生长型分类方案不同导致森林生态系统植物功能性状的统计偏差

将植物划分为不同的生长型来统计植物功能性状特征,是当前植物性状研究中常用的方法;但生长型分类方案的不同很可能造成植物功能性状统计分析的偏差,对此偏差的评估却尚未见报道。根据植物志描述及野外调查实际情况,将生长型划分为3种不同的分类方案：分类1：根据植物志信息划分为传统意义的乔木和灌木;分类2：根据树高和胸径划分乔木、小乔木和灌木;分类3：仅根据树高划分乔木层与灌木层的乔木和灌木。以东部亚热带常绿阔叶林区域的浙江金华北山35种优势阔叶木本植物的枝叶性状为研究对象,比较不同生长型分类对植物枝叶性状统计数据的影响。结果表明：（1）与传统的分类1相比,分类2对乔木植物枝叶性状影响的显著程度要高于分类3,而对灌木植物枝叶性状的影响程度低于分类3;但不同生长型分类方案中乔木和灌木的枝叶性状总体差异不显著。而与分类2小乔木相比,分类1以及分类2内部的乔木和灌木生长型的性状与分类2小乔木差异非常明显;（2）将不同生长型植物再划分为不同生活型后,不同生长型分类方案对性状统计的影响增大。无论是常绿还是落叶生活型的小乔木,其与不同生活型乔木和灌木的性状差异仍然显著。可见,不同的生长型分类方案可造成植物功能性状统计的差异;把小乔木植物这一功能类群划分出来,能更好地反映森林生态系统性状特征的差异性。     

Species traits as drivers of food web structure

The use of functional traits to describe community structure is a promising approach to reveal generalities across organisms and ecosystems. Plant ecologists have demonstrated the importance of traits in explaining community structure, competitive interactions as well as ecosystem functioning. The application of trait‐based methods to more complex communities such as food webs is however more challenging owing to the diversity of animal characteristics and of interactions. The objective of this study was to determine how functional structure is related to food web structure. We consider that food web structure is the result of 1) the match between consumer and resource traits, which determine the occurence of a trophic interaction between them, and 2) the distribution of functional traits in the community. We implemented a statistical approach to assess whether or not 35 466 pairwise interactions between soil organisms are constrained by trait‐matching and then used a Procrustes analysis to investigate correlations between functional indices and network properties across 48 sites. We found that the occurrence of trophic interactions is well predicted by matching the traits of the resource with those of the consumer. Taxonomy and body mass of both species were the most important traits for the determination of an interaction. As a consequence, functional evenness and the variance of certain traits in the community were correlated to trophic complementarity between species, while trait identity, more than diversity, was related to network topology. The analysis was however limited by trait data availability, and a coarse resolution of certain taxonomic groups in our dataset. These limitations explain the importance of taxonomy, as well as the complexity of the statistical model needed. Our results outline the important implications of trait composition on ecological networks, opening promising avenues of research into the relationship between functional diversity and ecosystem functioning in multi‐trophic systems.     

The effects of human disturbance on the species composition,species diversity and functional diversity of a Miombo woodland in northern Malawi

Anthropogenic disturbances have serious impacts on ecosystems across the world. Understanding the effects of disturbance on woodlands, especially in regions where local people depend on these natural resources, is essential for sustainable natural resource management and biodiversity conservation. In this study, we evaluated the effects of anthropogenic disturbance, specifically selective logging of Brachystegia floribunda, on woodlands by comparing species composition, species diversity and functional diversity of woody plants between disturbed and undisturbed woodlands. We combined species data and functional trait data for leaves, fruits and other traits related to resource and disturbance responses to calculate functional indices (functional richness, evenness and divergence) and community‐weighted means of each trait. Shifts in taxonomic species composition were analysed using nonmetric multi‐dimensional scaling. Species composition differed significantly between disturbed and undisturbed woodlands. Tree density was greater in disturbed woodlands, whereas evenness, functional evenness and functional divergence were greater in undisturbed woodlands. In terms of forest cover, selective logging of B. floribunda appeared to have little impact on Miombo woodlands, but some shifts in functional traits, such as the shift from a deciduous to evergreen phenology, may increase the vulnerability of these ecosystems to environmental change, especially drought.     

