Joint effect of phylogenetic relatedness and trait selection on the elevational distribution of Rhododendron species

Congeneric species may coexist at fine spatial scales through niche differentiation, however, the magnitude to which the effects of functional traits and phylogenetic relatedness contribute to their distribution along elevational gradients remains understudied. To test the hypothesis that trait and elevational range overlap can affect local speciesʼ coexistence, we first compared phylogenetic relatedness and trait (including morphological traits and leaf elements) divergence among closely related species of Rhododendron L. on Yulong Mountain, China. We then assessed relationships between the overlap of multiple functional traits and the degree of elevational range overlap among species pairs in a phylogenetic context. We found that phylogeny was a good predictor for most functional traits, where closely related species showed higher trait similarity and occupied different elevational niches at our study site. Species pairs of R. subgen. Hymenanthes (Blume) K. Koch showed low elevational range overlap and some species pairs of R. subgen. Rhododendron showed obvious niche differentiation. Trait divergence is greater for species in R. subgen. Rhododendron, and it plays an important role between species pairs with low elevational range overlap. Trait convergent selection takes place between co-occurring closely related species that have high elevational range overlap, which share more functional trait space due to environmental filtering or ecological adaptation in more extreme habitats. Our results highlight the importance of evolutionary history and trait selection for species coexistence at fine ecological scales along environmental gradients.     

Phylogenetic niche conservatism, phylogenetic signal and the relationship between phylogenetic relatedness and ecological similarity among species

Ecologists are increasingly adopting an evolutionary perspective, and in recent years, the idea that closely related species are ecologically similar has become widespread. In this regard, phylogenetic signal must be distinguished from phylogenetic niche conservatism. Phylogenetic niche conservatism results when closely related species are more ecologically similar that would be expected based on their phylogenetic relationships; its occurrence suggests that some process is constraining divergence among closely related species. In contrast, phylogenetic signal refers to the situation in which ecological similarity between species is related to phylogenetic relatedness; this is the expected outcome of Brownian motion divergence and thus is necessary, but not sufficient, evidence for the existence of phylogenetic niche conservatism. Although many workers consider phylogenetic niche conservatism to be common, a review of case studies indicates that ecological and phylogenetic similarities often are not related. Consequently, ecologists should not assume that phylogenetic niche conservatism exists, but rather should empirically examine the extent to which it occurs.     

Similarities between invaders and native species: Moving past Darwin's naturalization conundrum

Darwin's naturalization conundrum states that successful invaders must be closely related to native species to possess the traits to tolerate that environment, but distantly related enough to possess traits allowing exploitation of underutilized niches, thereby minimizing competition. Although influential, this hypothesis is based on several simplistic assumptions. In particular, the relationship among phylogenetic relatedness, similarity, and competition is more complex than assumed and changes with spatial and phylogenetic scale. Competitive interactions are determined by limiting similarity and trait hierarchies associated with separate traits. Successful invaders thus need to be similar to native species in some respects, but different in others. This combination of similarities and differences is unlikely to be conserved. Further, many invasive species are represented in their novel range by genotypes with extreme trait values or plasticity relative to the species mean. Selection for these genotypes may alter the similarity between invasive and native species, thus obscuring the relationship between competition and phylogenetic relatedness. As environmental filtering and competition often act on different spatial scales, approaches assessing how individual traits relate to invasion at these scales (species pools vs local community) may improve our understanding of the relationship between similarity and invasion.     

