Seasonal fluctuations in taxonomic and functional diversity in assemblages of catfishes in the Venezuelan Arauca River Floodplain

The Arauca River harbors a considerable fish biodiversity, yet it remains poorly sampled and the knowledge about its fish communities is incomplete. We studied the taxonomic and functional composition and diversity of catfish assemblages in one lotic and one lentic habitat of a segment of this floodplain during one hydrological cycle, from August 2014 to August 2015, comprising six samplings using gillnets, and identified the relationships between catfish traits and the environment based on five limnological variables. The functional structure was studied through 11 morphological measures and the species diets. We identified 31 catfish species and nine trophic groups. There were significant differences in species composition and diversity between habitats and months, but the functional structure of the catfishes was only determined by the temporal variability. The functional structure of the catfish assemblages was ordered by morphological traits related to locomotion, habitat use, and trophic ecology and these traits were correlated with the limnological variables, supporting the existence of environmental filters. Integrating the taxonomic and functional perspectives can provide a more complete picture of the ecological patterns of freshwater fish assemblages in the Neotropics and can help us predict how these assemblages might change in response to anthropogenic alterations of the environment.     

植物功能性状与外来植物入侵

揭示影响外来植物入侵性的功能性状及其生态机制是入侵植物生态学的核心任务之一。本文综述了植物功能性状与外来植物入侵性的研究进展, 通过分析植物功能性状对外来植物入侵的贡献以及外来植物的不同入侵阶段对其功能性状的需求, 探讨植物功能性状与外来植物入侵的相关性及其入侵机理。迄今研究较多的影响外来植物入侵性的功能性状主要包括形态性状、生长性状、生理性状、繁殖性状、种子性状、克隆性状、表型可塑性和遗传变异等。这些功能性状对外来植物入侵的贡献随着入侵阶段的不同而变化。在传播到达阶段, 种子性状对入侵具有重要影响; 在定居建群阶段, 与植物抗逆性和适应性相关的生理性状和繁殖性状发挥主要作用; 在扩散入侵阶段, 克隆性状和影响植物竞争能力的生理性状对植物成功入侵具有重要贡献。由于植物入侵性是其功能性状和环境因素互作的结果, 且功能性状的作用随环境因素和入侵阶段不同而异, 因此, 结合外来植物入侵阶段, 并考虑功能性状与环境因子的互作, 是入侵生物学中植物功能性状研究的发展趋势。     

植物叶片形态的生态功能、地理分布与成因

叶片是植物与环境进行水气交换的重要场所, 形态多变。叶片形态可直接影响植物的生理生化过程, 反映植物的资源获取策略。该文以叶片大小、叶形、叶缘特征(有无叶齿)和叶型(单、复叶)等形态性状为例, 总结了当前叶片形态的研究进展, 分析了叶形态性状的生态功能, 综述叶片形态的地理分布, 探讨叶片形态性状变化的驱动因素及其对生态系统功能的影响。现有研究主要聚焦于局域尺度的特定类群, 关注叶大小、叶缘具齿性以及叶型的地理分布与生态成因, 发现叶片的形态发育受基因调控, 叶形态性状与其他性状相互权衡, 其空间变异受气温和降水量共同驱动。以叶大小为代表的叶片形态性状影响水分和养分循环, 能够反映气候变化下的群落响应, 也可用于预测生态系统初级生产力。今后应结合新方法获得覆盖度高且区域无偏的数据, 探索叶形态在长时间尺度上的适应性进化, 研究叶形态特征及其对生态系统功能影响的尺度推绎。该文有助于从叶片的角度认识植物对环境变化的响应, 以性状为桥梁将个体适合度、群落动态与生态系统功能联系起来, 能够加深对植物群落生态学和功能生物地理学等相关领域研究进展的了解。     