Patterns in leaf traits of leguminous and non-leguminous dominant trees along a rainfall gradient in Ghana

Aims Both dominance distribution of species and the composition of the dominant species determine the distribution of traits within community. Leaf carbon (C) and nitrogen (N) isotopic composition are important leaf traits, and such traits of dominant species are associated with ecosystem C, water and N cycling. Very little is known how dominant species with distinct traits (e.g. N-fixing leguminous and non-leguminous trees) mediate resource utilization of the ecosystems in stressful environment.Methods Leaves of 81 dominant leguminous and non-leguminous trees were collected in forest (moist semi-deciduous and dry semi-deciduous ecosystems) and savanna (costal savanna, Guinean savanna and west Sudanian savanna ecosystems) areas and the transitional zone (between the forest and the savanna) along the transect from the south to the north of Ghana. We measured leaf traits, i.e. leaf δ 13 C, leaf δ 15 N, leaf water content, leaf mass per area (LMA) and C and N concentration. Correlation analyses were used to examine trait–trait relationships, and relationships of leaf traits with temperature and precipitation. We used analysis of covariance to test the differences in slopes of the linear regressions between legumes and non-legumes.Important findings Leaf δ 13 C, δ 15 N, leaf water content and LMA did not differ between leguminous and non-leguminous trees. Leaf N concentration and C:N ratio differed between the two groups. Moreover, leaf traits varied significantly among the six ecosystems. δ 13 C values were negatively correlated with annual precipitation and positively correlated with mean annual temperature. In contrast, leaf δ 15 N of non-leguminous trees were positively correlated with annual precipitation and negatively correlated with mean annual temperature. For leguminous trees, such correlations were not significant. We also found significant coordination between leaf traits. However, the slopes of the linear relationships were significantly different between leguminous and non-leguminous trees. Our results indicate that shifts in dominant trees with distinct water-use efficiency were corresponded to the rainfall gradient. Moreover, leguminous trees, those characterized with relative high water-use efficiency in the low rainfall ecosystems, were also corresponded to the relative high N use efficiency. The high proportion of leguminous trees in the savannas is crucial to mitigate nutrient stress.     

基于功能性状的中亚热带岩溶常绿落叶阔叶混交林物种多样性维持研究

理解植物功能性状和功能实体在森林群落的分布,有助于探讨物种丧失对森林生态系统功能、冗余和恢复力的影响。为了解脆弱的岩溶石山森林在应对生物多样性丧失的生态系统反馈,对桂林岩溶石山两块1hm²的常绿落叶阔叶混交林的木本植物数据进行了分析。包括基于功能性状计算功能多样性、构建功能实体计算功能冗余以及采用Pearson相关分析和Mantel检验评估物种多样性指标在生态系统的维持机制。结果显示:(1)青冈+大叶榉树群落的功能多样性指标均低于鱼骨木+青冈+圆叶乌桕群落,且两个群落间功能均匀度不相关(P ＞ 0.05),功能丰富度、功能离散度和Rao''s二次熵呈现极显著相关性(P ＜ 0.001),功能分散度呈现显著相关性(P ＜ 0.05)。(2)两个群落的物种丰富度与功能冗余指标表现出相似的线性关系,即物种丰富度与功能实体等级、功能冗余、功能超冗余呈正相关,与功能脆弱性呈负相关关系。(3)不同植物功能性状间、不同功能多样性指标间和不同功能冗余指标间的相关性较强,功能多样性指标和功能冗余指标间无显著相关性,但功能性状与功能多样性指标、功能性状与功能冗余指标均存在不同程度的相关性。而在功能实体与物种多样性指标的相关性方面,呈现出同物种丰富度与物种多样性指标相似的显著度。另外,物种多度与物种丰富度、功能分散度、功能离散度、Rao''s二次熵及功能脆弱性均显著相关。总之,在岩溶石山常绿落叶阔叶混交林中,高功能多样性的群落存在高功能冗余的现象,但功能多样性和功能冗余是相互独立的因素;物种丰富度高的群落所提供的保险效应无法抵消其生态系统的脆弱性。因此,不能仅通过保护物种丰富度来维持生态系统的特有功能,还应充分考虑多度对生态系统功能的贡献,以更有效地实现对岩溶石山森林生态系统的保护。     