Habitat filtering influences the phylogenetic structure of avian communities across a coastal gradient in southern Brazil

The evolution of a particular trait or combination of traits within lineages may affect subsequent evolutionary outcomes, leading closely related species to exhibit higher phenotypic similarity than expected under a simple Brownian‐motion evolutionary model. Niche theory postulates that phenotypes determine species distribution across environmental gradients, leading to a phylogenetic signature in the community assembly. Thus, the incorporation of species phylogeny in the analysis of community ecology structure allows one to link broader environmental, spatial and temporal factors to local, small‐scale ecological processes, thus enabling understanding of community assembly patterns in a broader context. We used the net relatedness index to assess phylogenetic structure within avian communities across a harshness gradient in coastal habitats in southern Brazil. We also evaluated phylogenetic beta diversity, to test whether closely related species exploit habitats with similar environmental conditions. In order to do so, we scaled up phylogenetic information from the species to site level using phylogenetic fuzzy weighting. We found a pattern of phylogenetic clustering in less‐vegetated habitats, namely sandy beach and dunes, which are subject to harsher conditions because of proximity to the ocean. Basal lineages were associated with the more structurally homogeneous sandy beach, while late‐divergence clades occurred in more complex habitats, which were positively related to vegetation cover and height. The observed pattern of phylogenetic clustering suggested the importance of harsh conditions in constraining the distribution of avian lineages. Furthermore, contrasting environmental features between habitats influenced phylogenetic variation, demonstrating the prevalence of phylogenetic habitat filtering. From an applied point of view, such as planning and management of biological reserves, we showed that the full array of habitat patches embedded within coastal ecological gradients must be included in order to preserve distinct evolutionary lineages.     

Measuring biodiversity to explain community assembly: a unified approach

One of the oldest challenges in ecology is to understand the processes that underpin the composition of communities. Historically, an obvious way in which to describe community compositions has been diversity in terms of the number and abundances of species. However, the failure to reject contradictory models has led to communities now being characterized by trait and phylogenetic diversities. Our objective here is to demonstrate how species, trait and phylogenetic diversity can be combined together from large to local spatial scales to reveal the historical, deterministic and stochastic processes that impact the compositions of local communities. Research in this area has recently been advanced by the development of mathematical measures that incorporate trait dissimilarities and phylogenetic relatedness between species. However, measures of trait diversity have been developed independently of phylogenetic measures and conversely most of the phylogenetic diversity measures have been developed independently of trait diversity measures. This has led to semantic confusions particularly when classical ecological and evolutionary approaches are integrated so closely together. Consequently, we propose a unified semantic framework and demonstrate the importance of the links among species, phylogenetic and trait diversity indices. Furthermore, species, trait and phylogenetic diversity indices differ in the ways they can be used across different spatial scales. The connections between large‐scale, regional and local processes allow the consideration of historical factors in addition to local ecological deterministic or stochastic processes. Phylogenetic and trait diversity have been used in large‐scale analyses to determine how historical and/or environmental factors affect both the formation of species assemblages and patterns in species richness across latitude or elevation gradients. Both phylogenetic and trait diversity have been used at different spatial scales to identify the relative impacts of ecological deterministic processes such as environmental filtering and limiting similarity from alternative processes such as random speciation and extinction, random dispersal and ecological drift. Measures of phylogenetic diversity combine phenotypic and genetic diversity and have the potential to reveal both the ecological and historical factors that impact local communities. Consequently, we demonstrate that, when used in a comparative way, species, trait and phylogenetic structures have the potential to reveal essential details that might act simultaneously in the assembly of species communities. We highlight potential directions for future research. These might include how variation in trait and phylogenetic diversity alters with spatial distances, the role of trait and phylogenetic diversity in global‐scale gradients, the connections between traits and phylogeny, the importance of trait rarity and independent evolutionary history in community assembly, the loss of trait and phylogenetic diversity due to human impacts, and the mathematical developments of biodiversity indices including within‐species variations.     

