Trade-offs between succulent and non-succulent epiphytes underlie variation in drought tolerance and avoidance

Epiphyte communities comprise important components of many forest ecosystems in terms of biomass and diversity, but little is known regarding trade-offs that underlie diversity and structure in these communities or the impact that microclimate has on epiphyte trait allocation. We measured 22 functional traits in vascular epiphyte communities across six sites that span a microclimatic gradient in a tropical montane cloud forest region in Costa Rica. We quantified traits that relate to carbon and nitrogen allocation, gas exchange, water storage, and drought tolerance. Functional diversity was high in all but the lowest elevation site where drought likely limits the success of certain species with particular trait combinations. For most traits, variation was explained by relationships with other traits, rather than differences in microclimate across sites. Although there were significant differences in microclimate, epiphyte abundance, and diversity, we found substantial overlap in multivariate trait space across five of the sites. We found significant correlations between functional traits, many of which related to water storage (leaf water content, leaf thickness, hydrenchymal thickness), drought tolerance (turgor loss point), and carbon allocation (specific leaf area, leaf dry matter content). This suite of trait correlations suggests that the epiphyte community has evolved functional strategies along with a drought avoidance versus drought tolerance continuum where leaf succulence emerged as a pivotal overall trait.

Soil fertility and water availability effects on trait dispersion and phylogenetic relatedness of tropical terrestrial ferns

Analysis of plant functional traits and their phylogenetic relationships has shed light on the processes structuring the occurrence patterns of angiosperm taxa across environmental gradients. In montane tropical forests, angiosperms coexist with diverse communities of terrestrial ferns, with distinct evolutionary histories, leaf morphology, and reproductive systems. Here we examined the functional traits, functional dispersion, and phylogenetic diversity of ferns across a well-described gradient of moisture and soil nutrient availability in a premontane tropical rainforest in western Panama. We measured 15 functional traits from 33 terrestrial fern species occurring in 12 one-ha plots. We applied RLQ and fourth-corner analyses to assess relationships between trait and environmental variables and used beta regression to evaluate how functional dispersion responds to environmental factors. In addition, we analyzed trait distributions with respect to fern phylogeny. We found that functional composition was predicted by soil variables and dry season rainfall. Leaf phosphorus (P) increased and leaf carbon (C) to nitrogen (N) ratio decreased with increasing soil total N:P ratio. Functional dispersion decreased with increasing soil total N:P in wet sites and with increasing manganese in dry sites, suggesting that low soil fertility and dry season moisture stress both tend to reduce functional diversity. Traits exhibited phylogenetic clustering primarily at deep nodes associated with tree versus herbaceous fern clades. Our results indicate that environmental filtering of functional traits affects ferns in a similar way to angiosperms and highlight the association of the early tree fern clade with low fertility soils.

METABOLIC: high-throughput profiling of microbial genomes for functional traits, metabolism, biogeochemistry, and community-scale functional networks

BACKGROUND

Advances in microbiome science are being driven in large part due to our ability to study and infer microbial ecology from genomes reconstructed from mixed microbial communities using metagenomics and single-cell genomics. Such omics-based techniques allow us to read genomic blueprints of microorganisms, decipher their functional capacities and activities, and reconstruct their roles in biogeochemical processes. Currently available tools for analyses of genomic data can annotate and depict metabolic functions to some extent; however, no standardized approaches are currently available for the comprehensive characterization of metabolic predictions, metabolite exchanges, microbial interactions, and microbial contributions to biogeochemical cycling.

RESULTS

We present METABOLIC (METabolic And BiogeOchemistry anaLyses In miCrobes), a scalable software to advance microbial ecology and biogeochemistry studies using genomes at the resolution of individual organisms and/or microbial communities. The genome-scale workflow includes annotation of microbial genomes, motif validation of biochemically validated conserved protein residues, metabolic pathway analyses, and calculation of contributions to individual biogeochemical transformations and cycles. The community-scale workflow supplements genome-scale analyses with determination of genome abundance in the microbiome, potential microbial metabolic handoffs and metabolite exchange, reconstruction of functional networks, and determination of microbial contributions to biogeochemical cycles. METABOLIC can take input genomes from isolates, metagenome-assembled genomes, or single-cell genomes. Results are presented in the form of tables for metabolism and a variety of visualizations including biogeochemical cycling potential, representation of sequential metabolic transformations, community-scale microbial functional networks using a newly defined metric "MW-score" (metabolic weight score), and metabolic Sankey diagrams. METABOLIC takes ~ 3 h with 40 CPU threads to process ~ 100 genomes and corresponding metagenomic reads within which the most compute-demanding part of hmmsearch takes ~ 45 min, while it takes ~ 5 h to complete hmmsearch for ~ 3600 genomes. Tests of accuracy, robustness, and consistency suggest METABOLIC provides better performance compared to other software and online servers. To highlight the utility and versatility of METABOLIC, we demonstrate its capabilities on diverse metagenomic datasets from the marine subsurface, terrestrial subsurface, meadow soil, deep sea, freshwater lakes, wastewater, and the human gut.

