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The intimate associations between plants and microbes that develop in rhizosphere soils may alter the sensitivity of bacterial communities to environmental filters during the process of community assembly. We compared the sensitivity of rhizosphere and bulk soil communities to ecological variables in several New England salt marshes dominated by Spartina alterniflora (Smooth Cordgrass), characterizing community variation based on linear combinations of 16S rDNA fragments representing bacterial taxonomic units. Rhizosphere microbes showed significantly greater sensitivity to plant biomass and pH, perhaps because of their relationships with the quality of plant exudates and availability of nutrients, respectively, while bulk microbes showed significantly greater sensitivity to elevation and redox potential, perhaps through waterlogging and an absence of plants oxygenating the soil. [ABSTRACT FROM AUTHOR]

Exploring the determinants of biological community structure is important not only for understanding the formation of the community, but also for promoting its biodiversity conservation. We monitored butterfly communities in a grassland and woodland area of Mount Fuji, Japan, and explored the environmental factors that influenced them. Multivariate regression tree (MRT) analysis generated a 3-leaved MRT (G1, G2, and G3) and showed the total explained variation of 64.4% in the species composition. The explanatory variables discriminating between the two branches in the first node and in the second node of the MRT were neighboring plant community and management status, respectively. The neighboring plant community was related to the distribution of butterfly dietary resources and contributed a lot in determining the species composition of the community while the management status was largely related to the amount of their dietary resources, affecting the species richness and diversity. The PCA results revealed that the three key groups (G1, G2, and G3) were formed along the gradients of these two factors. Consequently, maintaining mowing management and the diversity of neighboring vegetation is very important for the continuance of butterfly community diversity and composition and the conservation of Red Listed species in the area. [ABSTRACT FROM AUTHOR]

Indirect interactions among species within ecological communities govern ecological and evolutionary processes as much as, or even more, than direct effects. In insect‐pollinated plant communities, indirect interactions between plants can be mediated by shared pollinators, and may influence plant fitness, population growth and community structure. As individuals are the entities actually interacting in nature, rather than species, downscaling a hierarchical level (i.e. from species to individuals) is essential to understand the underlying processes promoting these indirect interactions. We combined empirical data on plant–pollinator interactions collected in Mediterranean shrublands with a novel modelling framework to assess how the patterns of heterospecific and conspecific pollinator sharing between plant individuals are generated and their fitness implications. We found that the effects of flowering synchrony on pollinator sharing among conspecific and heterospecific plant individuals outperformed those of spatial distance. Our results revealed that plant individuals that shared more pollinators with conspecifics were also involved in a higher pollinator sharing with heterospecifics. For most plant species, the sharing of pollinator species between heterospecific plant individuals produced positive mean fitness outcomes, as long as plants did not share many pollinator interactions, which had negative effects on their fitness. At the level of plant individuals, we found that specific combinations of conspecific and heterospecific pollinator sharing lead to distinct reproductive outcomes that placed each individual along a competition–facilitation continuum. Interestingly, most plant species included a higher proportion of individuals likely experiencing competition compared to those potentially involved in facilitation processes. Our contribution provides novel insights into the factors responsible for local‐scale indirect interactions within communities and their individual‐level functional consequences. Such intricate patterns of indirect interactions have far‐reaching implications, as the transitions of plant individuals along competitive or facilitative processes mediated by shared mutualists may contribute significantly to the functioning and coexistence of ecological communities. [ABSTRACT FROM AUTHOR]

The interruption of plant‐pollinator interactions may threaten global plant diversity, food security and ecosystem stability. Recent reports of strong declines in both insects and plants point to insect decline as a driver of plant decline. However, it is still unknown whether these trends are related as plants often produce seeds without the need for insect pollinators, and to what extent insect‐pollinated plants have declined in relation to plants not pollinated by insects.In this study, we hypothesise that natural plant communities have shifted away from insect‐pollination. We combined 365,768 vegetation plots from 1930 to 2017 in the Netherlands and plant traits to assess the changes in occurrences of plants pollinated by different modes. Furthermore, we included key drivers in plant decline—specifically nitrogen, moisture and habitat types—as interaction factors to explore the persistence of the observed changes under different environmental conditions.The proportion of insect‐pollinated plants has declined while that of wind‐pollinated plants has increased over the last 87 years. This proportional change reflects an absolute decrease in the number of insect‐pollinated species and an increase in the number of wind‐pollinated species.Synthesis and applications. This study implies that Dutch landscapes are losing insect‐pollinated plant species, which is likely due, at least in part, to the decline in pollination services. Our results of quantifying the decline in insect‐pollinated plants support the necessity and urgency of taking conservation initiatives. Several management strategies and policy recommendations could be applied to alleviate the decline of insect‐pollinated plants and ensure crop safety. For example, conserving natural environments by reducing nitrogen deposition may support local plants and insect pollinators. Additionally, there is a particular need for focused efforts to protect natural grasslands, as these areas harbour many insect‐pollinated plants, which have experienced declines. Finally, monitoring and assessing the state of both pollinators and (insect‐pollinated) plants is needed to assess the progress of conservation measures. While recognising the interdependence of pollinators and pollinated plants, it is crucial to extend efforts beyond pollinator conservation alone to effectively safeguard insect‐pollinated plants and ensure crop safety. [ABSTRACT FROM AUTHOR]

An increasing number of studies of above‐belowground interactions provide a fundamental basis for our understanding of the coexistence between plant and soil communities. However, we lack empirical evidence to understand the directionality of drivers of plant and soil communities under natural conditions: 'Are soil microorganisms driving plant community functioning or do they adapt to the plant community?' In a field experiment in an early successional dune ecosystem, we manipulated soil communities by adding living (i.e., natural microbial communities) and sterile soil inocula, originating from natural ecosystems, and examined the annual responses of soil and plant communities. The experimental manipulations had a persistent effect on the soil microbial community with divergent impacts for living and sterile soil inocula. The plant community was also affected by soil inoculation, but there was no difference between the impacts of living and sterile inocula. We also observed an increasing convergence of plant and soil microbial composition over time. Our results show that alterations in soil abiotic and biotic conditions have long‐term effects on the composition of both plant and soil microbial communities. Importantly, our study provides direct evidence that soil microorganisms are not "drivers" of plant community dynamics. We found that soil fungi and bacteria manifest different community assemblies in response to treatments. Soil fungi act as "passengers," that is, soil microorganisms reflect plant community dynamics but do not alter it, whereas soil bacteria are neither "drivers" nor "passengers" of plant community dynamics in early successional ecosystems. These results are critical for understanding the community assembly of plant and soil microbial communities under natural conditions and are directly relevant for ecosystem management and restoration. [ABSTRACT FROM AUTHOR]

Species traits may determine plant interactions along with soil microbiome, further shaping plant–soil feedbacks (PSFs). However, how plant traits modulate PSFs and, consequently, the dominance of plant functional groups remains unclear. We used a combination of field surveys and a two‐phase PSF experiment to investigate whether forbs and graminoids differed in PSFs and in their trait–PSF associations. When grown in forb‐conditioned soils, forbs experienced stronger negative feedbacks, while graminoids experienced positive feedbacks. Graminoid‐conditioned soil resulted in neutral PSFs for both functional types. Forbs with thin roots and small seeds showed more‐negative PSFs than those with thick roots and large seeds. Conversely, graminoids with acquisitive root and leaf traits (i.e., thin roots and thin leaves) demonstrated greater positive PSFs than graminoids with thick roots and tough leaves. By distinguishing overall and soil biota‐mediated PSFs, we found that the associations between plant traits and PSFs within both functional groups were mainly mediated by soil biota. A simulation model demonstrated that such differences in PSFs could lead to a dominance of graminoids over forbs in natural plant communities, which might explain why graminoids dominate in grasslands. Our study provides new insights into the differentiation and adaptation of plant life‐history strategies under selection pressures imposed by soil biota. [ABSTRACT FROM AUTHOR]