Phylogenetic diversity,trait diversity and niches: species assembly of ferns along a tropical elevational gradient

Aim To analyse the structure of pteridophyte assemblages, based on phylogenetic relatedness and trait properties, along an elevational gradient. Ecological theory predicts that co‐occurring species may be: randomly selected from a regional pool; ecologically sorted so that they are functionally different hence resulting in reduced competition (overdispersion); or functionally similar as an adaptation to specific ecological conditions (clustering). Location Braulio Carrillo National Park and Cerro de la Muerte, Costa Rica, Central America. Methods We used an empirical dataset of the quantitative pattern of species occurrences and individual numbers of ferns within 156 plots along a tropical elevational gradient to test whether directed ecological sorting might cause deviations in patterns of trait and phylogenetic diversity. Mean pairwise distances of species based on phylogenetic and trait properties were compared with two different sets of null assemblages, one maintaining species frequency distributions (constrained) and one not (unconstrained). Results Applying different null models resulted in varying degrees of overdispersion and clustering, but overall patterns of deviation from random expectations remained the same. Contrary to theoretical predictions, phylogenetic and trait diversity were relatively independent from one another. Phylogenetic diversity showed no patterns along the elevational gradient, whereas trait diversity showed significant trends for epiphytes. Main conclusions Under stressful environmental conditions (drought at low elevations and frost at high elevations), epiphytic fern assemblages tended to be clustered with respect to trait characteristics, which suggests environmental filtering. Conversely, under less extreme environmental conditions (middle of the transect), the sorting was biased towards high differentiation (overdispersion), presumably because of interspecific competition and trait shifts among closely related species (character displacement).     

Limiting similarity and Darwin’s naturalization hypothesis: understanding the drivers of biotic resistance against invasive plant species

Several hypotheses have been proposed to explain biotic resistance of a recipient plant community based on reduced niche opportunities for invasive alien plant species. The limiting similarity hypothesis predicts that invasive species are less likely to establish in communities of species holding similar functional traits. Likewise, Darwin’s naturalization hypothesis states that invasive species closely related to the native community would be less successful. We tested both using the invasive alien Ambrosia artemisiifolia L. and Solidago gigantea Aiton, and grassland species used for ecological restoration in central Europe. We classified all plant species into groups based on functional traits obtained from trait databases and calculated the phylogenetic distance among them. In a greenhouse experiment, we submitted the two invasive species at two propagule pressures to competition with communities of ten native species from the same functional group. In another experiment, they were submitted to pairwise competition with native species selected from each functional group. At the community level, highest suppression for both invasive species was observed at low propagule pressure and not explained by similarity in functional traits. Moreover, suppression decreased asymptotically with increasing phylogenetic distance to species of the native community. When submitted to pairwise competition, suppression for both invasive species was also better explained by phylogenetic distance. Overall, our results support Darwin’s naturalization hypothesis but not the limiting similarity hypothesis based on the selected traits. Biotic resistance of native communities against invasive species at an early stage of establishment is enhanced by competitive traits and phylogenetic relatedness.     

不同纬度植物群落系统发育与功能性状结构研究

研究植物群落系统发育和功能性状结构有助于了解植物多样性维持机制及物种间的亲缘关系。甘肃省地理环境复杂,显著而多变的气候梯度形成了区域植被和环境差异,丰富了栖息地类型,具有显著的纵向连通性和纬度隔离性,以甘肃省典型纬度梯度植物群落为研究对象,通过对其进行群落学调查和功能性状测定,计算净亲缘关系指数(Net relatedness index, NRI)和平均成对性状距离(Mean pairwise trait distance, PW)来分析植物群落系统发育结构和功能性状格局对不同纬度的响应。结果表明：(1) Shannon-Weiner多样性指数,物种丰富度,谱系α多样性指数表现出随纬度增加而显著降低的变化趋势(P<0.05),Pielou均匀度指数随纬度的升高没有显著的变化趋势;(2)系统发育结构在高、低纬度上趋于发散状态(NRI<0),在中纬度上又表现出聚集(NRI>0)的谱系结构,表明种间竞争作用减弱,环境过滤作用逐渐增强,随纬度继续升高相似性限制作用在物种聚集过程中占优势;而群落的功能性状结构随着纬度增加表现出与谱系结构相反的状态,因此植物群落的系统发育和功能...     

