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Background and aims: The introduced lineage of Phragmites australis (haplotype M) in North America outcompetes the native lineage (haplotype E). Previous studies have found that haplotype M is situated on the fast side of the trait economic spectrum compared to haplotype E in North America and Europe. The present study evaluated the plant traits and associated soil microbes of introduced and native Phragmites lineages using a common garden experiment. Methods: Four geographic groups, including the introduced lineage of North America (NAint, haplotype M), native lineage of North America (NAnat, haplotype E), European group (EU, haplotype M) and northwestern China group (CHN, haplotype M), were studied in two life-history stages – growing period and withering period. Results: No trait differences were observed among the four groups. The difference existed in the soil microbial structure. The soils derived from the four groups had different bacterial generic structures. NAnat gathered more plant pathogenic and ectomycorrhizal fungi in the growing period. In the withering period, NAint accumulated more plant pathogenic fungi, while NAnat accumulated more arbuscular mycorrhizal fungi. The soil microbial structure was different among NAint, EU and CHN despite the same haplotype. Conclusion: The interaction between plant traits and the soil microbes seemed weak. However, the long-term effects of microbial transition on the introduced and native lineages are unknown, and the potential plant-soil interactions need further exploration. [ABSTRACT FROM AUTHOR]

From micro to planetary scales, spatial heterogeneity-patchiness-is ubiquitous in ecosystems, defining the environments in which organisms move and interact. However, most large-scale models still use spatially averaged 'mean fields' to represent natural populations, while fine-scale spatially explicit models are mostly restricted to particular organisms or systems. In a conceptual paper, Grünbaum (2012, Interface Focus 2: 150-155) introduced a heuristic, based on three dimensionless ratios quantifying movement, reproduction and resource consumption, to characterise patchy ecological interactions and identify when mean-field assumptions are justifiable. We calculated these dimensionless numbers for 33 interactions between consumers and their resource patches in terrestrial, aquatic and aerial environments. Consumers ranged in size from bacteria to whales, and patches lasted from minutes to millennia, with separation scales from mm to hundreds of km. No interactions could be accurately represented by naive mean-field models, though 19 (58%) could be partially simplified by averaging out movement, reproductive or consumption dynamics. Clustering interactions by their non-dimensional ratios revealed several unexpected dynamic similarities. For example, bacterial Pseudoalteromonas exploit nutrient plumes similarly to Mongolian gazelles grazing on ephemeral steppe vegetation. We argue that dimensional analysis is valuable for characterising ecological patchiness and can link widely different systems into a single quantitative framework.

BackgroundInvestigating the causes and consequences of intraspecific trait variation (ITV) in plants is not novel, as it has long been recognized that such variation shapes biotic and abiotic interactions. While evolutionary and population biology have extensively investigated ITV, only in the last 10 years has interest in ITV surged within community and comparative ecology.ScopeDespite this recent interest, still lacking are thorough descriptions of ITV's extent, the spatial and temporal structure of ITV, and stronger connections between ITV and community and ecosystem properties. Our primary aim in this review is to synthesize the recent literature and ask: (1) How extensive is intraspecific variation in traits across scales, and what underlying mechanisms drive this variation? (2) How does this variation impact higher-order ecological processes (e.g. population dynamics, community assembly, invasion, ecosystem productivity)? (3) What are the consequences of ignoring ITV and how can these be mitigated? and (4) What are the most pressing research questions, and how can current practices be modified to suit our research needs? Our secondary aim is to target diverse and underrepresented traits and plant organs, including anatomy, wood, roots, hydraulics, reproduction and secondary chemistry. In addressing these aims, we showcase papers from the Special Issue.ConclusionsPlant ITV plays a key role in determining individual and population performance, species interactions, community structure and assembly, and ecosystem properties. Its extent varies widely across species, traits and environments, and it remains difficult to develop a predictive model for ITV that is broadly applicable. Systematically characterizing the sources (e.g. ontogeny, population differences) of ITV will be a vital step forward towards identifying generalities and the underlying mechanisms that shape ITV. While the use of species means to link traits to higher-order processes may be appropriate in many cases, such approaches can obscure potentially meaningful variation. We urge the reporting of individual replicates and population means in online data repositories, a greater consideration of the mechanisms that enhance and constrain ITV's extent, and studies that span sub-disciplines.

A growing need exists to consider effects of biodiversity dynamics on the functioning of natural and anthropised ecosystems. This requires including the concepts of functional ecology, especially comparative trait‐based ecology, in a broad range of theoretical and applied studies. In parallel, the importance of the below‐ground compartment is increasingly recognised, which has exponentially increased the number of studies that consider root functional traits, despite limited understanding of their meaning. This perspective article (i) describes the origins of the trait‐based ecology framework, (ii) highlights current limitations of root‐system studies and (iii) recommends ways to address these limitations.In recent years, studies claimed that above‐ground functional ecology had theoretical foundations without adequate empirical support. Root functional ecology has experienced the same problems and, for several reasons, its foundations seem even more unstable. Firstly, roots are difficult to collect, and it is difficult to precisely define components of the root system that have homogenous functions. Secondly, root systems are complex organs and have a diversity of functions, such as taking up nutrients and water, storing resources and anchoring plants. Thirdly, the theoretical background used in root functional ecology approaches is based on that of above‐ground ecology, specifically leaf functional ecology.In the past several decades, root ecology benefitted from following the footsteps of above‐ground trait‐based functional ecology, which highlighted the existence of a variety of trait spectra that were partially related to species' ecology or their interaction with symbiotic microorganisms. However, root functional ecology is currently at a crossroads and must move beyond this above‐ground path and rediscover the origins of root ecology and include new traits based on root architecture and anatomy. Doing so requires developing innovative approaches that are more specific to the below‐ground compartment to improve understanding of plant roots and include them in large‐scale studies. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

When comparing somatic growth thermal performance curves (TPCs), higher somatic growth across experimental temperatures is often observed for populations originating from colder environments. Such countergradient variation has been suggested to represent adaptation to seasonality, or shorter favourable seasons in colder climates. Alternatively, populations from cold climates may outgrow those from warmer climates at low temperature, and vice versa at high temperature, representing adaptation to temperature. Using modelling, we show that distinguishing between these two types of adaptation based on TPCs requires knowledge about (i) the relationship between somatic growth rate and population growth rate, which in turn depends on the scale of somatic growth (absolute or proportional), and (ii) the relationship between somatic growth rate and mortality rate in the wild. We illustrate this by quantifying somatic growth rate TPCs for three populations of Daphnia magna where population growth scales linearly with proportional somatic growth. For absolute somatic growth, the northern population outperformed the two more southern populations across temperatures, and more so at higher temperatures, consistent with adaptation to seasonality. In contrast, for the proportional somatic growth TPCs, and hence population growth rate, TPCs tended to converge towards the highest temperatures. Thus, if the northern population pays an ecological mortality cost of rapid growth in the wild, this may create crossing population growth TPCs consistent with adaptation to temperature. Future studies within this field should be more explicit in how they extrapolate from somatic growth in the lab to fitness in the wild. [ABSTRACT FROM AUTHOR]