CONCLUSION

METABOLIC enables the consistent and reproducible study of microbial community ecology and biogeochemistry using a foundation of genome-informed microbial metabolism, and will advance the integration of uncultivated organisms into metabolic and biogeochemical models. METABOLIC is written in Perl and R and is freely available under GPLv3 at https://github.com/AnantharamanLab/METABOLIC . Video abstract.

Rare and common species contribute disproportionately to the functional variation within tropical forests

Understanding how functional traits and functional entities (FEs, i.e., unique combinations of functional traits) are distributed within plant communities can contribute to the understanding of vegetation properties and changes in species composition. We utilized investigation data on woody plants (including trees, shrubs and lianas) from 17 1-ha plots across six old-growth tropical forest types on Hainan island, China. Plant species were categorized as common (>1 individuals/ha) and rare species (≤1 individuals/ha) according to their abundance to determine how they contributed to different ecosystem functions. First, we assessed the differences in traits between common and rare species, and second, we examined functional redundancy, functional over-redundancy, and functional vulnerability for common and rare species of the forests. We found that both common species and rare species in each of the forest types were placed into just a few FEs, leading to functional over-redundancy and resulting in functional vulnerability. Rare species tended to have different trait values than those of common species, and were differently distributed among FEs, indicating different contributions to ecosystem functioning. Our results highlighted the disproportionate contribution of rare species in all of the studied forests. Rare species are more likely than common species to possess unique FEs, and thus, they have a disproportionately large contribution to community trait space. The loss of such species may impact the functioning, redundancy, and resilience of tropical forests.

The characteristics of habitat, functional traits and medicinal components of Eucommia ulmoides from Guizhou

To find out the genuine characteristics of Eucommia ulmoides produced in Guizhou.The habitat, functional characters and the content of medicinal components of Eucommia ulmoides in Guizhou were studied by using the method of sample survey combined with typical survey, related laboratory experiments and quantitative analysis. The results showed that the yield of Eucommia ulmoides plantation in Guizhou was divided into low altitude, low middle and high temperature rain slope latitude mixing, short sunshine hours type(A type), medium altitude, low longitude and latitude, high temperature rain, positive oblique steep slope, medium sunshine hours type (B type), middle altitude, low longitude and latitude, moderate high temperature rain, shady side and sunny side have gentle deflection steep slope, medium sunshine hours type (C type), High altitude, low longitude and latitude, low temperature moderate rain, positive gentle slope, long sunshine hours type (D type); Different types of Eucommia ulmoides plantation, Different habitat quality, B type is intensity karst rocky desertification habitat, A type is potential karst rocky desertification habitat, the C and D types are light and moderate rocky desertification areas, respectively, the species diversity of shrub layer in Eucommia ulmoides plantation was higher in D type and B type, A type and C type followed; There was no significant difference in root carbon content and leaf nitrogen content in 4 types of Eucommia ulmoides plantation, Among the four types of A, B, C, D, there were significant or extremely significant differences in other indexes of plant functional traits; Both genipinic acid and aucubin had the highest content of root bark, followed by trunk bark and lowest leaves, Chlorogenic acid is the opposite, The content of geniposide was higher in trunk bark and lower in root bark and leaves; Genipinic acid is higher in D type, Aucubin is higher in A and D type, Chlorogenic acid has higher leaves content in B type, Geniposide was the highest in trunk bark of D type; The element enrichment coefficient K and Mn leaves are the largest, the largest in trunk bark is Ca and Zn, Fe root bark is the largest; Effects of soil potassium, phosphorus, pH value and bulk weight on the functional traits of Eucommia ulmoides were significant. The contents of medicinal components in root bark, trunk bark, and leaves was influenced by species diversity of shrub layer, The contents of geniposide in root bark, aucubin in root bark and trunk bark, genipinic acid in bark and chlorogenic acid in leaves were particularly affected by soil physical and chemical indexes and metal element contents, The functional traits of Eucommia ulmoides can affect the content of medicinal components in root bark, trunk bark, and leaves, Especially on the root bark, trunk bark, and leaves in the content of aucubin content; The content of medicinal components of Eucommia ulmoides was high and stable. The above research results have important theoretical reference significance for the cultivation of Eucommia ulmoides and the cultivation of target medicinal components and the comprehensive exploitation and utilization of resources.