Question: Changes caused by climate warming and nitrogen pollution are observed in forest, grassland and alpine ecosystems worldwide. However, still little is known about the impact of these globally influencing factors on natural rocky plant communities. Has species composition of natural rocky communities changed over time? What is the role of large‐scale and fine‐scale environmental factors in shaping the compositional, functional and habitat patterns in studied plant communities over time? Location: Sudetes Mountains, southwestern Poland. Methods: We used 214 pairs of replots (collected between 1989 and 2022) of rocky plant communities, with a mean timespan of 14.2 years. The changes in species composition, environmental conditions and functional traits were analysed using ordination techniques and generalised additive models (GAMs) and with reference to large‐scale factors (mean maximum temperatures, actual evapotranspiration, N deposition) and fine‐scale factors (light availability, bedrock type, initial site conditions) for each locality. Results: Species composition of the studied communities has not changed significantly over time. Only for 11 out of 258 species, statistically significant increases (from 2% to 8%) in their proportion were recorded. The changes in environmental conditions were significantly influenced mainly by fine‐scale factors such as changes in light availability and baseline site conditions. Plots that were initially less thermophilic or nitrophilic showed stronger signals of thermophilisation and eutrophication in the resurvey. The influence of large‐scale factors was considerably less pronounced. Similarly, the key role in explaining changes in plant traits for the data set under study falls to local factors, particularly changes in light availability. Conclusions: Our study confirms the validity of considering both large‐ and fine‐scale factors as well as initial site conditions in research on long‐term changes in plant communities. Rocky plant communities respond to global changes in a different way than other types of phytocoenose, showing high stability of species composition and functional traits over time. [ABSTRACT FROM AUTHOR]

Plants face trade‐offs between allocating resources to growth, while also defending against herbivores or pathogens. Species differences along defense trade‐off axes may promote coexistence and maintain diversity. However, few studies of plant communities have simultaneously compared defense trade‐offs against an array of herbivores and pathogens for which defense investment may differ, and even fewer have been conducted in the complex natural communities in which these interactions unfold. We tested predictions about the role of defense trade‐offs with competition and growth in diversity maintenance by tracking plant species abundance in a field experiment that removed individual consumer groups (mammals, arthropods, fungi) and added nutrients. Consistent with a growth–defense trade‐off, plant species that increased in mass in response to nutrient addition also increased when consumers were removed. This growth–defense trade‐off occurred for all consumer groups studied. Nutrient addition reduced plant species richness, which is consistent with trade‐off theory. Removing foliar fungi increased plant diversity via increased species evenness, whereas removal of other consumer groups had little effect on diversity, counter to expectations. Thus, while growth–defense trade‐offs are general across consumer groups, this trade‐off observed in wild plant communities does not necessarily support plant diversity maintenance. [ABSTRACT FROM AUTHOR]

Biodiversity can stabilize ecological communities through biological insurance, but climate and other environmental changes may disrupt this process via simultaneous ecosystem destabilization and biodiversity loss. While changes to diversity–stability relationships (DSRs) and the underlying mechanisms have been extensively explored in terrestrial plant communities, this topic remains largely unexplored in benthic marine ecosystems that comprise diverse assemblages of producers and consumers. By analyzing two decades of kelp forest biodiversity survey data, we discovered changes in diversity, stability, and their relationships at multiple scales (biological organizational levels, spatial scales, and functional groups) that were linked with the most severe marine heatwave ever documented in the North Pacific Ocean. Moreover, changes in the strength of DSRs during/after the heatwave were more apparent among functional groups than both biological organizational levels (population vs. ecosystem levels) and spatial scales (local vs. broad scales). Specifically, the strength of DSRs decreased for fishes, increased for mobile invertebrates and understory algae, and were unchanged for sessile invertebrates during/after the heatwave. Our findings suggest that biodiversity plays a key role in stabilizing marine ecosystems, but the resilience of DSRs to adverse climate impacts primarily depends on the functional identities of ecological communities. [ABSTRACT FROM AUTHOR]

Many wetland plants rely on insects for pollination. However, studies examining pollinator communities in wetlands remain limited. Some studies conducted in large wetlands (> 10 ha) have suggested that wetland-dependent flies, which spend their larval stage in aquatic and semi-aquatic habitats, dominate as pollinators. However, smaller wetlands surrounded by secondary forests are more prevalent in Japan, in which pollinators from the surrounding environment might be important. Additionally, information regarding floral traits that attract specific pollinator groups in wetland communities is scarce. Therefore, this study aimed to understand the characteristics of insect pollinators in a small natural wetland (2.5 ha) in Japan. We examined the major pollinator groups visiting 34 plant species and explored the relationship between the flower visitation frequency of each pollinator group and floral traits. Overall, flies were the most dominant pollinators (42%), followed by bees and wasps (33%). Cluster analysis indicated that fly-dominated plants were the most abundant among 14 of the 34 target plant species. However, 85% of the hoverflies, the most abundant flies, and 82% of the bees were non-wetland-dependent species, suggesting that these terrestrial species likely originated from the surrounding environment. Therefore, pollinators from the surrounding environment would be important in small natural wetlands. Flies tend to visit open and white/yellow flowers, whereas bees tended to visit tube-shaped flowers, as in forest and grassland ecosystems. The dominance of flies in small wetlands would be due to the dominance of flowers preferred by flies (e.g., yellow/white flowers) rather than because of their larval habitats. [ABSTRACT FROM AUTHOR]

Understanding how diversity is maintained in plant communities requires that we first understand the mechanisms of competition for limiting resources. In ecology, there is an underappreciated but fundamental distinction between systems in which the depletion of limiting resources reduces the growth rates of competitors and systems in which resource depletion reduces the time available for competitors to grow, a mechanism we call 'competition for time'. Importantly, modern community ecology and our framing of the coexistence problem are built on the implicit assumption that competition reduces the growth rate. However, recent theoretical work suggests competition for time may be the predominant competitive mechanism in a broad array of natural communities, a significant advance given that when species compete for time, diversity‐maintaining trade‐offs emerge organically. In this study, we first introduce competition for time conceptually using a simple model of interacting species. Then, we perform an experiment in a Mediterranean annual grassland to determine whether competition for time is an important competitive mechanism in a field system. Indeed, we find that species respond to increased competition through reductions in their lifespan rather than their rate of growth. In total, our study suggests competition for time may be overlooked as a mechanism of biodiversity maintenance. [ABSTRACT FROM AUTHOR]

Both bottom-up and top-down processes modulate plant communities. Fungal and oomycete pathogens are most common in global grasslands, and due to differences in their physiology, function, host range, and life cycles, they may differentially affect plants (in both intensity and direction). However, how fungal and oomycete pathogens regulate bottom-up and top-down effects on plant community biomass remains unclear. To this end, we conducted a 3-year field experiment in an alpine meadow incorporating mammalian herbivore exclosure, fungicide/oomyceticide application, and nitrogen addition treatments. We arranged 12 blocks with half randomly assigned to be mammalian herbivore exclosures (fenced to exclude grazing sheep), and the other half were fenced most of the year but not in winter (winter grazing control). Six 2.5 × 2.5 m square plots were established in each block, with each of the six plots assigned as control, nitrogen addition, fungicide application, oomyceticide application, nitrogen addition + fungicide application, and nitrogen addition + oomyceticide application. We found that fungicide application significantly increased plant community biomass (mainly Poaceae species) under nitrogen addition and promoted the bottom-up effect of nitrogen addition on plant community biomass by altering the community-weightedmean of plant height (via species turnover). Meanwhile, oomyceticide application significantly increased plant community biomass (mainly Poaceae species) when mammalian herbivores were excluded and weakened the top-down effect of winter grazing on plant community biomass by driving intraspecific variation in plant height. Our results highlight that fungal and oomycete pathogens play important (but differing) roles in mediating the effects of nutrient availability and higher trophic levels on plant community biomass. Mechanistically, we demonstrated that plant pathogen-related modulation of plant community biomass is achieved by alterations to plant height. Overall, this study combines both community and disease ecology to reveal complex interactions among higher trophic levels and their potential impacts on terrestrial ecosystem functioning under human disturbance. [ABSTRACT FROM AUTHOR]