The asymptotic height (Hmax) and the size‐scaling exponent (β), proxies of tree size and important forest architectural parameters of the relationships between height and tree diameter of forests, play important roles in the carbon (C) stocks and fluxes of forest ecosystems. However, the patterns and drivers of these values in continental China are not well known. Based on a national forest database of China, we explored the geographic patterns and ecological drivers of Hmax and β and their dynamic relationships with the C sequestration capabilities of the studied ecosystems, including the C stock and allocation, net ecosystem productivity (NEP), and mean ecosystem C turnover time. At the ecosystem scale, the Hmax values ranged from 10.37 to 37.07 m, with a mean value of 25.41 m, showing a decreasing trend with increasing latitude. However, β ranged from 0.598 to 0.73, with a mean value of 0.66, showing an increasing trend with latitude. The spatial patterns of the forest Hmax and β at the national scale were largely controlled by the mean annual temperature, mean annual precipitation, and forest age. These patterns were verified using biomass and forest C sequestration data, showing that the total vegetation C stock as a whole, in aboveground or belowground components, was significantly and positively correlated with Hmax (p < 0.05), revealing apparent "faster first, slower later" increasing trends with Hmax (R2 = 0.759, 0.821, and 0.527, respectively). In addition, for forest >20 m, NEP showed a significant strong negative correlation with Hmax (by −0.967% per 1 m of Hmax, R2 = 0.504, p < 0.05), and a 10‐m increase in Hmax resulted in a decrease in mean ecosystem C turnover time by 16.9% (7.43 years). Taller forests might indeed be expected to have higher autotrophic respiration consumption rates but lower mean ecosystem C turnover time and NEP values than shorter forests. The discovery that community‐level asymptotic height could be used as a comparative predictor of ecosystem C sequestration capacity and its difference among forest biomes underpins the fundamentals of ecological theories and modeling, which has important implications for forest restoration, policy, and management. [ABSTRACT FROM AUTHOR]

Abstract The asymptotic height (Hmax) and the size‐scaling exponent (β), proxies of tree size and important forest architectural parameters of the relationships between height and tree diameter of forests, play important roles in the carbon (C) stocks and fluxes of forest ecosystems. However, the patterns and drivers of these values in continental China are not well known. Based on a national forest database of China, we explored the geographic patterns and ecological drivers of Hmax and β and their dynamic relationships with the C sequestration capabilities of the studied ecosystems, including the C stock and allocation, net ecosystem productivity (NEP), and mean ecosystem C turnover time. At the ecosystem scale, the Hmax values ranged from 10.37 to 37.07 m, with a mean value of 25.41 m, showing a decreasing trend with increasing latitude. However, β ranged from 0.598 to 0.73, with a mean value of 0.66, showing an increasing trend with latitude. The spatial patterns of the forest Hmax and β at the national scale were largely controlled by the mean annual temperature, mean annual precipitation, and forest age. These patterns were verified using biomass and forest C sequestration data, showing that the total vegetation C stock as a whole, in aboveground or belowground components, was significantly and positively correlated with Hmax (p 20 m, NEP showed a significant strong negative correlation with Hmax (by −0.967% per 1 m of Hmax, R2 = 0.504, p

Phenotypic plasticity index (PI), the slope of reaction norm (K) and relative distances plasticity index (RDPI), the most commonly used estimators, have occasionally been found to generate different plasticity rankings between groups (species, populations, cultivars or genotypes). However, no effort has been made to determine how frequent this incongruence is, and the factors that influence the occurrence of the incongruence. To address these problems, we first proposed a conceptual framework and then tested the framework (its predictions) by reanalyzing 1248 sets of published data. Our framework reveals inherent conflicts between K and PI or RDPI when comparing plasticity between two groups, and the frequency of these conflicts increases with increasing inter-group initial trait difference and/or K values of the groups compared. More importantly, the estimators also affect the magnitude of the inter-group plasticity differences even when they do not change groups' plasticity rankings. The above-mentioned effects of plasticity estimators were confirmed by our empirical test using data from the literature, and the conflicts occur in 203 (16%) of the 1248 comparisons between K and indices, indicating that a considerable proportion of the comparative conclusions on plasticity in literature are estimator-dependent. The frequency of the conflicts is influenced by phylogenetic relatedness of the groups compared, being lower when comparing within relative to between species, but not by specific types of environments, traits and species. Our study indicates that care is needed to select estimator when comparing groups' plasticity, and that the conclusions in relevant literature should be treated with great caution. [ABSTRACT FROM AUTHOR]

Summary: Phenology, the study of seasonal timing of events in nature, plays a key role in the matching between organisms and their environment. Yet, it has been poorly integrated in trait‐based descriptions of the plant phenotype. Here, we focus on three phases of reproductive phenology – time of flowering, time of seed dispersal and duration of seed maturation – to test how these traits relate to other recognized dimensions of plant functioning.Traits describing reproductive phenology, together with reproductive plant height, seed mass, area of a leaf, and traits involved in leaf economics, were compiled for 139 species growing under Mediterranean climate conditions.Across all species, flowering time was positively related to reproductive height, while the duration of seed maturation was related to leaf economics. Relationships differed among growth forms, however: flowering time and reproductive height were related both in annuals and in herbaceous perennials, whereas the duration of seed maturation was related to seed mass only in annuals; no correlations were found for woody species.Phenology relates to other dimensions of plant functioning in a complex manner, suggesting that it should be considered as an independent dimension in the context of plant strategies. [ABSTRACT FROM AUTHOR]

Functional traits have long been considered the 'holy grail' in community ecology due to their potential to link phenotypic variation with ecological processes. Advancements across taxonomic disciplines continue to support functional ecology's objective to approach generality in community assembly. However, a divergence of definitions, aims and methods across taxa has created discord, limiting the field's predictive capacity. Here, we provide a guide to support functional ecological comparisons across taxa. We describe advances in cross‐taxa functional research, identify gaps in approaches, synthesize definitions and unify methodological considerations. When deciding which traits to compare, particularly response traits, we advocate selecting functionally analogous traits that relate to community assembly processes. Finally, we describe at what scale and for which questions functional comparisons across taxa are useful and when other approaches may be more constructive. Our approach promotes standardized methods for integrative research across taxa to identify broad trends in community assembly. [ABSTRACT FROM AUTHOR]

