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Using vegetation as a bioindicator in urban and degraded areas is an effective way to assess the status of the environment. In this work, we present the results of a phytosociological investigation of a suburban river and of its surroundings in southern Tuscany (Bestina river and its tributary Bestinino in Asciano, Province of Siena). By means of 94 phytosociological relevés, we identified 34 plant communities belonging to the 17 classes. Six habitats included in the 92/43/EEC Directive, plus two habitats recently proposed for inclusion, were identified, as well as one habitat of regional interest. The study revealed that, despite the high levels of human disturbance, aquatic and herbaceous riparian vegetation is still well-preserved, though mostly represented by stress-tolerant communities. On the contrary, most of the vegetation types not being directly linked to the river dynamic are in poor conservation status. Despite this, some habitats of community interest were detected even in non-riverine sites. Our work provides the basic knowledge for future restoration of the Bestina river and of its surroundings, wished by the Tuscany Region. [ABSTRACT FROM AUTHOR]

Riparian plant communities are key to ecosystem functioning and important providers of ecosystem services on which wildlife and people depend. Ecosystem functioning and stability depend on functional diversity and redundancy. Therefore, understanding which and how different drivers shape community assembly processes and functional patterns is crucial. However, there is limited knowledge of these processes at larger scales for the entire riparian vascular plant community.Two community assembly processes dominate: environmental filtering, where species living in similar environments have similar traits leading to trait convergence; and limiting similarity, where similar traits cause species to compete more strongly leading to trait divergence. We assessed functional diversity patterns of riparian vascular plant communities across an Atlantic–Mediterranean biogeographical gradient in north Portugal.We used functional diversity indices and null models to detect community assembly processes and whether these processes change along environmental gradients. We hypothesised that environmental filtering associated with precipitation and aridity would be the prevailing assembly process at a regional scale. We also expected a shift from environmental filtering to limiting similarity as precipitation‐related stress declined.As hypothesised, patterns of functional diversity were consistent with environmental filtering of species occurrences at the regional scale. Functional patterns were also consistent with a shift between environmental filtering and limiting similarity as cold and aridity stress declined. Under stressful environmental conditions, communities showed lower functional divergence and richness than expected by chance. Environmental filtering was more strongly associated with minimum temperatures than precipitation and aridity.Underlining the need for hierarchical approaches and the analysis of multiple climatic stressors, our results highlighted the relevance of large‐scale environmental stress gradients and the potential role of community assembly in influencing riparian functional diversity. Alterations in stress filters due to climate change will affect assembly processes and functional patterns, probably affecting ecosystem functioning and stability. [ABSTRACT FROM AUTHOR]

The article presents the results of a study of the plant communities of Ramonda serbica, primarily intended to increase knowledge of their species and syntaxonomic diversity. The dataset included 204 vegetation plots (relevés) of the two Balkan Ramondas (R. serbica and R. nathaliae), 174 digitised from published literature sources and 30 new ones from field sampling of R. serbica in Montenegro and North Macedonia. Nineteen associations and subassociations of R. serbica were identified, using hierarchical cluster analysis (the Sørensen index as a distance measure and the Flexible Beta method, ß −0.25). Three associations (Micromerio julianae-Ramondetum serbicae, Hylocomio splendentis-Ramondetum serbicae, Neckero pumillae-Ramondetum serbicae), three subassociations (Micromerio julianae-Ramondetum serbicae subass. allosoretosum persicae, Ceterachi officinarum-Ramondetum serbicae subass. festucetosum dalmaticae and subass. hylotelephietosum maximi) and one alliance Exsertotheco crispae-Ramondion serbicae are described as new. Both hierarchical cluster analysis and non-metric multidimensional scaling ordination support the distinction of 3 chorological/ecological groups of R. serbica communities: Adriatic-Ionian (xerophilous), Moesian (xero and mesophilous communities) and Illyrian-Scardo-Pindic (hygromesophilous). Communities of the Adriatic-Ionian cluster belongs to alliances Edraianthion, Centaureo cuspidatae-Portenschagillion ramosissimae and Campanulion versicoloris, of the Moesian one to Edraiantho graminifolii-Erysimion comati, and the Illyrian-Scardo-Pindic one to novel alliance Exsertotheco crispae-Ramondion serbicae. [ABSTRACT FROM AUTHOR]

Mass mortality events (MMEs) of wildlife are increasingly frequent and may destabilize communities. MMEs provide a unique ecological context because they simultaneously produce a resource pulse that is sometimes coupled with the loss or severe impairment of functional roles such as predation or herbivory. Moreover, these effects are complicated by global declines in obligate vertebrate scavengers.We designed an experiment to measure the relative importance of bottom‐up (nutrient addition) and top‐down (impairment of obligate scavenger and herbivore functional roles) forces experienced during MMEs on the local plant community.Increasing carrion biomass shifted local plant assemblages from the original state promoting plants more resistant to soil disturbance (i.e. annual plants), but this effect was unique to carrion as the same amount of macronutrients entering the system did not affect the plant community. This may indicate that the effects of carrion are primarily driven by interactions with consumers rather than bottom‐up processes. Additionally, restricting obligate vertebrate scavenger access to increasing amounts of carrion biomass shifted the net effects of the carrion on the plant community by limiting perennial vines. Impairment of the herbivore functional role released plants from top‐down control, increasing plant growth and survival.Our experiment indicates that top‐down forces may have strong effects on plant communities following MMEs. As such, the global increase in wildlife MMEs may have broad consequences on ecological communities, not only on the species affected. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Biodiversity emerges from niche mechanisms, in which the combination of traits determines species performance, and populations drift because of the inherent stochasticity of community assembly processes. Population biology dictates that small and isolated communities are more prone to show stochastic assemblages. However, a reduced mass effect in isolated communities may promote trait selection. In addition, large and connected communities have a larger species pool, higher functional redundancy, lower population sizes and more random recruitment, which also fosters stochasticity in community assembly. These contradictory expectations demand empirical analyses.Plant metacommunities in temporary ponds are assembled by the action of strong environmental filters and cover wide ranges of local community sizes and connectivity, representing ideal systems for identifying determinants of trait‐selection processes. Using a deviance partition method introduced by the theory of community assembly by trait selection, we evaluated the role of plant traits in local community assemblies along 60 communities from a 14‐year plant survey of temporary ponds.Variation in pond size, hydroperiod, connectitivity and heterogeneity determined a selection gradien in traits related to drought resistance, life history and disperal strategies; and also in the strength of trait‐mediated community assembly. The taxonomic and functional diversity of a pond and its physical heterogeneity fostered stochasticity in the assembly of the community, which also presented a hump‐shaped association with connectivity. The pond area increased taxonomic richness but decreased functional diversity, determining negative and positive indirect effects on stochasticity.Synthesis. Diversity provides the raw material for trait selection putatively reducing stochasticity, but here diversity was positively related to stochasticity. Having enough functional diversity, larger redundancy and lower population sizes in diverse communities is probably fostering stochastic assemblages. The hump‐shaped association between stochasticity and connectivity supports a larger role of trait selection in isolated systems due to a weak mass effect, but also on connected communities in which a set of more optimal traits for the selection scenario could be available. In the ongoing state of ecosystem fragmentation, these empirical trends contribute to the mechanistic understanding of the connection between landscape structure and biodiversity assembly. [ABSTRACT FROM AUTHOR]

Ecological restoration outcomes are highly variable, undermining efforts to recover biodiversity and ecosystem functions. One poorly understood source of variability is 'year effects'—interannual variation in environmental conditions during the first year of restoration that alter successional trajectories of plant communities.There have been few experimental tests disentangling planting years from other differences among restoration projects (e.g. edaphic conditions, restoration approach), particularly those resolving mechanisms for year effects such as planting‐year rainfall. Moreover, past year effect studies focused almost exclusively on species‐level consequences. Therefore, the extent to which year effects influence the traits of communities is unknown.To address these gaps and provide a mechanistic test of how precipitation contributes to year effects, we conducted an experiment where we manipulated rainfall (drought, average and high levels) during the first growing season, replicated across three establishment year treatments to disentangle the effects of precipitation from other drivers of year effects. In each establishment year, we seeded the same species mix to initiate grassland restoration. We then surveyed plant community compositions annually for 5 years to quantify trait responses of restored communities to planting year rainfall.We found that variation in planting‐year precipitation altered community assembly trajectories by influencing community‐weighted mean (CWM) trait composition, and these effects persisted for at least 5 years. Over time, CWM specific leaf area and CWM seed mass decreased and CWM plant height increased. The effect of age on CWM plant height was stronger in plots that received mean and high watering treatments compared to drought treatments. This effect was also observed for CWM seed mass, albeit weaker.We also found some evidence for planting year effects unrelated to planting‐year rainfall for the three CWM traits, illustrating how interannually varying environmental conditions besides rainfall can generate persistent year effect on plant communities through their traits.Synthesis and applications. Our results provide evidence for planting year rainfall interacting with community assembly to alter the functional trait composition of restored grasslands. This suggests that interannual variation in rainfall during establishment is an important source of divergent biodiversity and functional outcomes in restored grasslands. [ABSTRACT FROM AUTHOR]