A functional approach to understand natural plant communities helps elucidate the dynamics of environmental filters and community assembly. Species classification into functional groups allows the translation of ecological complexity into simplified and applicable knowledge. Here, we developed a plant functional type (PFT) system to investigate whether functional structure (PFT composition and abundance) of plant communities varies between substrate types and plant physiognomies in an old climatically buffered infertile landscape (OCBIL), namely Brazilian campo rupestre. We sampled the herbaceous and shrubby vegetation and collected soil variables in four different plant physiognomies growing in quartzitic and ferruginous substrates. We classified the sampled species according to life‐history traits related to species persistence, reproduction, and biological interactions. Functional dissimilarity among plant physiognomies and the two substrate types and the role of soil factors affecting the dissimilarities were assessed. Pollination and seed dispersal syndromes, mycorrhizal association, and reproductive phenology were the main traits defining the PFTs. We found distinct functional structure between plant communities of different substrates and physiognomies, with a marked influence of chemical and physical soil factors. Also, we defined main PFTs profiles for each physiognomy, identifying core PFTs with basic combinations of traits, common to all or almost all physiognomies. The functional perspective proposed by this study provides applicable knowledge to the restoration and conservation of campo rupestre ecosystem, reinforcing the importance of habitat heterogeneity for maintaining its functioning. [ABSTRACT FROM AUTHOR]

As bees' main source of protein and lipids, pollen is critical for their development, reproduction, and health. Plant species vary considerably in the macronutrient content of their pollen, and research in bee model systems has established that this variation both modulates performance and guides floral choice. Yet, how variation in pollen chemistry shapes interactions between plants and bees in natural communities is an open question, essential for both understanding the nutritional dynamics of plant-pollinator mutualisms and informing their conservation. To fill this gap, we asked how pollen nutrition (relative protein and lipid content) sampled from 109 co-flowering plant species structured visitation patterns observed among 75 subgenera of pollen-collecting bees in the Great Basin/Eastern Sierra region (USA). We found that the degree of similarity in co-flowering plant species' pollen nutrition predicted similarity among their visitor communities, even after accounting for floral morphology and phylogeny. Consideration of pollen nutrition also shed light on the structure of this interaction network: Bee subgenera and plant genera were arranged into distinct, interconnected groups, delineated by differences in pollen macronutrient values, revealing potential nutritional niches. Importantly, variation in pollen nutrition alone (high in protein, high in lipid, or balanced) did not predict the diversity of bee visitors, indicating that plant species offering complementary pollen nutrition may be equally valuable in supporting bee diversity. Nutritional diversity should thus be a key consideration when selecting plants for habitat restoration, and a nutritionally explicit perspective is needed when considering reward systems involved in the community ecology of pollination. [ABSTRACT FROM AUTHOR]

Aim: Stochastic and deterministic (biotic factors such as intraspecies competition or abiotic factors) processes affect the spatial patterns of ecological communities. These processes can be quantitatively assessed based on spatial autocorrelation (SAC) parameters. However, the global patterns of SAC and their differences across vegetation types remain unknown. We aimed to (1) quantitatively assess the SAC global pattern in plant communities and their variation from 1990 to 2020 and (2) identify the key drivers of SAC in plant communities in protected areas (PAs). Location: Global. Time Period: 1990–2020. Major Taxa Studied: Terrestrial plants. Methods: Using normalized difference vegetation index data extracted from remote sensing datasets, we calculated the SAC parameters, including the Nugget, Partial Sill (PSill), and Sill, in 147 samples from 49 PAs in 1990, 2000, 2010, and 2020. The random forest model was employed to identify the drivers among 10 annual and 120 monthly climatic variables. Results: The SAC patterns of plant communities in global PAs differed across vegetation types. It reached the highest in grasslands and evergreen needleleaved forests, mainly explained by annual energy metrics, and the lowest in tropical evergreen rain forests around equator and boreal coniferous forests near the Arctic Circle. From 1990 to 2020, the Nugget, PSill, and Sill decreased by 92.36%, 58.36%, and 60.61%, respectively, indicating biological homogeneity. Monthly climatic variables explain SAC variations better than annual ones. Main Conclusions: From 1990 to 2020, the SAC parameters decreased sharply across vegetation types, indicating an obvious biologically homogenous trend that was mainly driven by monthly climatic variation, vary across sites and vegetation types. Our results highlight the need to assess the SAC in different vegetation types separately to understand the shifts of global plant communities under climate change. [ABSTRACT FROM AUTHOR]

Summary: Controlled experiments at the level of individual plants show that legume species use different strategies for the regulation of symbiotic dinitrogen fixation in response to nitrogen availability. These strategies were suggested to improve legume fitness in the context of the plant community, although rarely studied at this level. We evaluated how nitrogen availability and conspecific vs heterospecific interactions influenced the strategy of regulation of nitrogen fixation.We grew two species of herbaceous legumes representing two different strategies of regulation without interaction, under treatments of deficient and sufficient nitrogen availability, with conspecific or heterospecific interaction.We found that Hymenocarpus circinnatus maintained a facultative strategy of downregulating nitrogen fixation when nitrogen was available under both con‐ and heterospecific interactions, as was also found for this species when grown alone. Vicia palaestina also downregulated nitrogen fixation under both con‐ and heterospecific interactions but did not regulate fixation when grown alone. Our results showed that under nitrogen limitation, interaction with a neighboring plant reduced fitness, reflecting a competitive effect.Our findings suggest that when interacting with other plants, downregulation of nitrogen fixation is more likely, therefore reducing the energetic cost of fixation, and improving plant performance in competitive ecological communities, especially when nitrogen is available. [ABSTRACT FROM AUTHOR]

In riverine ecosystems, human‐induced stressors related to flow regulation and bank stabilisation have accumulated over time. The restoration of these highly anthropised ecosystems has become a major issue over the last few decades, with ambitious stated objectives. However, while the individual impact of flow regulation and channelisation on river functioning has been extensively studied, the response of ecological communities to multiple co‐occurring human‐induced stressors remains largely unexplored.Using a sampling design based on five river reaches in the Rhône catchment, ranging from unregulated in flow and bedload transport to intensively regulated reaches, we sought to understand how the accumulation of anthropogenic stressors influenced the functional response of riparian plants communities on gravel bars. By using 12 ecological and morphological traits, we performed a classification analysis to construct six riparian guilds and investigated whether their representativeness, as well as the mean value of individual traits, varied with increasing levels of anthropogenic stressors.Species cover and redundancy in several guilds increased or decreased significantly with increasing pressures. Thus, the guild of small taproot herbs with low nutrient and soil moisture requirements (xero‐oligotro‐taproot species guild) and the guild of taproot herbs adapted to very bright and dry conditions (mesoxero‐mesotro‐taproot species guild) dominated the unregulated reaches with active bedload transport. Conversely, regulated reaches with stabilised baseflow and inactive transport were dominated by the guild of flood‐tolerant trees (hygro‐perennial tall species guild) and the guild of vegetatively reproducing and flood‐tolerant perennial herbs (hygro‐perennial clonal species guild).Analysis of individual traits revealed a shift in environmental conditions, from full light to shade tolerance and from dry to humid, with increasing anthropogenic stressors. In response to this decrease in drought levels, plants traits shifted from annual to perennial species, from sexual to vegetative strategies and from taproots to a fibrous root system.Our results highlight the accumulated effects that anthropogenic stressors can have on riparian communities, inducing a progressive shift in certain traits related to life history, reproductive strategies, and drought adaptations. This effect on a set of shared traits reveals the strong influence that human infrastructures can have on the ecological niche of species and the morphological adaptations of riparian vegetation.From an applied point of view, and for highly anthropised rivers, our results suggest that restoration actions targeting a single stressor will not be sufficient to reorient riparian plant communities towards an ecological state closer to reference systems. Since human‐induced stressors have often deeply altered the flow and sediment regimes of rivers, a more integrated approach based on the restoration of erosion and flooding processes is essential to allow the expression of a wider diversity of riparian plant communities and habitats. [ABSTRACT FROM AUTHOR]