A trait‐based trade‐off between growth and mortality: evidence from 15 tropical tree species using size‐specific relative growth rates

A life‐history trade‐off between low mortality in the dark and rapid growth in the light is one of the most widely accepted mechanisms underlying plant ecological strategies in tropical forests. Differences in plant functional traits are thought to underlie these distinct ecological strategies; however, very few studies have shown relationships between functional traits and demographic rates within a functional group. We present 8 years of growth and mortality data from saplings of 15 species of Dipterocarpaceae planted into logged‐over forest in Malaysian Borneo, and the relationships between these demographic rates and four key functional traits: wood density, specific leaf area (SLA), seed mass, and leaf C:N ratio. Species‐specific differences in growth rates were separated from seedling size effects by fitting nonlinear mixed‐effects models, to repeated measurements taken on individuals at multiple time points. Mortality data were analyzed using binary logistic regressions in a mixed‐effects models framework. Growth increased and mortality decreased with increasing light availability. Species differed in both their growth and mortality rates, yet there was little evidence for a statistical interaction between species and light for either response. There was a positive relationship between growth rate and the predicted probability of mortality regardless of light environment, suggesting that this relationship may be driven by a general trade‐off between traits that maximize growth and traits that minimize mortality, rather than through differential species responses to light. Our results indicate that wood density is an important trait that indicates both the ability of species to grow and resistance to mortality, but no other trait was correlated with either growth or mortality. Therefore, the growth mortality trade‐off among species of dipterocarp appears to be general in being independent of species crossovers in performance in different light environments.     

Trait convergence and diversification arising from a complex evolutionary history in Hawaiian species of <Emphasis Type="Italic">Scaevola</Emphasis>

Species variation in functional traits may reflect diversification relating to convergence and/or divergence depending on environmental pressures and phylogenetic history. We tested trait-environment relationships and their basis in finer-scale evolutionary processes among nine extant Hawaiian species of Scaevola L. (Goodeniaceae), a taxon with a complex history of three independent colonizations by different phylogenetic lineages, parallel ecological specialization, and homoploid hybridization events in Hawai‘i. Using a wild population for each species, we evaluated traits related to plant function (morphology, leaf and wood anatomy, nutrient and carbon isotope composition). Hawaiian Scaevola species were distributed across coastal, dry forest and wet forest environments; multivariate environmental analysis using abiotic and biotic factors further showed that species from distantly related lineages inhabited similar environments. Many traits correlated with environment (based on the multivariate environmental analysis), considering both distantly related species and more closely related species. Scaevola species within shared habitats generally showed trait convergence across distantly related lineages, particularly among wet forest species. Furthermore, trait diversification through divergence was extensive among closely related Scaevola species that radiated into novel environments, especially in plant morphology and traits affecting water relations. Homoploid hybrid-origin species were “intermediate” compared to their ancestral parent species, and possessed trait combinations relevant for their current habitat. The diversity in functional traits reflected strong influences of both ecology and evolutionary history in native Hawaiian Scaevola species, and trait correspondence with environment was due to the combination of multiple processes within the taxon: trait pre-adaptation and filtering, evolutionary convergence, divergence, and hybridization.     

Assessing functional redundancy in chronically trawled benthic communities

Fishing disturbance on ecosystems leads to changes in community structure and composition, which may have drastic implications for ecosystem functional performance. Functional redundancy, defined as species sharing similar functional roles, is a community property that plays an important role in preventing functional changes in ecosystems under pressure. In this study, we suggest that functional redundancy may be achieved through trait abundance (i.e. large amounts of a trait, hereafter “common traits”), or through trait richness (i.e. large numbers of distinct taxa exhibiting the same trait, hereafter “widespread traits”). We assessed the variability of both measures obtained from epifaunal and infaunal communities in soft-bottom trawling grounds. Sampling sites were located in four Mediterranean areas that were subjected to different levels of trawling effort. Common and widespread traits measures were based on the analysis of biological traits linked to key soft-bottoms functions such as nutrient cycling, bentho-pelagic coupling and habitat provision. The role of rare species in both measures was also assessed and we observed that, in our study sites, rare species generally exhibited the same traits as the most abundant species. Common and widespread traits measures provided complementary information on benthic functional redundancy. Thus, we suggest that a combination of the two measures should be used to appropriately assess benthic functional redundancy in trawling grounds. As redundancy is a component of ecosystem resilience, functional redundancy evaluation is important to assess the overall integrity of ecosystems.     