Scale dependence in the phylogenetic relatedness of alien and native taxa

达尔文的归化假说提出,由于生态位的不同,成功建群的外来物种与本地物种的关系不太密切。先前的研究对这一假设有支持也有反对,其中一个原因是外来物种和本地物种在大的空间尺度上有系统发育聚类的倾向,而在细微尺度上存在过度分散的倾向。然而,对于外来物种的系统发育关系如何改变其入侵群落的系统发育结构,以及在何种空间尺度上可能表现出这种影响,人们知之甚少。在本研究中,我们调查被入侵的森林下层植物群落在系统发育上是聚集的还是或过度分散的,亲缘关系如何随空间尺度变化,以及外来物种如何影响下层群落的系统发育模式。在澳大利亚东南部干旱森林的下层群落进行了5个空间尺度(1, 20, 500, 1500和4500 m²)的实地调查。使用两个指标的标准化效应量[(i)平均成对距离和(ii)平均最近分类单元距离]来量化群落与其外来和本地亚群落之间的系统发育关系,并研究系统发育模 式如何随空间尺度变化。研究结果表明,外来物种之间的亲缘关系非常密切,而且这种亲缘关系会随着尺度的增加而增加。在中等空间尺 度下(20–500 m²), 整个群落呈随机分布趋势,而本地物种高度分散,外来亚群落高度聚集。这说明亲缘关系密切的外来物种入侵使群落系统发育结构由过度分散向随机分布转变。外来物种和本地物种在空间尺度上是远亲,这支持了达尔文的归化假说,但只是在系统发育距离被量化为平均最近分类单元距离时成立。外来物种和本地物种的系统发育差异随着空间尺度的增加而增加,这与预期的模式相反。我们的研究结果表明,外来物种强大的系统发育聚类是由人类干预的引入驱动的,牵涉能够成功建群和传播的密切相关的类群。系统发育相关性的尺度依赖模式可能是由火灾和散布等随机过程引起的,这表明竞争和生境过滤并不是分别在小和大尺度上控制系统发育关系的唯一因素。区分不同进化深度的指标很重要,因为不同的指标可以显示不同的尺度依赖模式。     

Trait similarity, shared ancestry and the structure of neighbourhood interactions in a subtropical wet forest: implications for community assembly

Ecology Letters (2010) 13: 1503-1514 ABSTRACT: The phylogenetic structure and distribution of functional traits in a community can provide insights into community assembly processes. However, these insights are sensitive to the spatial scale of analysis. Here, we use spatially explicit, neighbourhood models of tree growth and survival for 19 tree species, a highly resolved molecular phylogeny and information on eight functional traits to quantify the relative efficacy of functional similarity and shared ancestry in describing the effects of spatial interactions between tree species on demographic rates. We also assess the congruence of these results with observed phylogenetic and functional structure in the neighbourhoods of live and dead trees. We found strong support for models in which the effects of spatial neighbourhood interactions on tree growth and survival were scaled to species-specific mean functional trait values (e.g., wood specific gravity, leaf succulence and maximum height) but not to phylogenetic distance. The weak phylogenetic signal in functional trait data allowed us to independently interpret the static neighbourhood functional and phylogenetic patterns. We observed greater functional trait similarity in the neighbourhoods of live trees relative to those of dead trees suggesting that environmental filtering is the major force structuring this tree community at this scale while competitive interactions play a lesser role.     

Testing Darwin's naturalization hypothesis in the Azores

Invasive species are a threat for ecosystems worldwide, especially oceanic islands. Predicting the invasive potential of introduced species remains difficult, and only a few studies have found traits correlated to invasiveness. We produced a molecular phylogenetic dataset and an ecological trait database for the entire Azorean flora and find that the phylogenetic nearest neighbour distance (PNND), a measure of evolutionary relatedness, is significantly correlated with invasiveness. We show that introduced plant species are more likely to become invasive in the absence of closely related species in the native flora of the Azores, verifying Darwin's 'naturalization hypothesis'. In addition, we find that some ecological traits (especially life form and seed size) also have predictive power on invasive success in the Azores. Therefore, we suggest a combination of PNND with ecological trait values as a universal predictor of invasiveness that takes into account characteristics of both introduced species and receiving ecosystem.     

