Towards a trait-based quantification of species niche

Aims Although the niche concept is of prime importance in ecology, the quantification of plant species' niches remains difficult. Here we propose that plant functional traits, as determinants of species performance, may be useful tools for quantifying species niche parameters over environmental gradients.Important findings Under this framework, the mean trait values of a species determine its niche position along gradients, and intraspecific trait variability determines its niche breadth. This trait-based approach can provide an operational assessment of niche for a potentially large number of species, making it possible to understand and predict species niche shifts under environmental changes. We further advocate a promising method that recently appeared in the literature, which partitions trait diversity into among- and within-community components as a way to quantify the species niche in units of traits instead of environmental parameters. This approach allows the switch of the focus from ecological niches to trait niches, facilitating the examination of species coexistence along undefined environmental gradients. Altogether, the trait-based approach provides a promising toolkit for quantifying the species ecological niche and for understanding the evolution of species niche and traits.     

三江平原典型沼泽湿地植物种群的生态位

采用Levins 公式,对三江平原典型沼泽湿地植物群落的优势种群生态位宽度和生态位重叠值进行了研究.结果表明：各湿地植物种的生态位宽度排序为漂筏苔草(0.907)>毛果苔草(0.864) >狭叶甜茅(0.855) >小叶章＝睡菜＝球尾花＝二歧银莲花(0.500).毛果苔草、漂筏苔草、睡菜与球尾花之间,以及狭叶甜茅、小叶章与二歧银莲花的生态位重叠值均较高,说明几种植物在同一资源位上出现的频率相近,利用资源的能力相似,在对资源利用上具有一定的竞争性.睡菜与小叶章和二歧银莲花,以及球尾花与小叶章和二歧银莲花的生态位重叠值均为0,表明几种植物适应环境的方式不同.水分是导致湿地植物生态适应性差异的主导因子,植物对环境生态位适应的程度是水分和营养状况等因素共同作用的结果.湿地植物的生态位特征能较好地表征各植物的生态适应性和分布幅度.     

Ant association facilitates the evolution of diet breadth in a lycaenid butterfly

The role of mutualistic interactions in adaptive diversification has not been thoroughly examined. Lycaenid butterflies provide excellent systems for exploring mutualistic interactions, as more than half of this family is known to use ants as a resource in interactions that range from parasitism to mutualism. We investigate the hypothesis that protection from predators offered to caterpillars by ants might facilitate host-range evolution. Specifically, experiments with the butterfly Lycaeides melissa investigated the role of ant association in the use of a novel host, alfalfa, Medicago sativa, which is a sub-optimal host for larval development. Survival on alfalfa is increased by the presence of ants, thus supporting the hypothesis that interaction with ants might be important for host-range evolution. Using a demographic model to explore ecological conditions associated with host-range expansion in L. melissa, we conclude that the presence of ants might be an essential component for populations persisting on the novel, sub-optimal host.     

三峡库区消落带现存草本植物组成与生态位

为揭示经历长期水位变动后,三峡水库消落带优势植物对可利用资源的分享状况、不同资源环境下植物种群生态位特征以及植物种间竞争和共存机制,对三峡库区秭归段典型消落带现存优势草本物种的种群空间格局及生态位特征进行研究.结果表明: 该区共有草本植物39种,隶属18科32属,以禾本科、菊科、蓼科和大戟科植物为主;狗牙根、狗尾草、狼把草和毛马唐具有较大的重要值和生态位宽度,为主要优势种;海拔145～155 m段植物生态位宽度前3位依次为狗牙根＞酸模叶蓼＞狗尾草;海拔155～165 m段植物生态位宽度前3位依次为狗尾草＞毛马唐＞狗牙根;海拔165～175 m段植物生态位宽度前3位依次为狗尾草＞狼把草＞红蓼;不同海拔物种间生态位重叠均保持较高状态,生态位宽度较小物种也可与生态位宽度较大物种有较大的生态位重叠值,仅凭生态位宽度不能判定生态位重叠值.消落带经历7次水位涨落周年后,大多数优势物种为一年生草本植物,生态位分化程度较低,在资源匮乏且不稳定的生境中种间竞争强烈,消落带植被仍处于群落演替的初级阶段.     