Intraspecific trait variation can weaken interspecific trait correlations when assessing the whole‐plant economic spectrum

The worldwide plant economic spectrum hypothesis predicts that leaf, stem, and root traits are correlated across vascular plant species because carbon gain depends on leaves being adequately supplied with water and nutrients, and because construction of each organ involves a trade‐off between performance and persistence. Despite its logical and intuitive appeal, this hypothesis has received mixed empirical support. If traits within species diverge in their responses to an environmental gradient, then interspecific trait correlations could be weakened when measured in natural ecosystems. To test this prediction, we measured relative growth rates (RGR) and seven functional traits that have been shown to be related to fluxes of water, nutrients, and carbon across 56 functionally diverse tree species on (1) juveniles in a controlled environment, (2) juveniles in forest understories, and (3) mature trees in forests. Leaf, stem, and fine root traits of juveniles grown in a controlled environment were closely correlated with each other, and with RGR. Remarkably, the seven leaf, stem, and fine root tissue traits spanned a single dimension of variation when measured in the controlled environment. Forest‐grown juveniles expressed lower leaf mass per area, but higher wood and fine root tissue density, than greenhouse‐grown juveniles. Traits and growth rates were decoupled in forest‐grown juveniles and mature trees. Our results indicate that constraints exist on the covariation, not just the variation, among vegetative plant organs; however, divergent responses of traits within species to environmental gradients can mask interspecific trait correlations in natural environments. Correlations among organs and relationships between traits and RGR were strong when plants were compared in a standardized environment. Our results may reconcile the discrepancies seen among studies, by showing that if traits and growth rates of species are compared across varied environments, then the interorgan trait correlations observed in controlled conditions can weaken or disappear.     

Functional diversity: back to basics and looking forward

Functional diversity is a component of biodiversity that generally concerns the range of things that organisms do in communities and ecosystems. Here, we review how functional diversity can explain and predict the impact of organisms on ecosystems and thereby provide a mechanistic link between the two. Critical points in developing predictive measures of functional diversity are the choice of functional traits with which organisms are distinguished, how the diversity of that trait information is summarized into a measure of functional diversity, and that the measures of functional diversity are validated through quantitative analyses and experimental tests. There is a vast amount of trait information available for plant species and a substantial amount for animals. Choosing which traits to include in a particular measure of functional diversity will depend on the specific aims of a particular study. Quantitative methods for choosing traits and for assigning weighting to traits are being developed, but need much more work before we can be confident about trait choice. The number of ways of measuring functional diversity is growing rapidly. We divide them into four main groups. The first, the number of functional groups or types, has significant problems and researchers are more frequently using measures that do not require species to be grouped. Of these, some measure diversity by summarizing distances between species in trait space, some by estimating the size of the dendrogram required to describe the difference, and some include information about species' abundances. We show some new and important differences between these, as well as what they indicate about the responses of assemblages to loss of individuals. There is good experimental and analytical evidence that functional diversity can provide a link between organisms and ecosystems but greater validation of measures is required. We suggest that non-significant results have a range of alternate explanations that do not necessarily contradict positive effects of functional diversity. Finally, we suggest areas for development of techniques used to measure functional diversity, highlight some exciting questions that are being addressed using ideas about functional diversity, and suggest some directions for novel research.     