Small-scale drivers on plant and ant diversity in a grassland habitat through a multifaceted approach

Semi-natural grasslands are characterized by high biodiversity and require multifaceted approaches to monitor their biodiversity. Moreover, grasslands comprise a multitude of microhabitats, making the scale of investigation of fundamental importance. Despite their wide distribution, grasslands are highly threatened and are considered of high conservation priority by Directive no. 92/43/EEC. Here, we investigate the effects of small-scale ecological differences between two ecosites present within the EU habitat of Community Interest of semi-natural dry grasslands on calcareous substrates (6210 according to Dir. 92/43/EEC) occurring on a Mediterranean mountain. We measured taxonomic and functional diversity of plant and ant communities, evaluating the differences among the two ecosites, how these differences are influenced by the environment and whether vegetation affects composition of the ant community. Our results show that taxonomic and functional diversity of plant and ant communities are influenced by the environment. While vegetation has no effect on ant communities, we found plant and ant community composition differed across the two ecosites, filtering ant and plant species according to their functional traits, even at a small spatial scale. Our findings imply that small-scale monitoring is needed to effectively conserve priority habitats, especially for those that comprise multiple microhabitats.

Ecological and environmental factors affecting transmission of sylvatic yellow fever in the 2017-2019 outbreak in the Atlantic Forest, Brazil

BACKGROUND

Yellow fever virus (YFV) is an arbovirus that, despite the existence of a safe and effective vaccine, continues to cause outbreaks of varying dimensions in the Americas and Africa. Between 2017 and 2019, Brazil registered un unprecedented sylvatic YFV outbreak whose severity was the result of its spread into zones of the Atlantic Forest with no signals of viral circulation for nearly 80 years.

METHODS

To investigate the influence of climatic, environmental, and ecological factors governing the dispersion and force of infection of YFV in a naïve area such as the landscape mosaic of Rio de Janeiro (RJ), we combined the analyses of a large set of data including entomological sampling performed before and during the 2017-2019 outbreak, with the geolocation of human and nonhuman primates (NHP) and mosquito infections.

RESULTS

A greater abundance of Haemagogus mosquitoes combined with lower richness and diversity of mosquito fauna increased the probability of finding a YFV-infected mosquito. Furthermore, the analysis of functional traits showed that certain functional groups, composed mainly of Aedini mosquitoes which includes Aedes and Haemagogus mosquitoes, are also more representative in areas where infected mosquitoes were found. Human and NHP infections were more common in two types of landscapes: large and continuous forest, capable of harboring many YFV hosts, and patches of small forest fragments, where environmental imbalance can lead to a greater density of the primary vectors and high human exposure. In both, we show that most human infections (~ 62%) occurred within an 11-km radius of the finding of an infected NHP, which is in line with the flight range of the primary vectors.

CONCLUSIONS

Together, our data suggest that entomological data and landscape composition analyses may help to predict areas permissive to yellow fever outbreaks, allowing protective measures to be taken to avoid human cases.

Diuron environmental levels effects on marine nematodes: Assessment of ecological indices, taxonomic diversity, and functional traits

Coastal marine systems are the most sensitive zones to emerging pollutants. The present study aims to investigate the effect of Diuron on the meiofaunal assemblages, collected from the Bizerte channel (Tunisia). Microcosm experiments were set up using four increasing Diuron concentrations [D1 (10 ng g^-1 dry weight (DW)), D2 (50 ng g^-1 DW), D3 (250 ng g^-1 DW) and (1250 ng g^-1 DW)] compared to non-contaminated sediments (controls) and all plots were incubated for 30 days. Our results show that Diuron-supplemented sediments provoked the significant decrease of meiofaunal abundance as well as a change in nematodes' diversity and structure composition. All univariate indices, as well as the cumulative k-dominance, were lower in the Diuron than the control plot. Additionally, the ordination of treatments according to the two-dimensional nMDS plots analysis showed a clear structural separation of the Diuron treated replicates from the controls based on the functional groups lists. These current data emphasize the utility of the use of biological traits in the detection of disturbances in the aquatic biotope.