Abstract: The phenology of organisms corresponds to the temporal match between the components of their life cycle and the seasonal distribution of resources and hazards. Flowering has been extensively studied to describe the reproductive phenology of plants, but in comparison, other key events for reproductive success such as the seed maturation period and the time of seed dispersal have been considerably less investigated. This study describes the temporal sequence of onset of flowering and seed dispersal, and the time necessary to mature seeds in 138 species growing in the strongly seasonal climate of Mediterranean southern France. Data for the three traits were compiled from several original surveys to characterize the reproductive phenology of 47 annual, 67 perennial herbaceous and 24 low stature woody species. The timing of these three phases was assessed in relation to local climatic conditions, and the degree to which they were coordinated was tested. All three phenological traits spanned a wide range of values from early spring to late summer. Annuals flowered slightly earlier than perennials but the largest difference between these groups was found for the seed maturation period, which was much shorter in annuals. This resulted in earlier dispersal dates in these species, which occurred before periods of high water deficit. Significant positive correlations were found between onset of flowering, onset of seed dispersal and seed maturation period. This suggests a consistent pattern of coordination between the different phases of reproductive phenology across species. Our results show that while the time slot for flowering appears restricted to periods with adequate temperature and water availability for most species, the seed maturation period and dispersal phase can occur during periods of substantial water deficit, at least for perennials. They also suggest that the different species can be arrayed along a fast‐slow continuum based on reproductive events, from early flowering species with short seed maturation and early dispersal to late flowering species with long seed maturation and late dispersal. Whether this relates to the postulated fast‐slow continuum identified for the functioning of vegetative organs is a promising avenue for future research. A plain language summary is available for this article. [ABSTRACT FROM AUTHOR]

The otter (Lutra lutra) in Romania uses a wide range of habitats: highland and lowland lakes, rivers and streams, as well as marshes, riparian forests, delta and coastal areas. These habitats lead to a high variability of otter's prey. From December 2012 until July 2014, diet of Eurasian otter was studied based on spraint analysis in Putna-Vrancea Natural Park (n=118 samples) and Lower Siret Valley Natura 2000 Site (n=56 samples), south - east Romania. The Percentage of Occurrence (PO), Relative Frequency of Occurrence (RFO) and Percentage Frequency of Occurrence (PFO) were calculated. Fish (PO = 56.1%) and amphibians (PO = 22.5%) were the primary diet components of otters in Putna-Vrancea, while in Lower Siret Valley, fish (PO = 36.7%) and crayfish (PO = 32.6%) formed the mass of the diet. Fish consumption was all seasons high in Putna-Vrancea, except in winter. In Lower Siret Valley, the highest fish consumption was in the autumn and the lowest in the summer. In Putna-Vrancea, amphibians were more frequently become part of the diet in the spring, while in Lower Siret Valley were during the summer. Crayfish were the primary elements of otter's diet from Lower Siret Valley in the summer, while in Putna-Vrancea remains of crayfish were not discovered in the spraints. The results indicate that the otter's feeding ecology was influenced by environmental factors of the ecosystems where the otters live, such as altitude, climate and different prey fauna. [ABSTRACT FROM AUTHOR]

The value of plant ecological datasets with hundreds or thousands of species is principally determined by the taxonomic accuracy of their plant names. However, combining existing lists of species to assemble a harmonized dataset that is clean of taxonomic errors can be a difficult task for non-taxonomists. Here, we describe the range of taxonomic difficulties likely to be encountered during dataset assembly and present an easy-to-use taxonomic cleaning protocol aimed at assisting researchers not familiar with the finer details of taxonomic cleaning. The protocol produces a final dataset (FD) linked to a companion dataset (CD), providing clear details of the path from existing lists to the FD taken by each cleaned taxon. Taxa are checked off against ten categories in the CD that succinctly summarize all taxonomic modifications required. Two older, publicly-available lists of naturalized Asteraceae in Australia were merged into a harmonized dataset as a case study to quantify the impacts of ignoring the critical process of taxonomic cleaning in invasion ecology. Our FD of naturalized Asteraceae contained 257 species and infra-species. Without implementation of the full cleaning protocol, the dataset would have contained 328 taxa, a 28% overestimate of taxon richness by 71 taxa. Our naturalized Asteraceae CD described the exclusion of 88 names due to nomenclatural issues (e.g. synonymy), the inclusion of 26 updated currently accepted names and four taxa newly naturalized since the production of the source datasets, and the exclusion of 13 taxa that were either found not to be in Australia or were in fact doubtfully naturalized. This study also supports the notion that automated processes alone will not be enough to ensure taxonomically clean datasets, and that manual scrutiny of data is essential. In the long term, this will best be supported by increased investment in taxonomy and botany in university curricula. [ABSTRACT FROM AUTHOR]

Contents1597I.1597II.1597III.1598IV.1598V.1600VI.1601VII.1601VIII.16011602References1602 Summary: Trait‐based approaches have led to significant advances in plant ecology, but are currently biased toward above‐ground traits. It is becoming clear that a stronger emphasis on below‐ground traits is needed to better predict future changes in plant biodiversity and their consequences for ecosystem functioning. Here I propose six ‘below‐ground frontiers’ in trait‐based plant ecology, with an emphasis on traits governing soil nutrient acquisition: redefining fine roots; quantifying root trait dimensionality; integrating mycorrhizas; broadening the suite of root traits; determining linkages between root traits and abiotic and biotic factors; and understanding ecosystem‐level consequences of root traits. Focusing research efforts along these frontiers should help to fulfil the promise of trait‐based ecology: enhanced predictive capacity across ecological scales. Editorial by Lennon & Dolan, 213: 1561. [ABSTRACT FROM AUTHOR]

Competitor, stress-tolerator, ruderal ( CSR) theory is a prominent plant functional strategy scheme previously applied to local floras. Globally, the wide geographic and phylogenetic coverage of available values of leaf area ( LA), leaf dry matter content ( LDMC) and specific leaf area ( SLA) (representing, respectively, interspecific variation in plant size and conservative vs. acquisitive resource economics) promises the general application of CSR strategies across biomes, including the tropical forests hosting a large proportion of Earth's diversity., We used trait variation for 3068 tracheophytes (representing 198 families, six continents and 14 biomes) to create a globally calibrated CSR strategy calculator tool and investigate strategy-environment relationships across biomes world-wide., Due to disparity in trait availability globally, co-inertia analysis was used to check correspondence between a 'wide geographic coverage, few traits' data set and a 'restricted coverage, many traits' subset of 371 species for which 14 whole-plant, flowering, seed and leaf traits (including leaf nitrogen content) were available. CSR strategy/environment relationships within biomes were investigated using fourth-corner and RLQ analyses to determine strategy/climate specializations., Strong, significant concordance ( RV = 0·597; P < 0·0001) was evident between the 14 trait multivariate space and when only LA, LDMC and SLA were used., Biomes such as tropical moist broadleaf forests exhibited strategy convergence (i.e. clustered around a CS/ CSR median; C:S:R = 43:42:15%), with CS-selection associated with warm, stable situations (lesser temperature seasonality), with greater annual precipitation and potential evapotranspiration. Other biomes were characterized by strategy divergence: for example, deserts varied between xeromorphic perennials such as Larrea divaricata, classified as S-selected (C:S:R = 1:99:0%) and broadly R-selected annual herbs (e.g. Claytonia perfoliata; R/ CR-selected; C:S:R = 21:0:79%). Strategy convergence was evident for several growth habits (e.g. trees) but not others (forbs)., The CSR strategies of vascular plants can now be compared quantitatively within and between biomes at the global scale. Through known linkages between underlying leaf traits and growth rates, herbivory and decomposition rates, this method and the strategy-environment relationships it elucidates will help to predict which kinds of species may assemble in response to changes in biogeochemical cycles, climate and land use. [ABSTRACT FROM AUTHOR]

