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ABSTRACT Aim Location Taxon Methods Results Main Conclusions Mountainous regions are rich in reptile biodiversity but face threats from climate and land use changes. Understanding how these factors affect reptile diversity in these regions can highlight key conservation hotspots that require effective conservation actions. Here, we explored reptile taxonomic and functional diversity patterns along the Sierra Madre del Sur region in southeast Mexico, and potential changes in future years caused by different climate and land use change scenarios.Sierra Madre del Sur, México.Reptiles.We used species distribution models and information on species traits to estimate taxonomic and functional diversity throughout the Sierra Madre del Sur (SMS) region under current and future climate and land use change scenarios.Greater taxonomic and functional diversity was observed in both temperate and tropical forests. Taxonomic diversity was higher in more drier areas at high elevations while higher functional diversity was observed in wetter areas at intermediate‐to‐high elevations. Lower diversity for both dimensions was associated with anthropic land uses. In future scenarios, both dimensions of diversity are expected to increase in temperate forest in highlands of central Oaxaca and decrease in the southcentral portion of the SMS, particularly for the worst scenarios due to increased deforestation rates.Higher taxonomic diversity in more drier areas at high elevations could be due to historical and evolutionary factors, while higher functional diversity in wetter areas at intermediate‐to‐high elevations may be explained by a higher environmental heterogeneity in forests within these conditions. Larger diversity losses in the southcentral portion of the SMS are probably due to larger predicted deforestation rates in those areas. Our results are valuable not just for informing conservation actions, such as the creation of protected natural areas but also to understand the underlying processes behind the patterns of reptile diversity. [ABSTRACT FROM AUTHOR]

Coastal dunes are characterised by strong gradients of abiotic stress, typically increasing in severity from inland areas towards the shoreline. Thus, dune gradients represent unique opportunities to study intraspecific responses to environmental changes and to investigate which factors drive community change. This study aims to examine functional trait variation in two coexisting species in response to environmental changes along a dune gradient in NW Spain. Trait convergence was also investigated and compared between both ends of the gradient. We measured functional leaf traits related to plant efficiency in the use of light, water and nutrients, also possible stressors (salt content and pH) and availability of limiting resources (water and nutrients) in the soil. Most soil variables showed changes following a non‐directional gradient. Differences in soil variables were site specific and depended on growth of the study species. Structural and functional traits depended on species and/or plant position on the gradient, except for effective quantum yield of PSII and leaf δ15N. The pattern of variation was mostly directional for reflectance indices related to leaf physiology. Multivariate analyses showed significant interspecific differences in the set of traits they exhibited along positions in the gradient. Species also differed in the combination of traits selected under given environmental conditions. Coexisting species display a specific set of traits that reflects different strategies to environmental stress. Our study highlights the overly simplistic nature of some previous studies that assume dune gradients are monotonically directional, without considering that these gradients may be differentially modified by species activity. [ABSTRACT FROM AUTHOR]

Background and Aims Understanding biomass allocation among plant organs is crucial for comprehending plant growth optimization, survival and responses to the drivers of global change. Yet, the mechanisms governing mass allocation in vascular plants from extreme elevations exposed to cold and drought stresses remain poorly understood. Methodology We analysed organ mass weights and fractions in 258 Himalayan herbaceous species across diverse habitats (wetland, steppe, alpine), growth forms (annual, perennial taprooted, rhizomatous and cushiony) and climatic gradients (3500–6150 m elevation) to explore whether biomass distribution adhered to fixed allometric or optimal partitioning rules, and how variations in size, phylogeny and ecological preferences influence their strategies for resource allocation. Key Findings Following optimal partitioning theory, Himalayan plants distribute more biomass to key organs vital for acquiring and preserving limited resources necessary for their growth and survival. Allocation strategies are mainly influenced by plant growth forms and habitat conditions, notably temperature, water availability and evaporative demands. Alpine plants invest primarily in below-ground stem bases for storage and regeneration, reducing above-ground stems while increasing leaf mass fraction to maximize carbon assimilation in their short growing season. Conversely, arid steppe plants prioritize deep roots over leaves to secure water and minimize transpiration. Wetland plants allocate resources to above-ground stems and below-ground rhizomes, enabling them to resist competition and grazing in fertile environments. Conclusions Himalayan plants from extreme elevations optimize their allocation strategies to acquire scarce resources under specific conditions, efficiently investing carbon from supportive to acquisitive and protective functions with increasing cold and drought. Intraspecific variation and shared ancestry have not significantly altered biomass allocation strategies of Himalayan plants. Despite diverse evolutionary histories, plants from similar habitats have developed comparable phenotypic structures to adapt to their specific environments. This study offers new insights into plant adaptations in diverse Himalayan environments and underscores the importance of efficient resource allocation for survival and growth in challenging conditions. [ABSTRACT FROM AUTHOR]