崇明东滩湿地芦苇种群内功能性状及生态对策变异分析

植物种群功能性状及生态对策变异对其自身环境适应能力及群落结构具有重要影响。该文基于崇明东滩湿地芦苇(Phragmites australis)种群内3个小种群不同发育时期分株集合的多项性状指标,分析了其性状及生态对策变异,并基于CSR、LHS生态对策体系,对各小种群的生态对策进行了排序。结果表明, 3个芦苇小种群的21项性状指标及C、R对策得分均存在显著差异。在LHS体系中,以比叶面积(11.5 mm2/mg)、株高(175 cm)和花序干质量(4 g)为分界线,可对3个小种群进行区分。处于生殖生长期的芦苇分株具有更大的植株大小、更高的叶片干物质含量及S对策得分,而处于营养生长期的分株则具有较小的植株大小、较大的比叶面积及R对策得分。总体而言,崇明东滩湿地3个芦苇小种群间及各小种群内处于不同生长发育阶段的分株集合间,都存在显著的性状差异及生态对策差异,且二者的差异模式基本吻合。芦苇种内性状及生态对策变异特征,可为该区芦苇种群的生态保育和恢复实践提供重要的理论参考和技术支撑。     

吉林蛟河针阔混交林功能性状分布格局及其对地形因素的响应

森林群落的构建过程及其内在机制是生态学研究的热点问题。植物功能性状是指能够代表植物的生活史策略,反映植物对环境变化响应的一系列植物属性。通过植物功能性状的分布格局及其对环境因素的响应有助于推测群落的构建过程及其内在作用机制。以吉林蛟河21.12hm²温带针阔混交林样地为研究对象,采集并测量了样地内34种木本植物的6种不同的功能性状。以20m×20m的样方为研究单元,通过计算平均成对性状距离指数（mean pairwise trait distance;PW）和平均最近邻体性状距离指数（mean nearest neighbor trait distance;NN）来探讨群落中单个性状和综合性状的分布格局。同时结合地形因子采用回归分析探讨功能性状的分布格局对局域生境变化的响应。基于PW的结果显示：单个性状中除叶面积外,其余性状的分布格局均为聚集分布多于离散分布;基于NN的结果显示：除叶面积和最大树高外,其余性状的分布格局为聚集分布多于离散分布。此外,由6种单个性状组成的综合性状的分布格局同样为聚集分布多于离散分布。基于回归分析的结果显示：森林群落中功能性状的分布格局受到海拔、坡度和坡向等因素的显著影响,而凹凸度的影响则不显著。研究结果表明包括环境过滤和生物相互作用的非随机过程能够影响温带针阔混交林的群落构建过程,中性过程对该区域群落构建过程的影响不显著。     

Pattern and process in Norwegian upland grasslands: a functional analysis

Abstract. Four classes of functional and morphological plant traits – established strategies (the CSR scheme sensu Grime 1979), life‐forms (sensu Raunkiaer 1934), morphology, and regenerative strategies – are used as tools for explaining vegetation gradients at summer farms in the mountains of western Norway. These farms are assembly points for free‐ranging domestic grazers, and differ floristically and ecologically from the surrounding heath or woodland vegetation. DCA and TWINSPAN are used to relate major gradients in a floristic data set from 12 summer farms to two sets of explanatory variables: (1) environmental variables representing physical factors, plot position, soils, and land use, and (2) the 4 classification schemes. The main floristic gradient parallels a spatial gradient from the centres of the farms to the surrounding vegetation. A functional interpretation based on the concurrent use of the 2 sets of explanatory variables suggests that the gradient is one of decreasing disturbance and increasing environmental stress caused by decreasing grazing and manure effects away from farms. Partial CCA is used to investigate the relationships between the 4 functional/morphological plant trait classes. The 4 classification schemes are partially redundant, and do not represent different trends of specialization within the landscape. There is no strong evidence for decoupling of the traits of the vegetative and regenerative phases within the data. The combination of general process‐based theories and specific plant attribute responses enhances the generality and interpretability of the study.     

Making sense of environmental sequencing data: Ecologically important functional traits of the protistan groups Cercozoa and Endomyxa (Rhizaria)

We have compiled a database of functional traits for two widespread and ecologically important groups of protists, Cercozoa and Endomyxa (Rhizaria). The functional traits of microorganisms are crucially important for interpreting results from environmental sequencing surveys. Linking morphological and ecological traits to environmental factors is common practice in studies involving micro‐ and macroorganisms, but is rarely applied to protists. Our database provides functional and ecologically significant traits linked to morphology, nutrition, locomotion and habitats. We discuss how the use of functional traits may help to unveil underlying ecosystem processes. This database is intended as a common reference for the molecular ecology community and will boost the understanding of ecosystem functions, especially those driven by biological interactions.     

