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14 páginas.- 6 figuras.- 1 tabla.- referencias.- Additional supporting information may be found in the online version of the article at the publisher’s website, Although plant–plant interactions (i.e. competition and facilitation) have long been recognised as key drivers of plant community composition and dynamics, their global patterns and relationships with climate have remained unclear. Here, we assembled a global database of 10,502 pairs of empirical data from the literature to address the patterns of and climatic effects on the net outcome of plant interactions in natural communities. We found that plant interactions varied among plant performance indicators, interaction types and biomes, yet competition occurred more frequently than facilitation in plant communities worldwide. Unexpectedly, plant interactions showed weak latitudinal pattern and were weakly related to climate. Our study provides a global comprehensive overview of plant interactions, highlighting competition as a fundamental mechanism structuring plant communities worldwide. We suggest that further investigations should focus more on local factors (e.g. microclimate, soil and disturbance) than on macroclimate to identify key environmental determinants of interactions in plant communities., This work was supported by the National Natural Science Foundation of China (32071524, 31770514 and 31870711). International research travel by J.H.C.C. was partly funded by the Royal Netherlands Academy of Arts and Sciences (KNAW, CEP grant 12CDP007).

The effects of selection on an organism’s genome are hard to detect on small spatial scales, as gene flow can erase signatures of local adaptation. Most genome scans to detect signatures of environmental selection are performed on large spatial scales, however divergent selection on the local scale (e.g. between contrasting soil conditions) has also been demonstrated, in particular for herbaceous plants. Here we hypothesize that in topographically complex landscapes, microenvironment variability is strong enough to leave a selective footprint in genomes of long-lived organisms. To test this, we investigated paired south- versus north-facingPinus pinasterstands in a Mediterranean mountain area. While north-facing (mesic) stands experience less radiation, south facing (xeric) stands represent especially harsh conditions, particularly during the dry summer season. Outlier detection revealed five putatively adaptive loci out of 4,034, two of which encoded non-synonymous substitutions. Additionally, one locus showed consistent allele frequency differences in all three stand pairs indicating divergent selection despite high gene flow on the local scale. Functional annotation of these candidate genes revealed biological functions related to abiotic stress response in other species. Our study highlights how divergent selection shapes the functional genetic variation within populations of long-lived forest trees on local spatial scales.

Facilitative interactions bind community species in intricate ecological networks, preserving species that would otherwise be lost. The traditional understanding of ecological networks as static components of biological communities overlooks that species interactions in a network can fluctuate. Analyzing the patterns that cause those shifts can reveal the principles that govern the identity of pair-wise interactions and whether they are predictable based on the traits of the interacting species and the local environmental contexts in which they occur. Here we explore how abiotic stress and phylogenetic and functional affinities constrain those shifts. Specifically, we hypothesize that the rewiring of facilitative interactions is more limited in stressful than in mild environments. We present evidence of a distinct pattern in the rewiring of facilitation-driven communities at different stress levels. In highly stressful environments with a firm reliance on facilitation, rewiring is limited to growing beneath nurse species with traits to overcome harsh stressful conditions. However, when environments are milder, rewiring is more flexible, though it is still constrained to nurses that are close relatives. Understanding the ability of species to rewire their interactions is crucial to predict how communities may respond to the unprecedented rate of perturbations on earth. This article is protected by copyright. All rights reserved.

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., Fondo Europeo de Desarrollo Regional, Grant/Award Number, ICTS-2017-08-CSIC-4; SUMHAL, Grant/Award Numbers: 418RT0555, 501100011033, LIFEWATCH-2019-09-CSIC-13, MCIN/ AEI/10.13039, PGC2018-100966-B-100, PID2020-113157GB-I00, POPE 2014-2020

15 Pág. Departamento de Medio Ambiente y Agronomía​, While biodiversity is expected to enhance multiple ecosystem functions (EFs), the different roles of multiple biodiversity dimensions remain difficult to disentangle without carefully designed experiments. We sowed plant communities with independent levels of functional (FD) and phylogenetic diversities (PD), combined with different levels of fertilization, to investigate their direct and indirect roles on multiple EFs, including plant-related EFs (plant biomass productivity, litter decomposability), soil fertility (organic carbon and nutrient pool variables), soil microbial activity (respiration and nutrient cycling), and an overall multifunctionality. We expected an increase in most EFs in communities with higher values of FD and/or PD via complementarity effects, but also the dominant plant types (using community weighted mean, CWM, independent of FD and PD) via selection effects on several EFs. The results showed strong direct effects of different dimensions of plant functional structure parameters on plant-related EFs, through either CWM or FD, with weak effects of PD. Fertilization had significant effects on one soil microbial activity and indirect effects on the other variables via changes in soil abiotic properties. Dominant plant types and FD showed only indirect effects on soil microbial activity, through litter decomposition and soil abiotic properties, highlighting the importance of cascading effects. This study shows the relevance of complementary dimensions of biodiversity for assessing both direct and cascading effects on multiple EFs., The study was supported by the Czech Science Foundation grant GAˇCR20-13637S, by Spanish Plan Nacional de I+D+i (project PGC2018-099027-B-I00), by a Marie Curie Intra-European Fellowship within the 7th European Community Framework Programme (TANDEM; project id. 626392) and by the Young Researchers R&D Project.Ref. M2165—INTRANESTI—financed by Community of Madrid and Rey Juan Carlos University. Enrique Valencia was funded by the 2017 program for attracting and retaining talent of Comunidad de Madrid (no.2017-T2/AMB-5406). Carlos P. Carmona was supported by the Estonian Research Council (PSG293) and theEuropean Regional Development Fund via the MobilitasPluss programme (MOBERC40).

Disclaimer textThe author has withdrawn this manuscript due to a duplicate posting of manuscript number BIORXIV/2021/467547. Therefore, the author does not wish this work to be cited as reference for the project. If you have any questions, please contact the corresponding author.

Predicting coexistence patterns is a current challenge to understand diversity maintenance, especially in rich communities where these patterns' complexity is magnified through indirect interactions that prevent their approximation with classical experimental approaches. We explore cutting-edge Machine Learning techniques called Generative Artificial Intelligence (GenAI) to predict species coexistence patterns in vegetation patches, training generative adversarial networks (GAN) and variational AutoEncoders (VAE) that are then used to unravel some of the mechanisms behind community assemblage. The GAN accurately reproduces real patches' species composition and plant species' affinity to different soil types, and the VAE also reaches a high level of accuracy, above 99%. Using the artificially generated patches, we found that high-order interactions tend to suppress the positive effects of low-order interactions. Finally, by reconstructing successional trajectories, we could identify the pioneer species with larger potential to generate a high diversity of distinct patches in terms of species composition. Understanding the complexity of species coexistence patterns in diverse ecological communities requires new approaches beyond heuristic rules. Generative Artificial Intelligence can be a powerful tool to this end as it allows to overcome the inherent dimensionality of this challenge., The authors thank the Yesaires team for making the fieldwork of quantification of species gypsum affinity possible. R.S.-M. was supported by the Ministry of Science and Innovations (FPU grant FPU17/00629). Financial support was provided by the projects RTI2018-099672-J-I00 and PID2020-113157GB-I00 (funded by MCIN/AEI/10.13039/501100011033 and ‘ERDF A way of making Europe’).