沙区生态系统恢复演变过程中固沙植物种间生态位关系变化的研究

以演变时间为生态位维 ,通过分析物种的生态位体积和生态位重叠 ,研究了荒漠生态系统恢复演变过程中固沙植物种间生态位关系的变化 ,同时也探讨了物种更替的生态学机制。这一研究对于实现沙区固沙植物群落的持续发展具有重要的指导意义     

Changes in the realized niche of the invasive succulent CAM plant Furcraea foetida

Furcraea foetida (Asparagaceae) is a native plant of Central America and northern South America but there is no information about its country of origin. The species was introduced into Brazil and is now considered invasive, particularly in coastal ecosystems. To date, nothing is known about the environmental factors that constrain its distribution and there is only inconclusive information about its location of origin. We used reciprocal distribution models (RDM) to assess invasion risk of F. foetida across Brazil and to identify source regions in its native range. We also tested the niche conservatism hypothesis using Principal Components Analyses and statistical tests of niche equivalency and similarity between its native and invaded ranges. For RDM analysis, we built two models using maximum entropy, one using records in the native range to predict the invaded distribution (forward‐Ecological Niche Model or forward‐ENM) and one using records in the invaded range to predict the native distribution (reverse‐ENM). Forward‐ENM indicated invasion risk in the Cerrado region and the innermost region of the Atlantic Forest, however, failed to predict the current occurrence in southern Brazil. Reverse‐ENM supported an existing hypothesis that F. foetida originated in the Orinoco river basin, Amazon basin and Caribbean islands. Prediction errors in the RDM and multivariate analysis indicated that the species expanded its realized niche in Brazil. The niche similarity test further suggested that the niche differences are because of differences in habitat availability between the two ranges, not because of evolutionary changes. We hypothesize that physiological pre‐adaptation (especially, the crassulacean acid metabolism), human‐driven propagule pressure and high competitive ability are the main factors determining the current spatial distribution of the species in Brazil. Our study highlights the need to include F. foetida in plant invasion monitoring programs, especially in priority conservation areas where the species has still not been introduced.     

天然林和人工林外来入侵和本地植物对比研究: 以弄岗国家级自然保护区为例

外来植物的入侵严重威胁了自然保护区的生物多样性。为探讨自然保护区内天然林和人工林林下外来植物入侵状况及其与本地优势植物的种间关系, 本研究以弄岗国家级自然保护区为研究区域, 结合保护区内4种生境72个样方的野外调查数据, 利用生态位宽度、生态位重叠和种间联结指数比较了不同生境中外来入侵草本植物的多样性和生态位宽度以及外来入侵草本植物与本土优势草本植物的生态位重叠和种间联结。结果表明: 弄岗国家级自然保护区4种生境共记录6种外来入侵草本植物, 隶属于3科6属, 其中菊科物种数量最多。外来入侵植物多样性呈现出秋枫(Bischofia javanica)人工林 > 麻竹(Dendrocalamus latiflorus)次生林 > 人面子(Dracontomelon duperreanum)人工林 > 广西澄广花(Orophea polycarpa)次生林的特征。除广西澄广花次生林生境的外来入侵草本植物丰富度与本土草本植物丰富度呈显著正相关外, 其余生境均无显著的相关关系。三叶鬼针草(Bidens pilosa)的生态位宽度最大, 为4种生境均有分布的外来入侵植物。4种生境的外来入侵植物与本土优势植物生态位重叠和种间联结程度均较低, 种间竞争较弱。本研究明确了弄岗国家级自然保护区天然林和人工林中外来入侵草本植物的分布及其与本土草本植物的种间关系。     

木本植物萌枝生态学研究进展

综述了萌枝的生物学特征、个体生活史策略、生物地理学特征,以及对种群和群落特征的影响.已有的研究虽然在干扰与萌枝关系、萌枝生活史策略等领域取得了众多成果,但生态学意义远未揭示清楚,尤其是萌枝对种群、群落结构和动态的影响还需要深入探索.我国在重视萌枝生态理论研究的基础上,应加强理论和植被恢复及生态系统管理实践相结合的研究.     

A study on the niches of the state’s key protected plants in Bawangling,Hainan Island

Aims An understanding on the living communities of the state’s key protected wild plants and the ability in utilizing resources and occupying ecological spaces by different populations is essential to the protection and propagation of rare and endangered plant species. We use our findings to highlight the knowledge gaps in the conservation strategies for the endangered species.
Methods Field investigations were conducted during 2009-2011. Based on the survey data on 70 forest plots in the Bawangling protected area, the niche breadths and overlaps of 12 species listed as the state’s key protected plants were calculated and analyzed.
Important findings The 12 species, by their niche breadth values in descending order, include Aquilaria sinensis, Nephelium topengii, Camellia sinensis var. assamica, Alseodaphne hainanensis, Keteleeria hainanensis, Podocarpus imbricatus, Firmiana hainanensis, Parakmeria lotungensis, Cephalotaxus mannii, Michelia hedyosperma, Ixonanthes reticulata, Dacrydium pierrei. The niche breadth value of a species is closely related to its range of geographical distribution; both Dacrydium pierrei and Parakmeria lotungensis had a narrow niche breadth corresponding to their narrow ranges of altitudinal distribution. In general, the niche overlap value is higher between species with greater niche breadth; the highest niche overlap value of 0.872 was found between Camellia sinensis var. assamica and Keteleeria hainanensis. However, the niche overlap value between species with smaller niche breadth could also be high; e.g. the niche overlap value was relatively high (0.693) between two species with smaller niche breadth, Michelia hedyosperma and Firmiana hainanensis, indicating that niche overlap value is dependent upon the biological characteristics and requirements for environmental resources of the species of comparison. Some species with low niche breadth values (e.g. Michelia hedyosperma and Ixonanthes reticulata) were found to have smaller populations. Due to lack of suitable community and habitats, these plant species are in dire need of more attention and prioritization for conservation. In conclusion, for the better protection and propagation of these endangered plants in the future, we should combine knowledge of their biological characteristics with that of their living communities such as the montane rainforests, etc.     

仙湖苏铁群落优势种群的生态位特征

采用生态位宽度和生态位重叠探讨仙湖苏铁群落优势种群的生态位特征。结果表明,群落中生态位宽度大的优势种群,对其它种群的生态位重叠大,而生态位宽度小的种群对生态位宽度大的种群的生态位重叠不一定大;如果2个种群生态位宽度相近,则存在着较大的生态位重叠。优势种之间生态位重叠大,由于存在资源竞争,导致群落组成和结构发生变化从而影响群落的演替发展。相同的物种对在不同层次其生态位重叠水平不一致,从林下层到立木层,物种对的生态位重叠程度降低。仙湖苏铁种群与立木层中生性树种的生态位重叠大,由于植株高度的差异,它们之间可能存在着促进而非竞争关系,因此调整群落林分组成,使群落向着以中生性树种为优势种的方向发展,也许是促进仙湖苏铁种群恢复和发展的有利措施。     

海南岛霸王岭国家重点保护植物的生态位研究

为进一步了解国家重点野生保护植物的生存群落及不同种群利用资源和占据生态空间的能力, 为制定国家重点保护植物种群的保护措施提供依据, 2009-2011年, 对霸王岭有国家重点保护植物分布的70个样地进行群落调查, 研究了霸王岭保护区内12种国家重点保护植物的生态位宽度以及物种间的生态位重叠。结果表明: (1)生态位宽度值从大到小依次为: 土沉香(Aquilaria sinensis)、海南韶子(Nephelium topengii)、普洱茶(Camellia sinensis var. assamica)、油丹(Alseodaphne hainanensis)、海南油杉(Keteleeria hainanensis)、鸡毛松(Podocarpus imbricatus)、海南梧桐(Firmiana hainanensis)、乐东拟单性木兰(Parakmeria lotungensis)、海南粗榧(Cephalotaxus mannii)、香子含笑(Michelia hedyosperma)、粘木(Ixonanthes reticulata)和陆均松(Dacrydium pierrei); (2)物种生态位宽度值的大小与其自身的地理分布范围密切相关, 如: 陆均松、乐东拟单性木兰等生态位宽度较小的原因与其分布的海拔范围狭窄有关。生态位宽度较大的种群对资源的利用能力较强, 与其他物种的生态位重叠一般较大, 如: 生态位宽度较大的普洱茶与海南油杉的生态位重叠值最大, 为0.872, 而一些生态位宽度较小的物种生态位重叠值较高, 如: 香子含笑的生态位宽度较小, 但与海南梧桐的生态位重叠较大, 为0.693。因此, 种群间的生态位重叠值与它们对环境资源利用的相似程度以及物种自身的生物学特性密切相关; (3)香子含笑、粘木等的生态位宽度较小, 而且个体数量较少, 适宜其生存的群落和生境极少, 应该给予更多的关注和优先保护; (4)未来对濒危植物的保护不仅要考虑各物种自身的生物学特性, 还应从植物群落的角度考虑。只有保护好这些濒危植物的生存群落, 如山地雨林等, 才能实现对濒危植物的有效保护。     

Invasions: the perspective of diverse plant communities

Exotic plant invasions represent a threat to natural and managed ecosystems. Understanding of the mechanisms that determine why a given species may invade a given ecosystem, or why some biomes and regions seem more prone to invasions, is limited. One potential reason for this lack of progress may lie in how few studies have addressed invasion mechanisms from the point of view of the invaded community. On the other hand, the renewed debate about the relationship between ecological diversity and ecosystem stability offers the opportunity to revisit existing theory and empirical evidence, and to attempt to investigate which characteristics of plant communities, including their diversity, contribute to their invasibility. Empirical studies have shown both positive and negative relationships between species diversity of resident plant communities and their invasibility by external species. Rather than attempting to build a larger collection of case studies, research now needs to address the mechanisms underlying these relationships. Previous knowledge about the mechanisms favouring invasion needs to be coupled with community theory to form the basis of these new investigations. Modern community theory offers hypotheses and techniques to analyse the invasibility of communities depending on their diversity and other factors, such as species’ life histories and environmental variability. The body of knowledge accumulated in invasion ecology suggests that the role of disturbances, in interaction with fertility, and the importance of interactions with other trophic levels, are specific factors for consideration. In addition, it is essential for future studies to explicitly tease apart the effects of species richness per se from the effects of other components of ecological diversity, such as functional diversity (the number of functional groups) and trophic diversity (the number of interactions among trophic levels).     

濒危植物矮牡丹的生态位研究

矮牡丹 (ＰａｅｎｏｎｉａｓｕｆｆｒｕｔｉｃｏｓａＡｎｄｒ .ｖａｒ .ｓｐｏｎｔａｎｅａＲｅｈｄ .)属毛茛科 (Ｒａｎｕｎｃｕｌａｃｅａｅ)芍药属植物[1] ,为我国特有种 ,仅分布于山西稷山马家沟、永济水峪口 ,陕西延安万花山、华阴二仙桥等地 ,其花具有一定的观赏价值 ,根作“丹皮”入药 ,既是宝贵的花卉种质资源 ,又是优良的药材资源 ;且为栽培牡丹的原始种之一[2 ] 。由于自然植被的破坏和 2 0世纪 60年代的大量采掘 ,致使矮牡丹分布范围日益缩小。目前已被列为国家三级保护植物。生态位的概念自Ｇｒｉｎｅｌｌ的“生物在栖息地所占…     

Niche separation and weak interactions in the high tidal zone of saltmarsh‐mangrove mixing communities

1. Saltmarsh‐mangrove ecotones occur at the boundary of the natural geographic distribution of mangroves and salt marshes. Climate warming and species invasion can also drive the formation of saltmarsh‐mangrove mixing communities. How these coastal species live together in a “new” mixed community is important in predicting the dynamic of saltmarsh‐mangrove ecosystems as affected by ongoing climate change or human activities. To date, the understanding of species interactions has been rare on adult species in these ecotones.
2. Two typical coastal wetlands were selected as cases to understand how mangrove and saltmarsh species living together in the ecotones. The leaves of seven species were sampled from these coastal wetlands based on their distribution patterns (living alone or coexisting) in the high tidal zone, and seven commonly used functional traits of these species were analyzed.
3. We found niche separation between saltmarsh and mangrove species, which is probably due to the different adaptive strategies they adopted to deal with intertidal environments.
4. Weak interactions between coexisting species were dominated in the high tidal zone of the two saltmarsh‐mangrove communities, which could be driven by both niche differentiation and neutral theory.
5. Synthesis. Our field study implies a potential opportunity to establish a multispecies community in the high tidal zone of saltmarsh‐mangrove ecotones, where the sediment was characterized by low salinity and high nitrogen.