Agroecosystem diversification with legumes or non-legumes improves differently soil fertility according to soil type

Plant diversification through crop rotation or agroforestry is a promising way to improve sustainability of agroecosystems. Nonetheless, criteria to select the most suitable plant communities for agroecosystems diversification facing contrasting environmental constraints need to be refined. Here, we compared the impacts of 24 different plant communities on soil fertility across six tropical agroecosystems: either on highly weathered Ferralsols, with strong P limitation, or on partially weathered soils derived from volcanic material, with major N limitation. In each agroecosystem, we tested several plant communities for diversification, as compared to a matching low diversity management for their cropping system. Plant residue restitution, N, P and lignin contents were measured for each plant community. In parallel, the soil under each community was analyzed for organic C and N, inorganic N, Olsen P, soil pH and nematode community composition. Soil potential fertility was assessed with plant bioassays under greenhouse controlled climatic conditions. Overall, plant diversification had a positive effect on soil fertility across all sites, with contrasting effects depending on soil type and legumes presence in the community. Communities with legumes improved soil fertility indicators of volcanic soils, which was demonstrated through significantly higher plant biomass production in the bioassays (+18%) and soil inorganic N (+26%) compared to the low diversity management. Contrastingly, communities without legumes were the most beneficial in Ferralsols, with increases in plant biomass production in the bioassays (+39%), soil Olsen P (+46%), soil C (+26%), and pH (+5%). Piecewise structural equation models with Shipley's test revealed that plant diversification impacts on volcanic soil fertility were related to soil N availability, driven by litter N. Meanwhile, Ferralsols fertility was related to soil P availability, driven by litter P. These findings underline the importance of multifactorial and multi-sites experiments to inform trait-based frameworks used in designing optimal plant diversification in agroecological systems.

Phenotypic variation among silverside populations (Atherinopsidae: Atherinella brasiliensis) from distinct environments in Northeastern Brazil

The successful adaptation of populations to a wide range of environments is a central topic in ecology. Based on the assumption that body shape may affect survival, we evaluated to what extent biotic and abiotic factors are capable of inducing morphological changes in Brazilian silverside populations (Atherinella brasiliensis). To reach this goal, we compared 18 morphological traits of specimens from five ecosystems representing three types of environment (estuary, coastal lagoon, reservoir). Populations from estuaries displayed greater anal fin area and greater caudal fin aspect ratio and area. Populations from coastal lagoons had more compressed bodies, larger heads, and slightly broader caudal peduncles. The fish from estuaries and coastal lagoons had longer caudal peduncles, larger pelvic fins and larger eye area. Population from reservoir had more depressed bodies and greater oral protrusion. Food availability explained 31% of the observed ecomorphological patterns. Overall, the morphology of the respective populations was consistent with each type of environment, making it possible to associate phenotypic variation with habitat and feeding patterns, although abiotic factors were more significant than biotic factors. In conclusion, landlocked populations of A. brasiliensis are sustainable and add to current knowledge of phenotypical variability in a species widely distributed along the Western Atlantic coast.

Leaf reflectance can surrogate foliar economics better than physiological traits across macrophyte species

BACKGROUND

Macrophytes are key players in aquatic ecosystems diversity, but knowledge on variability of their functional traits, among and within species, is still limited. Remote sensing is a high-throughput, feasible option for characterizing plant traits at different scales, provided that reliable spectroscopy models are calibrated with congruous empirical data, but existing applications are biased towards terrestrial plants. We sampled leaves from six floating and emergent macrophyte species common in temperate areas, covering different phenological stages, seasons, and environmental conditions, and measured leaf reflectance (400-2500 nm) and leaf traits (dealing with photophysiology, pigments, and structure). We explored optimal spectral band combinations and established non-parametric reflectance-based models for selected traits, eventually showing how airborne hyperspectral data could capture spatial-temporal macrophyte variability.

RESULTS

Our key finding is that structural-leaf dry matter content, leaf mass per area-and biochemical-chlorophyll-a content and chlorophylls to carotenoids ratio-traits can be surrogated by leaf reflectance with normalized error under 17% across macrophyte species. On the other hand, the performance of reflectance-based models for photophysiological traits substantively varies, depending on macrophyte species and target parameters.

CONCLUSIONS

Our main results show the link between leaf reflectance and leaf economics (structure and biochemistry) for aquatic plants, thus envisioning a crucial role for remote sensing in enhancing the level of detail of macrophyte functional diversity analysis to intra-site and intra-species scales. At the same time, we highlighted some difficulties in establishing a general link between reflectance and photosynthetic performance under high environmental heterogeneity, potentially opening further investigation directions.

Metagenomic insights into the microbial communities of inert and oligotrophic outdoor pier surfaces of a coastal city

BACKGROUND

Studies of the microbiomes on surfaces in built environment have largely focused on indoor spaces, while outdoor spaces have received far less attention. Piers are engineered infrastructures commonly found in coastal areas, and due to their unique locations at the interface between terrestrial and aquatic ecosystems, pier surfaces are likely to harbor interesting microbiology. In this study, the microbiomes on the metal and concrete surfaces at nine piers located along the coastline of Hong Kong were investigated by metagenomic sequencing. The roles played by different physical attributes and environmental factors in shaping the taxonomic composition and functional traits of the pier surface microbiomes were determined. Metagenome-assembled genomes were reconstructed and their putative biosynthetic gene clusters were characterized in detail.