Interactions between organisms are determined by species traits and differ in specialization, from generalist to highly specialized relationships. Although we expect that the effect of habitat loss and fragmentation on the abundance and survival of species depends on their degree of specialization, few studies have deepened into the interplay between interaction specialization and habitat loss.Here, we investigate the combined effect of habitat fragmentation and life traits (growth type and reproductive mode) on the specialization of lichen-forming fungi (mycobionts) towards its photosynthetic partners (photobionts) in lichen symbioses.We studied mycobiont specialization in epiphytic lichen communities present in ten fragments of Quercus rotundifolia trees embedded in an agricultural matrix. Both mycobionts and photobionts were identified through DNA sequencing and mycobiont specialization was measured through interaction parameters calculating the relative number of interactions (normalized degree; ND) and the specialization of each species based on its discrimination from a random selection of partners (d’). Phylogenetic generalized linear mixed models were used to analyze the effect of patch size as well as the life traits growth type (crustose, foliose, fruticose) and reproduction mode (sexual vs asexual) on mycobiont specialization.Both mycobiont and photobiont richness along the patch size gradient followed a hump-back pattern, which was more pronounced in photobionts. Mycobionts forming crustose biotypes established the largest number of interactions. Mycobiont specialization (d’) was larger for fruticose and foliose biotypes and for species with vegetative reproduction. Along the gradient of fragment size, the relative number of interactions decreased and the specialization of mycobionts with vegetative reproduction increased.Synthesis: The analysis of mycobiont specialization towards their photobionts in communities of epiphytic lichens in a fragmented Mediterranean forest revealed that the interaction between species life traits and habitat loss on specialization cannot be neglected. The results also pointed to the ability of some species to modulate their interactions to certain extent, suggesting that species might have a greater resilience to abiotic changes than expected, presumably creating extinction debt or even avoiding extinction processes to some extent.ResumenLas interacciones entre organismos están determinadas por los rasgos funcionales de las especies y difieren en su grado de especialización, desde interacciones generalistas hasta las altamente especializadas. Aunque se espera que el efecto de la pérdida y fragmentación del hábitat sobre la abundancia y la supervivencia de las especies dependa de su grado de especialización, pocos estudios han profundizado en la interacción entre la especialización de las interacciones y la pérdida de hábitat.En este artículo investigamos el efecto combinado de la fragmentación del hábitat y los rasgos funcionales de las especies (tipo de crecimiento y modo reproductivo) en la especialización de los hongos liquenizados (micobiontes) hacia sus socios fotosintéticos (fotobiontes) en las simbiosis de líquenes.Se estudió la especialización de micobiontes en comunidades de líquenes epífitos presentes en diez fragmentos de árboles de Quercus rotundifolia incrustados en una matriz agrícola. Tanto los micobiontes como los fotobiontes fueron identificados mediante la secuenciación del ADN y la especialización de los micobiontes se midió a través de parámetros de interacción calculando el número relativo de interacciones (grado normalizado; ND) y la especialización de cada especie en función de su discriminación de una selección aleatoria de simbiontes (d’). Se utilizaron modelos lineales mixtos generalizados filogenéticos para analizar el efecto del tamaño del parche, así como los rasgos de tipo de crecimiento (crustáceo, folioso, frutal) y el modo de reproducción (sexual frente a asexual) sobre la especialización de los micobiontes.Tanto la riqueza de micobiontes como de fotobiontes a lo largo del gradiente de tamaño de los parches siguió un patrón de U inversa, que fue más pronunciado en los fotobiontes. Los micobiontes que forman biotipos crustáceos establecieron el mayor número de interacciones. La especialización de los micobiontes (d’) fue mayor para los biotipos fruticulosos y foliosos y para las especies con reproducción vegetativa. A lo largo del gradiente del tamaño del fragmento, el número relativo de interacciones disminuyó y la especialización de los micobiontes con reproducción vegetativa aumentó.Síntesis: El análisis de la especialización de los micobiontes hacia sus fotobiontes en comunidades de líquenes epífitos en un bosque mediterráneo fragmentado reveló que no se puede descartar la interacción entre los rasgos de vida de las especies y la pérdida de hábitat sobre la especialización. Los resultados también apuntaron a la capacidad de algunas especies para modular sus interacciones hasta cierto punto, sugiriendo que las especies podrían tener una resiliencia a los cambios abióticos mayor de lo esperado, presumiblemente creando una deuda de extinción o incluso evitando los procesos de extinción hasta cierto punto. Palabras clave: Bosque mediterráneo, epífitos, fotobiontes, hongos liquenizados, selectividad.

© 2021 The Authors., Facilitation, an ecological interaction assembling plant communities worldwide, has been shown to modulate both species richness and ecosystem functions. Such a biodiversity–ecosystem functioning (BEF) relationship can be decomposed into different components not only related to species losses and gains but also to the identity of the species and the context in which they live. Using an extension of the classical BEF approach named CAFE (community assembly and the functioning of ecosystems), we quantified the contribution of these components to the BEF relationship in a Spanish semiarid plant community shaped by facilitation. We used species richness as a measure for biodiversity and plant cover as a proxy of multiple ecosystem functions including plant productivity, soil protection, soil fertility and microbial productivity. Nurse plants doubled the number of species that live beneath them relative to open ground, but caused a five-fold increase in plant cover. The disproportionate increase of plant cover was a consequence of the identity of the species enhanced by nurse plants, which were more productive than the average. We discuss these results in terms of sampling effects (i.e. the higher probability of richer communities to harbour hyperproductive species) and complementary effects (i.e. richer communities enhancing productivity through resource partitioning, abiotic facilitation or biotic feedbacks). The enhancement of ecosystem functions that plant facilitation produces by incorporating species with high functional values to the community may reverberate among other trophic levels and propagate beyond the local scale where the ecological interaction is produced., Financial support was provided by the Spanish Ministry of Economy and Competitiveness (CGL2014-58333-P, CGL2017-89751-R, PID2020-113157GB-I00).

In the brief time since the outbreak of the COVID 19 pandemic, and despite its proofreading mechanism, the SARS-CoV-2 coronavirus has accumulated a significant amount of genetic variability through recombination and mutation events. To test evolutionary trends that could inform us on the adaptive process of the virus to its human host, we summarize all this variability in the Sequence Compositional Complexity (SCC), a measure of genome heterogeneity that captures the mutational and recombinational changes accumulated by a nucleotide sequence along time. Despite the brief time elapsed, we detected many differences in the number and length of compositional domains, as well as in their nucleotide frequencies, in more than 12,000 high-quality coronavirus genomes from across the globe. These differences in SCC are phylogenetically structured, as revealed by significant phylogenetic signal. Phylogenetic ridge regression shows that SCC followed a generalized decreasing trend along the ongoing process of pathogen evolution. In contrast, SCC evolutionary rate increased with time, showing that it accelerates toward the present. In addition, a low rate set of genomes was detected in all the genome groups, suggesting the existence of a stepwise distribution of rates, a strong indication of selection in favor of different dominant strains. Coronavirus variants reveal an exacerbation of this trend: non-significant SCC regression, low phylogenetic signal and, concomitantly, a threefold increase in the evolutionary rate. Altogether, these results show an accelerated decline of genome heterogeneity along with the SARS CoV 2 pandemic expansion, a process that might be related to viral adaptation to the human host, perhaps paralleling the transformation of the current pandemic to epidemic.