     

COMMUNITY COMPOSITION AND NICHE CHANGE CHARACTERISTICS OF DOMINANT SPECIES IN THE WIND-BREAKING AND SAND-FIXING FOREST, XINJIANG, CHINA

 以塔里木河下游绿洲外围大型防风固沙林为研究对象, 采用基于Simpson多样性指数的生态位宽度公式和Pianka生态位重叠测度公式, 在群落梯度上按重要值大小筛选出优势种群进行生态位分析, 探讨这些群落在4~7年的发育过程中生态位变化特点。结果表明: 1)经过4年的发育, 植物种组成简单的人工防风固沙林由于乡土植物种的侵入, 演变成为人工-天然植物群落, 不同地段群落中的优势种群发生了较大的变化, 优势种群共7个。芦苇(Phragmites communis)、花花柴(Karelinia caspica)和盐生草(Halogeton glomeratus)这3个乡土植物种侵入后逐渐成为优势种群, 而原人工群落主要建群种宁夏枸杞(Lycium barbarum)种群逐渐消退; 7年后, 优势种群共6个。由于水分条件的变化, 多枝柽柳(Tamarix ramosissima)成为优势种群, 而芦苇降为亚优势种群, 盐生草种群发生消退; 2)人工-天然植物群落中优势种群以耐旱耐盐碱植物占主要优势向占绝对优势的方向发展, 其生态位宽度变化幅度为0.56~0.86, 生态位宽度排序为芦苇>花花柴>头状沙拐枣(Calligonum caput-medusae)>沙枣(Elaeagnus angustifolia)>胡杨(Populus euphratica)>多枝柽柳>梭梭(Haloxylon ammodendron)>盐生草; 3)生态位重叠最大值发生在头状沙拐枣和胡杨种群之间; 4)在乡土植物种向人工群落侵入的过程中, 生态位宽度较大(或较小)的种群, 它们所构成的种对间生态位重叠既有较大的, 也有较小的, 可见生态位宽度与生态位重叠程度无相关性; 表明在现阶段群落演变中, 植物对环境资源存在着激烈的竞争和高的空间异质性。     

The evolution of climate tolerance in conifer‐feeding aphids in relation to their host's climatic niche

Climate adaptation has major consequences in the evolution and ecology of all living organisms. Though phytophagous insects are an important component of Earth's biodiversity, there are few studies investigating the evolution of their climatic preferences. This lack of research is probably because their evolutionary ecology is thought to be primarily driven by their interactions with their host plants. Here, we use a robust phylogenetic framework and species‐level distribution data for the conifer‐feeding aphid genus Cinara to investigate the role of climatic adaptation in the diversity and distribution patterns of these host‐specialized insects. Insect climate niches were reconstructed at a macroevolutionary scale, highlighting that climate niche tolerance is evolutionarily labile, with closely related species exhibiting strong climatic disparities. This result may suggest repeated climate niche differentiation during the evolutionary diversification of Cinara. Alternatively, it may merely reflect the use of host plants that occur in disparate climatic zones, and thus, in reality the aphid species' fundamental climate niches may actually be similar but broad. Comparisons of the aphids' current climate niches with those of their hosts show that most Cinara species occupy the full range of the climatic tolerance exhibited by their set of host plants, corroborating the hypothesis that the observed disparity in Cinara species' climate niches can simply mirror that of their hosts. However, 29% of the studied species only occupy a subset of their hosts' climatic zone, suggesting that some aphid species do indeed have their own climatic limitations. Our results suggest that in host‐specialized phytophagous insects, host associations cannot always adequately describe insect niches and abiotic factors must be taken into account.     

Fitness consequences of plants growing with siblings: reconciling kin selection, niche partitioning and competitive ability

Plant studies that have investigated the fitness consequences of growing with siblings have found conflicting evidence that can support different theoretical frameworks. Depending on whether siblings or strangers have higher fitness in competition, kin selection, niche partitioning and competitive ability have been invoked. Here, we bring together these processes in a conceptual synthesis and argue that they can be co-occurring. We propose that these processes can be reconciled and argue for a trait-based approach of measuring natural selection instead of the fitness-based approach to the study of sibling competition. This review will improve the understanding of how plants interact socially under competitive situations, and provide a framework for future studies.