RESULTS

Surface material was found to be the strongest factor in structuring the taxonomic and functional compositions of the pier surface microbiomes. Corrosion-related bacteria were significantly enriched on metal surfaces, consistent with the pitting corrosion observed. The differential enrichment of taxa mediating biodegradation suggests differences between the metal and concrete surfaces in terms of specific xenobiotics being potentially degraded. Genome-centric analysis detected the presence of many novel species, with the majority of them belonging to the phylum Proteobacteria. Genomic characterization showed that the potential metabolic functions and secondary biosynthetic capacity were largely correlated with taxonomy, rather than surface attributes and geography.

CONCLUSIONS

Pier surfaces are a rich reservoir of abundant novel bacterial species. Members of the surface microbial communities use different mechanisms to counter the stresses under oligotrophic conditions. A better understanding of the outdoor surface microbiomes located in different environments should enhance the ability to maintain outdoor surfaces of infrastructures. Video Abstract.

Differential response of distinct copepod life history types to spring environmental forcing in Rivers Inlet, British Columbia, Canada

The temporal dynamics of five copepod species common to coastal waters of the Pacific Northwest were examined in relation to variability in spring temperature and phytoplankton dynamics in 2008, 2009, and 2010 in Rivers Inlet, British Columbia, Canada. The five species were differentiated by life history strategies. Acartia longiremis, Metridia pacifica, and Paraeuchaeta elongata remained active over most of the year. By contrast, the reproductive effort of Eucalanus bungii and Calanus marshallae was concentrated over the spring period and they spent most of the year in diapause as C5 copepodites. A delay in the timing of the spring bloom was associated with a shift in the phenology of all species. However, following the delay in spring bloom timing, recruitment to the G₁ cohort was reduced only for E. bungii and C. marshallae. Recruitment successes of E. bungii and C. marshallae was also drastically reduced in 2010, an El Niño year, when spring temperatures were highest. Reasons for the observed differential response to spring environmental forcing, and its effect on upper trophic levels, are discussed.

Greater functional similarity in mobile compared to sessile assemblages colonizing artificial coastal habitats

Among anthropogenic habitats built in the marine environment, floating and non-floating structures can be colonized by distinct assemblages. However, there is little knowledge whether these differences are also reflected in the functional structure. This study compared the functional diversity of sessile and mobile invertebrate assemblages that settle over three months on floating vs. non-floating artificial habitats, in two Chilean ports. Using morphological, trophic, behavioral, and life history traits, we found differences between mobile and sessile assemblages regarding the effect of the type of habitat on the functional diversity. Compared to sessile assemblages, a greater functional similarity was observed for mobile assemblages, which suggests that their dispersal capacity enables them to balance the reduced connectivity between settlement structures. No traits, prevailing or selected in one or the other habitat type, was however clearly identified; a result warranting for further studies focusing on more advanced stages of community development.

Effects of Prorocentrum donghaiense bloom on zooplankton functional groups in the coastal waters of the East China Sea

Blooms of the non-toxic dinoflagellate Prorocentrum donghaiense are common in the East China Sea; however, the in situ impacts of these blooms on zooplankton community functions have not yet been conducted in this area. Using functional trait-based methods, we found that P. donghaiense bloom significantly changed the zooplankton community structure and functions in the coastal water of the East China Sea. Zooplankton species richness and biodiversity increased after the bloom. Based on body length, feeding type, trophic group and reproductive mode, we categorized zooplankton into four functional groups and characterized their dynamics. Before and after the bloom, the zooplankton community was dominated by herbivorous- and free-spawner- lineages represented by copepods and tunicates, while during the bloom, the zooplankton community was dominated by carnivorous- and egg-brooding- lineages represented by small jellyfish, chaetognaths and copepods.

Distribution patterns and seasonal variations in phytoplankton communities of the hypersaline Pulicat lagoon, India