Aims: The influence of priority effects on plant community succession is increasingly discussed in community ecology. However, most grassland restoration approaches involving seed addition transfer all target species at the same time. Our objective was to tackle the question: does the order of arrival influence the establishment of restored communities? Location: La‐Bâtie‐Neuve, Southern Alps, France. Methods: We applied sequential sowing using two groups, one set of dominant species and one set of subordinate species, each comprising three different perennial plant species. We tested four sowing treatments: control (without any sowing), two sequential sowing treatments (dominants first or subordinates first) and synchronous sowing. We analysed plant cover each year for three years after sowing and calculated priority and earliness indices (the third year) for each group and each sown species. Results: Manipulating the order of arrival shaped community composition and trajectories. Some species of both groups were positively affected by being sown first compared to being sown synchronously. However, dominant and subordinate groups differed in their earliness index, showing a significant benefit for subordinates to be sown first. The subordinate species Onobrychis viciifolia and Plantago lanceolata established only when they were sown first, while Festuca cinerea showed greater establishment when sown first and simultaneously, compared to late sowing. The dominant Anthyllis vulneraria was not affected by date or type of sowing. However, the cover of the most dominant Bromopsis erecta was lower when being sown second, allowing a control of its dominance by delayed sowing. Conclusion: The strength of priority effects differs between species, which may depend on niche characteristics or microenvironment, influencing (negatively or positively) the establishment of late‐arriving species and affecting their competitive abilities. Our study provides evidence that plant community assembly was influenced by the order of arrival, but demonstrated a strong species‐specific response to priority effects. [ABSTRACT FROM AUTHOR]

Phenological segregation among species in a community is assumed to promote coexistence, as using resources at different times reduces competition. However, other unexplored nonalternative mechanisms can also result in a similar outcome. This study first tests whether plants can redistribute nitrogen (N) among them based on their nutritional temporal demand (i.e. phenology). Field 15N labelling experiments showed that 15N is transferred between neighbour plants, mainly from low N‐demand (late flowering species, not reproducing yet) to high N‐demand plants (early flowering species, currently flowering‐fruiting). This can reduce species' dependence on pulses of water availability, and avoid soil N loss through leaching, having relevant implications in the structuring of plant communities and ecosystem functioning. Considering that species phenological segregation is a pervasive pattern in plant communities, this can be a so far unnoticed, but widely spread, ecological process that can predict N fluxes among species in natural communities, and therefore impact our current understanding of community ecology and ecosystem functioning. [ABSTRACT FROM AUTHOR]

Assessments of species diversity and richness are essential to understand present ecological and biodiversity conditions for effective conservation management strategies. Biodiversity indicators determine rangeland health and response to grazing, fire regimes and climate change. This research examined species richness, diversity and composition in a protected mountainous grassland. Two data sets, both collected from a 30 × 30 m plot, with similar species composition and cover were combined. One data set was collected using a 100‐step point survey and the other from a series of 16 plots. A single‐factor analysis of variance was used to test if the mean species richness and diversity of the sites differed across the study area. Species accumulation curves were used to determine the relationship between species richness and the number of sampling units per site. The results from fitting a species–area equation showed that the estimated maximum species richness was slightly greater than the observed species pool in all sites, meaning that the sampling units were not adequate (albeit by small margins) to capture all vascular plant species in the sites. Diversity metrics could, thus, be used to monitor species change within grassland plant communities. [ABSTRACT FROM AUTHOR]

Plant diversity drives the trophic ecology of arthropod communities, and is the focus of thousands of studies and a growing field of meta-analysis. Although syntheses of plant diversity studies have yielded valuable insights, their sheer number and complexity limits broader interpretation. Here we scrutinize 23 syntheses published over three decades to identify common themes and contrasting results. We find that plant diversity consistently attracts more abundant and diverse communities of predators. Herbivore diversity tends to increase in response to plant diversity treatments, while herbivore abundance and plant damage generally decrease. Yet, these net effects often mask nuanced responses to plant diversity that depend on ecosystem, scale, and specialization. For instance, specialist herbivores often respond negatively to plant diversity, while generalists more often mount positive or neutral responses. Studies conducted at greater spatial scales show a dilution of effects on herbivores, but reveal conflicting effects on predators. Despite complexity in outcomes, syntheses show that diversifying plant communities holds great promise for enhancing the resilience of managed ecosystems. A closer examination of how insect diet breadth, spatial scale, and plant arrangement interactively determine the strength of trophic cascades will improve reliability and precision in how we leverage biodiversity for conservation and biocontrol. [ABSTRACT FROM AUTHOR]

Soil microbes can profoundly affect species coexistence and alien plant invasion via plant–soil feedbacks (PSFs). Theoretically, plants can modify soil biotic communities (e.g. fungal and bacterial communities) sequentially via rhizo‐inputs in the growing season and via litter decomposition in the non‐growing season, and in this way affect the performance of plant individuals that establish in the same soil in the following growing season. However, how plants affect soil microbes via sequential rhizosphere and litter inputs and how these soil microbial legacies feedback to subsequent plants remains unclear.Here, we first explored the sequential effects of living individuals and their leaf litter on soil fungal communities, using 42 common alien and native species in China, and then estimated their PSF effects on three common test species.Our results show that living plants growing in field soil developed distinct rhizosphere fungal communities within one season. After the removal of conditioning plants, the fungal communities in these conditioned soils changed more dramatically in the absence than in the presence of leaf litter, suggesting that leaf litter inputs prolonged the species‐specific legacies that conspecific living individuals exerted in the soil. Moreover, leaf litter induced general negative effects on all test species in the second growing season. Conditioning plant origin (native vs. alien) and life cycle (annual vs. perennial), respectively, had a slight or no impact on fungal community composition, and conditioning plant origin did not affect PSF responses of the test species.Synthesis: These findings show that leaf litter prolongs soil fungal legacies of conspecific living individuals, which can lead to carryover effects on heterospecific plant growth in the next season. Our findings highlight the importance of leaf litter for plant–soil interactions and thereby stress the potential importance of plant litter as a driver of plant community dynamics. [ABSTRACT FROM AUTHOR]

This paper specifies the invasibility of common plant community types in the natural habitats of the Middle Urals. Invasibility was defined as the vulnerability of a community to alien plant species invasions, regardless of the conditions in which the community existed. We analyzed 749 vegetation relevés made in natural bogs, floodplains, rocky grasslands, meadows, and forest communities. We surveyed urban and non-urban habitats (30–40 km from the city). Invasibility was calculated in two different ways based on two parameters: the number and proportion of alien species in the relevé. These invasibility parameters are widely applicable and comparable, scale-independent, measurable, and reliable, based on data that do not require the destruction of ecosystems or biota and are based on available data. Based on the invasibility degree, we identified three community-type groups with two subgroups in one group. In ascending order of invasibility degree, the community types were arranged as follows: (1) bogs with and without trees; (2a) coniferous forests; grass communities in floodplains; (2b) deciduous forests, coniferous plantations, floodplain communities with woody plants; and (3) dry meadows and rocky grasslands. Obtained results of the assessment of different plant community invasibility may be used to understand patterns of alien plant distribution in local habitats and the reasons for the different vulnerability of communities to plant invasions. [ABSTRACT FROM AUTHOR]

Fire plays a key role in structuring biotic communities around the world. In fire-prone regions, many plant species have acquired adaptive traits such as obligate seeders and resprouters that help them to survive, reproduce, and persist after fire disturbances. Seeder and resprouting species have different short-term responses to fire. Obligate seeders have faster growth rates, greater carbon allocation to reproduction, shorter life cycles, and lower shade tolerance than resprouters. A few years after fire, obligate seeders are expected to be more abundant than resprouter species within post-fire plant communities. We examined this hypothesis in burned pine plantations located along the African rim of the Western Mediterranean Basin. In this region, pine plantation is the commonest forestry practice, and such woodlands have undergone frequent fires during the last decades. Here, we describe habitat structure and plant species composition in burned and unburned plots located in four independently burned sites. Burned and unburned plots were structurally different, with the shrub and grass covers expanding after fire. In terms of functional plant composition, obligate seeders were more abundant than resprouters in burned pine plantations. The stronger short-term response of obligate seeders compared to resprouters can be related to the faster capacity of obligate seeders to respond to fire. Contrast in fire response between the two functional plant groups needs to be addressed in conservation planning to ensure the preservation of biodiversity in a future scenario of change in fire regime. [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]

