土壤纤毛虫群落对不同退还模式生态恢复的响应

为了探究土壤纤毛虫群落对不同退还模式生态恢复的响应及利用其群落特征来评价退还效果,于2014年4月至2015年7月在甘肃省天祝藏族自治县朵什乡退耕还林区选取了3个不同退还林型样点(云杉、沙棘混交林A1,云杉林A2,沙棘林B1)和2个对照耕地样点(小麦地A0,豌豆地B0)为研究样地,采用"非淹没培养皿法"、活体观察法和培养直接计数法对土壤纤毛虫群落特征进行了研究,同时测定了各样点土壤的相关环境因子,并分析了不同恢复模式下土壤纤毛虫群落特征与植被群落参数、土壤环境因子间的相关性。研究共鉴定到125种土壤纤毛虫,隶属于9纲19目29科34属。结果显示:退还样点和对照样点的土壤纤毛虫群落结构特征存在明显差异(P0.05),退还样点间的物种相似性减小,群落组成复杂化;退还样点土壤纤毛虫物种数、密度、物种多样性指数、均匀度指数和丰富度指数均明显增高(P0.05),且各样点间表现为A1B1A2B0A0;各样点优势类群的演替趋势,由对照样点的肾形目演替为退还样点的散毛目。相关性分析和冗余分析结果表明,退耕还林后,对纤毛虫群落结构稳定影响最主要的是有机质、含水量和全氮的含量,不同林型间土壤纤毛虫群落组成差异较大,表明土壤纤毛虫群落结构可作为对退耕还林生态恢复的评价指标。     

土壤纤毛虫群落对退耕还林生态恢复的响应——以侧柏林为例

为了了解土壤纤毛虫群落对退耕还林区生态恢复下土壤环境变化的响应及尝试利用土壤纤毛虫群落特征评价退耕还林生态恢复的效果,于2010年3月至9月采用"非淹没培养皿法"、活体观察法、蛋白银染色法和Foissner计数法对甘肃陇南武都退耕还林区5个不同恢复阶段的样点和1个荒草坡对照样点的土壤纤毛虫群落特征进行了研究,同时测定了p H值、温度、含水量及速效磷、有效钾、铵态氮、有机质和有机碳含量等土壤环境因子并分析了生态恢复条件下土壤纤毛虫群落特征与土壤环境因子的相关性。研究中共鉴定到71种纤毛虫,隶属于3纲、10目、22科、29属。研究发现,不同恢复年限的土样中土壤纤毛虫的物种分布存在明显差异,并随恢复时间的延长,样点间物种相似性减小,群落组成复杂化,物种数、种群密度和物种多样性指数总体均呈增长趋势。优势类群也发生了演替,由恢复初期的肾形目演替到后期的下毛目。相关性分析结果表明,在生态恢复条件下,土壤有机质和铵态氮含量是影响土壤纤毛虫群落结构稳定性的主要因素,不同纤毛虫类群对生态恢复的响应存在差异。冗余分析显示,土壤纤毛虫群落很好地响应了生态恢复过程中土壤环境条件的变化。     

甘肃天水麦积山风景名胜区土壤纤毛虫的物种多样性

用活体观察和固定染色方法对麦积山风景名胜区土壤纤毛虫物种多样性进行了研究。共鉴定到隶属于3纲12目41科55属的土壤纤毛虫115种,其中包括11个未定名种和26个中国土壤纤毛虫新纪录种。街子温泉景区、曲溪景区、麦积山石窟区、石门山和仙人崖景区各分布有47、46、44、33和26种,大弹跳虫、似织毛虫、膨大肾形虫、僧帽肾形虫、迅捷肾形虫、吻四膜虫、长刀口虫和苔藓刀口虫为广布物种。前口目和下毛目为风景名胜区土壤纤毛虫群落中的优势类群,肾形目和盾纤目为次优势类群,侧口目、吸管目和寡毛目为罕见类群。风景名胜区土壤纤毛虫物种多样性与我国已有研究报道的其他地区的均极不相似。研究结果表明,风景名胜区土壤纤毛虫物种十分丰富,特有和稀有物种繁多,群落结构复杂而特殊;土壤和水生纤毛虫群落物种组成极不相似,土壤和水生纤毛虫群落是不同的2个独立群落。     

Nearctic earthworm fauna in the southern USA: biodiversity and effects on ecosystem processes