Seed dispersal benefits plants and frugivores, and potentially drives co-evolution, with consequences to diversification evidenced for, e.g., primates. Evidence for macro-coevolutionary patterns in multi-specific, plant-animal mutualisms is scarce, and the mechanisms driving them remain unexplored. We tested for phylogenetic congruences in primate-plant interactions and showed strong co-phylogenetic signals across Neotropical forests, suggesting that both primates and plants share evolutionary history. Phylogenetic congruence between Platyrrhini and Angiosperms was driven by the most generalist primates, modulated by their functional traits, interacting with a wide-range of Angiosperms. Consistently similar eco-evolutionary dynamics seem to be operating irrespective of local assemblages, since co-phylogenetic signal emerged independently across three Neotropical regions. Our analysis supports the idea that macroevolutionary, coevolved patterns among interacting mutualistic partners are driven by super-generalist taxa. Trait convergence among multiple partners within multi-specific assemblages appears as a mechanism favouring these likely coevolved outcomes

While antagonistic interactions between plants have been a major topic of eco-evolutionary research, little evidence exists on the evolution of positive plant interactions (i.e., plant facilitation). Here, we first summarize the existing empirical evidence on the role of facilitation as a selection pressure on plants. Then, we develop a theoretical eco-evolutionary framework based on fitness-trait functions and interaction effectiveness that provides predictions for how facilitation-related traits may evolve. As evolution may act at levels beyond the individual (such as groups or species), we discuss the subject of the units of evolutionary selection through facilitation. Finally, we use the proposed formal evolutionary framework for facilitation to identify areas of future research based on the knowledge gaps detected., This work was supported by CYTED (Red 418RT0555) and the Swiss National Science Foundation (PP00P3_170645). This is a contribution to the Research Unit Modeling Nature, funded by the Consejería de Economía, Conocimiento, Empresas y Universidad, and European Regional Development Fund (ERDF), reference SOMM17/6109/UGR.

The tendency of closely related plant species to share natural enemies has been suggested to limit their co-occurrence and performance, but we lack a deep understanding on how mutualistic interactions such as the mycorrhizal symbiosis affect plant–plant interactions depending on the phylogenetic relatedness of the interacting plants. We hypothesise that the effect of the mycorrhizal symbiosis on plant-plant facilitative interactions depends on the phylogenetic distance between the nurse and facilitated plants. A recently published meta-analysis compiled the strength of plant facilitative interactions in the presence or absence (or reduced abundance) of mycorrhizal fungi. We use phylogeneti- cally informed Bayesian linear models to test whether the effect size is influenced by the phy- logenetic distance between the plant species Conspecific facilitative interactions are more strongly enhanced by mycorrhizal fungi than interactions between closely related species. In heterospecific interactions, the effect of the mycorrhizal symbiosis on plant facilitation increases with the phylogenetic distance between the nurse and facilitated plant species. Our result showing that the effect of mycorrhizal symbiosis on the facilitation interactions between plants depends on their phylogenetic relatedness provides new mechanisms to understand how facilitation is assembling ecological communities, AMN was supported by a postdoctoral contract from the Spanish Ministry of Economy and Competitiveness (FPDI-2013-16266; IJCI-2015-23498). Financial support was provided by Early Career Project Grant from the BES (3975-4849), the Spanish Ministry of Economy and Competitiveness (RTI2018-099672-J- I00), PAPIIT-DGAPA-UNAM (IN-213414-3; IN-210117), the regional government Generalitat Valenciana (PROMETEO/ 2016/021, GV/2016/187), Red CYTED (P417RT0228) and Ecometas excellence network (CGL2016-81706-REDT).

Navarro-Cano, J.A., Goberna, M., Verdu, M. 2019. Plant facilitation as a tool to restore diversity and ecosystem functions. Ecosistemas 28(2): 20-31. Doi.: 10.7818/ECOS.1747 Traditional restoration programmes have focused on conditioning plantation sites and reintroducing plant species. Nowadays, however, ecological restoration is conceived as the complete recovery of biodiversity and ecosystem performance. Here, we review the use of plant-plant facilitation as a tool to restore both diversity and ecosystem functions. Facilitation is an ecological interaction between a nurse species, which is able to colonize a stressful habitat and modify the microenvironment beneath its canopy, and the beneficiary species that are not so stress-tolerant and grow under the nurse. Differences in the establishment niche between the nurse and its beneficiaries imply that species sharing facilitative interactions have different functional traits, and can therefore coexist. This process increases, at the landscape scale, all taxonomic, functional and phylogenetic plant diversity. Plant diversity patterns further permeate into those of consumers and decomposers. Thus, restoration based on plant-plant facilitation allows the recovery of multiple facets of diversity at several trophic levels and, eventually, the restoration of essential ecosystem functions (fertility, productivity, or decomposition). We illustrate these cascading effects in the text by means of observational surveys in natural ecosystems governed by facilitation, as well as manipulative experiments and restoration activities.

Environmental conditions can modify the intensity and sign of ecological interactions. The stress gradient hypothesis (SGH) predicts that facilitation becomes more important than competition under stressful conditions. To properly test this hypothesis, it is necessary to account for all (not a subset of) interactions occurring in the communities and consider that species do not interact at random but following a specific pattern. We aim to assess elevational changes in facilitation, in terms of species richness, frequency and intensity of the interaction as a function of the evolutionary relatedness between nurses and their associated species. We sampled nurse and their facilitated plant species in two 1000–2000 m. elevation gradients in Mediterranean Chile where low temperature imposes a mortality filter on seedlings. We first estimated the relative importance of facilitation as a mechanism adding new species to communities distributed along these gradients. We then tested whether the frequency and intensity of facilitation increases with elevation, taking into account the evolutionary relatedness of the nurse species and the facilitated species. We found that nurses increase the species richness of the community by up to 35%. Facilitative interactions are more frequent than competitive interactions (56% versus 44%) and facilitation intensity increased with elevation for interactions involving distantly related lineages. Our results highlight the importance of including an evolutionary dimension in the study of facilitation to have a clearer picture of the mechanisms enabling species to coexist and survive under stressful conditions. This knowledge is especially relevant to conserve vulnerable and threatened communities facing new climate scenarios, such as those located in Mediterranean-type ecosystems., This work has been partially financed by ICM (P05-002) and by CONICYT (21140099). MV is supported by CYTED (Red 418RT0555). ROB and LAC are supported by Project CONICYT PIA support for CCTE AFB170008 funding the Institute of Ecology and Biodiversity.

Mammals kill both conspecific infants and adults. Whereas infanticide has been profusely studied, the killing of non-infants (adulticide) has seldom attracted the attention of researchers. Mammals kill conspecific adults by at least four, non-exclusive reasons: during intrasexual aggression for mating opportunities, to defend valuable resources, to protect their progeny and to prey upon conspecifics. In this study, we test which reason is most likely to explain male and female adulticide in mammals. For this, we recorded the presence of adulticide, the ecological and behavioural traits, and the phylogenetic relationship for more than 1000 species. Adulticide has been recorded in over 350 species from the most important Mammalian clades. Male adulticide was phylogenetically correlated with the presence of size dimorphism and intrasexually selected weapons. Female adulticide was phylogenetically associated with the occurrence of infanticide. These results indicate that the evolutionary pathways underlying the evolution of adulticide differ between sexes in mammals. Whereas males commit adulticide to increase breeding opportunities and to compete with other males for mating, females commit adulticide mainly to defend offspring from infanticidal conspecifics.