Globally, subalpine and alpine plant communities are receiving increasing attention owing to disproportionately rapid warming at high altitudes, and the resultant habitat shrinkage leaving high-altitude specialists with nowhere to migrate. The Hawaiian subalpine zone (1,700–3,000 m) is an interesting example of this potential phenomenon because of the high endemism. We analyzed plant species richness, cover, and density from 89 plots (1,000 m2) sampled in 2010–2018 across two volcanic mountains, Haleakalā on Maui, and Mauna Loa on Hawai'i. Most of the 139 plant species recorded were non-native (55%), with the remainder endemic (31%) and indigenous (14%). Plot-level richness differed from gamma diversity, with endemic species more abundant than non-native species. Non-native species richness was higher on Haleakalā than Mauna Loa. These communities are patchy with low-lying (<1 m) vegetation, and lower cover on younger drier Mauna Loa (36%) than Haleakalā (54%). Density was largely consistent with the understory cover data, with endemic Vaccinium reticulatum (>3,500/ha) and indigenous Leptecophylla tameiameiae (>2,430/ha) shrubs dominant on both volcanoes. Woodland communities were encountered only on Mauna Loa, with endemic trees Metrosideros polymorpha on wetter, south aspects, and Sophora chrysophylla on the drier, leeward side. Hawaiian subalpine vegetation varies among islands, volcanoes, and aspects, yet remains largely native-dominated, though with increasing threats from climate change, invasive non-native species, and wildfire. We recommend continued monitoring of biotic communities and climate in this sensitive zone, in situ physiological studies for the native matrix species, stricter non-native species biosecurity and sanitation protocols, wildfire prevention, and improved documentation of the effects of feral ungulates. [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]

Understanding how biotic interactions and environmental filtering mediated by soil properties shape plant community assembly is a major challenge in ecology, especially when studying complex and hyperdiverse ecosystems like tropical forests. To shed light on the influence of both factors, we examined how the edaphic optimum of species (their niche position) related to their edaphic range (their niche breadth) along different environmental gradients and how this translates into functional strategies. Here we tested four scenarios describing the shape of the niche breadth—niche position relationship, including one neutral scenario and three scenarios proposing different relative influences of abiotic and biotic factors on community assembly along a soil resource gradient. To do so, we used soil concentration data for five key nutrients (N, P, Ca, Mg, and K), along with accurate measurements of 14 leaf, stem, and root traits for 246 tree species inventoried in 101 plots located across Eastern (French Guiana) and Western (Peru) Amazonia. We found that species niche breadth increased linearly with species niche position along each soil nutrient gradient. This increase was associated with more resource acquisitive traits in the leaves and the roots for soil N, Ca, Mg, and K concentration, while it was negatively associated with wood density for soil P concentration. These observations agreed with one of our hypothetical scenarios in which species with resource conservation traits are confined to the most nutrient‐depleted soils (abiotic filter), but they are outperformed by faster‐growing species in more fertile conditions (biotic filter). Our results refine and strengthen support for niche theories of species assembly while providing an integrated approach to improving forest management policies. [ABSTRACT FROM AUTHOR]

The general shape (from linear to complex curve), direction (negative and positive) and strength (steepness of the slope) of abundance–impact relationships for different impact metrics are poorly known, despite their importance in understanding and predicting ecological repercussions of invasive species. It is also an open question how the functional traits of invasive species may influence the abundance–impact relationship.We studied 11 widespread herbaceous invasive alien species of East‐Central Europe and their 16 impact metrics (resident plant communities' ecological characteristics, trait composition, functional diversity and soil parameters) by sampling invaded and similar, uninvaded sites (space‐for‐time substitution method). Our aim was to (1) investigate the detailed ecological impacts of invasive plants on native plant communities; (2) explore the type of cover–impact relationships across impact metrics and their consistency across species and (3) study whether the cover–impact relationship depends on functional traits of invasive species.When considering all invasive species together, we found that invaded plant communities were less species rich and less functionally even but showed higher values of Rao's Q diversity index, and higher nitrogen, phosphorus and organic carbon soil nutrient content compared to uninvaded communities. However, the species‐wise analyses revealed strikingly different impacts among the 11 invasive species and also among impact metrics.Regarding the type of cover–impact relationships, we found no consistencies across invasive species and impact metrics. Still, nonlinear relationships prevailed when species were analysed together and linear relationships when species were studied individually. The functional traits of the invasive species explained only a small part of this response heterogeneity; mostly, the small‐seeded perennial invasive species affected the cover–species richness relationship.Synthesis: Herbaceous invasive plant species have a cover‐dependent impact on resident plant communities, but there are no consistent patterns across impact metrics and invasive species. Specific traits or trait syndrome of invasive species may affect the heterogeneity of cover–impact relationships, but that would need further study. We highlighted the importance of impact assessments involving invasive species' abundance to unmask cryptic impacts for species that show contrasting effects along an abundance gradient. [ABSTRACT FROM AUTHOR]

This paper presents the main directions and range of man-made changes to the vascular flora and their effects at the vegetation level. The native flora of Poland, located in the temperate zone of Central Europe, comprises approximately 2639 species. The effect of human pressure, which began in the Neolithic and has intensified in the last 200 years, has caused changes in the native flora and has included an inflow of 975 alien species, 560 of which have become permanently established. Currently, at least 704 native species are recognized as endangered, and only 623 are recognized as being able to occupy habitats that were created or strongly transformed by humans. Native species (apophytes) and aliens (anthropophytes) have co-created completely new plant communities in these habitats. Among the alien plants, neophytes (399 species) outnumber archaeophytes (161 species). Additionally, many neophytes (123 species) can penetrate seminatural and natural communities. Research has shown that the proportions of apophytes, alien plants, and declining species can be used to clearly differentiate plant communities and be used as an indicator of anthropogenic changes. A comparison of the man-made changes in Polish flora and vegetation in other countries showed that the changes in Poland are part of the global process of environmental degradation and are aggravated by the country's economic development. [ABSTRACT FROM AUTHOR]

Applications of ecological theory to natural communities often assume that competitive, negative density‐dependent processes are the only type of interaction important for diversity maintenance. Recent advances suggest that positive interactions within trophic levels (e.g., plant–plant) may also affect plant coexistence. Though positive plant–plant interactions theoretically might result in positive or nonmonotonic frequency or density dependence (FD/DD), less is known about how commonly these patterns occur or which ecological processes might result in such patterns in natural plant communities. In this study we tested for signals of variable frequency and density dependence in annual flowering plant communities in Western Australia and searched for evidence that interactions among plants during flowering might induce positive or nonmonotonic FD/DD in flowering plants. Using four common annual wildflower species, we ask if plant fecundity exhibited positive or nonmonotonic FD/DD and if pollinator‐mediated plant–plant interactions during flowering change patterns of FD/DD relative to pollinator‐independent plant interactions. Three species exhibited nonmonotonic (hump‐shaped) density dependence, and only one species experienced strictly negative density dependence. Each species exhibited a different pattern of frequency dependence (positive, negative, weakly nonmonotonic, and no detectable frequency dependence). Pollinator‐mediated plant–plant interactions during flowering induced both nonmonotonic density dependence and negative frequency dependence in one species. Importantly, the extent of variation in FD/DD observed in our study brings into question the dominance of negative density and frequency dependence in theory, suggesting instead that demographic responses of plants to their communities fall along a continuum of possible density‐ and frequency‐dependent patterns. [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]

Questions: Our study focused on spontaneous vegetation in urban greenspaces in a Mediterranean city with the aim of relating plant community properties with ecological services along soil disturbance gradients. We asked which plant communities have the greatest plant biodiversity and soil carbon storage and the best‐performing nutrient cycles and water regulation. Location: Madrid City (Central Spain). Methods: We studied four types of plant communities following soil disturbance gradients: vegetation on trampled soils, roadside vegetation, annual grasslands and perennial forbs. Regarding vegetation, we studied plant composition and productivity, plant diversity, plant growth forms and functional groups. Regarding soils, we determined soil organic carbon (TOC), available nutrients, the activity of seven enzymes relating to the main macronutrient cycles, and physical properties such as bulk density (BD) and soil water‐holding capacity (WHC). We used one‐way ANOVA to determine the influence of the plant community type on both soil and vegetation variables. Canonical correspondence analysis was performed to interpret the relationships between plant species assemblages with environmental gradients. Results: Perennial forbs showed greater biomass and developed on soils with the greatest TOC and available phosphorus. Annual grasslands displayed the highest plant diversity. Roadside vegetation developed on soils with higher phenoloxidase activity when compared to vegetation on trampled soils and annual grasslands. Vegetation on trampled soils developed on soils with lower WHC, lower beta‐glucosidase, arylamidase and phosphatase activities and higher BD when compared to perennial forbs. Plant community distribution followed gradients most significantly associated with soil organic matter content, soil compaction and nutrient cycling performance. Conclusions: We conclude that plant communities are good indicators of ecosystem function and services which are unevenly distributed throughout urban habitats. The management in Mediterranean unmaintained urban greenspaces should be aimed at avoiding soil compaction to promote biodiversity, carbon storage and water regulation. [ABSTRACT FROM AUTHOR]