Phylogenetic and ecological structure of Mediterranean caddisfly communities at various spatio‐temporal scales

Aim The evolutionary processes structuring the composition of communities remain unclear due to the complexity of factors active at various spatial and temporal scales. Here, we conducted ecological and evolutionary analyses of communities of caddisflies in the genus Hydropsyche (Insecta: Trichoptera) composed of ecomorphologically differentiated species. Location River ecosystems in the Iberian Peninsula and northern Morocco. Methods Nineteen environmental variables were assessed at 180 local study sites and species presence/absence at these sites was used to determine their ecological niche. The evolutionary framework for all 19 species of Hydropsyche encountered was generated by phylogenetic analysis of the mitochondrial cytochrome c oxidase subunit I gene and three nuclear genes: wingless, elongation factor 1‐alpha and 28S RNA. The phylogenetic tree was used: (1) to assess evolutionary niche conservatism by ecological trait correlation with the tree; and (2) to analyse the phylogenetic relatedness of community member species, at three spatial scales (local stream reaches, drainage basins, biogeographical regions). Results Ecological measurements grouped most species into either headwater, mid‐stream or lowland specialists, and traits presumably relevant to river zonation were found to be phylogenetically conservative. Species assemblages at local stream reaches were mostly mono‐ or dispecific. Species diversity increased at larger spatial scales, by adding species with non‐overlapping ecological niches at the level of river basins and by turnover of anciently differentiated lineages at the level of biogeographical regions. This indicates the effects of competition and niche filtering on community structure locally, and ancient ecological diversification and allopatric speciation, respectively, in building up the species pool at basin and biogeographical scales. Main conclusions The study demonstrates the importance of scale (grain size) in studying what determines community composition. Current ecological factors (i.e. competitive exclusion) in Hydropsyche were evident only when studying narrow local sites, while studies of assemblages at larger spatial scales instead demonstrated the roles of ecological niche differentiation, phylogenetic history of trait diversification and allopatric speciation. Increasing the grain size of investigation reveals different portions of correlated spatial and evolutionary processes.     

Searching for phylogenetic pattern in biological invasions

It has been suggested that alien species with close indigenous relatives in the introduced range may have reduced chances of successful establishment and invasion (Darwin's naturalization hypothesis). Studies trying to test this have in fact been addressing four different hypotheses, and the same data can support some while rejecting others. In this paper, we argue that the phylogenetic pattern will change depending on the spatial and phylogenetic scales considered. Expectations and observations from invasion biology and the study of natural communities are that at the spatial scale relevant to competitive interactions, closely related species will be spatially separated, whereas at the regional scale, species in the same genera or families will tend to co-occur more often than by chance. We also argue that patterns in the relatedness of indigenous and naturalized plants are dependent on the continental/island setting, spatial occupancy levels, and on the group of organisms under scrutiny. Understanding how these factors create a phylogenetic pattern in invasions will help us predict which groups are more likely to invade where, and should contribute to general ecological theory.     

Ecological traits influence the phylogenetic structure of bird species co‐occurrences worldwide

The extent to which species’ ecological and phylogenetic relatedness shape their co‐occurrence patterns at large spatial scales remains poorly understood. By quantifying phylogenetic assemblage structure within geographic ranges of >8000 bird species, we show that global co‐occurrence patterns are linked – after accounting for regional effects – to key ecological traits reflecting diet, mobility, body size and climatic preference. We found that co‐occurrences of carnivorous, migratory and cold‐climate species are phylogenetically clustered, whereas nectarivores, herbivores, frugivores and invertebrate eaters tend to be more phylogenetically overdispersed. Preference for open or forested habitats appeared to be independent from the level of phylogenetic clustering. Our results advocate for an extension of the tropical niche conservatism hypothesis to incorporate ecological and life‐history traits beyond the climatic niche. They further offer a novel species‐oriented perspective on how biogeographic and evolutionary legacies interact with ecological traits to shape global patterns of species coexistence in birds.     