An important aspect of biodiversity is the relative importance of species in the functioning of ecosystems; this is particularly so for the soil biota which regulate organic matter and nutrient dynamics in soil. This paper explores some of the relationships between biodiversity and ecosystem processes, using the example of the nearctic earthworm fauna in the glacial refugium of the southern USA. Competitive exclusion of nearctic earthworm species by exotic species has been postulated but there is little direct evidence of it; habitat alteration is the likely cause of native species decline. Reduced earthworm diversity may or may not strongly affect certain ecosystem processes, but more diverse assemblages may more effectively exploit soil resources and influence a wider array of processes. Nearctic species may be better adapted than exotics to local conditions and thus more strongly influence ecosystem processes. Earthworm communities provide a clear case for the union of functional and taxonomic biodiversity studies, because of the recognized ecological strategies of many species. However, some nearctic taxa may deviate from these strategies. Earthworms utilize course woody debris in forests both as a refuge and a resource, while enhancing the decomposition of wood. Management strategies to maintain or increase biodiversity of soil biota should include residual wood on the forest floor. An important task for ecosystem management is to restore biodiversity in degraded ecosystems; introduction programmes and techniques such as periodic burning may increase the abundance and diversity of native earthworm species. Whole ecosystem conservation and management are probably the most practical ways to conserve biodiversity generally and may be the only ways to maintain soil biodiversity.     

Genetic analysis of ciliates living on the groundwater amphipod Crangonyx islandicus (Amphipoda: Crangonyctidae)

Two endemic subterranean freshwater amphipod species have been discovered in groundwater of the volcanic active zone in Iceland, Crangonyx islandicus and Crymostygius thingvallensis. At least five different ciliate sequences were isolated from C. islandicus and the analysis of variation at the 18S ribosomal DNA gene suggests that they present previously unsequenced species, from the orders Apostomatida and Philasterida. Apostome ciliates are well known to be exuviotrophic epibionts on crustaceans. Analyses of ciliate epibionts from different groundwater amphipod species from North America and mainland Europe revealed distinct groups of ciliates and higher diversity on the epigean amphipod Crangonyx pseudogracilis. Analysis of geographic patterns of the most common ciliate within Iceland revealed population differentiation supporting limited current connectivity between the different groundwater systems. Our study reports an occurrence of previously undescribed ciliate species in a groundwater ecosystem characterized by low species diversity.     

Forest plant community as a driver of soil biodiversity: experimental evidence from collembolan assemblages through large‐scale and long‐term removal of oak canopy trees Quercus petraea

Plant–soil interactions are increasingly recognized to play a major role in terrestrial ecosystems functioning. However, few studies to date have focused on slow dynamic ecosystems such as forests. As they are vertically stratified by multiple vegetation strata, canopy tree removal by thinning operations could alter forest plant community through tree canopy opening. Very little is known about cascading effects on soil biodiversity. We conducted a large‐scale, multi‐site assessment of collembolan assemblage response to long‐term canopy tree removal in sessile oak Quercus petraea temperate forests. A total of 33 experimental plots were studied covering a large gradient of canopy tree basal area, stand age and local abiotic contexts. Collembolan abundance strongly declined with canopy tree removal in early forest successional stage and this was mediated by negative effect of understory plant community composition changes, i.e. shift from moss and forb to tree seedling, fern, shrub and grass species. Negative effect of this composition shift on collembolan species richness was largely offset by positive effect of the increase in understory plant species richness. This gives support to both the plant mass‐ratio and functional diversity hypotheses. Collembolan functional groups had contrasting response patterns, which were mediated by different ecological factors. Epedaphic (r‐strategist) abundance and species richness increased with canopy tree removal in relation with the increase in understory plant species richness. In contrast, euedaphic (K‐strategist) abundance and species richness declined with canopy tree removal in early forest successional stage in relation with changes in understory plant community composition and species richness, as well as microclimatic conditions. Overall, our study provides experimental evidence that forest plant community can be a strong driver of collembolan assemblages. It also emphasizes the role of trees as foundation species of forest ecosystems that can shape soil biodiversity through their regulation of understory plant community and ecosystem abiotic conditions.     