Co-occurrence patterns and morphological similarity of semiaquatic insects (Hemiptera: Gerromorpha) in streams of Eastern Amazonia

1. To understand how the semiaquatic bug communities are shaped, it was first verified whether there was a pattern of co-occurrence between species. It was subsequently tested whether the pattern found was related to environmental variables. Lastly, it was verified whether morphological divergence between species was present in the morphological and functional traits selected. 2. A pattern of species co-occurrence was found in the studied assemblage, related to both environmental variables and interspecific biological interactions. Pairs of species with negative, positive, and random co-occurrence were found. Traits related to predation competition, sexual competition, and interaction with the environment showed significant morphological divergence. 3. Therefore, more than one process defines species co-occurrence patterns in semiaquatic bug communities. It is suggested that environmental influence is related to species microhabitat preference. On the other hand, the morphological divergence found is related to competition and sharing of food resources.     

中国亚热带不同菌根树种的根叶形态学性状特征与生长差异: 以江西新岗山为例

探究植物功能性状的种内和种间变异不仅有助于揭示植物对环境的适应, 也能够反映植物的生态策略, 但不同菌根类型树木生长过程中根叶形态学功能性状的适应策略仍有待探究。本研究依托中国亚热带森林生物多样性与生态系统功能实验研究平台(BEF-China)选取7种丛枝菌根(AM)树木和7种外生菌根(EM)树木的纯林, 测定各个树种的比叶面积、叶干物质含量、比根长、根系直径、树高生长速率、地径生长速率及细根生物量等根叶形态学功能性状和生长指标, 探讨了两种菌根类型树种间的根叶形态学特征的差异。结果表明: 与AM树种相比, EM树种具有较小的比叶面积、吸收根平均直径和生长速率, 但具有更大的叶干物质含量; 两种菌根树种之间的比根长和细根生物量无显著差异。比叶面积、叶干物质含量、树高生长速率、地径生长速率和细根生物量等功能性状及生长指标在不同菌根类型、树种及二者的交互作用中均存在显著差异; 且树种、根功能型、菌根类型及三者之间的交互作用均对根功能性状有显著影响。EM树种地上指标的种内变异均大于种间变异, 而AM树种地上指标的种内和种间变异程度类似; 但两种菌根树种细根生物量的种间变异均大于种内变异。尽管两种菌根树种地上部分生长速率较快通常表现为较低的叶干物质含量, 但AM树种通常拥有较高的吸收根比根长, 而EM树种拥有较粗的运输根平均直径。吸收根比根长越低, 两类菌根树种的细根生物量就越多。由此可见, 根叶功能性状对植物地上部分的生长具有一定的协同效应, 其中运输根主要在EM树种地上生长过程中发挥重要作用, 吸收根主要与AM树种的地上部分生长有关; 但两类菌根树种的地下细根生物量均与吸收根有关。     

Phylogenetic effects on functional traits and life history strategies of Australian freshwater fish

Understanding the biogeographic and phylogenetic basis to interspecific differences in species’ functional traits is a central goal of evolutionary biology and community ecology. We quantify the extent of phylogenetic influence on functional traits and life‐history strategies of Australian freshwater fish to highlight intercontinental differences as a result of Australia's unique biogeographic and evolutionary history. We assembled data on life history, morphological and ecological traits from published sources for 194 Australian freshwater species. Interspecific variation among species could be described by a specialist–generalist gradient of variation in life‐history strategies associated with spawning frequency, fecundity and spawning migration. In general, Australian fish showed an affinity for life‐history strategies that maximise fitness in hydrologically unpredictable environments. We also observed differences in trait lability between and within life history, morphological and ecological traits where in general morphological and ecological traits were more labile. Our results showed that life‐history strategies are relatively evolutionarily labile and species have potentially evolved or colonised in freshwaters frequently and independently allowing them to maximise population performance in a range of environments. In addition, reproductive guild membership showed strong phylogenetic constraint indicating that evolutionary history is an important component influencing the range and distribution of reproductive strategies in extant species assemblages. For Australian freshwater fish, biogeographic and phylogenetic history contribute to broad taxonomic differences in species functional traits, while finer scale ecological processes contribute to interspecific differences in smaller taxonomic units. These results suggest that the lability or phylogenetic relatedness of different functional traits affects their suitability for testing hypothesis surrounding community level responses to environmental change.     