Aim: Understanding how combinations of ecological traits at the community‐level vary with environmental conditions is crucial to anticipate and respond to the biodiversity crisis. While this topic is popular, most attempts to analyse and predict multiple traits in space and time ignore the inherent correlations between these traits. In doing so, the predicted traits in unobserved environments are likely to be flawed (i.e. unrealistic trait combinations). Here, we propose a framework that addresses this methodological question in functional biogeography. Innovation: Our framework relies on joint trait distribution models to quantify how combinations of mean trait values at the community level co‐vary as a function of environmental conditions. Making use of joint probabilities and the constraints imposed by trait correlations, our framework not only predicts the most suitable combination of traits in a given environment but also the envelope of possible alternatives. This innovation allows visualizing how the correlation structure between traits imposes a strong constraint (or not) on the expected combination of traits in a given environment. The stronger trait correlations, the smaller the envelope of likely alternative states. We provide an R package implementing our framework. Main Conclusions: Applied to plant communities in the French Alps, our framework quantifies the variation of trait combinations at the community‐level along environmental gradients that, otherwise, could not be identified. Strong correlations in community mean leaf traits led to a low diversity of alternative combinations of community means, which can only vary along the acquisition‐conservation spectrum. Instead, height varied partly independently of leaf traits, leading to a higher diversity in the combinations of mean community traits. Our framework allows for a more integrated understanding and prediction of the distribution of traits, thus moving a descriptive functional biogeography to a more predictive science. [ABSTRACT FROM AUTHOR]

Virtually all plants employ direct and indirect defenses against herbivores. While it is known that plant defenses can be affected by belowground symbiotic microbes under controlled conditions, studies showing these multitrophic interactions in nature are surprisingly scarce. Here we tested for effects of rhizobia on insect attraction and direct defense (cyanogenesis) in wild lima bean (Phaseolus lunatus) plants in Costa Rica. We performed bioassays with rhizobia-inoculated (R+) and rhizobia-free (R-) potted plants distributed among native lima bean communities at two spatially separated field sites (450 km apart) and in two field seasons. Without affecting overall plant size, rhizobia altered leaf chemistry (cyanogenesis and soluble leaf nitrogen) and ultimately insect communities visiting the plants. Natural herbivorous chrysomelid beetles were strongly attracted to R + plants, while natural enemies, ants and parasitoid wasps, preferred R- plants resulting in a particularly high herbivore:carnivore ratio on R + plants. This suggests that symbiotic microbes mediate trophic interactions by influencing both direct and indirect plant defenses against herbivores. Our results show that rhizobia affect the plant defensive phenotype and have cascading effects on plant-insect interactions in nature. [ABSTRACT FROM AUTHOR]

Current challenges of functional responses in plant communities to climate change call for multi‐factorial experiments. Moreover, studies on climate change should focus on below‐ground responses since absorptive roots largely control soil C allocation and resource acquisition. Thus, we aimed to understand biomass allocation and traits of absorptive roots in young mesocosm grasslands subjected to simultaneous manipulation of three components of climate change.We tested grassland biomass and root traits under climate change while manipulating functional composition. Using 64 mesocosms with designed grasslands within four chambers of a controlled‐environment facility ('ecotron'), we simulated two contrasting IPCC climate change scenarios for elevated [CO2] and temperature ('eCO2' and 'eT'). We applied normal vs. reduced precipitation of early summer in Central Europe. We also tested the effect of functional composition by varying the proportion of grasses and forbs in the communities. Specifically, we quantified above‐ and below‐ground biomass, root diameter (RD), root tissue density (RTD), specific root length (SRL), and root length density (RLD).Functional composition played a significant role in biomass allocation of the grasslands, with grass‐dominated communities producing more below‐ground biomass than forb‐dominated ones, and the opposite pattern registered above‐ground. Below‐ground biomass did not respond to climate change factors, whereas root trait values responded significantly during early establishment of the grasslands. A higher RD indicated a more conservative strategy under reduced precipitation, while eT and eCO2 led to higher RTD. We detected interactive effects between climate change and functional composition on root traits. Moreover, root biomass primarily occupied the upper soil layer, while a warm and CO2‐rich environment promoted root allocation to the lower soil layer. Grass‐dominated communities quickly colonized all available soil volume, while forb‐dominated ones accumulated more root biomass in the upper soil layer.In the mesocosm grasslands, root trait variation rather than root biomass reflected below‐ground adjustments to climate change. Furthermore, functional composition and the associated trait diversity modulated biomass allocation. Thus, establishing plant communities that are more resilient to climate change must consider the functional and taxonomic composition of the seed mixtures designed to restore urban grasslands. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Understanding how species assemble into communities is a central issue in community ecology. So far, most studies have focused on the assembly mechanisms of vascular plant communities, while the role of deterministic (environmental filtering and biotic interactions) and stochastic (e.g. dispersal limitation) processes structuring bryophyte assemblages remains poorly understood.To evaluate how different assembly processes shape bryophyte communities in mountain streams, we examined functional trait patterns across spatial scales and along environmental gradients. To do so, we sampled 754 microhabitat plots (0.25 m2) nested within 165 sites (100‐m long stream segments) and 13 sub‐basins, located in the northwest and central‐west of Portugal. At each spatial scale, observed functional diversity indices (Functional Richness and Rao's quadratic entropy) were compared to random expectations derived from null models, followed by the analysis of changes in functional trait patterns along environmental gradients by fitting a series of generalized additive mixed models.At local scales (site and microhabitat plot), coexisting species tended to be more functionally similar than expected, suggesting the prevalence of environmental filtering effects. In contrast, no significant deviations from random expectations were detected at the broadest spatial scale (sub‐basin), indicating the prevalence of stochastic processes. We found contrasting assembly processes along environmental gradients: environmental filtering prevailed in stressful environments, while competitive interactions were more important in favourable conditions.Synthesis. Our results highlight the role of environmental filtering in bryophyte community assembly at fine spatial scales, emphasizing the importance of measuring environmental conditions at the same spatial scales where biotic interactions take place. In line with the stress‐dominance hypothesis, the relative importance of environmental filtering increased with abiotic stress. Thus, analysing functional trait patterns across different spatial scales and environmental gradients may contribute to a better understanding of the mechanisms underlying community assembly. [ABSTRACT FROM AUTHOR]

Fire is an ecological factor that strongly influences plant communities and functional traits. Communities respond differently to fire, either decreasing or increasing in flammability and resource acquisition strategies. This study aimed to investigate the influence of fire over traits associated with flammability and the plant economic spectrum in a stressful and infertile mountainous grassland located in the Espinhaço mountain range in Brazil. Non-graminoid plant species were sampled in 60 5 m × 5 m plots distributed in three fire frequency categories. We measured several traits related to flammability—leaf dry matter content (LDMC), twig dry matter content, leaf area, bark thickness, branching architecture, plant height, leaf toughness (LT), and specific leaf area (SLA). Traits responded differently to the increase in fire frequency. For instance, the LDMC and LT were lower while the SLA was higher at high fire frequencies, indicating a trend towards reduced heat release and fire residence time. This shift resulted in the dominance of plants with a relatively more acquisitive strategy. This study brings evidence that traits respond coordinately towards a reduction of flammability with the increase in fire frequency and are strong indicators of the filtering role that fire plays as a disturbance on rupestrian grassland vegetation. [ABSTRACT FROM AUTHOR]

Many theories have been proposed to explain the high diversity of plants in the tropics. However, we lack an understanding of the processes that drive plant diversity and community assembly at different spatial scales. Here, we applied beta‐diversity partitioning to test how biotic and abiotic factors are associated with seedling beta‐diversity in a tropical montane forest in southern Ecuador. We recorded seedling communities on 81 subplots in nine plots located at three elevations along a 2000 m elevational gradient. We measured biotic pressures (i.e. herbivory and fungal pathogen attacks) and environmental conditions (i.e. soil moisture and canopy closure) in all subplots and related them to species turnover and richness differences in seedling communities within and between elevations. We found that species turnover increased with differences in biotic dissimilarity within elevations, while differences in species richness within elevations increased with increasing environmental dissimilarity. Between elevations, species turnover increased with increasing environmental dissimilarity. Our findings show that species turnover and changes in species richness are related differently to abiotic and biotic factors, and that the importance of these factors for shaping seedling diversity is scale‐dependent. Our study contributes to better understand the processes driving seedling beta‐diversity and the assembly of plant communities in highly diverse tropical montane forests. [ABSTRACT FROM AUTHOR]