拉萨河中下游纤毛虫群落时空分布模式及其驱动机制

为了探究拉萨河中下游纤毛虫群落的组成模式、时空多样性格局及其维持机制, 本文于2015年5月和8月以及2016年10月在拉萨河中下游17个样点进行采样, 采用活体观察、鲁哥氏碘液固定染色以及Wilbert蛋白银法相结合的物种鉴定方法, 对纤毛虫群落结构进行了研究。通过Shannon多样性指数、Margalef丰富度指数、物种数分析群落结构时空上的差异性; 通过共现网络分析纤毛虫类群之间的相互作用; 通过冗余分析(redundancy analysis, RDA)探讨水体理化因子对纤毛虫群落结构的影响。结果表明, Shannon多样性指数在季节和河段间没有显著性差异; Margalef丰富度指数、物种数在河段间存在极显著性差异; 中游和下游河段共现网络节点间的相关关系均以正相关为主; 溶解氧(DO)、总氮(TN)、总磷(TP)、总溶解盐(TDS)是影响纤毛虫群落结构的关键因子。综上所述, 拉萨河中下游纤毛虫群落结构在季节间没有显著差异, 在空间上具有显著差异; 纤毛虫在纲级水平上类群间的相互作用以协同作用为主导, 不同类群间存在复杂的相互作用, 整体上互作关系在春季较为复杂、夏季较为简单; 影响拉萨河中下游纤毛虫群落结构是多个环境因子共同作用的结果。     

Ciliate diversity and distribution across horizontal and vertical scales in the open ocean

Ciliates are globally distributed eukaryotic organisms inhabiting virtually all environments on Earth. Although ciliates range from 10 µm to a few millimetres in cell size, they are repeatedly reported in the pico‐sized fraction (<2–3 µm) of molecular surveys. Here, we used existing data sets (BioMarKs and Tara Oceans) with different size fractions to demonstrate that the ciliate pico‐sized signal, probably derived from cell breakage during filtration, is informative and reliable to study marine ciliate biodiversity and biogeography. We then used sequences from the pico‐eukaryotic fraction of two circumnavigation expeditions, Malaspina‐2010 and Tara Oceans, to give insights into the taxonomic composition and horizontal and vertical distribution of ciliates in the global ocean. The results suggested a high homogeneity of ciliate communities along the ocean surface from temperate to tropical waters, with ciliate assemblages dominated by a few abundant and widely distributed taxa. Very few taxa were found in a single oceanic region, therefore suggesting a high level of ciliate cosmopolitanism in the global ocean. In vertical profiles, ciliates were detected up to 4,000 m depth, and a clear vertical community structuring was observed. Our results provided evidence supporting ciliates as deeply integrated organisms in the deep‐sea trophic web, where they may play a relevant role as symbionts of metazoans and grazers of prokaryotes and small eukaryotes in the water column and in aggregates.     

Effects of Metazoan Predators on Ciliates in Freshwater Plankton Communities1

ABSTRACT. Ciliates are often important members of aquatic communities in terms of their biomass, productivity, trophic roles, or numerical abundance. The interaction of metazoan predators with ciliates will be mediated by a number of biotic factors, including the potential of ciliate populations for growth, the relative size of ciliates and metazooplankton, the species structure of the metazooplankton, and the defenses of ciliates. This paper reviews some of the recent laboratory an field data pertaining to these particular factor. Studies have generally shown that metazoans can reduce ciliate population growth rates, but this impact varies greatly with the ciliate and metazoans involved. Smaller ciliates are generally more vulnerable to metazoan predators than larger species, although this relationship will be affected by the defenses a ciliate may possess. The structure of the metazooplankton community itself will also affect ciliatemetazoan interactions. The suppression of ciliate populations by metazoans has important ecological consequences, and more study is needed to understand the interaction of these groups in aquatic systems.     

Attitudes toward forest diversity and forest ecosystem services—a cross-cultural comparison between China and Switzerland