The promise of 'trait-based' plant ecology is one of generalized prediction across organizational and spatial scales, independent of taxonomy. This promise is a major reason for the increased popularity of this approach. Here, we argue that some important foundational assumptions of trait-based ecology have not received sufficient empirical evaluation. We identify three such assumptions and, where possible, suggest methods of improvement: (i) traits are functional to the degree that they determine individual fitness, (ii) intraspecific variation in functional traits can be largely ignored, and (iii) functional traits show general predictive relationships to measurable environmental gradients. [ABSTRACT FROM AUTHOR]

Saprotrophic microfungi were isolated from soil samples taken at different arctic ecosystems. Distinction of soil microfungi complexes taken at Arctic is shown. In the article, it is demonstrated that severe conditions of arctic area lead to formation of common characteristics for all complexes of soil microfungi, which are different from complexes of middle latitudes. Complexes of microfungi in the Arctic regions are characterized by latitudinal differentiation from the polar desert zone to tundra zone (sub-zone arctic, typical and southern tundra) and the tundra-forest zone. Adaptation to arctic natural conditions take place both at the level of a system, that is at the level of microfungi complexes, and at the level of species and isolates. The general decreases of fungal numbers have been often noted in soil along the steep gradient directed from south to north. In the polar desert, the species number decreases compared with more southern zones due to the poorness of soil's systematic content. Microfungi complexes at the polar desert show itself at the genus and species levels rather than at the level of more largescale systematic groups. In soil, the dynamics and mosaics of fungi distribution depend on diversity of microclimatic conditions at their sites of existence. Anthropogenic influence causes significant changes in the complexes of soil microfungi. In the article, it is shown that location in Arctic climatic zones and plantgeographical zones lead to appearance (formation) of different characteristics of soil microfungi complexes i.e., general number, biomass, species and kinetic structure of communities, morphological, biochemical and functional features of microfungi, indexes of population densities and abundance of species at microfungi complexes. [ABSTRACT FROM AUTHOR]

Five species of chameleons were observed in the continuous forest zone of southern Nigeria: Chamaeleo gracilis gracilis Hallowell, 1842, Chamaeleo owenii Gray, 1831, Chamaeleo cristatus Stutchbury, 1837, Chamaeleo wiedersheimi Nieden, 1910, and Rhampholeon spectrum (Bucholz 1874). Many original locality records are presented for each species. One species is apparently rare and confined to montane habitats (C. wiedersheimi), another species is relatively common and its habitat is generalist (C. gracilis), and the other three species are vulnerable and limited to specific micro-habitats. Female R. spectrum had clutch sizes of two eggs each and exhibited a prolonged reproductive season with oviposition likely occurring during the late phase of the dry season. Females of both C. cristatus (clutch sizes: 11-14 eggs) and C. owenii (clutch sizes: 15-19 eggs) have a shorter reproductive season with oviposition occurring most probably at the interphase between the end of the wet season and the onset of the dry season, and female C. gracilis (clutch sizes: 14-23 eggs) appeared to exhibit two distinct oviposition periods (one at the interphase between the end of the wet season and the onset of the dry season, and one at the peak phase of the dry season). Diets of four sympatric species of chameleons consisted almost exclusively of arthropods. There were significant inter-group differences at either intra-specific level (with the females of the two best studied species, i.e. R. spectrum and C. gracilis, having a wider food niche breadth than males) or inter-specific level (with a continuum of dietary specialization from the less generalist (C. cristatus) to the more generalist (C. gracilis). However, ‘thread-trailing’ experiments indicated that activity patterns of Nigerian chameleons were relatively similar among species. The overall abundance of chameleons (as estimated from the number of specimens observed in the time unit of field effort) was relatively similar in three contrasted habitat types, but lizards were more abundant in the mature secondary forest. When greatly altered by massive logging activity, the overall abundance of chameleons in the mature secondary forest habitat declined only slightly, whereas the species diversity declined drastically. This was an effect of (i) the simultaneous extinction of three of the four species originally present in the forest plot, and of (ii) the rapid increase in abundance of a single species (C. gracilis) as a response to habitat alteration. The conservation implications of all these data are also discussed.

Cover plants can be used as an ecological tool to manage weeds through competition for shared resources. Assessing the abilities of a large number of different plant species to compete for light remains difficult. Our aim was to characterise the light competition strategies of a range of species on the basis of a small number of traits related to both acquisition of light and interference abilities, to help farmers choose the most suitable cover plant species for banana cropping systems. Using a trait-based approach, we identified and measured the most representative plant morphological and functional traits to characterize the light acquisition strategies of 21 plant species including banana, cover plants, and weed species. We identified trade-offs between plant traits and light acquisition strategies. We identified light competition strategies by taking into account the aboveground interference abilities of plants as defined by their growth habit. There was a wide range of variations between species for all the traits. Two main trade-offs were identified: resource acquisition vs. conservation and carbohydrates investment in height vs. leaf area. Five traits selected in a multivariate analysis explained 80% of the variability of light acquisition strategies in our panel of species. These were related to plant morphology (height and plant crown width), light conversion efficiency (specific leaf area), carbohydrate allocation (aboveground leaf area ratio), and carbohydrates demand (aboveground biomass). The growth habit and the light acquisition strategies were related. The characterisation of plant species using functional traits enabled us to hypothesise three light acquisition strategies shaped by interference abilities in four light competing strategies. We propose a new method to characterise and distinguish species through their ability to acquire light and to interfere aboveground with their neighbours. [ABSTRACT FROM AUTHOR]

The Atlantic forest is among the hottest hotspots for biodiversity conservation. Within this biome, inselbergs are isolated granitic and gneiss rocks that rise sharply above the lowland surrounding forests. Due to prevailing stressful conditions and resource paucity of inselbergs, distinguished plant communities are formed in these rocky-associated vegetation, which comprise unusually high levels of endemic and threatened species. Here, we evaluated the importance of competitiveness:stress-tolerance:ruderalism ecological strategies in different vegetation patches on the inselberg, tested for a connection between patch structure and functional traits, and compared the variation in functional traits between native and an exotic species, which represents a major threat to inselberg communities. Despite the stressful conditions of inselbergs, we found a relatively high diversity of ecological strategies, but most species and patches lied between the S and C strategy. The invasive Melinis repens, in turn, was functionally distinctive from native communities, with the predominance of traits associated with ruderalism. We also found that most functional traits significantly correlated with at least one environmental driver, highlighting their role in structuring plant communities in this heterogeneous environment. Since inselberg patches were spatially heterogeneous, and the variation in resource availability implies in favouring different ecological strategies, some patch types were more invasive-prone than others. Our data provide significant advances for identifying the environmental drivers of biological invasion in resource-limited environments. We argue that further trait-based approaches will become critical for developing conservation and management strategies for inselberg plant communities, especially in the context of rapid habitat loss and fragmentation of the Atlantic forest. [ABSTRACT FROM AUTHOR]