Climate change predictions indicate that summer droughts will become more severe and frequent. Yet, the impact of soil communities on the response of plant communities to drought remains unclear. Here, we report the results of a novel field experiment, in which we manipulated soil communities by adding soil inocula originating from different successional stages of coastal dune ecosystems to a plant community established from seeds on bare dune sand. We tested if and how the added soil biota from later-successional ecosystems influenced the sensitivity (resistance and recovery) of plant communities to drought. In contrast to our expectations, soil biota from later-successional soil inocula did not improve the resistance and recovery of plant communities subjected to drought. Instead, inoculation with soil biota from later successional stages reduced the post-drought recovery of plant communities, suggesting that competition for limited nutrients between plant community and soil biota may exacerbate the post-drought recovery of plant communities. Moreover, soil pathogens present in later-successional soil inocula may have impeded plant growth after drought. Soil inocula had differential impacts on the drought sensitivity of specific plant functional groups and individual species. However, the sensitivity of individual species and functional groups to drought was idiosyncratic and did not explain the overall composition of the plant community. Based on the field experimental evidence, our results highlight the adverse role soil biota can play on plant community responses to environmental stresses. These outcomes indicate that impacts of soil biota on the stability of plant communities subjected to drought are highly context-dependent and suggest that in some cases the soil biota activity can even destabilize plant community biomass responses to drought. [ABSTRACT FROM AUTHOR]

Plasmids drive bacterial evolutionary innovation by transferring ecologically important functions between lineages, but acquiring a plasmid often comes at a fitness cost to the host cell. Compensatory mutations, which ameliorate the cost of plasmid carriage, promote plasmid maintenance in simplified laboratory media across diverse plasmid–host associations. Whether such compensatory evolution can occur in more complex communities inhabiting natural environmental niches where evolutionary paths may be more constrained is, however, unclear. Here, we show a substantial fitness cost of carrying the large conjugative plasmid pQBR103 in Pseudomonas fluorescens SBW25 in the plant rhizosphere. This plasmid fitness cost could be ameliorated by compensatory mutations affecting the chromosomal global regulatory system gacA/gacS , which arose rapidly in plant rhizosphere communities and were exclusive to plasmid carriers. These findings expand our understanding of the importance of compensatory evolution in plasmid dynamics beyond simplified lab media. Compensatory mutations contribute to plasmid survival in bacterial populations living within complex microbial communities in their environmental niche. [ABSTRACT FROM AUTHOR]

Many degraded ecosystems need active restoration to conserve biodiversity and re‐establish ecosystem function, both highlighted targets of the UN Decade on Ecosystem Restoration and the proposed EU Nature restoration law. Soil translocation, where both plant propagules and their associated soil biota are co‐introduced, has increasingly been proposed as a powerful restoration technique for terrestrial ecosystems. However, a synthesis of the effectiveness of this method across ecosystems is lacking.To address how soil translocation affects restoration success, we performed a meta‐analysis synthesizing data from 46 field experiments and their respective reference ecosystems in 17 countries across four continents. In each experiment, vegetation composition was recorded in response to soil translocation treatments and the resultant vegetational changes (diversity and composition) were quantified.We found that soil translocation leads to plant community development further away from the control and more towards the reference plant communities compared with treatments where only plant propagules were introduced. However, the variability of effect sizes among experiments was large, suggesting strong dependence of restoration success on restoration context. We found that restoration success was more likely on loamy soils and when translocation treatments were implemented over larger spatial areas (>180 m2).Furthermore, we found that restoration success either consistently increased or decreased over time depending on the experiment. Not only is this congruent with positive feedbacks between plant and soil communities driving plant community development, but it also suggests that the composition of the translocated plant and soil communities, and initial starting conditions, are critical for long‐term restoration success.Synthesis and applications. Our analysis highlights soil translocation can be a successful restoration method across a broad range of ecosystems. However, its implementation needs to depend on a thorough evaluation of local conditions and the potential added value. Further refinement of soil translocation techniques is needed to increase success rates. [ABSTRACT FROM AUTHOR]

Background: Soil microorganisms are in constant interaction with plants, and these interactions shape the composition of soil bacterial communities by modifying their environment. However, little is known about the relationship between microorganisms and native plants present in extreme environments that are not affected by human intervention. Using high-throughput sequencing in combination with random forest and co-occurrence network analyses, we compared soil bacterial communities inhabiting the rhizosphere surrounding soil (RSS) and the corresponding bulk soil (BS) of 21 native plant species organized into three vegetation belts along the altitudinal gradient (2400–4500 m a.s.l.) of the Talabre–Lejía transect (TLT) in the slopes of the Andes in the Atacama Desert. We assessed how each plant community influenced the taxa, potential functions, and ecological interactions of the soil bacterial communities in this extreme natural ecosystem. We tested the ability of the stress gradient hypothesis, which predicts that positive species interactions become increasingly important as stressful conditions increase, to explain the interactions among members of TLT soil microbial communities. Results: Our comparison of RSS and BS compartments along the TLT provided evidence of plant-specific microbial community composition in the RSS and showed that bacterial communities modify their ecological interactions, in particular, their positive:negative connection ratios in the presence of plant roots at each vegetation belt. We also identified the taxa driving the transition of the BS to the RSS, which appear to be indicators of key host-microbial relationships in the rhizosphere of plants in response to different abiotic conditions. Finally, the potential functions of the bacterial communities also diverge between the BS and the RSS compartments, particularly in the extreme and harshest belts of the TLT. Conclusions: In this study, we identified taxa of bacterial communities that establish species-specific relationships with native plants and showed that over a gradient of changing abiotic conditions, these relationships may also be plant community specific. These findings also reveal that the interactions among members of the soil microbial communities do not support the stress gradient hypothesis. However, through the RSS compartment, each plant community appears to moderate the abiotic stress gradient and increase the efficiency of the soil microbial community, suggesting that positive interactions may be context dependent. [ABSTRACT FROM AUTHOR]

Deserts are stressful environments where the living beings must acquire different strategies to survive due to the water stress conditions. From the late Albian to the early Cenomanian, the northern and eastern parts of Iberia were the location of the desert system represented by deposits assigned to the Utrillas Group, which bear abundant amber with numerous bioinclusions, including diverse arthropods and vertebrate remains. In the Maestrazgo Basin (E Spain), the late Albian to early Cenomanian sedimentary succession represents the most distal part of the desert system (fore-erg) that was characterised by an alternation of aeolian and shallow marine sedimentary environments in the proximity of the Western Tethys palaeo-coast, with rare to frequent dinoflagellate cysts. The terrestrial ecosystems from this area were biodiverse, and comprised plant communities whose fossils are associated with sedimentological indicators of aridity. The palynoflora dominated by wind-transported conifer pollen is interpreted to reflect various types of xerophytic woodlands from the hinterlands and the coastal settings. Therefore, fern and angiosperm communities abundantly grew in wet interdunes and coastal wetlands (temporary to semi-permanent freshwater/salt marshes and water bodies). In addition, the occurrence of low-diversity megafloral assemblages reflects the existence of coastal salt-influenced settings. The palaeobotanical study carried out in this paper which is an integrative work on palynology and palaeobotany, does not only allow the reconstruction of the vegetation that developed in the mid-Cretaceous fore-erg from the eastern Iberia, in addition, provides new biostratigraphic and palaeogeographic data considering the context of angiosperm radiation as well as the biota inferred in the amber-bearing outcrops of San Just, Arroyo de la Pascueta and La Hoya (within Cortes de Arenoso succesion). Importantly, the studied assemblages include Afropollis, Dichastopollenites, Cretacaeiporites together with pollen produced by Ephedraceae (known for its tolerance to arid conditions). The presence of these pollen grains, typical for northern Gondwana, associates the Iberian ecosystems with those characterising the mentioned region. [ABSTRACT FROM AUTHOR]