Aims Despite the current interest in services provided by ecosystems and the role of biodiversity, the relationship among human attitudes, biodiversity and ecosystem services has hardly been investigated. Moreover, few studies have examined attitudes toward nature in cross-cultural comparisons. This study investigates the attitudes of Chinese and Swiss people, both environmental experts and laypersons, toward forest biodiversity and ecosystem services.Methods Overall, 640 people in China and Switzerland were interviewed with the help of a standardized questionnaire. In each country, the study population was equally divided into an urban (80 city dwellers and 80 environmental science students) and a rural (80 forest visitors and 80 farmers) study group. The 15-minute interviews took place in the cities of Beijing and Zurich and in the rural forested areas of Dujiangyan, Sichuan Province and Lake Sempach, canton Lucerne. Attitudes toward forest biodiversity were investigated with the help of color photographs that depicted both monocultures and species-rich forests typical for China and Switzerland. Attitudes toward ecosystem services were investigated with the help of 13 statements on provisioning, regulating, cultural and supporting services of forests.Important findings On average, Chinese participants showed no strong preferences for biodiversity, whereas the Swiss clearly preferred species-rich forests over monocultures. However, Chinese environmental science students did prefer species-rich forests and attributed to them a higher conservation value because of their higher biodiversity. Although there were no strong preferences for Chinese versus Swiss forests, all participants correctly answered that Chinese forests are more species rich in terms of plants and animals and thus found them less boring and more interesting, but also less managed, than Swiss forests. All participants highly valued the ecosystem services provided by forests; especially the regulating and supporting ones. Environmental science students and farmers placed more importance on the provisioning services, whereas city dwellers and forest visitors emphasized more on the regulating services. The disjuncture between the high ecological quality of species-rich forests and their low attractiveness to Chinese study participants points to a potential conflict between conservation policies and the public's preferences. A better communication of ecosystem services provided by forest biodiversity to the public might change these preferences in favor of ecological quality, as already observed among Chinese environmental science students.     

Species richness promotes ecosystem carbon storage: evidence from biodiversity-ecosystem functioning experiments

Plant diversity has a strong impact on a plethora of ecosystem functions and services, especially ecosystem carbon (C) storage. However, the potential context-dependency of biodiversity effects across ecosystem types, environmental conditions and carbon pools remains largely unknown. In this study, we performed a meta-analysis by collecting data from 95 biodiversity-ecosystem functioning (BEF) studies across 60 sites to explore the effects of plant diversity on different C pools, including aboveground and belowground plant biomass, soil microbial biomass C and soil C content across different ecosystem types. The results showed that ecosystem C storage was significantly enhanced by plant diversity, with stronger effects on aboveground biomass than on soil C content. Moreover, the response magnitudes of ecosystem C storage increased with the level of species richness and experimental duration across all ecosystems. The effects of plant diversity were more pronounced in grasslands than in forests. Furthermore, the effects of plant diversity on belowground plant biomass increased with aridity index in grasslands and forests, suggesting that climate change might modulate biodiversity effects, which are stronger under wetter conditions but weaker under more arid conditions. Taken together, these results provide novel insights into the important role of plant diversity in ecosystem C storage across critical C pools, ecosystem types and environmental contexts.     

Ecosystem Services and Biodiversity in a Rapidly Transforming Landscape in Northern Borneo

Because industrial agriculture keeps expanding in Southeast Asia at the expense of natural forests and traditional swidden systems, comparing biodiversity and ecosystem services in the traditional forest–swidden agriculture system vs. monocultures is needed to guide decision making on land-use planning. Focusing on tree diversity, soil erosion control, and climate change mitigation through carbon storage, we surveyed vegetation and monitored soil loss in various land-use areas in a northern Bornean agricultural landscape shaped by swidden agriculture, rubber tapping, and logging, where various levels and types of disturbance have created a fine mosaic of vegetation from food crop fields to natural forest. Tree species diversity and ecosystem service production were highest in natural forests. Logged-over forests produced services similar to those of natural forests. Land uses related to the swidden agriculture system largely outperformed oil palm or rubber monocultures in terms of tree species diversity and service production. Natural and logged-over forests should be maintained or managed as integral parts of the swidden system, and landscape multifunctionality should be sustained. Because natural forests host a unique diversity of trees and produce high levels of ecosystem services, targeting carbon stock protection, e.g. through financial mechanisms such as Reducing Emissions from Deforestation and Forest Degradation (REDD+), will synergistically provide benefits for biodiversity and a wide range of other services. However, the way such mechanisms could benefit communities must be carefully evaluated to counter the high opportunity cost of conversion to monocultures that might generate greater income, but would be detrimental to the production of multiple ecosystem services.     