Understanding the mechanisms underlying species' distribution limits is critical for predicting how species may respond to environmental change. For species restricted to mountain summits, there is concern that climatic changes may result in increasingly restricted distributions. Two central mechanisms govern species distribution limits: (i) niche limitations–environmental conditions beyond distribution limits that are insufficient for survival and reproduction, and (ii) dispersal limitations that prevent colonization of suitable habitat beyond distribution limits. Here, we conducted a transplant experiment to examine the effect of niche versus dispersal limitation on the altitudinal distribution limit of the Ghost Antler Lichen (Pseudevernia cladonia (Tuck.) Hale & Culb.) that, within Québec, Canada, is restricted to high-elevation mountain summits in the southeast. Along an elevation gradient, we transplanted individuals into sites within its distribution, at the edge, and beyond its distribution. We observed that survival and performance were greatest within its distribution and decreased markedly beyond its distribution, supporting our prediction that this lichen is niche limited along the elevation gradient. We suggest that cooler and more humid conditions at the summit are important environmental factors for this species' persistence. Our findings suggest that projected climatic changes in these montane habitats may result in less suitable habitat for this species. [ABSTRACT FROM AUTHOR]

Understanding how plant nutrient acquisition strategies respond to grazing at the community level is critical understanding ecosystem structure and functioning in grasslands. However, few studies have simultaneously compared the difference in above‐ground (leaf) and below‐ground (root) nutrient‐acquisition strategies in response to long‐term grazing, especially at the regional scale.Here, we measured a set of leaf and fine‐root traits that correspond to the fast‐slow economic spectrum at the community level in 10 experimental sites from paired grazed and ungrazed grasslands across a soil nutrient gradient covering three major types of grasslands in northern China.We found that patterns of variations of leaf and fine‐root traits were consistent with both a leaf and root economic spectrum at the community level for both grazed and non‐grazed plots. Grazing had minor effect on community‐level leaf nutrient‐acquisition strategies but strongly influenced community‐level root nutrient‐acquisition strategies. Specifically, root nutrient‐acquisition strategies were shifted to more exploitative resource use in grazed communities. Moreover, soil nutrient contributed to the changes in both leaf and root nutrient‐acquisition strategies, which tended towards a more resource acquisition strategy with increasing soil nutrient levels. Grazing significantly interacted with soil nutrient to affect root nutrient‐acquisition strategies, and grazing contributed more to root nutrient‐acquisition strategies than soil nutrient.Synthesis. Our results demonstrated completely inconsistent responses of community‐level above‐ and below‐ground resource acquisition strategies to long‐term grazing, and below‐ground acquisition strategies were more sensitive to long‐term grazing. Our findings also suggest that high intensity anthropogenic activities such as grazing may strongly modify below‐ground resource acquisition strategies. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Central African rainforests are predicted to be disproportionately affected by future climate change. How species will cope with these changes is unclear, but rapid environmental changes will likely impose strong selection pressures. Here we examined environmental drivers of genomic variation in the central African puddle frog (Phrynobatrachus auritus) to identify areas of elevated environmentally-associated turnover. We also compared current and future climate models to pinpoint areas of high genomic vulnerability where allele frequencies will have to shift the most in order to keep pace with future climate change. Neither physical landscape barriers nor the effects of past Pleistocene refugia influenced genomic differentiation. Alternatively, geographic distance and seasonal aspects of precipitation are the most important drivers of SNP allele frequency variation. Patterns of genomic differentiation coincided with key ecological gradients across the forest-savanna ecotone, montane areas, and a coastal to interior rainfall gradient. Areas of greatest vulnerability were found in the lower Sanaga basin, the southeastern region of Cameroon, and southwest Gabon. In contrast with past conservation efforts that have focused on hotspots of species richness or endemism, our findings highlight the importance of maintaining environmentally heterogeneous landscapes to preserve genomic variation and ongoing evolutionary processes in the face of climate change. [ABSTRACT FROM AUTHOR]