Why close relatives make bad neighbours: phylogenetic conservatism in niche preferences and dispersal disproves Darwin's naturalization hypothesis in the thistle tribe

The number of exotic plant species that have been introduced into the United States far exceeds that of other groups of organisms, and many of these have become invasive. As in many regions of the globe, invasive members of the thistle tribe, Cardueae, are highly problematic in the California Floristic Province, an established biodiversity hotspot. While Darwin's naturalization hypothesis posits that plant invaders closely related to native species would be at a disadvantage, evidence has been found that introduced thistles more closely related to native species are more likely to become invasive. To elucidate the mechanisms behind this pattern, we modelled the ecological niches of thistle species present in the province and compared niche similarity between taxa and their evolutionary relatedness, using fossil‐calibrated molecular phylogenies of the tribe. The predicted niches of invasive species were found to have higher degrees of overlap with native species than noninvasive introduced species do, and pairwise niche distance was significantly correlated with phylogenetic distance, suggesting phylogenetic niche conservatism. Invasive thistles also displayed superior dispersal capabilities compared to noninvasive introduced species, and these capabilities exhibited a phylogenetic signal. By analysing the modelled ecological niches and dispersal capabilities of over a hundred thistle species, we demonstrate that exapted preferences to the invaded environment may explain why close exotic relatives may make bad neighbours in the thistle tribe.     

Global patterns of phylogenetic relatedness of invasive flowering plants

Aim

The ability of predicting which naturalized non-native species are likely to become invasive can help manage and prevent species invasions. The goal of this study is to test whether invasive angiosperm (flowering plant) species are a phylogenetically clustered subset of naturalized species at global, continental and regional scales, and to assess the relationships of phylogenetic relatedness of invasive species with climate condition (temperature and precipitation).

Location

Global.

Time period

Current.

Taxon

Angiosperms (flowering plants).

Methods

The globe is divided into 290 regions, which are grouped into seven biogeographic (continental) regions. Two phylogenetic metrics (net relatedness index and nearest taxon index), which represent different evolutionary depths, are used to quantify phylogenetic relatedness of invasive angiosperms, with respect to different tailor-made species pools. Phylogenetic relatedness of invasive angiosperms is related to climatic variables.

Results

The global assemblage of invasive angiosperm species is a strongly phylogenetically clustered subset of the species of the entire global angiosperm flora. Most invasive angiosperm assemblages are a phylogenetically clustered subset of their respective naturalized species pools, and phylogenetic clustering reflecting shallow evolutionary history is greater than that reflecting deep evolutionary history. In general, the phylogenetic relatedness of invasive species is greater in regions with lower temperature and precipitation across the world.

Main conclusions

The finding that invasive angiosperm assemblages across the globe are, in general, phylogenetically clustered subsets of their respective naturalized species pools has significant implications in biological conservation, particularly in predicting and controlling invasive species based on phylogenetic relatedness among naturalized species.     

Co-occurrence of tree species at fine spatial scale in a woodland cerrado,southeastern Brazil

Species co-occurrence at fine spatial scales is expected to be nonrandom in relation to species phylogenetic relatedness and functional similarity. On the one hand, closely related species that occur together and experience similar environmental conditions are likely to share phenotypic traits due to the process of environmental filtering. On the other hand, species that are too similar are unlikely to co-occur due to competitive exclusion. We surveyed a woodland cerrado, southeastern Brazil, to test whether co-occurrence in tree species shows functional or phylogenetic structuring at fine spatial scale. Searching for correlations between an index of species co-occurrence and both functional trait differences and phylogenetic distances, we provided evidence for a predominant role of environment filters in determining the co-occurrence of functionally similar tree species in cerrado. However, we did not find any effect of phylogenetic relatedness on tree species co-occurrence. We suggest that the phylogenetic relatedness of co-occurring cerrado tree species did not present a pattern, because the species functional traits were randomly distributed on the phylogeny. Thus, phylogenetic relatedness and functional similarity do not seem to limit the co-occurrence at fine spatial scale of cerrado tree species.     

Does phylogenetic relatedness influence the strength of competition among vascular plants?

A widely assumed but largely untested hypothesis central to ecology and evolutionary biology has been Charles Darwin's suggestion that closely related species will be more ecologically similar, and thus will compete more strongly with each other than they will with more distantly related species. We provide one of the first direct tests of the “competition-relatedness hypothesis” by combining two data sets: the relative competitive ability of 50 vascular plant species competing against 92 competitor species measured in five multi-species experiments, and measures of the phylogenetic relatedness of these species. In contrast to Darwin's assertion, there were weak relationships between the strength of competition and phylogenetic relatedness. Across all species studied, the competition-relatedness relationship was weak and not significant. This overall lack of pattern masked different responses of monocot and eudicot focal (phytometer) species. When monocots served as the focal (phytometer) species, the intensity of competition increased with the phylogenetic distance separating species, while competition decreased with phylogenetic distance for eudicot phytometers. These results were driven by the monocot-eudicot evolutionary split, such that monocots were poor competitors against eudicots, while eudicots are most strongly suppressed by other eudicots. There was no relationship between relatedness and competition for eudicots competing with other eudicots, while monocots did compete more intensely with closely related monocots than with distantly related monocots. Overall, the relationships between competition intensity and relatedness were weak compared to the strong and consistent relationships between competitive ability and functional traits such as plant size that have been reported by other studies. We suggest that Darwin's assertion that competition will be strongest among closely related species is not supported by empirical data, at least for the 142 vascular plant species in this study.     

Competitive interactions between forest trees are driven by species' trait hierarchy, not phylogenetic or functional similarity: implications for forest community assembly

The relative importance of competition vs. environmental filtering in the assembly of communities is commonly inferred from their functional and phylogenetic structure, on the grounds that similar species compete most strongly for resources and are therefore less likely to coexist locally. This approach ignores the possibility that competitive effects can be determined by relative positions of species on a hierarchy of competitive ability. Using growth data, we estimated 275 interaction coefficients between tree species in the French mountains. We show that interaction strengths are mainly driven by trait hierarchy and not by functional or phylogenetic similarity. On the basis of this result, we thus propose that functional and phylogenetic convergence in local tree community might be due to competition-sorting species with different competitive abilities and not only environmental filtering as commonly assumed. We then show a functional and phylogenetic convergence of forest structure with increasing plot age, which supports this view.     

Phylogenetic plant community structure along elevation is lineage specific

The trend of closely related taxa to retain similar environmental preferences mediated by inherited traits suggests that several patterns observed at the community scale originate from longer evolutionary processes. While the effects of phylogenetic relatedness have been previously studied within a single genus or family, lineage‐specific effects on the ecological processes governing community assembly have rarely been studied for entire communities or flora. Here, we measured how community phylogenetic structure varies across a wide elevation gradient for plant lineages represented by 35 families, using a co‐occurrence index and net relatedness index (NRI). We propose a framework that analyses each lineage separately and reveals the trend of ecological assembly at tree nodes. We found prevailing phylogenetic clustering for more ancient nodes and overdispersion in more recent tree nodes. Closely related species may thus rapidly evolve new environmental tolerances to radiate into distinct communities, while older lineages likely retain inherent environmental tolerances to occupy communities in similar environments, either through efficient dispersal mechanisms or the exclusion of older lineages with more divergent environmental tolerances. Our study illustrates the importance of disentangling the patterns of community assembly among lineages to better interpret the ecological role of traits. It also sheds light on studies reporting absence of phylogenetic signal, and opens new perspectives on the analysis of niche and trait conservatism across lineages.