Seed limitation can narrow down the number of coexisting plant species, limit plant community productivity, and also constrain community responses to changing environmental and biotic conditions. In a 10‐year full‐factorial experiment of seed addition, fertilisation, warming and herbivore exclusion, we tested how seed addition alters community richness and biomass, and how its effects depend on seed origin and biotic and abiotic context. We found that seed addition increased species richness in all treatments, and increased plant community biomass depending on nutrient addition and warming. Novel species, originally absent from the communities, increased biomass the most, especially in fertilised plots and in the absence of herbivores, while adding seeds of local species did not affect biomass. Our results show that seed limitation constrains both community richness and biomass, and highlight the importance of considering trophic interactions and soil nutrients when assessing novel species immigrations and their effects on community biomass. [ABSTRACT FROM AUTHOR]

Aims: This study aims to identify some of the key soil-related factors that underpin the distribution of plant communities and provide a more comprehensive understanding of an old, climatically buffered infertile landscape including kwongkan habitats. We investigate the pedological, topographical and hydrological correlates of abundance and floristic community distribution within the Alison Baird Reserve, a floristically diverse, old and climatically weathered landscape in south-west Western Australia. Methods: Fifty-four soil samples were collected across 0.165 km2 and analysed for a range of physical and chemical properties. Samples were taken from the topsoil and subsurface, and a combination of statistical and geostatistical methods were used to examine soil–plant community distribution relationships. Results: Elevation, sub-surface moisture, electrical conductivity and clay content were the most important factors in determining vegetation composition and distribution; with sub-surface properties varying more between floristic communities and correlating more strongly than topsoil factors. Associations between soil nutrients (Phosphorus, Nitrogen, Carbon) and community distributions were not as significant as expected, likely due to the depleted nature of the soil system. Conclusion: The significance of soil parameters including particle size, moisture, elevation, water repellence and depth to water table suggests that water availability and retention within the soil is a key correlate of the distribution of floristic communities at the site and may act as a pathway to explain large scale variation in plant communities across the south-west of Western Australia. This understanding will help conservation and management of areas with such high biodiversity including relocation of endangered flora. [ABSTRACT FROM AUTHOR]

Purpose: Nitrogen (N) deposition is well known to affect plant community assembly, but the underlying mechanisms are still poorly understood. How different processes, including environmental and biotic filtering, drive plant community assembly can be quantified by trait range restrictions and patterns of trait convergence and divergence. However, few studies have combined species abundances data to simultaneously explore how these two processes function and further affect community assembly along N addition gradients by progressively examining multiple trait range restrictions and trait patterns. Methods: We conducted a four-year N addition experiment with eight N addition levels in a temperate desert steppe, Inner Mongolia. We investigated species composition and then collected aboveground biomass (AGB). In addition, six soil properties and functional traits were measured. Community-weighted trait means (CWM) and community-weighted trait variances (CWV) at eight N addition levels were calculated based on species abundances and their corresponding traits. We quantified environmental filtering as a restriction of trait range, and trait patterns depended on CWV. We calculated the effect size (ES) values of six trait ranges and CWVs by comparing the observed community with two simulated null communities generated by a two-step trait-based approach. Using the one-tailed Wilcoxon signed-ranks tests (W) and the Spearman's rank correlations (S) methods, we further explored changes in six trait ranges and trait patterns along experimental N addition gradients by the ES values. Results: We found that high N addition altered species composition, and the dominant S-strategy species (conservative species) in high-barren and low-disturbance environments were gradually replaced by R-strategy species (acquisitive species) in low-barren and high-disturbance environments. The polynomial regression showed that AGB was highest at 27 g.m−2 N addition level. The responses of six CWM values under N24 and N48 were significantly different from those under other N addition treatments, and they showed two opposite trends along N addition gradients. The CWM values of three traits (i.e., plant height (H), leaf dry matter content (LDMC) and leaf carbon content (LCC)) significantly decreased, while the CWM values of other three traits (i.e., leaf thickness (LT), specific leaf area (SLA) and leaf nitrogen content (LNC)) significantly increased. The trait range of H, LDMC and LCC was wider than expected in N-poor communities, while narrower than expected in N-rich communities, and the opposite was true for LT and LNC. The trait range of SLA was overall narrower than expected at eight N addition levels. These results indicate that environmental filtering restricts the trait range of H, LDMC and LCC in N-rich communities, while restricts the trait range of LT and LNC in N-poor communities, and restricts the trait range of SLA under almost all N addition treatments. All six traits converged first, and then diverged along N addition gradients, indicating that high N addition induces functional trait differentiation in a temperate desert steppe. Conclusion: Our study clearly demonstrates that environmental and biotic filtering play important roles in assembling communities along N addition gradients in desert steppe. Changes in trait ranges induced by environmental filtering strongly depend on the types of functional traits along environmental gradients. In the processes of biotic filtering, trait hierarchy drives the outcomes of competitive interactions among coexisting species in N-poor communities and further determines community assembly, as evidenced by trait convergence and large differences in competitive ability among species. In contrast, trait divergence and small differences in competitive ability among coexisting species in N-rich communities reveal that trait dissimilarity drives community assembly, corresponding to large functional trait differentiation. In summary, shifts in patterns of trait convergence and divergence along N addition gradients largely support the stress-dominance hypothesis, but our results also reveal that community assembly mechanisms are more complex. When attempting to explore assembly mechanisms along environmental gradients, not only species multiple traits and occurrences but also their abundances and specific environments should be considered. [ABSTRACT FROM AUTHOR]

Aim: The ongoing climate warming is expected to reshuffle understorey plant community composition by increasing the occurrence of warm‐adapted species at the expense of cold‐adapted species. This process has been evidenced before by a warming community temperature index (CTI) over time. However, data indicate that the local tree canopy can partly explain an observed lag between understorey plant CTI and climate warming rates, though landscape‐scale forest cover effects have not yet been investigated. Here, we test the hypothesis that the amount of forest cover in the landscape lowers local CTI. Location: Temperate forests in France. Time period: 2005–2019. Major taxa studied: Forest vascular plants. Methods: We compared 2,012 pairs of neighbouring French forest inventory plots with contrasting percentages of forest cover within a 1‐km radius area (landscape forest cover). We computed the difference in the CTI of the understorey communities for each pair and tested the contributions of the landscape‐scale forest cover, local canopy cover, and soil conditions to the differences in CTI. Results: Plots located in highly forested areas (> 80% in the 1‐km area) had an average CTI 0.26 °C lower (0.81 °C SD) than plots in sparsely forested areas (< 30% in the 1‐km area). Fifty percent of this difference was explained by landscape‐scale forest cover. Bioindicated soil conditions such as pH and available nutrients, which correlated with cold‐adapted species preferences, explained the remaining 50%. Main conclusions: Highly forested landscapes allow cold‐adapted species to survive in given macroclimatic conditions. These landscapes meet cold‐adapted species' soil requirements and may cool the regional climate. Further microclimatic studies are needed to confirm the cooling capacity of landscape‐scale forest cover. [ABSTRACT FROM AUTHOR]

Aim: Palms are iconic and dominant elements of neotropical forests. In the Amazon region, palms have been used and managed by humans for food, material, medicine and other purposes for millennia. It is, however, debated to what extent the structure of modern palm communities reflects long‐term human modification. Here, we investigate the complex interplay of ecological and societal factors that influence the distributions of both human‐used and non‐used palms in western Amazonia. Location: Amazonia. Time period: Present. Major taxa studied: Palms (Arecaceae). Methods: We used Bayesian hierarchical joint species distribution models to predict the distributions and environmental niche dimensions of 78 western Amazonian species, and to explore their relationships with their diversity of human uses and with specific uses (food, construction and medicine). The models were parameterized with a comprehensive set of field‐ and satellite‐derived environmental predictors. Results: Our results suggest that a combination of ecological and anthropogenic factors drive the present‐day distributions of Amazonian palms. The modelled ecological niches of the species revealed use‐related species‐sorting along soil, climatic, accessibility and drainage gradients. We found peaks in the proportions of useful palms and their diversity of uses in fertile soils, close to rivers, and on floodplains. These are habitats favourable for human settlement, although they harbour naturally restricted palm species pools. We also found a negative correlation between predicted palm species richness and number of human uses across western Amazonia. Main conclusions: Soil characteristics, accessibility, and species pool size all contribute to defining palm–human relationships. At the basin scale, the signature of human use on palm communities was predicted to be stronger in the species‐poor south‐west than in central‐western Amazonia. Overall, we conclude that environmental conditions have influenced modern Amazonian palm distributions both directly and indirectly, by regulating human settlement patterns and natural resource use over extended time periods. [ABSTRACT FROM AUTHOR]