Biodiversity as a solution to mitigate climate change impacts on the functioning of forest ecosystems

Forest ecosystems are critical to mitigating greenhouse gas emissions through carbon sequestration. However, climate change has affected forest ecosystem functioning in both negative and positive ways, and has led to shifts in species/functional diversity and losses in plant species diversity which may impair the positive effects of diversity on ecosystem functioning. Biodiversity may mitigate climate change impacts on (I) biodiversity itself, as more‐diverse systems could be more resilient to climate change impacts, and (II) ecosystem functioning through the positive relationship between diversity and ecosystem functioning. By surveying the literature, we examined how climate change has affected forest ecosystem functioning and plant diversity. Based on the biodiversity effects on ecosystem functioning (B→EF), we specifically address the potential for biodiversity to mitigate climate change impacts on forest ecosystem functioning. For this purpose, we formulate a concept whereby biodiversity may reduce the negative impacts or enhance the positive impacts of climate change on ecosystem functioning. Further B→EF studies on climate change in natural forests are encouraged to elucidate how biodiversity might influence ecosystem functioning. This may be achieved through the detailed scrutiny of large spatial/long temporal scale data sets, such as long‐term forest inventories. Forest management strategies based on B→EF have strong potential for augmenting the effectiveness of the roles of forests in the mitigation of climate change impacts on ecosystem functioning.     

甘南亚高寒草甸土壤纤毛虫群落结构变化对不同坡向的响应

土壤纤毛虫不但是土壤生态系统的重要组成部分,而且是生态系统物质循环、能量流动过程的重要驱动因子。为了查明甘南亚高寒草甸不同坡向土壤纤毛虫群落特征,于2015年7月21—26日对同一山头的阳坡、半阳坡、西坡、半阴坡、阴坡五个坡向进行了调查。结果表明:(1)经"非淹没培养皿法"鉴定得到纤毛虫142种,隶属于9纲18目32科55属,各坡向物种数、个体数大小关系呈现出西坡半阳坡阳坡半阴坡阴坡;优势类群有旋毛纲、裂口纲、寡膜纲、肾形纲其优势度依次为28.17%、19.72%、13.38%、12.68%。(2)不同坡向上土壤纤毛虫的物种数、个体数、Shannon指数均具有显著性差异(P0.05),表明甘南亚高寒草甸生态系统中的土壤纤毛虫对于坡向这一微气候环境的变化具有敏感性。(3)各坡向土壤纤毛虫的物种数、个体数都具有明显的表聚性。(4)利用皮尔森相关性分析得出,在所测得的土壤理化因子中对纤毛虫的物种数、个体数均具有显著正相关(P0.05)的是全氮、有机质。综合分析,影响甘南亚高寒草甸不同坡向上土壤纤毛虫群落结构变化的主要因素为全氮、土壤有机质以及地上植被状况。     

植物多样性与生态系统土壤保持功能关系及其生态学意义

测定物种丰富度呈梯度变化的半湿润常绿阔叶林不同次生演替阶段小区地表径流、土壤侵蚀和总磷流失及影响这些过程的植物群落郁闭度、个体密度、胸高断面积、植物叶吸附水,分析物种多样性与生态系统土壤保持功能、稳定性及直接影响土壤保持功能的群落结构、树冠截留间的关系。结果表明,在降雨、坡度、坡向、坡位、土壤类型等水土保持影响因子相同条件下,随着各小区物种多样性的增加,地表产流次数不断下降;在3个降雨季节,物种多样性最低的小区产生地表径流77次,而物种多样性最高小区产生地表径流才9次;系列小区地表径流、土壤侵蚀和总磷流失随着物种多样性增加呈幂指数下降;物种多样性最低的小区地表径流、土壤侵蚀和总磷流失分别为960.20 m³·hm^-2·a^-1,11.4 t·hm^-2·a^-1,127.69 kg·hm^-2·a^-1,而物种多样性最高的小区为75.55 m³·hm^-2·a^-1、0.28 t·hm^-2·a^-1、4.71 kg·hm^-2·a^-1,分别相差12、50和25倍;地表径流、土壤侵蚀和总磷流失变异系数也呈幂指数下降,物种多样性最高的小区地表径流、土壤侵蚀和总磷流失的变异系数分别为57.93、187.94和 59.2,而物种多样性最低的小区变异系数高达287.6、534.21、315.47,分别相差4、3和5倍。物种多样性与影响土壤保持功能的群落郁闭度、密度和胸高断面积呈正相关关系。不同演替阶段植物叶吸附水量差异显著,吸附水量最高的演替阶段是次生半湿润常绿阔叶林,为12.28 t·hm^-2·a^-1, 最低是云南松(Pinus yunnanensis)林, 为4.15 t·hm^-2·a^-1。“植物多样性-土壤保持功能相关群落结构因子及树冠截留效应-生态系统土壤保持功能”的耦合关系表明了植物多样性通过植物群落结构削弱了降雨动能,减少了地表径流,减轻了土壤及营养元素的流失,以间接方式调控生态系统土壤保持功能,维持系统营养的持续性,在不同尺度上实现生态系统生产力。物种多样性的提高,促进了生态系统土壤保持功能的稳定性。植物多样性-生态系统土壤保持过程的研究可能是生态系统稳定性研究的好方法。用植物叶吸附水测定可评价群落树冠截留效应。由于植物多样性与生态系统土壤保持功能间存在相关关系,基于植物多样性对生态系统土壤保持功能作用模式,可增进对生命系统和地球系统界面间相互作用关系的了解。     

The effect of biodiversity on tree productivity: from temperate to boreal forests

Aim An important issue regarding biodiversity concerns its influence on ecosystem functioning. Experimental work has led to the proposal of mechanisms such as niche complementarity. However, few attempts have been made to confirm these in natural systems, especially in forests. Furthermore, one of the most interesting unresolved questions is whether the effects of complementarity on ecosystem functioning (EF) decrease in favour of competitive exclusions over an increasing productivity gradient. Using records from permanent forest plots, we asked the following questions. (1) Is tree productivity positively related to diversity? (2) Does the effect of diversity increase in less productive forests? (3) What metric of diversity (e.g. functional or phylogenetic diversity) better relates to tree productivity? Location Temperate, mixed and boreal forests of eastern Canada. Methods Over 12,000 permanent forest plots, from temperate to boreal forests, were used to test our hypotheses in two steps. (1) Stepwise regressions were used to identify the best explanatory variables for tree productivity. (2) The selected climatic and environmental variables, as well as density and biodiversity indices, were included in a structural equation model where links (paths) between covarying variables are made explicit, making structural equation modelling the best tool to explore such complicated causal networks. Results This is the first large‐scale demonstration of a strong, positive and significant effect of biodiversity on tree productivity with control for climatic and environmental conditions. Important differences were noted between the two forest biomes investigated. Main conclusions We show for the first time that complementarity may be less important in temperate forests growing in a more stable and productive environment where competitive exclusion is the most probable outcome of species interactions, whereas in the more stressful environment of boreal forests, beneficial interactions between species may be more important. The present work is also a framework for the analysis of large datasets in biodiversity–ecosystem functioning (B‐EF) research.     

Diversity and Distributional Patterns of Ciliates in Guaymas Basin Hydrothermal Vent Sediments

Little is known about protists at deep‐sea hydrothermal vents. The vent sites at Guaymas Basin in the Gulf of California are characterized by dense mats of filamentous pigmented or nonpigmented Beggiatoa that serve as markers of subsurface thermochemical gradients. We constructed 18S rRNA libraries to investigate ciliate assemblages in Beggiatoa mats and from bare sediments at the Guaymas vent site. Results indicated a high diversity of ciliates, with 156 operational taxonomic units identified in 548 sequences. Comparison between mat environments demonstrated that ciliate and bacterial assemblages from pigmented mats, nonpigmented mats, and bare sediments were significantly different and highly correlated with bacterial assemblages. Neither bacterial nor ciliate assemblages were correlated with environmental factors. The most abundant ciliates at Guaymas were more likely to be represented in clone libraries from other hydrothermal, deep‐sea, and/or anoxic or microaerophilic environments, supporting the hypothesis that these ciliate species are broadly distributed. The orange mat environment included a higher proportion of ciliate sequences that were more similar to those from other environmental studies than to cultured ciliate species, whereas clone libraries from bare sediments included sequences that were the most highly divergent from all other sequences and may represent species that are endemic to Guaymas.     