[Aims]: Harsh edaphic environments harbor species with different soil affinities. Plant’s responses to specific edaphic constraints may be compromised against responses to prevalent stresses shared with other semi-arid environments. We expect that species with high edaphic affinity may show traits to overcome harsh soil properties, while species with low affinity may respond to environmental constraints shared with arid environments. [Methods]: We quantified the edaphic affinity of 12 plant species co-occurring in gypsum outcrops and measured traits related to plant responses to specific gypsum constraints (rooting and water uptake depth, foliar accumulation of Ca, S and Mg), and traits related to common constraints of arid environments (water use efficiency, macronutrients foliar content). [Results]: Plants in gypsum outcrops differed in their strategies to face edaphic limitations. A phylogenetic informed PCA segregated species based on their foliar Ca and S accumulation and greater water uptake depths, associated with plant responses to specific gypsum limitations. Species’ gypsum affinity explained this segregation, but traits related to water or nutrient use efficiency did not contribute substantially to this axis. [Conclusions]: Plant’s specializations to respond to specific edaphic constraints of gypsum soils do not limit their ability to deal with other non-specific environmental constraints., RSM was supported by the Ministry of Science and Innovations (FPU grant FPU17/00629). JPF was supported by Grupo de Referencia H09_20R (Aragón regional government, Spain). Financial support was provided by the Valencian Regional Government (GV/2016/187) and the Spanish Ministry of Science, Innovation and Universities (RTI2018-099672-J-I00; CGL2013-48753-R co-funded by FEDER).

Denitrification causes nitrogen losses from terrestrial ecosystems. The magnitude of nitrogen loss depends on the prevalence of denitrifiers, which show ecological differences if they harbour nirS or nirK genes encoding nitrite reductases with the same biological function. Thus, it is relevant to understand the mechanisms of co-existence of denitrifiers, including their response to environmental filters and competition due to niche similarities. We propose a framework to analyse the co-existence of denitrifiers across multiple assemblages by using nir gene-based co-occurrence networks. We applied it in Mediterranean soils before and during 1 year after an experimental fire. Burning did not modify nir community structure, but significantly impacted co-occurrence patterns. Bacteria with the same nir co-occurred in space, and those with different nir excluded each other, reflecting niche requirements: nirS abundance responded to nitrate and salinity, whereas nirK to iron content. Prior to fire, mutual exclusion between bacteria with the same nir suggested competition due to niche similarities. Burning provoked an immediate rise in mineral nitrogen and erased the signals of competition, which emerged again within days as nir abundances peaked. nir co-occurrence patterns can help infer the assembly mechanisms of denitrifying communities, which control nitrogen losses in the face of ecological disturbance., Financial support was provided by the Spanish Ministerio de Economía y Competitividad (CGL2017-89751-R) and the Generalitat Valenciana (SEJI/2017/030). The authors thank the organizers of the experimental fire, within the GRACCIE research net (CONSOLIDER-Ingenio program, Ministerio de Ciencia e Innovación, Spain), for kindly inviting us to participate and Maria Hellman for her help with the laboratory work.

Progressive evolution, or the tendency towards increasing complexity, is a controversial issue in biology, which resolution entails a proper measurement of complexity. Genomes are the best entities to address this challenge, as they encode the historical information of a species’ biotic and environmental interactions. As a case study, we have measured genome sequence complexity in the ancient phylum Cyanobacteria. To arrive at an appropriate measure of genome sequence complexity, we have chosen metrics that do not decipher biological functionality but that show strong phylogenetic signal. Using a ridge regression of those metrics against root-to-tip distance, we detected positive trends towards higher complexity in three of them. Lastly, we applied three standard tests to detect if progressive evolution is passive or driven—the minimum, ancestor– descendant, and sub-clade tests. These results provide evidence for driven progressive evolution at the genome-level in the phylum Cyanobacteria., Generalitat Valenciana Prometeo/2018/A/133, European Union (EU), Fulbright fellowship (Spanish Minister of Science, Innovation and Universities), SAF2015-65878-R, AGL2017-88702-C2-2-R, PGC2018-099344-B-I00

Under global change, how biological diversity and ecosystem services are maintained in time is a fundamental question. Ecologists have long argued about multiple mechanisms by which local biodiversity might control the temporal stability of ecosystem properties. Accumulating theories and empirical evidence suggest that, together with different population and community parameters, these mechanisms largely operate through differences in functional traits among organisms. We review potential trait-stability mechanisms together with underlying tests and associated metrics. We identify various trait-based components, each accounting for different stability mechanisms, that contribute to buffering, or propagating, the effect of environmental fluctuations on ecosystem functioning. This comprehensive picture, obtained by combining different puzzle pieces of trait-stability effects, will guide future empirical and modeling investigations., This study is the result of an international workshop financed by the Valencian government in Spain (Generalitat Valenciana, reference AORG/2018/) and was supported by Spanish Plan Nacional de I+D+i (project PGC2018-099027-B-I00). E.V. was supported by the 2017 program for attracting and retaining talent of Comunidad de Madrid (no. 2017-T2/ AMB-5406).

Identifying the plant traits that determine the outcome of facilitation interactions is essential to understand how communities are assembled and can be restored. Plant facilitation networks are phylogenetically structured but which traits are behind such a pattern is unknown. We sampled plant interactions in stressful ecosystems from south-eastern Spain to build seedling and adult facilitation networks. We collected 20 morphological and ecophysiological traits for 151 species involved in interactions between 879 nurse individuals benefiting 24 584 seedlings and adults. We detected a significant phenotypic signal in the seedling facilitation network that was maintained in the adult network, whereby functionally similar nurses tended to facilitate functionally similar species whose traits differ from those of their nurses. We provide empirical evidence to support a long-lasting theoretical postulate stating that facilitation networks are phenotypically structured. Trait matching through which nurse and facilitated species avoid phenotypic overlap, and consequently competition, is the main linkage rule shaping plant facilitation networks., The study was funded by the projects Mintegra (I Convocatoria de ayudas de la Fundación BBVA a proyectos de Investigación), Red 418RT0555 (CYTED) and CGL2014-58333-P, CGL2017-8975-R (Spanish Ministerio de Economía y Competitividad). D. Rodríguez and B. López Gurillo provided field and laboratory assistance, R.M. López drew Figure 1 and V. Bastazini helped with the statistical analysis.

Progressive evolution, the tendency towards increasing complexity, is a controversial issue in Biology, whose resolution requires a proper measurement of complexity. Genomes are the best entities to address this challenge, as they record the history and information gaining of organisms in their ongoing biotic and environmental interactions. Using six metrics of genome complexity, none of which is primarily associated to biological function, we measure genome complexity in 91 genomes from the phylum Cyanobacteria. Several phylogenetic analyses reveal the existence of progressive evolution towards higher genome complexity: 1) all the metrics detect strong phylogenetic signals; 2) ridge regressions detect positive trends towards higher complexity; and 3) classical proofs for progressive evolution (the minimum, the ancestor-descendent and the sub-clade tests), show that some of these positive trends are driven, being mainly due to natural selection. These findings support the existence of progressive genome evolution in this ancient and diverse group of organisms.

Ecological facilitation, though accepted as a main mechanism of plant community assembly, is just starting to be utilized in restoration programmes. Constructing nurse objects that mimic the effect of natural nurse species can be an option to trigger plant nucleation processes in disturbed stressful ecosystems. We hypothesized that arranged log piles might imitate plant facilitation by alleviating abiotic stress and expanding the regeneration niche of beneficiary species, eventually promoting plant establishment, fitness and diversity. With this aim, within a pilot restoration programme in abandoned mining structures in SE Spain where climatic and edaphic stresses concur, we constructed 133 pine log piles from natural wastes generated by local silvicultural activities. We monitored 51 of them plus their adjacent open areas for 15 months, measuring soil temperature, radiation and humidity. We recorded natural seedling establishment, plant nutritional status and heavy metal accumulation. We further performed a seed sowing experiment to investigate how log piles affect plant taxonomic and functional diversity based on 11 establishment and phytostabilization traits. Pine log piles significantly softened microclimatic conditions and accelerated plant establishment in unfertile and metal-polluted mining substrates, simultaneously capturing water, providing shade and pine seeds. Plant communities that naturally established beneath the piles were 15 times denser and five times taxonomically more diverse than those in open areas, despite being skewed towards pine recruitment. Experimental communities sown under log piles were also 1.4 times functionally more diverse, as theory predicts for relaxed abiotic conditions. Log piles improved seedling nutritional status, in terms of P and K content, at the cost of increased metal accumulation. At the landscape scale, nurse objects triggered plant establishment promoting taxonomic and functional diversity in extremely stressful environments. This study exemplifies how soft restoration tools can be based on mechanisms that are widely accepted in the ecological theory.

Plants’ responses to conficting stresses may result in physiological trade-ofs due to the inter-dependent and costly nature of physiological investments. Physiological tradeofs have been proved within species, but to what extent these trade-ofs are the result of phylogenetic constraints remains poorly known. Environmental stresses can vary widely in diferent biomes, and therefore assessing physiological tradeofs across species must account for this variation. One way of doing so is to assess it within a community, where the co-occurring species have faced a shared combination of flters to establish. Considering a representative sample of species in a single community, we use a macroevolutionary approach to test the hypothesis that plant physiological trade-ofs are evolutionarily conserved within this community (i.e., closely-related species tend to solve the trade-ofs similarly). We analyze the content of fve metabolites in thirty co-occurring plant species, capturing their range of contrasting exposures to abiotic and biotic stresses (growing solitary and in vegetation patches). Our results support that species investment in response to abiotic stress (i.e., proline and abscisic acid content) is traded of against their investment to face biotic stress (i.e., jasmonic acid and salicylic acid), shown by the contrasting loadings of these two groups of metabolites in the frst axes of a principal component analysis (PCA). In addition, the metabolic strategies observed in this community are evolutionarily conserved, as closely related species tend to have similar scores in this PCA, and thus resemble each other in their balance. This is shown by a signifcant phylogenetic signal in the species’ scores along the frst axes of the PCA. Incorporating the evolutionary history of plant species into physiological studies can help to understand the response of plants to multiple stresses currently acting in ecological communities., AMN was supported by a postdoctoral contract from the Spanish Ministry of Economy and Competitiveness (IJCI‐2015‐23498). RSM was supported by the Ministry of education and professional training, Spain (FPU Grant FPU17/00629). Financial support was provided by the Spanish Ministry of Economy and Competitiveness (RTI2018-099672-J-I00, AGL2016-76574-R). Hormone measurements were carried out at the central facilities (Servei Central d’Instrumentació Científca, SCIC) of the Universitat Jaume I

Fire is an ecological disturbance that alters soil microbiomes and the functions they mediate in terrestrial ecosystems. Soil microbial diversity in Mediterranean Basin ecosystems shows resilience to fire following the restoration of plant-soil feedbacks. We hypothesised that microbial functions related to organic matter decomposition and nutrient cycling might show similar patterns of recovery. We quantified the rates of microbial respiration and enzymatic activities related to C, N and P cycling in three 20-year fire chronosequences including 150 transects in 50 burned and unburned plots (no historical fire registers) in a paired experimental design. Microbial functions, except for the hydrolysis of N compounds, were sensitive to fire but recovered the levels of unburned plots in approximately 20–24 years. The recovery of microbial functions responded to abiotic and biotic drivers. Total soil nitrogen concentration was overall strong predictor of microbial functions. In addition, fungal phylogenetic diversity significantly explained the post-fire trajectories of potentially mineralizable C, while bacterial diversity was involved in the restoration of organic C and P hydrolysis. Our results suggest that the long-term recovery of soil biodiversity in Mediterranean Basin ecosystems creates resilience to restore essential ecosystem functions after fire., Financial support was provided by the Spanish Ministry of Economy and Competitiveness, and Generalitat Valenciana (grant numbers CGL2017-89751-R, BES-2012-062331, SEJI/2017/030).

10 Pág.., Soil ecology is witnessing exponential growth in the number of studies using co-occurrence network analysis. Researchers reconstruct networks based on the co-occurrence of taxa or genes across soil samples at a wide range of geographic scales - from single aggregates to the whole planet - and taxonomic scopes, some studies targeting specific taxa or guilds to others surveying the whole microbiome as well as micro- and mesofauna. Co-occurrence networks can be very useful to extract simple patterns from complex datasets. Applications include the detection of abiotic and biotic factors that determine community structure, the identification of keystone taxa and their relationship to specific soil functions, and the inference of mechanisms of community assembly. However, networks are more and more often misused and serve as mere graphic tools with no attempt at hypothesis testing. In this perspectives article, we first review the main usage of co-occurrence network analysis in soil ecology during the last decade. We then discuss the applications and caveats of network analysis in soil ecology, leaving apart strictly methodological aspects of network reconstruction, which is beyond the focus of this article. Finally, we include recommendation guidelines – such as the possibility of informing networks with geographic, environmental and/or phylogenetic information – with the hope that this will facilitate network analysis to become a useful tool that helps elucidate meaningful patterns in soil ecology., The authors received grants CGL2017-8975-R and PID2020-119634GB-I00 funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”.