Elaeagnus angustifolia is one of the highly invasive shrubs in Ukraine, which escaped from the culture and started to form plant communities in different habitats. We aimed to: (i) analyze information about the history of cultivation, introduction, and current distribution of E. angustifolia in Ukraine; (ii) conduct a phytosociological classification of E. angustifolia-dominated stands in Ukraine; (iii) characterize the units described; (iv) compare synecological characteristics of different E. angustifolia communities; (v) reveal some reasons for the invasion success of E. angustifolia on the territory of Ukraine. We established that E. angustifolia is widespread nowadays in the steppe zone of Ukraine, but shows a tendency to expand its range northward. We identified four associations (Lactuco tataricae-Elaeagnetum angustifoliae, Plantago arenariae-Elaeagnetum angustifoliae, Balloto nigrae-Elaeagnetum angustifoliae, Leymo sabulosi-Elaeagnetum angustifoliae) and one community (Elytrigia repens-Elaeagnus angustifolia) with the dominance of oleaster in Ukraine. Using DCA-ordination, it was demonstrated that the main gradients of a plant community's differentiation are the climate's aridity-humidity and thermoregime of the territory. The invasion success of E. angustifolia is caused by anthropogenic pressure as well as the biological peculiarities of this species. [ABSTRACT FROM AUTHOR]

There is a common agreement that, to maximise our understanding of trait‐based community assembly, traits related to different organs should be considered as they relate to different ecological niche axes. Floral traits, in particular, have been suggested to play an important role in the plant community assembly along with environmental gradients as they determine reproductive success, one of the key functions in plants. However, the role of floral traits in community assembly research remains largely unverified empirically.Using a large and novel dataset on plant traits and plant communities, we analysed the variability of six floral traits of 139 herbaceous species in 21 sites located along an elevation gradient (2000–4000 m) in the western Himalayas. The variability of floral traits along the gradient was analysed using community‐weighted mean (CWM) trait values and functional diversities (FDs) calculated for each study community.The CWMs showed that with increasing elevation, flowering began later, and flowers tended to be larger with decreasing specific flower area (SFA). Along with the convergence in the onset of flowering and SFA (i.e. lower FD at high‐elevation sites), these patterns suggest that abiotic filtering and plant–pollinator interactions could affect the floral trait composition of the communities. Most likely, increasing low‐temperature stress towards high‐elevation sites selected for late‐flowering species that produce flowers with larger display areas. The low abundance and activity of pollinators at high elevation could also explain why these traits were selected in the communities studied. Delayed flowering with increasing elevation might facilitate the phenological overlap of plants and their pollinators, as pollinator activity at higher elevation peaks in the second half of the vegetation period. The dominance of a species with low SFA and larger display area in high‐altitude communities could be attributable to increased flower longevity and attraction of pollinators, respectively, to maximise pollination success under pollinator scarcity.Synthesis. Our study provides empirical support for the recent argument that floral traits contribute considerably to the assembly of plant communities along environmental gradients. Thus, such traits should be included in community assembly research as they represent key ecological functions for reproduction. [ABSTRACT FROM AUTHOR]

Plant invasions are closely related to environmental filtering and biointeractions; however, the variations in invasive plant niches along latitudinal gradients in heterogeneous habitats remain unclear. In this study, we conducted a two-year survey in China spanning 21° N–37° N to explore the niche characteristics of plant species within communities invaded by the amphibious alien weed Alternanthera philoxeroides in both terrestrial and aquatic habitats as well as their latitudinal trends. We found that A. philoxeroides had the greatest niche breadth in the studied communities. The species pairs with the highest niche similarity were A. philoxeroides–Digitaria sanguinalis in terrestrial communities and Cyperus rotundus–Kyllinga brevifolia in aquatic communities. The niche similarity between A. philoxeroides and its accompanying species in terrestrial habitats was significantly higher than that in aquatic habitats (t = 5.954; p < 0.001). The niche breadth of A. philoxeroides had no obvious latitudinal trend, while the niche breadth of its accompanying species in the terrestrial community significantly decreased with increasing latitude (F7, 57 = 4.364, p = 0.001). In the terrestrial communities, the niche similarity between A. philoxeroides and its accompanying species significantly decreased with increasing latitude (F7, 57 = 3.671, p = 0.003), while the niche overlap significantly increased with increasing latitude (F7, 57 = 8.916, p < 0.001). However, the aquatic species' niche characteristics had no obvious latitudinal trends. These findings indicated that habitat heterogeneity significantly affected the species' niche characteristics in A. philoxeroides-invaded communities. Environmental filtering at low latitudes allowed the invasive and accompanying species to evolve similar niches, while the cold climate at high latitudes increased the niche overlap between the invader and accompanying species. Our findings are crucial for predicting the dynamics of invasive plant communities under global change and for understanding the mechanisms of species coexistence. [ABSTRACT FROM AUTHOR]

Phenology has long been hypothesized as an avenue for niche partitioning or interspecific facilitation, both promoting species coexistence. Tropical plant communities exhibit striking diversity in reproductive phenology, but many are also noted for large synchronous reproductive events. Here we study whether the phenology of seed fall in such communities is nonrandom, the temporal scales of phenological patterns, and ecological factors that drive reproductive phenology. We applied multivariate wavelet analysis to test for phenological synchrony versus compensatory dynamics (i.e., antisynchronous patterns where one species' decline is compensated by the rise of another) among species and across temporal scales. We used data from long‐term seed rain monitoring of hyperdiverse plant communities in the western Amazon. We found significant synchronous whole‐community phenology at multiple timescales, consistent with shared environmental responses or positive interactions among species. We also observed both compensatory and synchronous phenology within groups of species (confamilials) likely to share traits and seed dispersal mechanisms. Wind‐dispersed species exhibited significant synchrony at ~6‐month scales, suggesting these species might share phenological niches to match the seasonality of wind. Our results suggest that community phenology is shaped by shared environmental responses but that the diversity of tropical plant phenology may partly result from temporal niche partitioning. The scale‐specificity and time‐localized nature of community phenology patterns highlights the importance of multiple and shifting drivers of phenology. [ABSTRACT FROM AUTHOR]

Aim: Theoretical, experimental and observational studies have shown that biodiversity–ecosystem functioning (BEF) relationships are influenced by functional community structure through two mutually non‐exclusive mechanisms: (1) the dominance effect (which relates to the traits of the dominant species); and (2) the niche partitioning effect [which relates to functional diversity (FD)]. Although both mechanisms have been studied in plant communities and experiments at small spatial extents, it remains unclear whether evidence from small‐extent case studies translates into a generalizable macroecological pattern. Here, we evaluate dominance and niche partitioning effects simultaneously in grassland systems world‐wide. Location: Two thousand nine hundred and forty‐one grassland plots globally. Time period: 2000–2014. Major taxa studied: Vascular plants. Methods: We obtained plot‐based data on functional community structure from the global vegetation plot database "sPlot", which combines species composition with plant trait data from the "TRY" database. We used data on the community‐weighted mean (CWM) and FD for 18 ecologically relevant plant traits. As an indicator of primary productivity, we extracted the satellite‐derived normalized difference vegetation index (NDVI) from MODIS. Using generalized additive models and deviation partitioning, we estimated the contributions of trait CWM and FD to the variation in annual maximum NDVI, while controlling for climatic variables and spatial structure. Results: Grassland communities dominated by relatively tall species with acquisitive traits had higher NDVI values, suggesting the prevalence of dominance effects for BEF relationships. We found no support for niche partitioning for the functional traits analysed, because NDVI remained unaffected by FD. Most of the predictive power of traits was shared by climatic predictors and spatial coordinates. This highlights the importance of community assembly processes for BEF relationships in natural communities. Main conclusions: Our analysis provides empirical evidence that plant functional community structure and global patterns in primary productivity are linked through the resource economics and size traits of the dominant species. This is an important test of the hypotheses underlying BEF relationships at the global scale. [ABSTRACT FROM AUTHOR]

Understanding of the mechanisms underlying species coexistence within plant communities is crucial to predict their fate given the current context of biodiversity loss. Freshwater ecosystems are among the most abiotically constrained habitats because they harbour clonal macrophyte communities. Strong habitat filtering in these ecosystems influences the functional composition and diversity of macrophyte communities, determining the outcome of interactions between neighbours and ultimately affecting local spatial arrangement between neighbours (LSA). This influence may be modulated by environmental conditions in abiotically constrained habitats, such as freshwater ecosystems.We focused on macrophyte communities living in ponds in the Iles Kerguelen, in the sub‐Antarctic. These freshwater ecosystems are especially abiotically constrained (cold climate), and their plant communities are remarkably species‐poor, simplifying the study of interactions between neighbours. We measured several abiotic variables in the ponds, species LSA and interspecific interactions (using the log response ratio metric), and the functional composition of the community using aerial, root and clonal traits. We also determined the biomass of the whole macrophyte community.Our results showed that LSA does not effectively assess interactions between neighbours at very small scales, neither at the community (one species vs. all neighbouring species) nor the species level (between pairs of species). Secondly, aerial (leaf and stem) and root traits related to resource acquisition played a more important role in interactions between neighbours than clonal traits (i.e. internode length and specific internode mass related to space acquisition and resource storage, respectively).Depending on the target species, (1) interactions responded positively or negatively to mean trait and functional diversity of the community; and (2) different traits of neighbours (aerial or root traits) triggered an interaction response. Lastly, abiotic variables, in particular water temperature and light intensity, influenced macrophyte community biomass and plant community structure (i.e. species richness, functional diversity and LSA), either directly or through the modulation of other abiotic variables.Our results lead to the following conclusions: (1) interactions between neighbours do not reflect their local spatial arrangements but are strongly associated with abiotic variables and neighbourhood functional traits (depending on species); (2) joint integration of biotic and abiotic variables in multivariate analyses enables better inference of biodiversity responses to environment, and the subsequent consequences for ecosystem function, especially in the context of climate change. [ABSTRACT FROM AUTHOR]