Forest biodiversity,ecosystem functioning and the provision of ecosystem services

Forests are critical habitats for biodiversity and they are also essential for the provision of a wide range of ecosystem services that are important to human well-being. There is increasing evidence that biodiversity contributes to forest ecosystem functioning and the provision of ecosystem services. Here we provide a review of forest ecosystem services including biomass production, habitat provisioning services, pollination, seed dispersal, resistance to wind storms, fire regulation and mitigation, pest regulation of native and invading insects, carbon sequestration, and cultural ecosystem services, in relation to forest type, structure and diversity. We also consider relationships between forest biodiversity and multifunctionality, and trade-offs among ecosystem services. We compare the concepts of ecosystem processes, functions and services to clarify their definitions. Our review of published studies indicates a lack of empirical studies that establish quantitative and causal relationships between forest biodiversity and many important ecosystem services. The literature is highly skewed; studies on provisioning of nutrition and energy, and on cultural services, delivered by mixed-species forests are under-represented. Planted forests offer ample opportunity for optimising their composition and diversity because replanting after harvesting is a recurring process. Planting mixed-species forests should be given more consideration as they are likely to provide a wider range of ecosystem services within the forest and for adjacent land uses. This review also serves as the introduction to this special issue of Biodiversity and Conservation on various aspects of forest biodiversity and ecosystem services.     

Tree species identity determines wood decomposition via microclimatic effects

Empirical evidence suggests that the rich set of ecosystem functions and nature's contributions to people provided by forests depends on tree diversity. Biodiversity–ecosystem functioning research revealed that not only species richness per se but also other facets of tree diversity, such as tree identity, have to be considered to understand the underlying mechanisms. One important ecosystem function in forests is the decomposition of deadwood that plays a vital role in carbon and nutrient cycling and is assumed to be determined by above‐ and belowground interactions. However, the actual influence of tree diversity on wood decay in forests remains inconclusive. Recent studies suggest an important role of microclimate and advocate a systematical consideration of small‐scale environmental conditions. We studied the influence of tree species richness, tree species identity, and microclimatic conditions on wood decomposition in a 12‐year‐old tree diversity experiment in Germany, containing six native species within a tree species richness gradient. We assessed wood mass loss, soil microbial properties, and soil surface temperature in high temporal resolution. Our study shows a significant influence of tree species identity on all three variables. The presence of Scots pine strongly increased wood mass loss, while the presence of Norway spruce decreased it. This could be attributed to structural differences in the litter layer that were modifying the capability of plots to hold the soil surface temperature at night, consequently leading to enhanced decomposition rates in plots with higher nighttime surface temperatures. Therefore, our study confirmed the critical role of microclimate for wood decomposition in forests and showed that soil microbial properties alone were not sufficient to predict wood decay. We conclude that tree diversity effects on ecosystem functions may include different biodiversity facets, such as tree identity, tree traits, and functional and structural diversity, in influencing the abiotic and biotic soil properties.     

Climate change-predicted shifts in the temperature regime of shallow groundwater produce rapid responses in ciliate communities

The ciliates living in a shallow groundwater system in southern Ontario, Canada were subjected to an in situ temperature manipulation over 14 months. Ciliates were collected from the bed surface of a small springbrook and from interstitial water collected at five depths beneath its surface. Mean temperature elevations established at each depth (?20, ?40, ?60, ?80, and ?100 cm) between the experiment's control and treatment blocks were 1.9, 3.5, 3.9, 3.8, and 3.6 °C, respectively, and were based on global warming projections for the region. In total, 160 species of ciliate belonging to 85 genera were identified. Overall, the treatment block had a higher density (6510±342 cells L^?1; ±1 SE) than the control (5797±237 cells L^?1), but densities were both vertically and longitudinally variable. Control densities decreased with depth, whereas treatment densities were more equal among depths. Total species richness showed no significant difference between blocks when combining all sampling dates and depths, although species composition changed. The ciliate community was dominated by small (15–50 μm), followed by medium (50–200 μm), and only a few large‐sized (>200 μm) species. Small ciliates contributed 82–97% of the total density. Small ciliates also contributed more to the treatment (94%) than the control block (88%). The most common ciliate feeding groups were bacterivores, omnivores, predators, and algae‐diatom feeders, with bacterivores being most dominant (83–99% of the total numbers collected). Ordination analyses revealed that ciliate distribution was strongly correlated with groundwater temperature, although dissolved oxygen level, concentrations of ammonia and nitrate, and depth also appeared to be influential. Peak densities of many species occurred in either the control or treatment blocks, but not in both. The benefits of using ciliates as a proxy for higher, much longer‐lived, eukaryotes in climate change studies are discussed.