Traits,neighbors, and species performance in prairie restoration

Questions: Are traits related to the performance of plant species in restoration? Are the relationships between traits and performance consistent across the functional groups of annual forbs, perennial forbs and grasses? Do the relationships between traits and performance depend on neighboring functional groups? Location: A former agricultural field, being restored to native upland prairie, in the Willamette Valley of western Oregon, USA. Methods: Twenty‐eight native species, representing three functional groups, were sown in seven different combinations. Eleven functional traits were measured from plants in the laboratory and in the field. Correlations between individual traits and performance variables were measured and regression techniques used to determine which sets of traits were most strongly related to performance. Results: Sets of traits explained up to 56% of variation in cover, and up to 48% of variation in establishment frequency. The relationships between traits and performance were influenced by functional group identity; the functional group identity of neighboring species also influenced species' cover and the relationships between traits and cover. Species' establishment rate in monoculture was the trait most strongly correlated to both establishment and cover in mixtures. In multi‐trait models, annual forb functional group identity was strongly related to establishment in mixtures, and height, leaf weight ratio at 7 d and seed mass were strongly related to cover. Conclusions: Multiple‐trait models should be a useful way of predicting the performance of species prior to sowing in restoration. The functional group identity of each species and the other species being sown may need to be taken into account when making predictions.     

Plant functional identity as the predictor of carbon storage in semi-arid ecosystems

Background: There is an increasing consensus that ecosystem processes are governed by functional identity and trait variation rather than species richness. Despite its importance, the relative effect of relevant functional traits for carbon storage has remained mostly untested in different bioclimatic regions.

Aims: In this study, different components of functional diversity such as community-weighted means of trait values (CWM), functional trait diversity (Rao’s quadratic diversity), functional richness (FRi), functional evenness (FEv) and functional divergence (FDiv) were used to associate carbon content of above-ground biomass, litter and soil in four bioclimatic regions including warm and cold-steppe, semi-steppe rangelands and oak dry forest in the south-west of Iran.

Methods: Several key important traits highly associated with carbon storage including specific leaf area (SLA), height (H), leaf dry matter content, leaf nitrogen and phosphorus content (LNC and LPC), leaf longevity, wood specific gravity and life form were determined to quantify single and multiple traits that contribute to different components of plant functional diversity.

Results: The results showed that CWM of H, Chamaephyte life form, LNC and LPC were among the most important aspects of functional diversity that positively predicted carbon storage in above-ground biomass and soil. We also observed the negative association of carbon storage with FEv of LNC, Rao of LNC and FEv of multiple traits in the rangelands and the negative association of carbon storage with FDiv of SLA in the forest.

Conclusions: Our results indicate that different components of functional diversity are essential for a mechanistic understanding of the role of plant diversity for carbon storage. The negative associations between FDiv and FEv and carbon storage do not provide support for the complementarity niche hypothesis. Our results suggest that in the more functionally diverse ecosystems dominated by functionally important species with key traits, the so-called functional identity does indeed promote carbon storage, at least in these semi-arid ecosystems.     

BryForTrait – A life‐history trait database of forest bryophytes

In ecological research, plant functional trait analyses are widely applied to understand to what extent the inter‐specific variation in trait attributes has an adaptive value or to predict ecosystem processes and changes. Compared to vascular plants, trait studies using bryophytes are scarce, which is likely due to missing trait information for bryophyte species. With the BryForTrait database, we want to reduce this deficit. Our database represents a compilation of autecological information and morphological and regenerative trait data on different stages of the life cycle of bryophytes occurring in forest ecosystems. The database contains information for 35 traits and 721 Central European bryophyte species; in total more than 23,000 trait values. The BryForTrait database will enable future trait studies, providing new insights into bryophyte‐dominated ecosystems.     

Determinants of litter decomposition rates in a tropical forest: functional traits,phylogeny and ecological succession

Plant litter decomposition is one of the most important processes in terrestrial ecosystems, as it is a key factor in nutrient cycling. Decomposition rates depend on environmental factors, but also plant traits, as these determine the character of detritus. We measured litter decomposition rate for 57 common tree species displaying a variety of functional traits within four sites in primary and four sites in secondary tropical forest in Madang Province, Papua New Guinea. The phylogenetic relationships between these trees were also estimated using molecular data. The leaves collected from different tree species were dried for two days, placed into detritus bags and exposed to ambient conditions for two months. Nitrogen, carbon and ash content were assessed as quantitative traits and used together with a phylogenetic variance– covariance matrix as predictors of decomposition rate. The analysis of the tree species composition from 96 quadrats located along a successional gradient of swidden agriculture enabled us to determine successional preferences for individual species. Nitrogen content was the only functional trait measured to be significantly positively correlated with decomposition rate. Controlling for plant phylogeny did not influence our conclusions, but including phylogeny demonstrated that the mainly early successional family Euphorbiaceae is characterized by a particularly high decomposition rate. The acquisitive traits (high nitrogen content and low wood density) correlated with rapid decomposition were characteristic for early successional species. Decomposition rate thus decreased from early successional to primary forest species. However, the decomposition of leaves from the same species was significantly faster in primary than in secondary forest stands, very probably because the high humidity of primary forest environments keeps the decomposing material wetter.     