喀斯特常绿落叶阔叶林木本植物功能性状变异及其适应策略

叶片功能性状能反映植物对环境的高度适应能力和复杂生境下的自我调控能力,同时也能反映植物的基本特征和对资源的有效利用率。以木论国家级自然保护区喀斯特常绿落叶阔叶林144种优势木本植物为研究对象,测定其叶厚(LT)、叶面积(LA)、比叶面积(SLA)、叶长宽比(L/W)、叶组织密度(LTD)叶片形态性状和12种叶元素性状特征及变异程度,并探讨植物对喀斯特生境的适应策略。结果表明：17个性状变异程度不同,其中叶面积变异系数最大,达到133.31%,叶片碳变异系数最小,为7.73%,叶元素变异程度普遍高于叶形态性状变异程度。不同叶习性物种间叶厚、比叶面积、叶长宽比、叶氮含量性状差异达到显著水平。部分叶性状呈显著相关,得到一系列最佳功能性状组合,体现植物对喀斯特地区特殊生境的适应性。沿着性状贡献率较高的PC1轴,能够定义出叶经济谱,大部分常绿植物采取经济保守策略,而大部分落叶植物则聚集在资源获取的一侧。相较于邻近非喀斯特地区,喀斯特地区植物有较小的LA、SLA。这些结果体现了喀斯特地区植物叶片形成的不同叶性状特征,以及分布于经济谱两端的常绿和落叶植物的不同资源获取策略,揭示了植物对生境的适应策略...     

蚂蚁群落与栖境关系研究进展及新趋势

生物群落与栖境的关系是生态学研究的核心之一,蚂蚁群落由于在陆地生态系统中的生物量、分布以及具备的生态功能的重要性,是研究这种关系的理想对象。在查阅大量文献的基础上,简述了蚂蚁物种多样性与栖境关系研究现状。介绍了蚂蚁功能群划分以及在不同尺度上与栖境关系的应用研究,评述了功能群应用的限制。阐明了功能特征的定义以及基于形态特征和营养级方面的蚂蚁群落功能特征与栖境的研究,并对功能特征的研究趋势进行了展望。     

Functional traits reveal the expansion and packing of ecological niche space underlying an elevational diversity gradient in passerine birds

Variation in species richness across environmental gradients may be associated with an expanded volume or increased packing of ecological niche space. However, the relative importance of these alternative scenarios remains unknown, largely because standardized information on functional traits and their ecological relevance is lacking for major diversity gradients. Here, we combine data on morphological and ecological traits for 523 species of passerine birds distributed across an Andes-to-Amazon elevation gradient. We show that morphological traits capture substantial variation in species dietary (75%) and foraging niches (60%) when multiple independent trait dimensions are considered. Having established these relationships, we show that the 14-fold increase in species richness towards the lowlands is associated with both an increased volume and density of functional trait space. However, we find that increases in volume contribute little to changes in richness, with most (78%) lowland species occurring within the range of trait space occupied at high elevations. Taken together, our results suggest that high species richness is mainly associated with a denser occupation of functional trait space, implying an increased specialization or overlap of ecological niches, and supporting the view that niche packing is the dominant trend underlying gradients of increasing biodiversity towards the lowland tropics.     