The problem of positioning wireless sensor networks is an important and challenging topic in all walks of life. Inspired by the evolution behavior of natural plant communities and traditional positioning algorithms, a novel positioning algorithm based on the behavior of artificial plant communities is designed and presented here. First, a mathematical model of the artificial plant community is established. Artificial plant communities survive in habitable places rich in water and nutrients, offering the best feasible solution to the problem of positioning a wireless sensor network; otherwise, they leave the non-habitable area, abandoning the feasible solution with poor fitness. Second, an artificial plant community algorithm is presented to solve the positioning problems encountered in a wireless sensor network. The artificial plant community algorithm includes three basic operations, namely seeding, growing, and fruiting. Unlike traditional artificial intelligence algorithms, which always have a fixed population size and only one fitness comparison per iteration, the artificial plant community algorithm has a variable population size and three fitness comparisons per iteration. After seeding by an original population size, the population size decreases during growth, as only the individuals with high fitness can survive, while the individuals with low fitness die. In fruiting, the population size recovers, and the individuals with higher fitness can learn from each other and produce more fruits. The optimal solution in each iterative computing process can be preserved as a parthenogenesis fruit for the next seeding operation. When seeding again, the fruits with high fitness can survive and be seeded, while the fruits with low fitness die, and a small number of new seeds are generated through random seeding. Through the continuous cycle of these three basic operations, the artificial plant community can use a fitness function to obtain accurate solutions to positioning problems in limited time. Third, experiments are conducted using different random networks, and the results verify that the proposed positioning algorithms can obtain good positioning accuracy with a small amount of computation, which is suitable for wireless sensor nodes with limited computing resources. Finally, the full text is summarized, and the technical deficiencies and future research directions are presented. [ABSTRACT FROM AUTHOR]

Earth systems are nearing a global tipping point, beyond which the dynamics of biological communities will become unstable. One major driver of instability is species invasion, especially by organisms that act as "ecosystem engineers" through their modification of abiotic and biotic factors. To understand how native organisms respond to modified habitat, it is essential to examine biological communities within invaded and non‐invaded habitat, identifying compositional shifts in native and non‐native taxa as well as measuring how modification by ecosystem engineers has affected interactions among community members. Using dietary metabarcoding, our study examines the response of a native Hawaiian generalist predator (Araneae: Pagiopalus spp.) to habitat modification by comparing biotic interactions across metapopulations of spiders collected in native forest and sites invaded by kāhili ginger. Our study shows that, although there are shared components of the dietary community, spiders in invaded habitat are eating a less consistent and more diverse diet consisting of more non‐native arthropods which are rarely or entirely undetected in spiders collected from native forest. Additionally, the frequency of novel interactions with parasites was significantly higher in invaded sites, reflected by the frequency and diversity of non‐native Hymenoptera parasites and entomopathogenic fungi. The study highlights the role of habitat modification driven by an invasive plant in altering community structure and biotic interactions, threatening the stability of the ecosystem through significant changes to the biotic community. [ABSTRACT FROM AUTHOR]

Field margins are major habitats for biodiversity conservation and ecosystem functioning in agricultural landscapes, but biotic homogenization of plant communities threatens their ecological and agronomic functions. Our objective is to determine the drivers of plant diversity in field margins for conservation and restoration purposes. To do so, we assessed the effects of field margin structure and long-term management over 20 years (1995–2015) on the taxonomic and functional α- and β-diversity, and the functional composition of herbaceous plant communities. In 2015, we surveyed 302 field margins in bocage landscapes of Brittany, northwestern France. Results were very similar between taxonomic and functional diversity but revealed important discrepancies between the drivers of α- and β-diversity. Deep ditches, mowing and grazing increased α-diversity but did not affect β-diversity. Denser hedgerows had lower α-diversity than other field margins but strongly contributed to β-diversity by harbouring more unique sets of species or life strategies. Long-term herbicide spraying in field margins and cropping intensity in adjacent habitats did not affect α-diversity, but had more complex effects on β-diversity and selected for common weeds. All in all, preservation of dense hedgerows, abandonment of herbicide spraying, and protection against agrochemical drifts are key measures to prevent the establishment of common weeds and biotic homogenization of herbaceous plant communities in field margins. Above all, our study shows how important it is to go beyond α-diversity to make robust conservation and restoration decisions. [ABSTRACT FROM AUTHOR]

Plant recruitment interactions (i.e., what recruits under what) shape the composition, diversity, and structure of plant communities. Despite the huge body of knowledge on the mechanisms underlying recruitment interactions among species, we still know little about the structure of the recruitment networks emerging in ecological communities. Modeling and analyzing the community‐level structure of plant recruitment interactions as a complex network can provide relevant information on ecological and evolutionary processes acting both at the species and ecosystem levels. We report a data set containing 143 plant recruitment networks in 23 countries across five continents, including temperate and tropical ecosystems. Each network identifies the species under which another species recruits. All networks report the number of recruits (i.e., individuals) per species. The data set includes >850,000 recruiting individuals involved in 118,411 paired interactions among 3318 vascular plant species across the globe. The cover of canopy species and open ground is also provided. Three sampling protocols were used: (1) The Recruitment Network (RN) protocol (106 networks) focuses on interactions among established plants ("canopy species") and plants in their early stages of recruitment ("recruit species"). A series of plots was delimited within a locality, and all the individuals recruiting and their canopy species were identified; (2) The paired Canopy‐Open (pCO) protocol (26 networks) consists in locating a potential canopy plant and identifying recruiting individuals under the canopy and in a nearby open space of the same area; (3) The Georeferenced plot (GP) protocol (11 networks) consists in using information from georeferenced individual plants in large plots to infer canopy‐recruit interactions. Some networks incorporate data for both herbs and woody species, whereas others focus exclusively on woody species. The location of each study site, geographical coordinates, country, locality, responsible author, sampling dates, sampling method, and life habits of both canopy and recruit species are provided. This database will allow researchers to test ecological, biogeographical, and evolutionary hypotheses related to plant recruitment interactions. There are no copyright restrictions on the data set; please cite this data paper when using these data in publications. [ABSTRACT FROM AUTHOR]

Ecological restoration is one of the most promising strategies to combat historical wetland losses caused by land use changes. Restored areas are ideal sites to study plant succession and changes in ecosystem functions over time. However, little is known about the influence of restoration on plant succession along environmental stress gradients. Knowing the processes and mechanisms driving the succession over time in contrasting abiotic conditions might provide new insight into the ultimate success of an ecological restoration.Relying on long‐term vegetation monitoring, we studied the community succession of 4 plant communities along a restored waterlogging gradient in North‐East Italy (from high to low soil saturation level): (i) Cladium fens, (ii) low alkaline fens, (iii) Molina wet meadows and (iv) dry meadows. We monitored 23 permanent plots distributed along the gradient, spanning from 1 to 21 years since restoration, and 4 plots as target vegetation (natural habitats). We analysed the changes in plant communities in terms of functional traits, diversity and species composition.We found that exotic and annual species decreased in mature stages of restoration while leaf dry matter content increased over time. Nutrient indicator value and leaf area showed opposite trends at the extreme points of the gradient. Across the successional stages, species richness decreased in Cladium fens and increased in alkaline fens and meadows. Species composition moved toward target vegetation showing contrasting dynamics between different restored habitats.Synthesis and applications. During succession waterlogging stress acts as main abiotic filter, triggering contrasting trajectories of plant communities. This filter seems to be stronger at the extreme points of the gradient generating opposite but faster dynamics than at intermediate conditions. Time and waterlogging promoted a continuous selection of species consistent to target vegetation in terms of richness, functional traits and composition. The evidenced trajectories suggest the need to develop habitat‐specific protocols concerning the selection of restoration site and subsequent management decisions, with particular regard to plant communities at intermediate ecological conditions. [ABSTRACT FROM AUTHOR]

Background and Aims When plant communities are exposed to herbicide 'drift', wherein particles containing the active ingredient travel off-target, interspecific variation in resistance or tolerance may scale up to affect community dynamics. In turn, these alterations could threaten the diversity and stability of agro-ecosystems. We investigated the effects of herbicide drift on the growth and reproduction of 25 wild plant species to make predictions about the consequences of drift exposure on plant–plant interactions and the broader ecological community. Methods We exposed potted plants from species that commonly occur in agricultural areas to a drift-level dose of the widely used herbicide dicamba or a control solution in the glasshouse. We evaluated species-level variation in resistance and tolerance for vegetative and floral traits. We assessed community-level impacts of drift by comparing the species evenness and flowering networks of glasshouse synthetic communities comprised of drift-exposed and control plants. Key Results Species varied significantly in resistance and tolerance to dicamba drift: some were negatively impacted while others showed overcompensatory responses. Species also differed in the way they deployed flowers over time following drift exposure. While drift had negligible effects on community evenness based on vegetative biomass, it caused salient differences in the structure of co-flowering networks within communities. Drift reduced the degree and intensity of flowering overlap among species, altered the composition of groups of species that were more likely to co-flower with each other than with others and shifted species roles (e.g. from dominant to inferior floral producers, and vice versa). Conclusions These results demonstrate that even low levels of herbicide exposure can significantly alter plant growth and reproduction, particularly flowering phenology. If field-grown plants respond similarly, then these changes would probably impact plant–plant competitive dynamics and potentially plant–pollinator interactions occurring within plant communities at the agro-ecological interface. [ABSTRACT FROM AUTHOR]

Agri-environmental schemes (AES) are used to enhance pollinator diversity on agricultural farms within the UK. Though the impacts of these schemes on archetypal pollinator species such as the bumblebee (Bombus) and honeybee (Apis) are well-studied, the effects on non-target bee species like solitary bees, in the same environment, are generally lacking. One goal of AES is to alter floral provision and taxonomic composition of plant communities to provide better forage for pollinators, however, this may potentially impact other ecological communities such as fungal diversity associated with plant-bee communities. Fungi are integral in these bee communities as they can impact bee species both beneficially and detrimentally. We test the hypothesis that alteration of the environment through provision of novel plant communities has non-target effects on the fungi associated with solitary bee communities. We analyse fungal diversity and ecological networks formed between fungi and solitary bees present on 15 agricultural farms in the UK using samples from brood cells. The farms were allocated to two categories, low and high management, which differ in the number of agri-environmental measures implemented. Using internal transcribed spacer metabarcoding, we identified 456 fungal taxa that interact with solitary bees. Of these, 202 (approximately 44%) could be assigned to functional groups, the majority being pathotrophic and saprotrophic species. A large proportion was Ascosphaeraceae, a family of bee-specialist fungi. We considered the connectance, nestedness, modularity, nestedness overlap and decreasing fill, linkage density and fungal generality of the farms' bee–fungi ecological networks. We found no difference in the structure of bee–fungi ecological networks between low and high management farms, suggesting floral provision by AES has no significant impact on interactions between these two taxonomic groups. However, bee emergence was lower on the low management farms compared to high management, suggesting some limited non-target effects of AES. This study characterizes the fungal community associated with solitary bees and provides evidence that floral provision through AES does not impact fungal interactions. [ABSTRACT FROM AUTHOR]

Positive interactions have been hypothesised to influence plant community dynamics and species invasions. However, their prevalence and importance relative to negative interactions remain unclear to understand community change and invasibility. We examined pairwise biotic interactions using over 50 years of successional data to assess the prevalence of positive interactions and their effects on each focal species (either native or exotic). We found that positive interactions were widespread and the relative frequency of positive and negative interactions varied with establishment stage and between native and exotic species. Specifically, positive interactions were more frequent during early establishment and less frequent at later stages. Positive interactions involving native species were more frequent and stronger than those between exotic species, reducing the importance of invasional meltdown on succession. Our study highlights the role of positive native interactions in shielding communities from biological invasion and enhancing the potential for long‐term resilience. [ABSTRACT FROM AUTHOR]

Anthropogenic nutrient enrichment is known to alter the composition and functioning of plant communities. However, how nutrient enrichment influences multiple dimensions of community‐ and ecosystem‐level stability remains poorly understood. Using data from a nitrogen (N) and phosphorus (P) addition experiment in a temperate semi‐arid grassland that experienced a natural drought, we show that N enrichment, not P enrichment, decreased grassland functional and compositional temporal stability, resistance and recovery but increased functional and compositional resilience. Compositional stability and species asynchrony, rather than species diversity, were identified as key determinants of all dimensions of grassland functional stability, except for recovery. Whereas grassland functional recovery was decoupled from compositional recovery, N enrichment altered other dimensions of functional stability primarily through changing their corresponding compositional stability dimensions. Our findings highlight the need to examine ecological stability at the community level for a more mechanistic understanding of ecosystem dynamics in the face of environmental change. [ABSTRACT FROM AUTHOR]

Premise: Numerous processes influence plant distributions and co‐occurrence patterns, including ecological sorting, limiting similarity, and stochastic effects. To discriminate among these processes and determine the spatial scales at which they operate, we investigated how functional traits and phylogenetic relatedness influence the distribution of temperate forest herbs. Methods: We surveyed understory plant communities across 257 forest stands in Wisconsin and Michigan (USA) and applied Bayesian phylogenetic linear mixed‐effects models (PGLMMs) to quantify how functional traits and phylogenetic relatedness influence the environmental distribution of 139 herbaceous plant species along broad edaphic, climatic, and light gradients. These models also allowed us to test how functional and phylogenetic similarity affect species co‐occurrence within microsites. Results: Leaf height, specific leaf area, and seed mass all influenced individualistic plant distributions along landscape‐scale gradients in soil texture, soil fertility, light availability, and climate. In contrast, phylogenetic relationships did not consistently predict species‐environment relationships. Neither functionally similar nor phylogenetically related herbs segregated among microsites within forest stands. Conclusions: Trait‐mediated ecological sorting appears to drive temperate‐forest community assembly, generating individualistic plant distributions along regional environmental gradients. This finding links classic studies in plant ecology and prior research in plant physiological ecology to current trait‐based approaches in community ecology. However, our results fail to support the common assumption that limiting similarity governs local plant co‐occurrences. Strong ecological sorting among forest stands coupled with stochastic fine‐scale interactions among species appear to weaken deterministic, niche‐based assembly processes at local scales. [ABSTRACT FROM AUTHOR]

Root hemiparasitic plants both compete with and extract resources from host plants. By reducing the abundance of dominant plants and releasing subordinates from competitive exclusion, they can have an outsized impact on plant communities. Most research on the ecological role of hemiparasites is manipulative and focuses on a small number of hemiparasitic taxa. Here, we ask whether patterns in natural plant communities match the expectation that hemiparasites affect the structure of plant communities. Our data were collected on 129 national park units spanning the continental United States. The most common hemiparasite genera were Pedicularis, Castilleja, Krameria, and Comandra. We used null models and linear mixed models to determine whether hemiparasites were associated with changes in community richness and evenness. Hemiparasite presence did not affect community metrics. Hemiparasite abundance was positively associated with increasing evenness of herbaceous species, but not with species richness. The associations that we observed on a continental scale are consistent with evidence that the impacts of root hemiparasitic plants on evenness can be substantial and abundance dependent but that effects on richness are less pronounced. Hemiparasites mediate competitive exclusion in communities to facilitate species coexistence and merit consideration of inclusion in ecological theories of coexistence. [ABSTRACT FROM AUTHOR]

Marsh Fern (Thelypteris palustris) is a hygrophytic plant uncommon to the flora of Bulgaria. It is also a vulnerable species, with small and isolated localities in several parts of the country. This paper provides new data on syntaxonomy of the communities in which this fern participates, as well as on a new important locality near Pleven town, Danubian Plain. The paper also attempts to summarize the published and more recent information on the distribution of this species in Bulgaria. [ABSTRACT FROM AUTHOR]