Plant species traits across a riparian‐zone/forest ecotone

Abstract. We examined the changes in prevalence of nine plant traits – including the presence of woody stem tissue, leaf longevity, nitrogen fixation, seed longevity, dispersal vector, pollination vector, and clonal growth form – across a riparian/forest‐understory ecotone. This ecotone, found along headwater streams in boreal mixed‐wood forests, supports four distinct vegetation zones: streambank, riparian, transition, and upland forest understory. The objective of this study was to identify specific trait patterns that may indicate functional responses to the changes in environmental factors such as nutrient availability and wind exposure that occur across the ecotone. The suites of plant species traits found in each zone were distinct, with a strong change in the prevalence of several traits. Wind and insect pollination, wind and vertebrate diaspore dispersal, and deciduous and evergreen leaves showed the greatest change in prevalence between the vegetation types. Some traits, including insect pollination and vertebrate diaspore dispersal, were strongly correlated within species. The consistent cooccurrence of pairs of traits in the same species suggests common responses by very different traits to the same environmental factor. This study demonstrates that an ecotone can be characterized not only as a discontinuity in species distributions or environmental factors, but also as a discontinuity in the trait spectrum. Examining ecotones from a trait perspective has strong potential for identifying the environmental factors and associated species functional responses that encourage the development of distinct vegetation boundaries.     

Comparing biological classifications of freshwater phytoplankton: a case study from South China

The use of ecological classification systems is becoming more and more widely used when studying phytoplankton. Grouping phytoplankton species into ecologically coherent groups allow to reduce redundancy and in this way, to handle a minor number of biological variables when investigating the ecological status of aquatic ecosystems. Three ecological classifications are mostly used when freshwater phytoplankton is studied: functional groups or coda, morpho-functional groups (MFGs) and morphology-based functional groups (MBFGs). In this study, these three ecological classifications were comparatively used along with two taxonomic classifications based on species and genera to analyse phytoplankton response to environmental variability in three sub-tropical Chinese reservoirs. Canonical correspondence analysis was performed to compare the five mentioned biological classifications. When ecological classifications were used, the percentage of variance explained in the biological groups?Cenvironmental variables was higher than that explained by the taxonomic classifications. Coda and MFGs showed a very high degree of overlapping, but since coda are associated to very detailed environmental templates, this method was more helpful in explaining phytoplankton variability in relation to environmental factors.     

鼎湖山南亚热带常绿阔叶林叶功能性状沿群落垂直层次的种内变异

探究功能性状沿着环境梯度如何变化一直以来是基于性状的群落生态学的核心问题之一。尽管功能性状存在种内和种间变异, 但种内变异沿环境梯度如何变化仍有待探究。本文以鼎湖山南亚热带常绿阔叶林1.44 ha塔吊样地内16个树种的2,820个个体为研究对象, 探究4种叶功能性状(比叶面积、叶干物质含量、叶厚度和叶面积)沿群落垂直层次的种内变异。首先, 利用随机效应线性模型量化塔吊样地内的种内变异和种间变异; 其次, 利用Kmeans函数将森林的垂直层次划分为灌木层、亚冠层和林冠层, 并通过构建回归模型探究叶功能性状在群落垂直层次中的种内变异格局。最后, 应用混合线性模型和单因素方差分析的方法探究叶功能性状沿垂直层次的种内变异是否具有物种依赖性。结果表明: 在局域群落中, 并非所有叶功能性状的种内变异都低于种间变异; 叶功能性状在不同垂直层次的种内变异格局存在显著差异, 且种内变异与垂直范围呈正相关; 叶功能性状的种内变异具有较强的物种依赖性, 因此树种差异相对于小环境解释了更多的性状变异; 此外, 不同叶功能性状的种内变异沿垂直层次的变化趋势并不一致。本研究发现种内变异对于物种共存具有重要作用。     