Phytoplankton structure and patterns are key components to forecast the net result of the gain and loss process that outline the resilience of the lagoon ecosystem. In order to understand the phytoplankton community structure and its relationship with the environmental variables in the shallow hypersaline Pulicat lagoon, east coast of India, observations were carried out during August 2018-January 2019 covering the three seasons: premonsoon (PrM), monsoon (M), and postmonsoon (PoM). The salinity of the lagoon varied with a minimum of 12.1 for the M and a maximum of 81.65 during the PoM. The clustering analysis performed on the phytoplankton abundance data separated the lagoon into three sectors: north sector (NS), central sector (CS), and south sector (SS). A total of 59 taxa/morphotypes from four taxonomic classes (Bacillariophyceae, Chlorophyceae, Cyanophyceae, and Dinophyceae) were recorded during the study period. The class Bacillariophyceae was dominant in the lagoon both spatially and temporally by 44.06% with Chaetoceros borealis as dominant species. Presence of characteristic species like Dunaliella sp. was observed in the higher salinity, whereas Pediastrum duplex and Scenedesmus sp. were dominant in the freshwater influx areas. The individual-based functional approach allowed grouping these taxa into 11 functional entities based on the derived 4 functional trait values (cell size, trophic regime, mobility, and coloniality). Formation of algal blooms of Protoperidinium sp. (3.3×10⁵ind L^-1) and Odentella sp. (2.8×10⁵ind L^-1) was observed in the SS during PoM as a result of reduced water exchange in the lagoon. During the same period, toxin-producing strains like Anabaena sp. and Nostoc sp. of Cyanophyceae were also recorded. Correlating the three sectors of the lake (NS, CS, and SS), it is observed that the physical, chemical, and biological properties of the lake varied continuously depending on the season and freshwater availability. Seasonal nutrient stoichiometry played a significant role in regulating the community structure and distribution pattern of phytoplankton communities of the lagoon.

Trait-based responses to cessation of nutrient enrichment in a tundra plant community

Plant communities worldwide show varied responses to nutrient enrichment-including shifts in species identity, decreased diversity, and changes in functional trait composition-but the factors determining community recovery after the cessation of nutrient addition remain uncertain. We manipulated nutrient levels in a tundra community for 6 years of nutrient addition followed by 8 years of recovery. We examined how community recovery was mediated by traits related to plant resource-use strategy and plant ability to modify their environment. Overall, we observed persistent effects of fertilization on plant communities. We found that plants with fast-growing traits, including higher specific leaf area, taller stature and lower foliar C:N, were more likely to show a persistent increase in fertilized plots than control plots, maintaining significantly higher cover in fertilized plots 8 years after cessation of fertilization. Additionally, although graminoids responded most strongly to the initial fertilization treatment, forb species were more vulnerable to fertilization effects in the long-term, showing persistent decline and no recovery in 8 years. Finally, these persistent fertilization effects were accompanied by modified environmental conditions, including persistent increases in litter depth and soil phosphorous and lower soil C:N. Our results demonstrate the potential for lasting effects of nutrient enrichment in nutrient-limited systems and identify species traits related to rapid growth and nutrient-use efficiency as the main predictors of the persistence of nutrient enrichment effects. These findings highlight the usefulness of trait-based approach for understanding the persistent feedbacks of nutrient enrichment, plant dynamics, and niche construction via litter and nutrient build-up.

Assessing the feasibility and value of employing an ecosystem services approach in chemical environmental risk assessment under the Water Framework Directive

The feasibility and added value of an ecosystem services approach in retrospective environmental risk assessment were evaluated using a site-specific case study in a lowland UK river. The studied water body failed to achieve good ecological status temporarily in 2018, due in part to the exceedance of the environmental quality standard (annual average EQS) for zinc. Potential ecosystem service delivery was quantified for locally prioritised ecosystem services: regulation of chemical condition; maintaining nursery populations and habitats; recreational fishing; nature watching. Quantification was based on observed and expected taxa or functional groups within WFD biological quality elements, including macrophytes, benthic macroinvertebrates and fish, and on published functional trait data for constituent taxa. Benthic macroinvertebrate taxa were identified and enumerated before, during and after zinc EQS exceedance, enabling a generic retrospective risk assessment for this biological quality element, which was found to have good ecosystem service potential. An additional targeted risk assessment for zinc was based on laboratory-based species sensitivity distributions normalised using biotic-ligand modelling to account for site-specific, bioavailability-corrected zinc exposure. Risk to ecosystem services for diatoms (microalgae) was found to be high, while risks for benthic macroinvertebrates and fish were found to be low. The status of potential ecosystem service delivery (ESD) by fish was equivalent to high ecological status defined under the WFD, while ESD was higher for benthic macroinvertebrates than defined by WFD methods. The illustrated ecosystem services approach uses readily available data and adds significantly to the taxonomic approach currently used under the WFD by using functional traits to evaluate services that are prioritised as being important in water bodies. The main shortcomings of the illustrated approach were lack of: representation of bacteria and fungi; WFD predicted species lists for diatoms and macrophytes; site-specific functional trait data required for defining actual (rather than potential) ecosystem service delivery.

Are non-indigenous species hitchhiking offshore farmed mussels? A biogeographic and functional approach

The epifauna associated to farmed mussels in southern Portugal coast was analysed, aiming at identifying the species with spreading potential through commercial transport. The presence of a relevant number of the species here found is not reported to at least one of the common mussel export/transposition countries. Indeed, important species biogeographic dissimilarities between the mussel farm area and the Greater North Sea and Western Mediterranean Sea sub-regions were detected, suggesting the potential transport of non-indigenous species (NIS) into other countries. Among them, fouling species such as the anemones Paractinia striata and Urticina felina, the acorn barnacles Balanus glandula and Balanus trigonus or the bryozoans Bugulina stolonifera and Schizoporella errata exhibit functional attributes that allow them to colonise and spread in new areas. This combined biogeographic and functional approach may contribute to clarify the role of aquaculture on the transport of NIS and to predict and prevent their spreading worldwide.

Tree growth response to soil nutrients and neighborhood crowding varies between mycorrhizal types in an old-growth temperate forest

Forest dynamics are shaped by both abiotic and biotic factors. Trees associating with different types of mycorrhizal fungi differ in nutrient use and dominate in contrasting environments, but it remains unclear whether they exhibit differential growth responses to local abiotic and biotic gradients where they co-occur. We used 9-year tree census data in a 25-ha old-growth temperate forest in Northeast China to examine differences in tree growth response to soil nutrients and neighborhood crowding between tree species associating with arbuscular mycorrhizal (AM), ectomycorrhizal (EM), and dual-mycorrhizal (AEM) fungi. In addition, we tested the role of individual-level vs species-level leaf traits in capturing differences in tree growth response to soil nutrients and neighborhood crowding across mycorrhizal types. Across 25 species, soil nutrients decreased AM tree growth, while neighborhood crowding reduced both AM and EM tree growth, and neither soil nor neighbors impacted AEM tree growth. Across mycorrhizal types, individual-level traits were stronger predictors of tree growth than species-level traits. However, most traits poorly mediated tree growth response to soil nutrients and neighborhood crowding. Our findings indicate that mycorrhizal types strongly shape differences in tree growth response to local soil and crowding gradients, and suggest that including plant-mycorrhizae associations in future work offers great potential to improve our understanding of forest dynamics.

Effects of microplastics on the functional traits of aquatic benthic organisms: A global-scale meta-analysis

Microplastics are widespread in the aquatic environment and thus available for many organisms at different trophic levels. Many scientific papers focus their attention on the study of the effects of microplastics on different species at individual level. Here we performed a global scale meta-analysis focusing our work on the study of the effect of microplastics on the functional traits of aquatic benthic organisms. Overall, microplastics showed a moderate negative effect on the examined functional traits of benthic organisms. Our results show that some crucial functional traits, such as those linked to behaviour and feeding, appear to be unaffected by microplastics. In contrast, traits related to the capacity of organisms to assimilate energy are affected. Moreover, traits with possible effects at population level appear to be negatively affected by microplastics. We discuss how the direct impact of organismal performance may have indirect repercussions at higher levels in the ecological hierarchy and represent a risk for the stability and functioning of the ecosystem.

Taxonomic, functional and phylogenetic bat diversity decrease from more to less complex natural habitats in the Amazon

The high levels of biodiversity in the Amazon are maintained mostly due to its composition as a natural mosaic of different habitats, including both unflooded and flooded forests, campinaranas, and savannahs. Here, we compared multiple dimensions of α- and β- bat biodiversity between four natural Amazonian habitats (savannah, campinarana, forest patches, and continuous forest). In addition, we explored the extent to which bat communities in the different habitats are nested within one another, and compared the community-level functional uniqueness and community-weighted mean traits between habitats. Our results show that taxonomic, functional and phylogenetic α-diversity of bats is higher in continuous forest than in any of the other habitat types. The continuous forest also harbours more unique species, and indeed, the bat community assemblages in the less-complex habitats, including forest patches, campinarana and savannahs, are taxonomic, functional and phylogenetic sub-sets of the assemblage found in the continuous forest. By examining β-diversity partitions and species composition, we are able to shed light on the mechanisms behind the variation in diversity between the four habitat types, which reflect a process of environmental sorting along a habitat gradient going from a more complex to a less complex habitat. We conclude that nesting patterns along the mosaic of habitats are determined by differences in complexity between habitats and that taxonomic and functional uniqueness contribute to overall regional bat diversity and functionality. Ongoing human-induced disturbances of these habitats could provoke an unprecedented loss of bat diversity and functionality with negative consequences for biodiversity and ecosystem services.