Metal mining in drylands generates waste tailings with high toxicity, physical instability, as well as water and thermal stresses that hamper their biological colonization. This limits the restoration of ecosystem functions that are essential to re‐integrate these artificial micro‐deserts within the landscape matrix. We assessed the functional role of local nurse plant species and their traits to restore ecosystem functions related to soil fertility, soil microbial productivity and the reduction of abiotic stress. We sampled 30 metalliferous tailings in a mining district from semi‐arid Spain to detect nurse plant species and quantify their ability to promote essential functions from their establishment on the barren substrate up to the adult stage. We found 11 plant species acting as nurses out of 102 species able to colonize barren soils. Ten nurses further triggered a cascade of effects increasing soil fertility and microbial productivity and/or lowering soil abiotic stress. Plant species with larger life‐forms and longer periods of establishment since tailing abandonment contributed the most to the promotion of ecosystem functions. C4 plant species developing root systems with lower intensivity and depth:laterality ratios, as well as leaves with lower carbon:nitrogen ratios (C:N) induced a faster recovery of ecosystem functions. Synthesis and applications. We propose a protocol for selecting key species to be used in restoration programmes based on their ability to restore ecosystem functions under extremely stressful conditions. We encourage combination of multiple target species with complementary traits in order to reinforce the rehabilitation of ecosystem functions., This work was supported by the I Convocatoria de ayudas de la Fundación BBVA a proyectos de Investigación (project Mintegra) and the Spanish Ministerio de Economía y Competitividad (project CGL2014‐58333‐P and MG's Ramon y Cajal contract).

Fire is a major disturbance linked to the evolutionary history and climate of Mediterranean ecosystems, where the vegetation has evolved fire‐adaptive traits (e.g., serotiny in pines). In Mediterranean forests, mutualistic feedbacks between trees and ectomycorrhizal (ECM) fungi, essential for ecosystem dynamics, might be shaped by recurrent fires. We tested how the structure and function of ECM fungal communities of Pinus pinaster and Pinus halepensis vary among populations subjected to high and low fire recurrence in Mediterranean ecosystems, and analysed the relative contribution of environmental (climate, soil properties) and tree‐mediated (serotiny) factors. For both pines, local and regional ECM fungal diversity were lower in areas of high than low fire recurrence, although certain fungal species were favoured in the former. A general decline of ECM root‐tip enzymatic activity for P. pinaster was associated with high fire recurrence, but not for P. halepensis. Fire recurrence and fire‐related factors such as climate, soil properties or tree phenotype explained these results. In addition to the main influence of climate, the tree fire‐adaptive trait serotiny recovered a great portion of the variation in structure and function of ECM fungal communities associated with fire recurrence. Edaphic conditions (especially pH, tightly linked to bedrock type) were an important driver shaping ECM fungal communities, but mainly at the local scale and probably independently of the fire recurrence. Our results show that ECM fungal community shifts are associated with fire recurrence in fire‐prone dry Mediterranean forests, and reveal complex feedbacks among trees, mutualistic fungi and the surrounding environment in these ecosystems., This work was supported by the projects MyFUNCO (CGL2011-29585-C02-02) and PiroPheno (CGL2017-89751-R) founded by the Spanish Ministry for Economy and Competitiveness (MINECO), and by the LABoratoire d'EXcellence Arbre (LABEX Arbre). L.P.I. held a pre-doctoral fellowship awarded by MINECO. We also acknowledge three anonymous reviewers for their con-structive comments that greatly improved the quality of the manuscript

Co-occurrence network analysis based on amplicon sequences is increasingly used to study microbial communities. Patterns of co-existence or mutual exclusion between pairs of taxa are often interpreted as reflecting positive or negative biological interactions. However, other assembly processes can underlie these patterns, including species failure to reach distant areas (dispersal limitation) and tolerate local environmental conditions (habitat filtering). We provide a tool to quantify the relative contribution of community assembly processes to microbial co-occurrence patterns, which we applied to explore soil bacterial communities in two dry ecosystems. First, we sequenced a bacterial phylogenetic marker in soils collected across multiple plots. Second, we inferred co-occurrence networks to identify pairs of significantly associated taxa, either co-existing more (aggregated) or less often (segregated) than expected at random. Third, we assigned assembly processes to each pair: patterns explained based on spatial or environmental distance were ascribed to dispersal limitation (2%–4%) or habitat filtering (55%–77%), and the remaining to biological interactions. Finally, we calculated the phylogenetic distance between taxon pairs to test theoretical expectations on the linkages between phylogenetic patterns and assembly processes. Aggregated pairs were more closely related than segregated pairs. Furthermore, habitat-filtered aggregated pairs were closer relatives than those assigned to positive interactions, consistent with phylogenetic niche conservatism and cooperativism among distantly related taxa. Negative interactions resulted in equivocal phylogenetic signatures, probably because different competitive processes leave opposing signals. We show that microbial co-occurrence networks mainly reflect environmental tolerances and propose that incorporating measures of phylogenetic relatedness to networks might help elucidate ecologically meaningful patterns., Financial support was provided by the Spanish Ministry of Economy and Competitiveness (CGL2014‐58333‐P; CGL2017‐89751‐R) and the Generalitat Valenciana (SEJI/2017/030). MG acknowledges support by the Ramón y Cajal Programme and AGF by the FPI Programme (BES‐2015‐072580).

Mycorrhizal symbiosis has important implications for the diversity and productivity of plant communities. However, our mechanistic understanding of its influence on the outcome of plant-plant interactions is still expanding. In this review we propose a framework that might be useful to efficiently approach the effects of mycorrhizal fungi (MF) on plant-plant interactions. We propose several scenarios that can theoretically result in different outcomes of plant-plant interactions based on the combination of two processes: the diversity of resources provided by MF taxa to their host (resource dissimilarity) and contrasting ways of distributing those resources (resource distribution). Then, we illustrate our arguments with different ecological contexts where certain combinations of these two processes are prone to occur. The proposed framework suggests testable hypotheses that can contribute to elucidate relevant processes underlying the effects of mycorrhizal symbiosis on plant-plant interactions., AMN was supported by a postdoctoral contract from the Spanish Ministry of Economy and Competitiveness (FPDI-2013-16266; IJCI-2015-23498) and the National Research Program for Development and Innovation CGL2013-42312-R/BOS. Financial support was also provided by PAPIIT-DGAPA-UNAM (IN-213414-3; IN-210117), the regional government Generalitat Valenciana (PROMETEO/2016/021, GV/2016/187), and Spanish Ministry of Economy and Competitiveness (CGL2014-53840-REDT; CGL2014-58333-P).

Plant species identity is assumed to be a major driver of belowground microbial diversity and composition. However, diagnosing which plant functional traits are responsible for shaping microbial communities remains elusive. Primary succession on barren metalliferous mining substrates was selected as the framework to study above-belowground interactions, and plant functional traits that lead the successional trajectories of soil bacterial communities were identified. The impact of the plant functional group (i.e. trees, shrubs, dwarf shrubs, perennial grasses), a trait integrating the life span and morphological structure, on the bacterial primary succession was monitored. Bacterial diversity and composition was estimated along plant size gradients including over 90 scattered patches ranging from seedlings to mature multispecific patches. Soil bacterial diversity was affected by heavy metals levels and increased towards higher resource availability underneath mature patches, with stress-tolerant heterotrophs and phototrophs being replaced by competitive heterotrophs. The plant functional group modulated these general patterns and shrubs had the greatest impact belowground by inducing the largest increase in soil fertility. Functional traits related to leaf decomposability and root architecture further determined the composition and structure of bacterial communities. These results underline the importance of plant functional traits in the assembly of soil bacterial communities, and can help guiding restoration of degraded lands., This work was supported by the I Convocatoria de ayudas de la Fundación BBVA a proyectos de investigación, the Spanish Ministerio de Economía y Competitividad (projects CGL2014-58333-P; CGL2017-89751-R) and the Generalitat Valenciana (project SEJI/2017/030). MG acknowledges support by the Ramón y Cajal programme (Ministerio de Economía y Competitividad).