Increasing atmospheric nitrogen (N) deposition leads to ecosystem N–P imbalances worldwide, with important consequences on ecosystem services by altering plant N:P ratios. While the direct and positive effects of N inputs on plant N:P ratio at the species level is well established, it remains unclear how the N-induced changes in species composition contribute to the community-level alterations of N:P ratio, which are more closely related with ecosystem properties and functioning. Based on a field experiment with six N addition levels ranging from 0 to 50 g N m−2 yr−1 in a temperate semiarid grassland, we report more sensitive responses of community-level plant N:P ratio when considering changes in species composition than the expectation based only on arithmetic means of different species. Such exacerbation of plant N–P imbalances was caused by the fact that N inputs stimulated the dominance of two species with higher N:P stoichiometry flexibility. By linking species-specific variation of stoichiometry flexibility and the changes in species dominance with community-level variations of N:P ratio, our results uncover a new mechanism underlying the N-induced N–P imbalances in plant communities, which should be considered in biogeochemical modeling. [ABSTRACT FROM AUTHOR]

Background: Studying plant–soil feedback (PSF) is of great significance to understanding plant community dynamics. Aims: We aimed to determine the temporal variation in PSF at different stages of grassland community succession and the influencing factors. Methods: We conducted a 3‐year experiment to examine how PSF changes during different successional stages (early‐, mid‐ and late‐). Setaria viridis, Stipa bungeana and Bothriochloa ischaemum were selected as representative and dominant early‐, mid‐ and late‐species, respectively, in the semiarid grassland of the Loess Plateau, China. Results: The temporal variation in the PSF pattern was found to be species‐specific. Negative and neutral PSF patterns in early‐ and mid‐species, respectively, were found within the 3‐year growth periods. A positive PSF pattern for late‐species was found in the second growth period, and a negative PSF pattern was found in the third growth period. The shoot biomass of early‐species was overall positively correlated with soil nutrients and enzyme activity in the soil of the three species. However, the shoot biomass of late‐species was overall negatively correlated with soil nutrients and enzyme activity in early‐species soil. Conclusions: We suggest that the negative PSF of early‐species over the growing period explains why the advantage of these early colonizers is temporary. In contrast, the positive PSF of late‐species likely contributes to their successful colonization and the entire community succession process. Our results indicated that PSF plays an important role in the progression of plant community succession. [ABSTRACT FROM AUTHOR]

The functional response of plant communities to disturbance is hypothesised to be controlled by changes in environmental conditions and evolutionary history of species within the community. However, separating these influences using direct manipulations of repeated disturbances within ecosystems is rare. We evaluated how 41 years of manipulated fire affected plant leaf economics by sampling 89 plant species across a savanna‐forest ecotone. Greater fire frequencies created a high‐light and low‐nitrogen environment, with more diverse communities that contained denser leaves and lower foliar nitrogen content. Strong trait–fire coupling resulted from the combination of significant intraspecific trait–fire correlations being in the same direction as interspecific trait differences arising through the turnover in functional composition along the fire‐frequency gradient. Turnover among specific clades helped explain trait–fire trends, but traits were relatively labile. Overall, repeated burning led to reinforcing selective pressures that produced diverse plant communities dominated by conservative resource‐use strategies and slow soil nitrogen cycling. [ABSTRACT FROM AUTHOR]

Peatland ecosystems are of global conservation and environmental importance storing globally significant amounts of ancient carbon, regulating regional temperatures and hydrological regimes, and supporting unique biodiversity. Livestock grazing, land‐use change, drainage, nutrient and acid deposition, and wildfire threaten the composition and function of many peatlands including those in the uplands of the United Kingdom. Presently, little is known about either the short‐ or long‐term effects of wildfires within these systems in the UK. Our study aimed to evaluate how plant communities respond to wildfires across a range of vegetation communities, soil types, and burn severities. We evaluated wildfire burn severity using the ground‐based Composite Burn Index adapted for treeless peatlands. Using paired burned–unburned plots, we quantified differences in the abundance of plant families and functional groups, vegetation diversity, and community composition. Multivariate differences in composition between burned and unburned areas were used as an index of community resilience to fire. Plots in heathland communities with shallow organic soils burned at the highest severities and had the greatest reductions in plant diversity and richness. There were significant declines in plot‐scale species richness and diversity with increasing burn severity. Graminoids were resilient to fire whilst Ericaceae tended to increase with higher severity. Bryophyte composition was substantially altered—pleurocarpous species declined and acrocarpous species increased with greater burn severity. Community resilience was related to ground layer burn severity with higher burn severity driving greater changes in communities. Wildfire effects on temperate peatlands are a function of fire weather and site environmental and ecological characteristics. Management policy should ensure that the risk of severe wildfires is mitigated to protect ecosystem function and biodiversity. This will require system‐specific fire management prescriptions across the gradient of peatland soil and vegetation types. [ABSTRACT FROM AUTHOR]

Aims: Plant–soil feedback (PSF) is an important mechanism controlling plant growth, vegetation dynamics, and longer-term and larger-scale patterns of plant community diversity. We know that feedback between plants and soil biota depends on several external factors, such as nutrient and water availability, and interactions with neighbouring plants. We argue that in the 'real world', PSF are not working in isolation but instead proceed within a complex context of multiple interacting factors. Fire is one of those complex external factors which could greatly alter PSF by re-setting or re-directing plant-soil biota interactions. Methods: We reviewed key literature on the effects of fire on soil biota and soil physicochemical properties with soil depth, to generate predictions on the complex effects of fire on PSF. Results: We highlight that fire has strong potential to directly and indirectly affect the strength of PSF. To what extent this influences longer-term plant community trajectories depends on the interactions between fire characteristics and ecosystem type. Here, we conceptualized these effects of fire on soil properties and biota, and then discuss the main pathways through which fire should alter PSF. Conclusions: We think that PSF processes should be nullified under and after fire. Average neutral PSF responses are expected to be more common in the short-term or within the timeframe required for major soil microbial players to regain their pre-fire abundances and diversity. We conclude by providing directions for future research and possible methods to study fire effects on PSF both in the field and under controlled conditions. [ABSTRACT FROM AUTHOR]

We compared the reindeer forage stocks at two landfills in the southern part of the Yamal Peninsula for the period from the early 1930s to 2017–2019. Data from [30] was used to characterize the feedstock in the 1930s. Feedstocks in the 1930s and 2017–2019 in plant communities in the basins of the the Erkatayakha and Baidaratayakha rivers were compared in the following vegetation divisions: lichen and shrub tundras; moss and grass tundras; shrub tundra; meadow communities; and bogs. The following hypotheses were tested: (1) the total supply of feed in Yamal decreased since the 1930s; (2) the decrease in stocks affected the lichen component to the greatest extent. Both hypotheses were confirmed. The general changes in the stocks and structure of food in the plant communities of South Yamal over the 85–87 years include delichenization, a decrease in the mass of lichens and the proportion of lichen food. The average stock of lichen fodder from the 1930s to 2017–2019 decreased by 5 times in the communities at the Erkatayakha test site and by 2 times at the Baidaratayakha test site. The mass of green fodder for 85–87 years has not changed. Thus, the change in the masses of economically important components of tundra vegetation over a uniquely long period, almost 90 years, has been characterized. [ABSTRACT FROM AUTHOR]

Understanding the environmental and disturbance determinants of tree species dominance and community composition in an ecosystem, is important for informing management and conservation decisions, through maintaining or improving the existing forest composition and structure. This study was carried out to quantify the relationship between forest tree composition structure and environmental and disturbance gradients, in a tropical sub-montane forest of Eastern Usambara. Vegetation, environmental, and anthropogenic disturbance data for 58 plots across Amani and Nilo nature forest reserves were obtained. Agglomerative hierarchical cluster analysis and canonical correspondence analysis (CCA) were used to identify plant communities and analyze the influence of environmental variables and anthropogenic disturbances on tree species and community composition respectively. Four communities were identified and CCA results showed that the variation was significantly related to elevation, pH, Annual mean temperature, temperature seasonality, phosphorus nutrients and pressures from adjacent villages and roads. Likewise, environmental factors (climate, soil and topography) explained the most variation (14.5%) of tree and community composition in relation to disturbance pressure (2.5%). The large and significant variation in tree species and community patterns explained by environmental factors suggests a need for site-specific assessment of environmental properties for biodiversity conservation plans. Similarly, the intensification of human activities and associated impacts on natural environment should be minimized to maintain forest species composition patterns and communities. The findings are useful in guiding in policy interventions that focus on minimizing human disturbances in the forests and could aid in preserving and restoring the functional organization and tree species composition of the sub-tropical montane forests. [ABSTRACT FROM AUTHOR]