Phylogenetic and morphological relationships between nonvolant small mammals reveal assembly processes at different spatial scales

The relative roles of historical processes, environmental filtering, and ecological interactions in the organization of species assemblages vary depending on the spatial scale. We evaluated the phylogenetic and morphological relationships between species and individuals (i.e., inter‐ and intraspecific variability) of Neotropical nonvolant small mammals coexisting in grassland‐forest ecotones, in landscapes and in regions, that is, three different scales. We used a phylogenetic tree to infer evolutionary relationships, and morphological traits as indicators of performance and niche similarities between species and individuals. Subsequently, we applied phylogenetic and morphologic indexes of diversity and distance between species to evaluate small mammal assemblage structures on the three scales. The results indicated a repulsion pattern near forest edges, showing that phylogenetically similar species coexisted less often than expected by chance. The strategies for niche differentiation might explain the phylogenetic repulsion observed at the edge. Phylogenetic and morphological clustering in the grassland and at the forest interior indicated the coexistence of closely related and ecologically similar species and individuals. Coexistence patterns were similar whether species‐trait values or individual values were used. At the landscape and regional scales, assemblages showed a predominant pattern of phylogenetic and morphological clustering. Environmental filters influenced the coexistence patterns at three scales, showing the importance of phylogenetically conserved ecological tolerances in enabling taxa co‐occurrence. Evidence of phylogenetic repulsion in one region indicated that other processes beyond environmental filtering are important for community assembly at broad scales. Finally, ecological interactions and environmental filtering seemed important at the local scale, while environmental filtering and historical colonization seemed important for community assembly at broader scales.     

Global warming and potential shift in reference conditions: the case of functional fish-based metrics

The reference condition approach, advocated by the Water Framework Directive, is the basis of most currently used multimetric indices using functional traits of fish species. The ecological status of streams is assessed by measuring the deviation of the observed trait values from the theoretical values of reference conditions in the absence of anthropogenic disturbances. While reference conditions serve as baselines for ecological assessment, they vary with natural environmental conditions. Therefore, global warming appears to be a major threat to the use of current indices for diagnosing future stream conditions, as climate change is projected to modify assemblage composition, suggesting that the functional structure of fish assemblages will also be affected. The main objectives of this study are to assess the potential effect of climate change on the trait composition of fish assemblages and the consequences for the establishment of reference conditions. The results highlight the relation between environmental, especially climatic, conditions and functional traits and project the effects of climate change on trait composition. Traits based on species intolerance are expected to be most negatively affected by the projected climatic shift. The consequences for the development of multimetric indices based on fish functional traits are discussed.     

Functional diversity analysis helps to identify filters affecting community assembly after fen restoration by top-soil removal and hay transfer

Top-soil removal followed by species introduction through hay transfer has appeared as a method to restore drained fens. This method addresses abiotic constraints by restoring hydrology and nutrient status, and biotic constraints by removing an unwanted seed bank and counteracting dispersal-limitation. Restoration works by altering environmental filters. Knowledge about the restoration actions effect on functional traits is necessary to understand which types of species may establish. In this study we analyse which factors in top-soil removal followed by hay transfer influence selection and composition of functional traits. Top-soil removal followed by hay transfer from reference sites was conducted at two sites in the Całowanie fen, 33 km SE of Warsaw, Poland. Species and abundance data were recorded for three consecutive years. These data, combined with data on functional traits were used to analyse the effect of the restoration actions on four functional diversity-indices and the community weighted mean of functional traits. Our results reveal a strong habitat filter in the restoration site that follows an elevation gradient. At low elevation this filter selects low values of autochory and specific leaf area and high values of clonal lateral spread, Ellenberg moisture values, and dispersal through hydrochory. The transferred hay differs in trait characteristics compared to the reference site vegetation by having species of higher specific leaf area, lower Ellenberg moisture value and lower dispersal by autochory and hydrochory. The result presented here has three important implications for fen restoration. First, the difference in trait-characteristics between the transferred hay and the reference site it was harvested from limits the restoration potential. Second, since for several fen species important functional traits are filtered along an elevation-gradient, careful planning regarding depth of top-soil removal is needed. Finally the results illustrate how a functional analysis can be used to detect environmental filters acting during ecological restoration.     

森林幼苗更新对光环境异质性的响应研究进展

在分析森林光环境异质性特点的基础上,从幼苗的光合、热耗散、生物量累积和分配、形态特征、萌发和种群动态等方面综述了国内外在森林幼苗更新对光环境异质性响应的研究进展.从森林物种多样性维持、森林演替和植被恢复角度探讨了幼苗更新对光环境异质性不同响应的生态学意义,并对今后该方面研究提出建议.     

玛曲高寒沼泽化草甸51种植物光合生理和叶片形态特征的比较

基于功能性状的研究方法广泛地应用于生态学研究, 用于解释不同层次的复杂的生态学过程, 而绿色植物叶片的功能性状长期被认为对植物的生存、生长和繁殖具有重要的影响。该研究对玛曲高寒沼泽化草甸51个植物种(分属于14科)的叶片形态和光合性状进行测量, 比较不同物种和不同功能群(莎草科、禾本科和双子叶类杂草)的差异, 分析叶片形态特征和叶片光合性状之间的相关性。结果表明: 1)不同物种、不同功能群之间在比叶面积、净光合速率和水分利用效率等叶片形态和光合特征方面有着显著的差异, 例如禾本科植物具有较高的比叶面积和水分利用效率, 双子叶类杂草具有较大的叶面积, 而莎草科植物具有较高的净光合速率。2)相关性分析结果显示, 无论在物种水平还是功能群水平, 叶片形态和叶片光合性状之间都具有显著的相关关系。该研究揭示了高寒沼泽化草甸植物物种在叶片功能性状上的显著分化, 进而使得这些物种能在同一个草地群落中共存, 而群落中不同功能群物种的组成差异将会对群落的结构、功能和资源利用产生显著的影响。该研究将为进一步研究高寒沼泽化草甸提供基础研究数据并为其保护和恢复提供生理生态学依据。     

Traits reveal how habitat‐quality gradients structure small mammal communities in a fragmented tropical landscape

Understanding the relationships among community structure, vegetation structure and availability of food resources are a key to unravelling the ecological processes that structure biological communities. In this study, we tested (i) whether the composition of small mammal communities changed across gradients in habitat quality in tropical forest fragments, and (ii) whether any observed change could be explained by the functional traits of species. We sampled 24 trapping grids in fragments of semi‐deciduous forest, in each of two 6‐month periods. We considered each trapping grid as a sampling unit, for which we collected three datasets: an environmental matrix (vegetation structure and food resource availability), the abundance of small mammal species (community structure) and a matrix of functional traits (ecological and morphological traits which express tolerance to habitat disturbance and trophic guild). We used an RLQ approach to evaluate the association between traits and environmental gradients. Forest‐specialist and scansorial–arboreal species were associated with more complex habitat that had greater litter and canopy cover and more fallen logs. In relation to trophic guilds, granivore (fruit seeds), insectivorous and omnivorous species were also associated with higher complexity habitat, while frugivores were associated with shrub cover and availability of fruits. We conclude that functional traits (habitat use, use of vertical strata and diet) provide valuable insights into the distribution of small mammals along gradients of habitat quality in tropical forest fragments. We highlight that communities studies in fragmented landscapes should investigate the different components of biodiversity not only in landscape‐scale but also in habitat scale. Abstract in Portuguese is available with online material.     

植物功能性状研究进展

植物功能性状是指植物体具有的与其定植、存活、生长和死亡紧密相关的一系列核心植物属性,且这些属性能够显著影响生态系统功能,并能够反映植被对环境变化的响应.越来越多的研究表明,相比大多数基于植物分类和数量的研究,植物功能性状在种群、群落和生态系统尺度上,都已成为解决重要生态学问题的可靠途径.本文回顾了植物功能性状研究的发展历程,总结了近10年来基于植物功能性状研究的前沿科学问题,包括功能性状的全球分布格局和内在关联,沿环境梯度的变化规律,功能多样性的定义及应用,与群落物种共存机制和群落动态变化的关系,与系统发育的关系,对生态系统功能的影响以及对各类干扰的影响和响应.尽管功能性状研究已经延伸到生态学领域的各个方面,有力推动了各个前沿科学问题的研究发展,仍然有很多值得关注和着重研究的方向.本文也对未来基于植物功能性状的研究,从性状测量和选取、研究方法以及研究方向上提出了展望,并指出,在当前全球气候变化背景下,功能性状也可应用于指导生物多样性保护和生态系统管理政策的制定.