• Some tree genera have wet forest (WF) and dry forest (DF) adapted species. • Anatomically, the wood of DF species has more storage tissue. • The wood of WF species has larger, more solitary vessels and more fibres. • Habitat is an environmental filter that drives trait behaviour across related species. Forest tree species in wet and dry habitats are generally considered functionally divergent in leaf and stem functional traits such as leaf area, leaf mass per area, wood density and tree height. Yet, these traits have limited utility for characterizing plant water transport adaptations and strategies. We tested the hypothesis that wet and dry forest trees are functionally divergent in their water conducting apparatus. To assess trait differences and adaptations, we sampled branch wood from nine same-genus species-pairs, each species-pair occurring respectively in the wet (>1500 mm annual rainfall) and dry forest (<800 mm annual rainfall) in tropical Queensland, Australia. From branch wood sections, we measured anatomical traits involved in water conduction (stem vessel dimensions, fractions and their spatial distributions, theoretical water conductivities), storage (parenchyma), and providing hydraulic safety functions (fibres fractions, vulnerability index). Relative to wet forest species, we found on overall that dry forest trees had trait combinations showing adaptations to aridity such as more storage tissue and greater vessel connectivity which may provide alternative pathways for water transport should vessel embolism occur. Habitat is an environmental filter that influences trait behaviour across related species. However, depending on the genera, species in both dry and wet forest habitats also exhibit various tradeoffs in trait values, highlighting the existence of diverse hydraulic strategies within wet forest and dry forest trees. [ABSTRACT FROM AUTHOR]

The classification of plant species according to the CSR ecological strategy scheme has been proposed as a common language that allows comparison among species, communities, and floras. Although several studies on European continent have demonstrated a consistent association between CSR strategies and key ecosystem processes, studies of this type are still lacking in other ecoregions worldwide. For the first time, the CSR strategy scheme is applied in a tropical plant community. In a Brazilian mountain grassland ecosystem characterized by both high biodiversity and environmental stress, we sampled various functional traits of 48 herbaceous species in stony and sandy grasslands, and evaluated the relationship between CSR strategies and functional traits with several environmental parameters. The extremely infertile soils in the two studied habitats may have acted as a major environmental filter leading to a clear predominance of the stress-tolerant strategy in both communities. However, fine-scale environmental differences between the two communities resulted in the filtering of distinct functional trait values. The sites with coarser soil texture, lower percentage of plant cover and (paradoxically) higher mineral nutrient concentrations favored plants with narrower leaves, higher stress tolerance, lower competitiveness, and higher sclerophylly (i.e., lower specific leaf area and higher leaf dry matter content). The comparison between the functional character of stony and sandy communities evidenced the influence of soil texture and water availability in the environmental filtering. This study highlighted the validity of the CSR classification outside the temperate region where it was originally developed and corroborated. [ABSTRACT FROM AUTHOR]

Questions One central assumption of trait screening approaches in comparative plant ecology, i.e. simultaneous measurement of traits on a large number of species or populations, is that the species level captures a major part of trait variation. The current development of large databases has led to a new screening approach that relies on the extraction of trait values from databases, rather than on measurement of traits in the field. We tested this assumption with the following questions: (1) is the magnitude of intra-specific variability of co-occurring species lower than inter-specific variability for a given trait, in comparisons at different spatial scales; (2) is species hierarchy based on trait values conserved across different spatial scales and data sets (stable species hierarchy hypothesis); and (3) when we compare different traits, what is the more stable trait that is conserved across different spatial scales and data sets? Methods We combined approaches commonly used in functional ecology, i.e. experimental data, field observations and extraction of data from a global database, and analysed the magnitude of intra-specific and inter-specific trait variations for a large number of traits across contrasting environmental conditions for 18-39 (mostly) herbaceous species, according to the data set used. Results For most traits, inter-specific variability was higher than intra-specific variability, and species ranking was conserved across different data sets and spatial scales. However, we also detected important differential responses in terms of intra-specific trait variability, depending on the trait examined: SLA, LDMC, SM, seed N concentration and onset of flowering were more stable, whereas leaf chemical traits and RH were more flexible traits. Conclusions Our study validated, for the species studied, the stable species hierarchy hypothesis in the case of several, but not all, widely used traits. The main conclusion is that the strength of the species signal is strong enough for some traits to allow values to be used from different data sets (experiments, databases) to characterize local populations of species: for SM, seed N concentration, RH, SLA and LDMC. [ABSTRACT FROM AUTHOR]

Species in high-rainfall regions have two major alternative approaches to quickly drain off water, i.e., increasing leaf inclination angles relative to the horizontal plane, or developing long leaf drip tips. We hypothesized that shade-adapted species will have more pronounced leaf drip tips but not greater inclination angles (which can reduce the ability to intercept light) compared to sun-adapted species and that length of leaf drip tips will be negatively correlated with photosynthetic capacity [characterized by light-saturated net photosynthetic rates ( A), associated light compensation points (LCP), and light saturation points (LSP)]. We tested this hypothesis by measuring morphological and physiological traits that are associated with light-interception and water shedding for seven shade-adapted shrub species, ten sun-adapted understory shrub species, and 15 sun-adapted tree species in a subtropical Chinese rainforest, where mean annual precipitation is around 1,600 mm. Shade-adapted understory species had lower LMA, A, LSP, and LCP compared to understory or canopy sun-adapted species; their leaf and twig inclination angles were significantly smaller and leaf drip tips were significantly longer than those in sun-adapted species. This suggests that shade-adapted understory species tend to develop pronounced leaf drip tips but not large leaf inclination angles to shed water. The length of leaf drip tips was negatively correlated with leaf inclination angles and photosynthetic capacity. These relationships were consistent between ordinary regression and phylogenetic generalized least squares analyses. Our study illustrates the trade-offs between light interception and leaf water shedding and indicates that length of leaf drip tips can be used as an indicator of adaptation to shady conditions and overall photosynthetic performance of shrub species in subtropical rainforests. [ABSTRACT FROM AUTHOR]