We analyzed the two main drivers (climate and land uses) shaping the composition of small mammal communities at 16 localities situated in the confluence of the Mediterranean and Eurosiberian regions (Barcelona, Spain). The study area represents a land use and land cover gradient showing urbanization and crop intensification in the lowlands and forest encroachment in mountain areas. We identified 2458 small mammal individuals of 12 different species from barn owl (Tyto alba) pellets. Three open-land species (Microtus duodecimcostatus, Crocidura russula, and Mus spretus) and one forest/generalist species (Apodemus sylvaticus) were dominant in the diet, accounting for 93% of prey. In order to disentangle the effects of both main drivers on the small mammal community, we used partial constrained ordination techniques, which allowed us to determine the pure effects (and shared effects) of the environmental factors. Land use predictors explained 33.4% of the variance (mostly crops), followed by 23.4% of the variance explained by the geo-climatic variables (mostly rainfall), and an additional 24.8% of the variance was shared by both groups of predictors, totaling 81.6% of environmental variance. The remaining 18.4% of variance was unexplained by environmental matrices. This pattern was consistent with expected associations of species and biotic influences at small spatial scales and highlighted that the number of species increased from the crops in the lowlands towards the highlands covered by deciduous and coniferous forests. [ABSTRACT FROM AUTHOR]

In a warming Arctic, circumpolar long‐term monitoring programs are key to advancing ecological knowledge and informing environmental policies. Calls for better involvement of Arctic peoples in all stages of the monitoring process are widespread, although such transformation of Arctic science is still in its infancy. Seabirds stand out as ecological sentinels of environmental changes, and priority has been given to implement the Circumpolar Seabird Monitoring Plan (CSMP). We assessed the representativeness of a pan‐Arctic seabird monitoring network focused on the black‐legged kittiwake (Rissa tridactyla) by comparing the distribution of environmental variables for all known versus monitored colonies. We found that with respect to its spatiotemporal coverage, this monitoring network does not fully embrace current and future environmental gradients. To improve the current scheme, we designed a method to identify colonies whose inclusion in the monitoring network will improve its ecological representativeness, limit logistical constraints, and improve involvement of Arctic peoples. We thereby highlight that inclusion of study sites in the Bering Sea, Siberia, western Russia, northern Norway, and southeastern Greenland could improve the current monitoring network and that their proximity to local populations might allow increased involvement of local communities. Our framework can be applied to improve existing monitoring networks in other ecoregions and sociological contexts. [ABSTRACT FROM AUTHOR]

Abstract: Background: The question of which ecological and evolutionary processes structure the distribution of biodiversity has intrigued scientists for centuries, and historically, inferences have been gained predominantly by studying animals and plants. Although substantial progress has been made towards understanding the multitude of factors that shape host‐associated microbial communities (i.e., microbiomes), it remains largely unknown whether large‐scale geographical patterns in diversity observed for macroorganisms also apply for their microbiomes and whether microbiomes are shaped by the same processes that appear key for determining biogeographical patterns in their hosts. The geographical distribution of microbiome diversity: We discuss challenges and potential approaches for studying microbiome biogeography, with the goal of inspiring future lines of research that can stimulate the development of new ecological and evolutionary theory in the microbiome field. The theory and examples presented here focus specifically on bacterial microbiomes, and we give an overview of host‐associated bacterial microbiome research beginning to examine some of the classic biodiversity patterns central to the fields of ecology and evolution. Potential impacts of microbiome variation for host ecology and evolution: Microbiome diversity patterns are particularly important to consider because microbes are crucial for many aspects of the biology of their hosts. We discuss how more comprehensive knowledge of the geographical variation of microbiome diversity at the host individual and population levels might be crucial for understanding host ecology and evolution.

Background: In plants, environmental gradients can promote similar morphophysiological traits in species that inhabit areas with similar climatic conditions. Here, to evaluate possible causes of morphological similarity, we analyzed leaf morphological and functional variation in toothed-leaf oaks and its relationships with environmental and geographic variables. Hypotheses: We expected that species with a greater degree of environmental overlap would exhibit similar leaf morphology, and those with a broader range of environmental tolerance would exhibit greater leaf morphological variation. Studied species: Acutifoliae group (Fagaceae, Quercus) Study sites and dates: Leaf samples were collected from adult trees distributed in diverse forest types between 495 and 2,566 meters above sea level (m asl) in Mexico and Guatemala. