means of height and leaf phosphorous concentration and functional diversity in specific leaf area exhibited positive correlations with tree biomass, suggesting that both positive selection effects and complementarity occur. However, high shrub biomass is associated with greater dissimilarity in seed mass and multidimensional trait space, while species richness or phylogenetic diversity is the most important predictor for herbaceous biomass, indicating that species complementarity is especially important for understory function. The strength of diversity‐biomass relationships increases at larger spatial scales. We conclude that strata‐ and scale‐ dependent assessments of community structure and function are needed to fully understand how biodiversity influences ecosystem function.     

A mixing model analysis of stream solute dynamics and the contribution of a hyporheic zone to ecosystem function*

1. We monitored streamwater and streambed sediment porewaters from White Clay Creek (WCC), SE Pennsylvania, for dissolved organic carbon (DOC), dissolved oxygen (DO) and conductivity to investigate organic matter processing within the hyporheic zone. Dissolved organic carbon and DO concentrations were higher in the streamwater than in the porewaters and, in many cases, concentrations continued to diminish with increasing depth into the streambed. 2. Hydrological exchange data demonstrated that the permeability of the stream bed declines with depth and constrains downwelling, effectively isolating porewaters >30 cm from streamwater. 3. End‐member mixing analysis (EMMA) based on conductivity documented a DOC source and DO sink in the hyporheic zone. We calculated hyporheic streambed DOC fluxes and respiration from the EMMA results and estimates of water flux. Based upon our calculations of biodegradable DOC entering the hyporheic zone, we estimate that DOC supports 39% of the hyporheic zone respiration, with the remaining 61% presumably being supported by entrained particulate organic carbon. Hyporheic respiration averaged 0.38 g C m^?2 d^?1, accounted for 41% of whole ecosystem respiration, and increased baseflow ecosystem efficiency from 46 to 59%. 4. Advective transport of labile organic molecules into the streambed concentrates microbial activity in near‐surface regions of the hyporheic zone. Steep gradients in biogeochemical activity could explain how a shallow and hydrologically constrained hyporheic zone can dramatically influence organic matter processing at the ecosystem scale.     

Species richness matters for the quality of ecosystem services: a test using seed dispersal by frugivorous birds

The positive link between biodiversity and ecosystem functioning is a current paradigm in ecological science. However, little is known of how different attributes of species assemblages condition the quality of many services in real ecosystems affected by human impact. We explore the links between the attributes of a frugivore assemblage and the quantitative and qualitative components of its derived ecosystem service, seed dispersal, along a landscape-scale gradient of anthropogenic forest loss. Both the number and the richness of seeds being dispersed were positively related to frugivore abundance and richness. Seed dispersal quality, determined by the fine-scale spatial patterns of seed deposition, mostly depended on frugivore richness. In fact, richness was the only attribute of the frugivore assemblage affecting the probability of seed dispersal into deforested areas of the landscape. The positive relationships between frugivore richness per se (i.e. independent of frugivore abundance and composition) and all components of seed dispersal suggest the existence of functional complementarity and/or facilitation between frugivores. These links also point to the whole assemblage of frugivores as a conservation target, if we aim to preserve a complete seed dispersal service and, hence, the potential for vegetation regeneration and recovery, in human-impacted landscapes.     

Establishing the evidence base for maintaining biodiversity and ecosystem function in the oil palm landscapes of South East Asia

The conversion of natural forest to oil palm plantation is a major current threat to the conservation of biodiversity in South East Asia. Most animal taxa decrease in both species richness and abundance on conversion of forest to oil palm, and there is usually a severe loss of forest species. The extent of loss varies significantly across both different taxa and different microhabitats within the oil palm habitat. The principal driver of this loss in diversity is probably the biological and physical simplification of the habitat, but there is little direct evidence for this. The conservation of forest species requires the preservation of large reserves of intact forest, but we must not lose sight of the importance of conserving biodiversity and ecosystem processes within the oil palm habitat itself. We urgently need to carry out research that will establish whether maintaining diversity supports economically and ecologically important processes. There is some evidence that both landscape and local complexity can have positive impacts on biodiversity in the oil palm habitat. By intelligent manipulation of habitat complexity, it could be possible to enhance not only the number of species that can live in oil palm plantations but also their contribution to the healthy functioning of this exceptionally important and widespread landscape.     

Ecosystem function for water retention and forest ecosystem conservation in a watershed of the Yangtze River

The ecosystem function for water retention in a watershed of the Yangtze River was discussed in this study. The watershed was divided into 90 types of vegetation–soil–slope complex. A GIS-embodied spatial database was used to explore the relationships between the capacity of water retention by a complex and its types of vegetation, soil and slope. Furthermore, the capacity of water retention of every complex was estimated statistically by using estimation models. The spatial distribution of various capacity of water retention in the watershed was demarcated on a map based on the attributions and the locations of complexes. In addition, we evaluated integrally the situation of water retention in the watershed based on the estimation for the complexes from which it was distinctly recognized that the serious situation mainly results from the poor capacity of water retention of vegetation. The variation-location effect describes the phenomenon in which an identical variation of a factor may produce different effects on overall situation, when this variation occurs in a different spatial location. According to the variation-location effect on the expansion of forestland, a strategy 'spatial pattern-based forestland extension was proposed to conserve forest ecosystem and improve the situation of water retention in the watershed.