In facilitative interactions, facilitated plants gain a benefit from growing associated to a nurse plant, without damaging the nurse. The persistence of these positive interactions or their shift to competition might depend on whether the nurse shrub also gains some benefit from the association. We hypothesized that nurse shrubs can receive water stored in the parenchyma of their facilitated Neobuxbaumia tetetzo once the cactus becomes an adult. We injected deuterium-enriched water into the water storage tissues of N. tetetzo adults, and sampled the xylem water of the nurse Mimosa luisana plant in the shared vegetation patch before and after the injection of the tracer. We also sampled spatial-control individuals of M luisana outside the vegetation patch. We found a significant enrichment in deuterium concentration in the xylem water of the associated M. luisana but not in individuals outside the patch. This suggests that in semiarid environments, nurse plants can benefit from growing associated to succulent columnar cacti by gaining water transferred from their storage tissues during dry periods, potentially enhancing persistence of facilitative interactions., This work was supported by Ministerio de Economía y Competitividad [FPDI-2013-16266, IJCI-2015-23498]; British Ecological Society [Early Career Project Grant 3975-4849] and Programa de Apoyo a Proyectos de Investigación e Innovación Tecnológica, Dirección General de Asuntos del Personal Académico [IN-213414-3].

Ecological network studies are providing important advances about the organization, stability and dynamics of ecological systems. However, the ecological networks approach is being integrated very slowly in plant community ecology, even though the first studies on plant facilitation networks (FNs) were published more than a decade ago. The study of interaction networks between established plants and plants recruiting beneath them, which we call Recruitment Networks (RNs), can provide new insights on mechanisms driving plant community structure and dynamics. RNs basically describe which plants recruit under which others, so they can be seen as a generalisation of the classic FNs since they do not imply any particular effect (positive, negative or neutral) of the established plants on recruiting ones. RNs summarise information on the structure of sapling banks. More importantly, the information included in RNs can be incorporated into models of replacement dynamics to evaluate how different aspects of network structure, or different mechanisms of network assembly, may affect plant community stability and species coexistence. To allow an efficient development of the study of FNs and RNs, here we unify concepts, synthesise current knowledge, clarify some conceptual issues, and propose basic methodological guidelines to standardise sampling methods that could make future studies of these networks directly comparable., Red CYTED (P417RT0228), Project COEXMED II and PIROPHENO (CGL2015‐69118‐C2‐1‐P; CGL2017‐89751‐R; Spanish Ministerio de Economía y Competitividad and FEDER funds from the EU) funded this project.

Nurse plants drive the assembly of facilitated communities and commonly promote plant–soil feedbacks, and are thus recognized as key engineers in abiotically stressful ecosystems. The literature neglects; however, the role of the communities which benefit from the presence of the nurse as contributors to soil ecosystem functions. We hypothesized that the nurse and its beneficiaries synergistically enhance essential ecosystem functions mediated by soil microbiota. To track how plant–plant facilitation impacts plant–soil feedbacks, we selected three nurse species in semi-arid mine tailings and defined three microsites (open space, nurse canopy and nurse + facilitated canopy). In each microsite, we quantified 18 abiotic and biotic variables associated with four functions: reduction in climatic stress, reduction in edaphic stress, soil fertility and soil microbial productivity (decomposition and nutrient cycling). Litter biomass increased from open spaces to the microsite beneath the nurses, and further beneath the nurses and their beneficiaries. Litter biomass was a good predictor of both the reduction in climatic stress and increase in edaphic stress (likely owing to metal bioaccumulation). We attributed increments in soil organics and heterotrophic respiration beneath the nurses and their beneficiaries, compared to nurses alone, to biomass effects through increased litter deposition. Variation in fertility and microbial productivity among microsites shaped by the nurses and their facilitated communities was attributed to both diversity and biomass effects. In particular, fertility was promoted beneath phenotypically diverse facilitated communities, as inferred from ten above- and below-ground traits. However, microbial productivity increased at low levels of root biomass likely due to reduced plant–microbe competition for nutrients. Synthesis. Our results show that facilitated plant communities sheltered by nurse species relieve local abiotic stress and promote plant–microbe interactions, both through biomass and biodiversity effects. These observations shift the conception of facilitated species from simple beneficiaries of the nurse's effects to co-drivers of essential ecosystem functions., This work was supported by the I Convocatoria de ayudas de la Fundación BBVA a proyectos de Investigación (project Mintegra) and the Spanish Ministerio de Ciencia, Innovación y Universidades (projects CGL2014‐58333‐P, CGL2017‐89751‐R and MG's Ramón y Cajal contract).

The ecosystem functions performed by soil microbial communities can be indirectly altered by ecological disturbances that deeply modify abiotic factors. Fire, a widespread disturbance in nature, is well known to alter soil abiotic properties but we still ignore how these shifts are translated into changes in the structure of soil microbial communities and the ecosystem functions they deliver. The phylogenetic structure of soil bacterial communities has been shown to be a good predictor of ecosystem functioning, and therefore we used it as a measure linking the temporal variation of soil abiotic properties and ecosystem functions caused by an experimental fire in a Mediterranean shrubland. Fire immediately favoured a basal phylogenetic clade containing lineages that are able to thrive with high temperatures and to take advantage of the post-fire nutrient release. Later changes in the phylogenetic structure of the community were dominated by phyla from another basal clade that show competitive superiority coinciding with high levels of oxidizable carbon in soil. The phylogenetic structure of the bacterial community significantly explained not only microbial biomass, respiration and specific enzymatic activities related to C, N and P cycles but also the community-weighted mean number of 16S rRNA gene copies, an integrative proxy of several functions. While most of the ecosystem functions recovered one year after the fire, this was not the case of the structure of bacterial community, suggesting that functionally equivalent communities might be recovering the pre-disturbance levels of ecosystem performance., Financial support was provided by the Spanish Ministry of Science and Innovation (R+D Project CGL2011-29585-C02-01), the Ministry of Economy and Competitiveness (CGL2014-58333-P; CGL2017-89751-R) and the Generalitat Valenciana (SEJI/2017/030). Experimental burning was organised within the GRACCIE research net (CONSOLIDER-Ingenio program, Ministry of Science and Innovation, Spain). We thank the organisers, in particular Jaime Baeza, for kindly inviting us to participate in the experimental burning. EPV acknowledges support by the FPI Programme (BES-2012-062331) and MG by the Ramón y Cajal Programme of the Spanish Ministry of Economy and Competitiveness.

Defaunation erodes millions of years of evolutionary history of bird–seed dispersal interactions in human-modified landscapes., Species on Earth are interconnected with each other through ecological interactions. Defaunation can erode those connections, yet we lack evolutionary predictions about the consequences of losing interactions in human-modified ecosystems. We quantified the fate of the evolutionary history of avian–seed dispersal interactions across tropical forest fragments by combining the evolutionary distinctness of the pairwise-partner species, a proxy to their unique functional features. Both large-seeded plant and large-bodied bird species showed the highest evolutionary distinctness. We estimate a loss of 3.5 to 4.7 × 104 million years of cumulative evolutionary history of interactions due to defaunation. Bird-driven local extinctions mainly erode the most evolutionarily distinct interactions. However, the persistence of less evolutionarily distinct bird species in defaunated areas exerts a phylogenetic rescue effect through seed dispersal of evolutionarily distinct plant species.