In this era of rapidly urbanising human populations, urban practitioners are under increasing pressure to create resilient and sustainable cities and towns. Urban ecologists currently have a unique opportunity to apply solid, evidence-based research to help create biodiversity-rich and sustainable cities and towns for the future. Unfortunately, there is currently a mismatch between the questions planners, designers and decision-makers are asking urban ecologists that would allow them to improve the biodiversity outcomes in urban areas, and the questions urban ecologists must ask to contribute to the development and application of the science of urban ecology. For a number of reasons, urban ecologists over the past 25 years have primarily focused on describing the patterns of biodiversity in cities and towns using broad, aggregate predictor variables (e.g., distance to city center, land-use, percent cover of impermeable surfaces and vegetation, etc.). We refer to these results as 'low-hanging fruit'. If the discipline of urban ecology is going to provide the necessary information to inform actions to preserve and enhance urban biodiversity, we need to move beyond place-based research, and work towards the development of confirmed generalizations regarding the relationship between the structure and function of urban ecosystems and biodiversity. We propose three essential strategies for achieving this refined understanding: 1) defining the study window to place the study into a broader global context, 2) collecting and using more explicit question-driven measures of the urban condition in order to improve our understanding of urban ecological drivers, as well as recording more detailed ecological responses to provide insights into the ecological mechanisms underlying an observed response, and 3) expanding studies to include multiple cities, regions and countries. These strategies will help to expedite the ability of urban ecology to contribute to the creation of biodiversity-rich, healthy, resilient cities and towns. [ABSTRACT FROM AUTHOR]

A structural and functional assessment of the microbial foodweb of Lakes Superior, Huron, Erie and Ontario was undertaken during late summer (August) between 2001 and 2004. One lake was sampled in each year. Our analysis included microscopic enumerations of bacteric, autotrophic picoplankton, phytoplankton, heterotrophic nanoflagellates and cilia tes coupled with radio.so lope tracer measurements ofprimary productivity (14C) and bacterial growth (3H). Phytoplankton biomass was highest on average in Lake Erie (≈1.9 g m-3) and lowest in Lake Ontario (≈O.2 g m-3), whereas microbial loop biomass was highest in Lake Ontario (≈2. 4 g or-3) and lowest in Lake Huron (≈0. I g m-3). The organic carbon pool was found to be predominantly autotrophic (>80%) in Lakes Superior (≈280 mg C m-3), Huron (≈195 mg C m-3) and Erie (≈660 mg C m-3) and smaller picoplanklon had the highest caroon turnover rates (≈0. 4-1.5 d-1). However, in Lake Ontario (≈335 mg C m-3) the carbon pool was about 75% heterotrophic and larger net plankton had the highest carbon turnover rates (≈6.8 d-1). Despite differences in trophic state, the microbial foodwebs of Lakes Superior, Huron and Erie appeared to function in a similar and efficient manner in contrast, the micro bialfoodweb of Lake Ontario appeared to be uahealthy with autochthonous production being sequestered by heterotrophic nanoflagellates. More detailed work is needed to understand the foodweb linkages both within the Great Lakes and among them. [ABSTRACT FROM AUTHOR]

Delayed seed release (serotiny) is a convergent plant trait in fire-prone regions of the world but explaining the degree of serotiny has remained elusive because of the paucity of community data. Selective forces involving seed predators, fire and soil nutrients have been suggested as factors influencing serotiny. We tested whether protection of seeds and/or synchronized dispersal were associated with different levels of serotiny and if resprouting ability influences selection for strong serotiny. We compared the numbers and abundance of 146 woody species with delayed dispersal among five community types varying in combinations of fire severity, fire frequency, soil fertility and seed predators. The strength of the relationship between levels of serotiny and environmental factors was tested among community types ranging from rainforests to heathlands. Highest levels of serotiny were recorded in low nutrient shrublands with intermediate fire return intervals that burn at high severity, while the lowest were recorded in high nutrient, low flammability forests. Both protection of seeds and synchronized seed release were related to fire effects in nutrient-limited environments. Strong serotiny is prominent in species killed by fire whereas weak serotiny is more common in resprouting species. Recruitment failure in the inter-fire interval appears to drive selection for strong maternal care of seeds and synchronized seed dispersal in fire-prone environments. Weak serotiny is proposed as a bet-hedging strategy that relies on resprouting after fire for population persistence and higher probability of inter-fire recruitment. The spectrum of serotiny (weak to strong) in these communities is proposed to be driven by the interactive effect of both fire and soil nutrients on the selection for delayed seed dispersal. [ABSTRACT FROM AUTHOR]

While it is well known that the success of alien plants in new environments greatly depends on their functional traits, to date only a few other studies have tested whether coexisting alien and native species show converging or diverging functional attributes. To our knowledge, no comparative analysis between native and alien species has been carried out in the same mountain habitats. We characterized the main habitats of the Italian Alps on the basis of plant species traits and we then tested for evidence of functional axes of variation among the habitats for native and alien plants. Finally, we tested the 'try-harder' and the 'join-the-locals' hypotheses to understand whether coexisting native and alien plant species showed converging or diverging functional attributes. Ordination analysis showed a distribution of the habitats according to the Grime's CSR strategies, and associated to plant growth form and resource acquisition. Co-inertia analysis showed a significant association between native and alien plant traits at habitat level (RV = 0.73; Monte-Carlo test, p = 0.035). Across all species and habitats, the comparative analysis of individual traits showed that alien species have 25% higher plant height, 250% higher leaf mass, 19% lower leaf dry matter content, 10% higher SLA, and 17% longer flowering duration than native species. Overall, our findings demonstrated that aliens differ in many traits from native species in the Italian Alps, but that many of these differences disappear when one compares aliens and natives that co-occur in the same types of habitats. [ABSTRACT FROM AUTHOR]

Comparative functional ecology seeks to understand why and how ecological systems and their components operate differently across environments. Although traditionally used in (semi)-natural situations, its concepts and methods could certainly apply to address key issues in the large variety of agricultural systems encountered across the world. In this review, we present major advances in comparative plant functional ecology that were made possible over the last two decades by the rapid development of a trait-based approach to plant functioning and prospects to apply it in agricultural situations. The strength of this approach is that it enables us to assess the interactions between organisms and their environment simultaneously on a large number of species, a prerequisite to address questions relative to species distribution, community assembly and ecosystem functioning. The trait concept will be first defined, before presenting a conceptual framework to understand the effects of environmental factors on plant community structure and ecosystem properties via plant traits. We will then argue that leading dimensions of variation among species can be captured by some selected traits and show that a combination of three easily measured traits-specific leaf area (the ratio of leaf area to leaf dry mass), plant height and seed mass-enables us to assess how different species use their resources, interact with neighbours and disperse in time and space. The use of traits to address central questions in community ecology will be reviewed next. It will be shown that traits allow us to (1) understand how plant species are sorted according to the nature of environmental gradients, (2) evaluate the relative importance of habitat filtering and limiting similarity in the process of community assembly and (3) quantify two main components of community functional structure, namely, community-weighted means of traits and community functional divergence. The relative impacts of these two components on ecosystem properties will then be discussed in the case of several components of primary productivity, litter decomposition, soil water content and carbon sequestration. There is strong support for the biomass ratio hypothesis, which states that the extent to which the traits of a species affect those ecosystem properties depends on the abundance of this species in the community. Assessing the role of functional divergence among species on ecosystem properties will require major methodological breakthroughs, both in terms of metrics and statistical procedures to be used. In agricultural situations, we show that trait-based approaches have been successfully developed to assess the impacts of management practices on (1) the agronomic value of grasslands and (2) the functional composition and structure of crop weed communities and how these could affect the functioning of the crop. Applications in forestry are still poorly developed, especially in temperate regions where the number of species in managed forest remains relatively low. The last decades of research have led to the constitution of large data sets of plant traits, which remain poorly compatible and accessible. Recent advances in the field of ecoinformatics suggest that major progress could be achieved in this area by using improved metadata standards and advancing trait domain ontologies. Finally, concluding remarks, unanswered questions and directions for research using the functional approach to biodiversity made possible by the use of traits will be discussed in the contexts of ecological and agronomical systems. The latter indeed cover a wide range of environmental conditions and biological diversity, and the prospect for reducing environmental impacts in highly productive, low-diversity systems will certainly imply improving our skills for the management of more diverse systems prone to a trait-based approach as reviewed here. [ABSTRACT FROM AUTHOR]

Plants often survive disturbances such as fire by resprouting which involves having both protection traits and carbohydrate storage capacity. Protection traits not only act directly to insulate meristems but also prevent combustion of carbohydrate stores. Rapid stem growth also allows replenishment of carbohydrate stores ensuring persistence through another event. Resource availability may, however, constrain the ability to develop resilience to high-severity fires through either nutrient limitation or light limitation. We tested whether fire severity influenced resprouting ability of woody plants in two contrasting environments, low nutrient dry sclerophyll forest and more fertile wet sclerophyll forest. We tested which fire protection and growth traits were associated with resprouting ability (27 species) and resprouting vigour (16 species). Fire severity did not limit the ability of most species to resprout in either forest type. There was no generalized protection syndrome for surviving top kill, but combinations of bud protection and growth together with storage capacity appear to drive resprouting ability. In nutrient-limited forests, low specific leaf area (SLA) may reduce stem growth in resprouters, causing more reliance on bud protection through bark thickness. Conversely, in the more fertile forests, where light becomes limiting with time-since-fire, high SLA appears to increase the capacity for rapid stem growth with less emphasis on developing thicker bark. These different syndromes appear to be adaptive as fire severity did not influence survival in either forest type. [ABSTRACT FROM AUTHOR]

Abstract: Trait-based studies have become extremely common in plant ecology. Trait-based approaches often rely on the tacit assumption that intraspecific trait variability (ITV) is negligible compared to interspecific variability, so that species can be characterized by mean trait values. Yet, numerous recent studies have challenged this assumption by showing that ITV significantly affects various ecological processes. Accounting for ITV may thus strengthen trait-based approaches, but measuring trait values on a large number of individuals per species and site is not feasible. Therefore, it is important and timely to synthesize existing knowledge on ITV in order to (1) decide critically when ITV should be considered, and (2) establish methods for incorporating this variability. Here we propose a practical set of rules to identify circumstances under which ITV should be accounted for. We formulate a spatial trait variance partitioning hypothesis to highlight the spatial scales at which ITV cannot be ignored in ecological studies. We then refine a set of four consecutive questions on the research question, the spatial scale, the sampling design, and the type of studied traits, to determine case-by-case if a given study should quantify ITV and test its effects. We review methods for quantifying ITV and develop a step-by-step guideline to design and interpret simulation studies that test for the importance of ITV. Even in the absence of quantitative knowledge on ITV, its effects can be assessed by varying trait values within species within realistic bounds around the known mean values. We finish with a discussion of future requirements to further incorporate ITV within trait-based approaches. This paper thus delineates a general framework to account for ITV and suggests a direction towards a more quantitative trait-based ecology. [Copyright &y& Elsevier]

Understanding large scale patterns in trait variation in climbing plants (lianas, vines, scramblers, twiners) is important for the development of a stronger theoretical understanding of climbing plant ecology and for more applied issues such as prediction of community assembly under changing climatic conditions. We compared values of five key functional traits for 388 species of climbing plant from tropical and temperate regions of Australia to quantify variation between these two biogeographic regions. Australia. Data on dispersal mode, growth habit, leaf form, leaf size and seed mass were compiled from field measurements and published sources. Comparative analyses were performed in three ways: (1) across species where each species was treated as an independent data point, (2) using evolutionary divergence analyses for each trait, and (3) in multidimensional space using a matrix of similarities between species. Tropical climbing plants had 22-fold greater seed mass and four times greater leaf size than did temperate species. Tropical climbers were more likely to be woody (63%) than were temperate species (40%). Surprisingly we found a similar proportion of animal-dispersed seeds in the two regions, although we expected animal-dispersed seeds to be more prevalent in the tropics. We also found similar proportions of simple- and compound-leaved species between the two regions. All of our findings were consistent between cross-species and phylogenetic analyses indicating that patterns in present-day species are reflected in the evolutionary history of Australian climbers. Multivariate analyses suggested that there is a spectrum of variation among climbing plants, with tropical species having greater seed mass, leaf size and woody growth compared with temperate climbing plant species. Tropical and temperate climbers of Australia exhibit a mixture of similar and contrasting traits and ecological strategies. Understanding strategy variation along latitudinal gradients will be particularly informative for predicting ecosystem and community structure with climate change. [ABSTRACT FROM AUTHOR]

1. Westoby’s [ Plant and Soil (1998), 199, 213] Leaf-Height-Seed (LHS) plant strategy scheme quantifies the strategy of a plant based on its location in a three-dimensional space defined by three functional traits: specific leaf area (SLA), height, and seed mass. This scheme is based on aboveground traits and may neglect strategies of belowground resource capture if root functioning is not mirrored in any of the axes. How then do fine roots fit into the LHS scheme? 2. We measured 10 functional traits on 133 plant species in a ponderosa pine forest in northern Arizona, USA. This data set was used to evaluate how well the LHS scheme accounts for the variation in above and belowground traits. 3. The three most important plant strategies were composed of multiple correlated traits, but SLA, seed mass, and height loaded on separate principle components. The first axis reflected the widely observed ‘leaf economics spectrum’. Species at the high end of this spectrum had high SLA, high leaf and fine root nitrogen (N) concentration, and low leaf dry matter content. The second axis reflected variation in seed mass and fine root morphology. Plants at the positive end of this spectrum were plants with large seeds and low specific root length (SRL). The third axis reflected variation in height and phenology. Plants at the positive end of this spectrum were tall species that flower late in the growing season. 4. Leaf N concentration was positively correlated with fine root N concentration. SRL was weakly positively correlated with SLA. SRL was not correlated with fine root N concentration. Leaf litter decomposition rate was positively correlated with the leaf economics spectrum and was negatively correlated with the height and phenology spectrum. 5. Leaf traits, seed mass, and height appear to be integrating properties of species that reflect much of the variation in plant function, including root function. Fine root N concentration was positively mirrored by the leaf economics spectrum, and SRL was inversely mirrored by seed mass. The leaf and height axes play a role in controlling leaf litter decomposability, indicating that these strategy axes have important consequences for ecosystem functioning. [ABSTRACT FROM AUTHOR]