Social License to Operate (SLO) is a way to ensure community acceptance for entrepreneurial operations. This study describes and discusses the perspectives from communities, and external agents involved in SLO acquisitions and maintenance for a Small Hydroelectric Power Plant (SHP). Then, we reflect upon SLO applications for fair socio-environmental management. We used a case study for the research design. Data were collected using documents provided by the entrepreneur and semi-structured interviews of 15 stakeholders. We performed content analysis on the information obtained, along with literature discussion. Community representatives and external stakeholders reported not knowing about the SLO term and expected more benefits for the affected region. We observed that the main characteristic SLO results occurred in the phases preceding project operations. After the project was completed, the relationship among the parties weakened. Although it can't be possible to measure SLO level based on data from this case study, we point that SLO must take participatory systems, collective work, environmental protection, and social guarantees into account at all enterprise life cycle, to promote honest pathways for regional development. This study can contribute to discussions on implementing SLO in new contexts, such as SHP. [ABSTRACT FROM AUTHOR]

Aim: The occurrence, relative richness and abundance of N‐fixing plants are the main features of the N‐fixing potential of vascular plant communities. We aimed to unveil how climate, biome type and land management regime affect the N‐fixing potential of vegetation. Since the world is witnessing an invincible transition of all those environmental factors during the last century, we examined the global growth trends of N‐fixers throughout recent history. Location: Global. Taxon: Vascular plant species. Materials and Methods: We conducted a meta‐analysis of publicly available vegetation data from 290 communities. Combined with the species' N‐fixation capability, we examined the occurrence, abundance and richness of N‐fixing vascular species across varying climate conditions, land use regimes and potential habitat types. Results: There are relatively more N‐fixing vascular plants in warmer and drier climatic conditions. Management of communities by cutting woody plants, grazing and mowing hay increases the number and abundance of N‐fixing species. The effect of management is pronounced in wet conditions, where a dense canopy would otherwise emerge. As a result, semi‐natural grasslands exhibit higher N‐fixer occurrence than natural grasslands and non‐tropical forests, cessation of management results in a temporary increase in the abundance of N‐fixers. Repeated observations of sites indicated that the global occurrence of N‐fixers increased slightly in managed communities from 1906 to 2018, but there were no other temporal trends. Main conclusions: The overall number of N‐fixers in plant communities is low. The occurrence, relative richness and abundance of N‐fixing species are higher in sparse vegetation in dry climates and in extensive management where biomass is removed from communities. A probable explanation is the high light availability in dry vegetation and due to biomass removal, which provides a competitive advantage to light‐demanding N‐fixers. A lack of consistent temporal trends suggests that global change is not yet an active driver of N‐fixing potential in plant communities. [ABSTRACT FROM AUTHOR]

Restorations change across the growing season. Because of this, the point in the season that a restoration is sampled may affect the conclusions reached based on the sample. In this study, we explore seasonal changes in a prairie restoration experiment in eastern Kansas and investigate how these changes affect observed composition, biodiversity, and the effects of seeding density treatment on the plant community based on when, and how completely, vegetation is sampled. Free State Prairie was established in 2014 to test the effects of forb seeding density on forb establishment, diversity, and restoration success. We compared absolute cover data collected in early June and early September 2019 to each other and to combined data. We found changes in both composition and biodiversity from early-to-late in the season. Sown forbs decreased in cover and richness, while sown grasses increased in cover and richness. Nonsown species did not change in cover but decreased in richness. Neither individual sample fully represented the overall composition or biodiversity of the community. We detected a significant negative effect of forb seeding density on diversity in June, and with combined data, but not in September. As sampling time can affect both broad patterns of composition and diversity and observed results of establishment and management techniques, sampling multiple times in a year will provide the fullest and most accurate picture of the community. When multiple samples are impractical, sampling time should be selected carefully based on the phenology of the restoration and the variables of interest. [ABSTRACT FROM AUTHOR]

Anthropogenic impacts on biodiversity can lead to biotic homogenization (BH) and biotic differentiation (BD). BH is a process of increasing similarity in community composition (including taxonomic, functional, and phylogenetic components), whereas BD is a process of decreasing similarity over space and time. Here, we conducted a systematic review of BH and BD in plant communities in tropical and subtropical forests to identify trends and knowledge gaps. Our bibliometric search in the Web of Science returned 1989 papers, of which 151 matched our criteria and were included in the analysis. The Neotropical region had the largest number of articles, and Brazil was the most represented country with 92 studies. Regarding the type of change, homogenization was more frequent than differentiation (noted in 69.6% of publications). The taxonomic diversity component was measured more often than functional and phylogenetic diversity components. Most studies (75.6%) assessed homogenization and differentiation based on a single observation in time; as opposed to few studies that monitored plant community over multiple years. Forest fragmentation was cited as the main determinant of homogenization and differentiation processes (57.2% of articles). Our results highlight the importance of evaluating community composition over time and more than taxonomic components (i.e., functional and phylogenetic) to advance understanding of homogenization and differentiation. Both processes were scale dependent and not mutually exclusive. As such, future research should consider differentiation as a potential transition phase to homogenization and that potential differences in both processes may depend on the spatial and temporal scale adopted. Understanding the complexity and causes of homogenization and differentiation is essential for biodiversity conservation in a world increasingly affected by anthropogenic disturbances. [ABSTRACT FROM AUTHOR]

In the high Arctic, plant community species composition generally responds slowly to climate warming, whereas less is known about the community functional trait responses and consequences for ecosystem functioning. The slow species turnover and large distribution ranges of many Arctic plant species suggest a significant role of intraspecific trait variability in functional responses to climate change. Here we compare taxonomic and functional community compositional responses to a long‐term (17‐year) warming experiment in Svalbard, Norway, replicated across three major high Arctic habitats shaped by topography and contrasting snow regimes. We observed taxonomic compositional changes in all plant communities over time. Still, responses to experimental warming were minor and most pronounced in the drier habitats with relatively early snowmelt timing and long growing seasons (Cassiope and Dryas heaths). The habitats were clearly separated in functional trait space, defined by 12 size‐ and leaf economics‐related traits, primarily due to interspecific trait variation. Functional traits also responded to experimental warming, most prominently in the Dryas heath and mostly due to intraspecific trait variation. Leaf area and mass increased and leaf δ15N decreased in response to the warming treatment. Intraspecific trait variability ranged between 30% and 71% of the total trait variation, reflecting the functional resilience of those communities, dominated by long‐lived plants, due to either phenotypic plasticity or genotypic variation, which most likely underlies the observed resistance of high Arctic vegetation to climate warming. We further explored the consequences of trait variability for ecosystem functioning by measuring peak season CO2 fluxes. Together, environmental, taxonomic, and functional trait variables explained a large proportion of the variation in net ecosystem exchange (NEE), which increased when intraspecific trait variation was accounted for. In contrast, even though ecosystem respiration and gross ecosystem production both increased in response to warming across habitats, they were mainly driven by the direct kinetic impacts of temperature on plant physiology and biochemical processes. Our study shows that long‐term experimental warming has a modest but significant effect on plant community functional trait composition and suggests that intraspecific trait variability is a key feature underlying high Arctic ecosystem resistance to climate warming. [ABSTRACT FROM AUTHOR]

Numerous studies note the overwhelming influence of functional diversity on ecosystem functioning. It remains unclear how functional diversity affects the productivity of aquatic plant communities with different life-forms. We constructed free-floating plant communities dominated by Salvinia natans and submerged plant communities dominated by Vallisneria natans to explore the effects of disturbance (clonal fragmentation) on functional diversity-productivity relationships under different nutrient availability. Results showed that, in free-floating plant communities, disturbance had significant impacts on three community-weighted means traits (average leaf length, average leaf width and average root length), functional evenness (FEve) and productivity under high nutrient conditions. Three single-trait indices and FEve showed reverse correlations with productivity. In submerged plant communities, disturbance-induced considerable variations of single- and multi-trait indices and inapparent variation of productivity. Functional evenness was negatively related to community productivity under low nutrient conditions. Our results suggest that mechanisms of mass ratio and niche complementarity can simultaneously explain variations in free-floating plant community productivity under high nutrient conditions. Niche complementarity had a weak explanatory power for variations in submerged plant community productivity under low nutrient conditions. Our study provides the first evidence for the non-negligible role of nutrients and life-forms in functional diversity-productivity relationships of aquatic plant communities. [ABSTRACT FROM AUTHOR]

Climate change may disrupt plant–pollinator mutualisms by generating phenological asynchronies and by altering traits that shape interaction costs and benefits. Our knowledge is limited to studies that manipulate only one partner or focus on either phenological or trait‐based mismatches. We assembled communities of three annual plants and a solitary bee prior to flowering and emergence to test how springtime warming affects phenologies, traits, interactions and reproductive output. Warming advanced community‐level flowering onset, peak and end but did not alter bee emergence. Warmed plant communities produced fewer and smaller flowers with less, more‐concentrated nectar, reducing attractiveness, and warmed bees were more generalized in their foraging, reducing their effectiveness. Plant–bee interactions were less frequent, shorter and peaked earlier under warming. As a result, warmed plants produced fewer, lighter seeds, indicating pollinator‐mediated fitness costs. Climate change will perturb plant–pollinator mutualisms, causing wide‐ranging effects on partner species and diminishing the ecosystem service they provide. [ABSTRACT FROM AUTHOR]