闽楠叶形态与叶脉网络性状关系对城市生长环境的响应

植物叶形态与叶脉网络功能性状的协同变异与权衡关系,对深入理解植物叶脉网络功能性状对环境变异的生态适应,以及预测植物物种生活习性对城市化过程的响应具有重要意义。闽楠作为珍贵的常绿阔叶树种,正在城市绿化中逐步推广。针对不同生长环境中（行道与植物园混交林）的闽楠,开展了叶形态与叶脉网络功能性状关系对城市生长环境的响应研究。研究结果表明：闽楠叶性状值基本满足正态分布,各性状变异系数保持在10%-20%之间,群体内性状变异较为丰富,单因素方差分析表明两种环境对叶形态性状的影响比叶脉网络系统的影响更明显;两种生长环境下闽楠叶形态性状组与叶脉网络功能性状组都具有极显著相关性,行道和植物园混交林典型性相关系数分别为0.804和0.795,叶形态性状与叶脉直径呈显著正相关,形态性状、叶脉直径与初级脉密度呈显著负相关;闽楠在响应城市生长环境的过程中呈现出相应的经济权衡机制,行道环境中闽楠以较大的初级脉密度和较小叶面积来确保水分获取和光合之间的平衡,植物园闽楠则采用较低初级叶脉密度、较高叶面积和叶脉直径的叶形态和叶脉网络构建模式。在选择闽楠作为城市绿化树种时,可将叶片形态性状组与叶脉网络功能性状组的协同变化和权衡关系作为选种依据,以提高闽楠在城市环境中的成活率和适应性。     

Assessing the Importance of Intraspecific Variability in Dung Beetle Functional Traits

Functional diversity indices are used to facilitate a mechanistic understanding of many theoretical and applied questions in current ecological research. The use of mean trait values in functional indices assumes that traits are robust, in that greater variability exists between than within species. While the assertion of robust traits has been explored in plants, there exists little information on the source and extent of variability in the functional traits of higher trophic level organisms. Here we investigated variability in two functionally relevant dung beetle traits, measured from individuals collected from three primary forest sites containing distinct beetle communities: body mass and back leg length. In doing so we too addressed the following questions: (i) what is the contribution of intra vs. interspecific differences in trait values; (ii) what sample size is needed to provide representative species mean trait values; and (iii) what impact does omission of intraspecific trait information have on the calculation of functional diversity (FD) indices from naturally assembled communities? At the population level, interspecific differences explained the majority of variability in measured traits (between 94% and 96%). In accordance with this, the error associated with calculating FD without inclusion of intraspecific variability was low, less than 20% in all cases. This suggests that complete sampling to capture intraspecific variance in traits is not necessary even when investigating the FD of small and/or naturally formed communities. To gain an accurate estimation of species mean trait values we encourage the measurement of 30–60 individuals and, where possible, these should be taken from specimens collected from the site of study.     

Patch isolation and shape predict plant functional diversity in a naturally fragmented forest

Aims It is known that taxonomic diversity can be predicted by the spatial configuration of the habitat, in particular by its area and degree of isolation. However, taxonomic diversity is a poor predictor of ecosystem functioning. While functional diversity is strongly linked to the functionality and stability of ecosystems, little is known about how changes in the spatial configuration of the habitat affect functional diversity. In this study, we evaluated whether the spatial configuration of forest patches predicts the functional diversity of plants in a fragmented forest.Methods Five functional leaf traits (leaf dry matter content, leaf punch force, specific leaf area, leaf size and leaf thickness) were measured for 23 dominant plant species in 20 forest patches in a naturally fragmented forest on the Yucatan Peninsula. Abundance-weighted multivariate and individual trait metrics of functional diversity were calculated and correlated with size, degree of isolation and the shape of forest patches.Important findings Patch shape was negatively correlated with multivariate and individual trait (leaf dry matter content and leaf size) metrics of functional diversity. Patch isolation measures were also negatively correlated with individual trait (leaf dry matter content, leaf punch force and leaf size) metrics of functional diversity. In other words, greater patch shape irregularity and isolation degree impoverish plant functional variability. This is the first report of the negative effects of patch shape irregularity and isolation on the functional diversity of plant communities in a forest that has been fragmented for a long time.