Abstract: Analyses of the spatial patterns of pairs of sympatric congeneric species present unique opportunities and challenges in explaining species coexistence. In this study, we compared the population structure and spatial patterns of six coexisting species of Acer (maple) in a large-scale 25-ha old-growth temperate forest plot in northern China with the aim of gaining insight into the coexistence of these congeners. A second-order spatial point pattern analysis based on the pair-correlation function was used to evaluate spatial patterns and examine intra- and interspecies associations among them. The abundance varied from 251 to 6609 individuals, but these species showed similar, distinct L-shaped size-class distributions. All six species were aggregated at small scales. The degree of aggregation of the three species with low abundance was in fact higher than that for the others at small scales. Aggregated patterns were also found for small and large trees at small scales. For spatial associations among the congeners, the goodness-of-fit (GoF) test revealed significant associations for only 10 of 30 species pairs, indicating no clear evidence for interspecific competition within them. In comparing the relationships among different size classes, we found no significant relationship for most of the analyzed species pairs. The GoF test detected significant associations for 6 of 20 species pairs among large trees of different species, 6 of 30 species pairs among small trees of different species, and 11 of 30 species pairs between large and small trees of different species. Based on a comparison of population structure, spatial patterns and associations, we infer that for these congeners there exists no significant difference in seed dispersal, competitive ability, or the requirement for specific topographic and light environments. Other factors (e.g., seed production and other habitat requirements) may contribute to the coexistence of these congeners and the trade-off between species commonness and rarity. [Copyright &y& Elsevier]

Despite the importance of stomata in leaf functioning, and despite the recent interest in interspecific leaf trait covariation in functional ecology, little is known about how stomatal density relates to other leaf traits in a broad interspecific context. This is especially important because stomatal density has been widely used to deduce temporal variation in atmospheric CO2 concentrations [CO2atm] from fossilized or herbarium leaves. We therefore measured stomatal density, specific leaf area (SLA) and its components, leaf thickness, and leaf chlorophyll content in both sun and shade leaves of 169 individuals from 52 angiosperm species in southwestern Quebec. Using mixed models, we show that stomatal density decreases allometrically with increasing SLA and chlorophyll content, and increases allometrically with increasing lamina thickness. The sun–shade contrast changes the intercepts, but not the slopes, of these relationships. It is important to take into consideration these relations when correlating stomatal density with [CO2], to avoid spurious interpretations. [ABSTRACT FROM AUTHOR]

Aim Taxonomic comparisons of alien floras across climatically similar regions have been proposed as a powerful approach for increasing our understanding of plant invasions across scales. However, detailed comparisons between the alien biotas of climatically similar regions are scarce. This study aims to compare the taxonomic patterns of alien species richness in mediterranean-type climate areas of central Chile and California, in order to better understand how climatically similar regions converge or diverge in terms of their alien flora. Location Central Chile and California, United States. Methods We compared the alien floras of the state of California in the United States and central Chile, considering within-region variation and taxonomic composition up to the species level. To test for within-region variation, administrative units and counties were grouped within seven latitudinal bands for each region. We tested for differences in the relative contributions of the various origins of the naturalized species to each region. We used a family naturalization index to establish which families had relatively higher numbers of naturalized species in each region. We evaluated the similarity, using cluster analyses with Jaccard’s similarity index, of alien taxa between regions and latitudinal bands using presence–absence matrices at the species, genus and family levels. We used principal components analysis to determine the presence of a compositional gradient including all latitudinal bands. Results We recorded 1212 alien plant species in California and 593 in central Chile, of which 491 are shared between the two regions. These figures include 25 species that are native to California and 37 that are native to Chile. A comparison between the alien floras of central Chile and California reveals three major trends: (1) higher naturalized species diversity for California than for Chile, at all taxonomic levels; (2) differences in the proportion of species according to origin, with America, Africa, Asia and Australia providing a larger number of species in California than in Chile; (3) segregation between regions in terms of taxonomic composition of their alien flora, and a rather weak differentiation within regions; and (4) a trend towards higher similarity between the alien floras of latitudinal bands associated with higher levels of human disturbances. Main conclusions The alien floras of central Chile and California are significantly different, but this difference diminishes in highly disturbed areas. Thus, the current high levels of species movement caused by globalization, together with increasing levels of anthropogenic disturbances, should reduce the differentiation of the alien floras in these regions, increasing overall biotic homogenization. [ABSTRACT FROM AUTHOR]

Question: How does form (leaf and trunk morphology) relate to function (tolerance of shade and nutrient storage) in trees? Location: Los Toldos montane valley in NW Argentina. Methods: We analysed the relationships amongst (1) ten vegetative and four reproductive traits across 40 tree species, (2) a distribution based measure of recruitment under shade and (3) a distribution based measure of recruitment over a soil fertility gradient. Results: Ordinations revealed three main axes of species' morphological differentiation: (1) evergreen species had leaves with a lower specific leaf area, greater tensile resistance and slower decomposition rate, denser wood and thinner bark than deciduous species; (2) tall tree species that lack spines and are anemochorous were separated from short, spinescent and zoochorous species and (3) species were distinguished according to clonal growth, seed mass and pollination syndromes. Notably, species' recruitment under shade and over a soil fertility gradient were independent of each other, but both were correlated with species' scores along the first axis of morphological variation (tolerant species have attributes that favour resource conservation). Different sets of traits were correlated with recruitment under shade and over a soil fertility gradient when traits where assessed individually. Amongst shade tolerant species, recruitment under shade was negatively correlated with species' maximum height, suggesting differential responses to vertical gradients of light. Conclusions: These results provide new evidence of integration between leaf and stem morphology which is consistent with an evolutionary compromise between high rate of resource acquisition and resource conservation. Generalizations about the functional value of individual morphological characteristics and of ‘strategies’ vary with the resolution of analyses. [ABSTRACT FROM AUTHOR]

Heterochrony (changes in the relative timing of development between species) has been studied almost exclusively using morphological characters, with a focus on changes in size and shape (as a surrogate for time) between ancestral species and their descendents. Such an approach is restrictive in that it precludes the investigation of heterochronies in other, non-morphological traits and, therefore, hampers a more integrated approach to heterochrony. Such an integrated approach, where cellular, molecular and genetic approaches are used within a comparative phylogenetic framework to investigate developmental sequences, has been advocated by workers such as Smith and Raff. Here we suggest that equal emphasis should be given to the importance of physiological and ecological mechanisms that relate to changes in developmental sequence. Reviews of the history and status of physiological and ecological heterochrony reveal several examples for each, although progress has been hampered to some degree by a lack of recognition of physiological heterochrony and a lack of mechanistic understanding (heterochronies in evolutionary ecology). What emerges is that each discipline potentially brings something quite different, and complementary, to the study of heterochrony. The emergence of physiological heterochrony has arguably put the emphasis back on the object of selection and how the developing organism works: studies relating ecology and heterochrony have sought to establish whether or not there is an adaptive basis to altered sequences. We propose that any future studies of heterochrony should seek to exploit these different strengths rather than see them as merely complementary approaches. [ABSTRACT FROM AUTHOR]