The diversity of pathways through which mycorrhizal fungi alter plant coexistence hinders the understanding of their effects on plant‐plant interactions. The outcome of plant facilitative interactions can be indirectly affected by mycorrhizal symbiosis, ultimately shaping biodiversity patterns. We tested whether mycorrhizal symbiosis enhances plant facilitative interactions and whether its effect is consistent across different methodological approaches and biological scenarios. We conducted a meta‐analysis of 215 cases (involving 21 nurse and 29 facilitated species), in which the performance of a facilitated plant species is measured in the presence or absence of mycorrhizal fungi. We show that mycorrhizal fungi significantly enhance plant facilitative interactions mainly through an increment in plant biomass (aboveground) and nutrient content, although their effects differ across biological contexts. In semiarid environments mycorrhizal symbiosis enhances plant facilitation, while its effect is non‐significant in temperate ecosystems. In addition, arbuscular but not ecto‐mycorrhizal (EMF) fungi significantly enhance plant facilitation, particularly increasing the P content of the plants more than EMF. Some knowledge gaps regarding the importance of this phenomenon have been detected in this meta‐analysis. The effect of mycorrhizal symbiosis on plant facilitation has rarely been assessed in other ecosystems different from semiarid and temperate forests, and rarely considering other fungal benefits provided to plants besides nutrients. Finally, we are still far from understanding the effects of the whole fungal community on plant‐plant interactions, and on plant species coexistence., AMN was supported by a postdoctoral contract from the Spanish Ministry of Economy and Competitiveness (FPDI‐2013‐16266; IJCI‐2015‐23498) and an Early Career Project Grant from the BES (3975‐4849). Financial support was also provided by PAPIIT‐DGAPA‐UNAM (IN‐213414‐3), the Spanish Ministry of Economy and Competitiveness (CGL2014‐58333‐P), the regional government Generalitat Valenciana (PROMETEO/2016/021, GV/2016/187) and Ecometas excellence network (CGL2016‐81706‐REDT).

Plant facilitation, an ecological interaction that benefits at least one species without harming the other, is increasingly used as a restoration tool. To restore degraded habitats under a facilitation framework, practitioners must correctly select both the benefactor (nurse) and the beneficiary (facilitated) species. Based on community assembly and species coexistence theory, we propose selecting plant species that largely differ in a suite of functional traits so that competition is minimized and facilitation maximized due to functional complementarity. To apply this guideline in a pilot restoration experiment performed in metalliferous mine tailings in South-Eastern Spain, we first built the plant–plant facilitative interaction network naturally occurring in a set of 12 tailings. After characterizing each species with 20 morphological and physiological traits, we verified that facilitative interactions were predominantly established between functionally distant species. Then, we designed a sowing experiment combining 50 nurse-facilitated species pairs separated by a wide range of functional distances. The success of seedling establishment significantly increased with the functional distance between the nurse and the facilitated plant species. Synthesis and applications. We encourage the use of ecological facilitation together with trait-based species selection to design restoration programmes based on the principle of increasing functional distance between target species. This method may not only promote the restoration of the plant cover but also impact paramount ecosystem functions, thus being an efficient low-cost restoration practice in abiotically stressful ecosystems., This work was supported by the I Convocatoria de ayudas de la Fundación BBVA a proyectos de Investigación (project Mintegra), the Spanish Ministerio de Economía y Competitividad (project CGL2014‐58333‐P and MG's Ramon y Cajal contract) and the project LIFE13NAT/ES/000436 (Conservation of Habitat 9570 *Tetraclinis articulata forest in the European continent.

Phylogenetic diversity enhances ecosystem functioning but restoration ecology has not taken advantage of this knowledge. We propose plant facilitation as a mechanism to promote phylogenetic diversity in restoration practices. We planted three functionally different species (Gypsophila struthium, Sedum album, and Limonium sucronicum) in a degraded gypsum ecosystem in Spain and found that after 7 years, the species with nurse traits (G. struthium) survived longer and facilitated the establishment of new species forming phylogenetically diverse neighborhoods. These facilitation-driven phylodiverse communities may potentially produce a cascade of benefits on ecosystem functioning.

Plant facilitative interactions may persist in the long term when there are benefits for the interacting adult plants. Whereas persistent benefits for adult nurse plants have been demonstrated, the long-term benefits derived by adult facilitated plants have been largely unexplored. We hypothesize that common mycorrhizal networks (CMNs) can provide a pathway through which nurse species can benefit adult facilitated plants persistently. We specifically test whether nitrogen can be transferred from nurse plants to their adult facilitated plants, and evaluate to which extent CMNs mediate the transfer. We selected 32 adult individuals of 6 facilitated plant species growing in 15 vegetation patches in a Mexican desert. We treated some vegetation patches with fungicide and left others as controls. Then, we labeled the nurse plants with 15N-enriched urea and quantified the amount of 15N transferred to their adult facilitated plants. We expected a greater 15N transfer to facilitated individuals growing in vegetation patches with intact CMNs than in those treated with fungicide. Facilitated plants growing in patches with intact CMNs showed on average a greater increment in their foliar δ15N (i.e. difference between post-labeling–pre-labeling) than those in patches treated with fungicide. Our results provide evidence that CMNs enhance nitrogen transfer among adult plants, thus providing a potential mechanism contributing to the long-term persistence of plant facilitative associations., AMN was supported by a postdoctoral contract from the Ministerio de Economía y Competitividad (FPDI-2013-16266) and an Early Career Project Grant from the BES (3975-4849). Funding was also provided by PAPIIT-DGAPA-UNAM (IN-213414-3).

Phylogenetic diversity reflects both community assembly and evolutionary diversification processes. Communities with low phylogenetic diversity might be the outcome of environmental filters favouring the occurrence and/or the diversification of lineages from particular clades. This rationale applies for regional assemblages. Here we propose to integrate phylogenetic diversity into paleobotanical studies aimed to reconstruct temporal shifts in plant assemblages in the past. To do so we first compiled a fossil dataset of 619 vascular plant taxa occurring through the Cenozoic in the Iberian flora, then we reconstructed their phylogenetic relationships, and finally we calculated temporal changes in phylogenetic diversity. The results reveal high phylogenetic diversity in the early Cenozoic (Danian to Lutetian) followed by an abrupt decline around 40 million years ago and a time interval of lower values during the Oligocene and the Miocene. A decreasing trend of phylogenetic diversity was also detected over the Piacenzian and the Early Pleistocene. Early values of high phylogenetic diversity were not explained by null models, and we speculate on putative causes related to climate. Overall, we propose to combine paleobotanical and phylogenetic information for detecting evolutionary changes that shaped our biodiversity across relevant geological scales., This work is a contribution to NECLIME (Neogene Climate Evolution in Eurasia, www.neclime.de) and has been funded by projects CSO2015-65216-C2-2-P, CGL2015-68604-P (MINECO, Spain), 296/2011 (OAPN, Spain) and 19434/PI/14, 20788/PI/18 (Fundación Séneca), Murcia, Spain. Manuel Casas-Gallego publishes with permission of CGG Robertson.