Over 40 years ago, Kempton (Biometrics, 35, 1979, 307) reported significant modification to plant community structure following a long‐term fertilization experiment. Many researchers have investigated this phenomenon in the years since. Collectively, these studies have shown consistent shifts in rank abundance relationships among species in communities following fertilization. The previous studies indicated that fertilization affects community structure through several critical processes, including trait‐based functional response, reordering of species in rank abundance diagram (RAD), and niche dimensionality, although some questions have remained. How does the species reordering driven by the plant responses cause characteristic trends in temporal changes of RAD? Why are those trends ubiquitous in various systems? To answer those questions, we theoretically investigated the effects of fertilization on community structure based on a colonization model (or Levins model) with competition–fecundity trade‐offs, which can result in the coexistence of multiple species under competition. The model represents characteristic RAD, which can be an adequate tool to study community composition. Our theoretical model comprehensively represents observed trends in rank abundance relationships following long‐term fertilization and suggests that competitive interactions among species are a critical factor in structuring species diversity in plant communities. [ABSTRACT FROM AUTHOR]

Peatlands have their own, specific insect fauna. They are a habitat not only for ubiquistic but also stenotopic moths that feed on plants limited to wet, acid and oligotrophic habitats. In the past, raised bogs and fens were widely distributed in Europe. This has changed since 20th c. Due to irrigation, modern forestry, and increasing human settlement, peatlands have become isolated islands in an agricultural and urban landscape. Here, we analyze the flora in a degraded bog situated in a large Lodz city agglomeration in Poland in relation to the diversity and composition of moth fauna. Over the last 40 years since the bog has become protected as a nature reserve, birch, willow, and alder shrubs replaced the typical raised bog plant communities due to the decreased water level. The analysis of moth communities sampled in 2012 and 2013 indicates dominance of ubiquistic taxa associated with deciduous wetland forests and rushes. Tyrphobiotic and tyrphophile moth taxa were not recorded. We conclude that the absence of moths typical of bog habitats and the dominance of common, woodland species are associated with hydrological changes, the expansion of trees and brushes over typical bog plant communities, and light pollution. [ABSTRACT FROM AUTHOR]

Beta-diversity partitioning has shown that the nestedness component is developed with environmental stress in a variety of taxa. However, soil fungal community may maintain its turnover components in contrast to the development of plants' nestedness component, and the potential causes remain unclear. To investigate the process of species turnover of soil fungi along a stress gradient in the Arctic, we divided species turnover component into sub-components: βsim_hete and βsim_homo representing species turnover with and without a change in the guilds, respectively. The results indicate that fungal communities maintain their turnover components, unlike plant communities; however, their βsim_hete increased under stressful conditions. Additionally, GDM analysis showed that βsim_hete was mainly explained by stress gradient and plant nestedness, suggesting that the functionality of soil fungi was ecologically filtered by environmental stress and plant community structure. The discordant trend of beta-diversity values between plant and fungi (i.e. development of plant nestedness and maintenance of fungal turnover) is possibly not caused by different assembly rules working in parallel on the two taxa, but according to an ecological rule that reflects plant–fungal interaction. [ABSTRACT FROM AUTHOR]

The Palestinian environment suffered from abuse and neglect for decades. As a nascent state, Palestine aspired to protect and restore its environment, in line with international standards and conventions. Yet, many challenges remain, including a lack of data, the science–policy–practice gaps, and the lack of sovereignty. The management of protected areas (PAs) is particularly challenging under these circumstance. Two key protected areas in the northern West Bank (Wadi Qana and Wadi Al-Zarqa Al-Ulwi) were surveyed, with a focus on plant communities and dealing with threats. The two areas had similar Mediterranean flora with differences, including in rare plants. Both areas have important but different wetlands in their buffer zones. The data show that the protection of the two areas is important because of the differences noted, and both areas are valued as IUCN category IV (habitat/species management area) protection. Such protection is possible by working with local communities and bridging the science–policy–practice gaps. [ABSTRACT FROM AUTHOR]

With the help of gradient analysis and Ellenberg eco-scales, factors of differentiation of vegetation cover (moisture, illumination, soil acidity, and soil richness in mineral nitrogen) were revealed. Using nonmetric scaling, an ordination diagram of the distribution of geobotanical descriptions was created for 50 years of research (from 1971 to 2021). Correlation of ordination axes and ecological factors was carried out. On the ordination diagram and according to the results of cluster analysis, geobotanical descriptions form three distinct groups corresponding to certain time periods. Changes in the species composition in plant communities are caused by changes in illumination, moisture, and trophicity. Under the influence of drainage and successions of the vegetation cover for 50 years, on the site of a mesotrophic hummock-flark herb sphagnum mire, represented by mesotrophic hydrohygrophilous mire species, an oligotrophic hummock lawn dwarf-sphagnum pine forest was formed, formed by oligotrophic, mesohygrophilic forest-mie species. [ABSTRACT FROM AUTHOR]

To explore the community structural characteristics and spatial distribution pattern of dominant species, three companion communities of Chimonobambusa angustifolia (Doupengshan, Laoshanjie, and Leigongshan） were selected as research objects, and the communities were investigated using quadrat method. The community vertical structure, diameter class structure, height class structure, species importance value, and spatial distribution pattern of dominant species were studied, and the factors affecting community structure and spatial distribution pattern were also analyzed. The results showed the following: the vertical structure of the three communities was clear, and it could be divided into three layers-tree layer, shrub layer and herb layer from the canopy to the ground. The interlayer plants were underdeveloped with few vines and epiphytes. The diameter class structure（DBH≥1 cm） of the three communities had an inverse "J" shape, indicating successful regeneration, and the average diameter was ranked as follows: Laoshanjie (16.02 cm)＞Leigongshan (11.38 cm)＞Doupengshan（8.98 cm）, but the individual density showed the opposite trend. The diameter class structure of dominant species had an inverse "J" shape in Doupengshan and Leigongshan, implying that the population was a growing type. However, the diameter structure of dominant species had a unimodal type in Laoshanjie. The population of Fagus lucida was a declining type, and there was a degradation risk in the population of Cyclobalanopsis multinervis and Quercus engleriana. Dominant species of Laoshanjie will be replaced gradually by other plants with community succession. Overall, the height class structure of the communities was an inverse "J" shape, and the average height was ranked as follows: Doupengshan (8.14 m)＞Leigongshan (6.87 m)＞Laoshanjie (6.69 m). The height class structures of dominant species were different, and most were an inverse "J" shape, followed by unimodal type. The importance values of communities and layers were different, and the importance values of dominant species accounted for 47.58%, 57.72%, and 25.81% of the importance values of the tree layer in Doupengshan, Laoshanjie, and Leigongshan, respectively. The spatial distribution pattern of dominant species tended to be uniform or clumped in small size (DBH＜10 cm), but it tended to be uniform or random in middle size（10 cm≤DBH＜30 cm） and large size (DBH≥30 cm). This suggest that the community structure and spatial distribution pattern of dominant species in the three communities were comprehensively influenced by combined factors. Community succession time and competitive exclusion were the major factors affecting the community structure, whereas dispersal limitation and competitive exclusion were the major factors affecting the spatial distribution pattern of dominant species. [ABSTRACT FROM AUTHOR]

Questions: The extent to which metacommunities contain species exhibiting metapopulation dynamics is poorly understood. We investigate this issue within sandstone outcrop plant communities scattered across an upland hardwood forest. We investigate the life forms of metapopulation species and relationships between taxonomic, phylogenetic, and functional diversity, composition, and environmental factors. Location: Twenty‐three sandstone outcrop communities in southern Illinois, USA. Methods: Following vegetation surveys, species exhibiting metapopulation dynamics were identified and compared to all species based on origin, growth form, and lifecycle. Cohesion, turnover, and boundary clumping were utilized to determine metacommunity structure. Correlations evaluated associations between site‐based variables, and regressions evaluated associations between diversity indices. Multivariate analyses compared sites to determine which variables contributed to compositional differences. Results: Twenty of 130 species exhibited metapopulation dynamics and were usually annual or biennial exotics. Metacommunity elements indicated a metacommunity structure where groups of species tended to replace one another across sites, in which species exhibiting metapopulation dynamics were subordinate as opposed to dominant or transient. The largest sites were the most regularly shaped, but not the most diverse. Species richness and species exhibiting metapopulation dynamics determined phylogenetic and functional diversity, but largely non‐standardized measures of diversity, indicating independence between types of diversity. Multivariate analyses showed that diversity metrics explained community composition differences, where more species‐rich sites with more metapopulation species were also more phylogenetically and functionally diverse. Conclusions: Sandstone outcrop communities exhibited diverse plant communities, where phylogenetic and functional diversity were driven by both the number of all species and the subset of metapopulation species independently. SM dynamics were usually short‐lived and exotic species with their low number likely constrained via dispersal limitations. The communities exhibited a metacommunity structure indicating predictable community assemblages which tend to be replaced with others as opposed to just individual species being replaced individually, consistent with the concept of an integrated community. Functional traits indicated that these communities include species adapted to xeric, substrate‐poor conditions. [ABSTRACT FROM AUTHOR]

Changes in the amount and timing of precipitation may affect plant species coexistence. However, little is known about how these changes in precipitation structure plant communities. Here, we conducted a 6-year field precipitation manipulation experiment in the semi-arid steppe of Inner Mongolia, China, to assess the importance of species extinction and colonization in community assembly by incorporating information on phylogenetic and functional relatedness. Our results demonstrated that the decline in plant species richness under decreasing precipitation in the late and entire growing season could be attributed to a decrease in species colonization and an increase in species loss, respectively. The increase in species richness under increasing precipitation in the late growing season was mainly caused by increases in colonizing species. The loss of species that were more closely related to other residents under decreasing precipitation in the late growing season did not alter patterns of phylogenetic overdispersion, and the colonization of species that were more distantly related to residents under increasing precipitation in the late growing season shifted functional relatedness from clustering to randomness. Increasing precipitation may weaken the strength of environmental filtering induced by water stress in this semi-arid steppe and thus increase the probability of successful colonization of functionally dissimilar species relative to residents. Our study suggests that incorporating information on the functional and phylogenetic relatedness of locally lost resident species and the colonization of new species into analyses of community assembly processes can provide new insights into the general responses of plant communities to global change. [ABSTRACT FROM AUTHOR]

Ecosystems are faced with an onslaught of co-occurring global change drivers. While frequently studied independently, the effects of multiple global change drivers have the potential to be additive, antagonistic, or synergistic. Global warming, for example, may intensify the effects of more variable precipitation regimes with warmer temperatures increasing evapotranspiration and thereby amplifying the effect of already dry soils. Here, we present the long-term effects (11 years) of altered precipitation patterns (increased intra-annual variability in the growing season) and warming (1 °C year-round) on plant community composition and aboveground net primary productivity (ANPP), a key measure of ecosystem functioning in mesic tallgrass prairie. Based on past results, we expected that increased precipitation variability and warming would have additive effects on both community composition and ANPP. Increased precipitation variability altered plant community composition and increased richness, with no effect on ANPP. In contrast, warming decreased ANPP via reduction in grass stems and biomass but had no effect on the plant community. Contrary to expectations, across all measured variables, precipitation and warming treatments had no interactive effects. While treatment interactions did not occur, each treatment did individually impact a different component of the ecosystem (i.e., community vs. function). Thus, different aspects of the ecosystem may be sensitive to different global change drivers in mesic grassland ecosystems. [ABSTRACT FROM AUTHOR]

Biotic interactions in plant communities affect individual fitness and community dynamics. Interactions between plants vary in space, over time and with organisational complexity. Yet it is challenging to quantify temporal, spatial and functional determinants of different types of interactions between long‐lived perennial plant species and their effect on lifetime fecundity.We studied how plant–plant, pollinator‐ and seed predator‐mediated interactions affect year‐to‐year variation in three fecundity components (cone production, seed set and seed survival) during post‐fire recovery. Age‐stratified data on the three fecundity components were collected in 19 even‐aged communities comprising 20 serotinous Protea shrub species in the South African Fynbos. We analyse data on these fecundity components with neighbourhood models to infer the sign and strength of interactions throughout post‐disturbance recovery, the neighbour plant traits that shape them and the spatial scale at which interactions take place. For each fecundity component, these models describe how neighbourhood effects change over time and with spatial distance between plants. We then predicted neighbourhood effects on individual fecundity components and cumulative reproductive output at different post‐fire stand ages for each focal plant.Competitive effects on cone production and seed set increased with post‐fire stand age as biomass and floral resources for pollinators build up. In contrast, neighbourhood effects on seed survival were weak throughout post‐disturbance recovery. Plant–plant interactions were shaped by neighbour traits related to resource acquisition, whereas animal‐mediated interactions depended on neighbour traits related to resource availability for pollinators and seed predators. The spatial scale of the interactions increased from plant–plant over predator‐mediated to pollinator‐mediated interactions. The joint effect of these interactions on cumulative reproductive output caused the proportion of focal plants experiencing competition to increase with time since fire.Synthesis. We show that temporal changes in biotic interactions throughout post‐disturbance recovery of perennial plant communities depend on functional traits and can be integrated into neighbourhood effects on lifetime fecundity. Studying the temporal, spatial and functional determinants of neighbourhood effects on lifetime fecundity is important for predicting not only individual plant fitness but also population and community dynamics in changing environments. [ABSTRACT FROM AUTHOR]

Elevational gradients are useful for predicting how plant communities respond to global warming, because communities at lower elevations experience warmer temperatures. Fine root traits and root trait variation could play an important role in determining plant community responses to warming in cold‐climate ecosystems where a large proportion of plant biomass is allocated belowground. Here, we investigated the effects of elevation‐associated temperature change on twelve chemical and morphological fine root traits of plant species and plant communities in a Swedish subarctic tundra. We also assessed the relative contributions of plant species turnover and intraspecific variation to the total amount of community‐level root trait variation explained by elevation. Several root traits, both at the species and whole community levels, had significant linear or quadratic relationships with elevation, but the direction and strength of these relationships varied among traits and plant species. Further, we found no support for a unidirectional change from more acquisitive root trait values at the lower elevations towards trait values associated with greater nutrient conservation at the higher elevations, either at the species or community level. On the other hand, root trait coefficients of variation at the community level increased with elevation for several root traits. Further, for a large proportion of the community‐level traits we found that intraspecific variation was relatively more important than species turnover, meaning that trait plasticity is important for driving community‐level trait responses to environmental factors in this tundra system. Our findings indicate that with progressing global warming, intraspecific trait variation may drive plant community composition but this may not necessarily lead to shifts in root resource–acquisition strategy for all species. [ABSTRACT FROM AUTHOR]

Characterizing plant functional diversity is essential to decipher community assembly rules and ecosystem functioning. Most studies focused on above‐ground traits whereas the analysis of root diversity lags far behind. We analyzed the structure of fine root (< 2 mm) diameter distribution at the community level as an indicator of root morphological diversity, and hypothesized that the shape of the distribution provide insights on root types and root exploration strategies. We tested this hypothesis along a successional gradient (6–69 year‐old) with yearly mowing to better understand assembly rules regarding to belowground processes, and explored the relations between the parameters describing its modes and the vegetation composition and ecological properties of plant communities. Most communities showed a multimodal distribution, with two main modes corresponding to absorptive roots (thinner root mode) and transport roots (coarser root mode), and a third mode of lower importance corresponding to large transport roots. In early succession, the thinnest root mode was prominent, reflecting the dominance of thin absorptive roots and a low proportion of transport roots, resulting in a low root morphological diversity. As succession proceeds, the relative proportion of the second mode increased, and the proportions of the two main modes were more balanced, resulting in an increased variance and root morphological diversity. Furthermore, the first root mode (absorptive roots) became wider and shifted from very thin to thicker roots, suggesting the coexistence of various root strategies for resource exploration. Yearly mowing did not affect root diameter distribution, which may relate to the relative low mowing pressure that enabled woody species to remain, with stunted stature. Overall, our study demonstrates that the distribution of fine root diameters sheds light on root morphological diversity at the community level, and provide hints on the co‐existence of root types and strategies for resource use and exploration. [ABSTRACT FROM AUTHOR]

Ecological restoration often relies on disturbance as a tool for establishing target plant communities, but disturbance can be a double‐edged sword, at times initiating invasion and unintended outcomes. Here we test how fire disturbance, designed to enhance restoration seeding success, combines with climate and initial vegetation conditions to shift perennial versus annual grass dominance and overall community diversity in Pacific Northwest grasslands. We seeded both native and introduced perennial grasses and native forbs in paired, replicated burned‐unburned plots in three sites along a latitudinal climate gradient from southern Oregon to central‐western Washington. Past restoration and climate manipulations at each site had increased the variation of starting conditions between plots. Burning promoted the expansion of extant forbs and perennial grasses across all sites. Burning also enhanced the seeding success of native perennial grass and native forbs at the northern and central site, and the success of introduced perennial grasses across all three sites. Annual grass dominance was driven more by latitude than burning, with annuals maintaining their dominance in the south and perennials in the north. At the same time, unrestored grasslands surrounding all sites remained dominated by perennial grasses, suggesting that initial plot clearing may have allowed for annual grass invasion in the southern site. When paired with disturbance, further warming may increase the risk of annual grass dominance, a potentially persistent state. [ABSTRACT FROM AUTHOR]