Estimation model and its trade-off strategy of Mangifera persiciforma Colletotrichum gloeosporioides degree based on leaf reflection spectrum

Colletotrichum gloeosporioides is one of the most common and serious fungal diseases of the tree Mangifera persiciforma. Yet we lack an effective method to evaluate this ecological interaction accurately. Here, we measured the functional traits and leaf reflectance spectrum of the host plants under different disease degrees. The findings provide a fast and efficient method for large-scale and high-precision monitoring of C. gloeosporioides in M. persiciforma stands. Using the collected leaf reflection data, we set up a prediction model of the optimal disease degree. Firstly, we found that leaf functional traits of M. persiciforma generally consisted of low leaf thickness, low relative chlorophyll content, small specific leaf area, high leaf tissue density, high dry matter content, low stomatal density, and large stomatal area. Secondly, leaf reflectivity increases with damage of C. gloeosporioides, which corresponds to five main reflection peaks and five absorption valleys in the spectral reflectance curve of leaves at the same positions (350-1800 nm). Thirdly, with the increase of infection degree, red edge slope and yellow edge slope decrease, while green peak reflectance, red valley reflectance, and blue edge slope all increase. Blue shift was detected in the red edge, green peak, and red valley, while red shift appeared at the blue edge and yellow edge. Finally, the best predictive model was that based on green peak reflectance (y=3.6396-0.0693x, R²=0.5149, RMSE [root-mean-square error] =0.2735), with an R²=0.92 and RMSE=0.0042 between its predicted vs. observed values. Because of its high inversion accuracy, the model can be used to predict the invasion conditions of M. persiciforma by C. gloeosporioides. Our study demonstrated that when plants are infected by C. gloeosporioides, there was a strong trade-off relationship between leaf functional traits. On the global leaf economics spectrum, the leaves tended toward the "slow investment-return" end when infected by C. gloeosporioides.

Distinct strategies of abundant and rare bacterioplankton in river-reservoir system: Evidence from a 2800 km plateau river

Riverine bacterioplankton are highly responsive to river alterations and their abundant and rare sub-communities may have different roles in biogeochemical cycling. However, with the rapid development of dam constructions, our knowledge on adaptation mechanism of these sub-communities in regulated river ecosystem was still limited, especially with regard to their functional traits. Here, our study was conducted in the 2800 km Yarlung Tsangpo River on the Tibetan Plateau to address the question of how abundant and rare bacterioplankton would respond taxonomically and functionally to river damming using 16S rRNA gene sequencing combined with Geochip microarray technique. Our results showed that abundant sub-community dominated taxonomic composition while rare sub-community largely determined functional composition. It is also observed that taxonomic diversity of abundant sub-community was significantly stimulated in the reservoir while that of rare sub-community was markedly inhibited. Moreover, abundant sub-community exhibited functional redundancy under damming disturbances since altered taxonomic composition and unaltered functional composition co-occurred simultaneously. Meanwhile, due to portfolio effect, rare sub-community maintained a greater stability under damming disturbances with little variation in taxonomic and functional compositions. In addition, the Stegen null model analysis revealed that stochastic process governed community assembly in both abundant and rare sub-communities. However, according to source tracking analysis, the taxonomic dispersion of abundant sub-community was less significantly impeded by the dam while the functional dispersion of rare sub-community was less strongly interrupted, indicating that the dispersal process in the dominated sub-community was less susceptible to damming. Therefore, by considering bacterioplankton functional traits, our study provided comprehensive evidences for the distinct strategies of abundant and rare sub-communities in response to damming.

Colonization history meets further niche processes: how the identity of founders modulates the way predation structure fouling communities

Community assembly relies on deterministic niche-based processes (e.g., biotic interactions), and stochastic sources of unpredictable variation (e.g., colonization history), that combined will influence late-stage community structure. When community founders present distinct functional traits and a colonization-competition trade-off is not operating, initial colonization can result in late-stage assemblages of variable diversity and composed by different species sets, depending if early colonizers facilitate or inhibit subsequent colonization and survival. By experimentally manipulating the functional identity of founders and predators access during the development of fouling communities, we tested how founder traits constrain colonization history, species interactions and thereby regulate community diversity. We used as founders functionally different fouling organisms (colonial and solitary ascidians, and arborescent and flat-encrusting bryozoans) to build experimental communities that were exposed or protected against predation using a caging approach. Ascidians and bryozoans are pioneer colonizers in benthic communities and also good competitors, but the soft-body of ascidians makes them more susceptible to predators than mineralized bryozoans. When ascidians were founders, their dominance (but not richness) was reduced by predation, resulting in no effects of predators on overall diversity. Conversely, when bryozoans were founders, both space limitation and predator effects resulted in species-poor communities, with reduced number and cover of ascidian species and high overall dominance at the end of the experiment. We, thus, highlight that current species interactions and colonization contingencies related to founder identity should not be viewed as isolated drivers of community organization, but rather as strongly interacting processes underlying species distribution patterns and diversity.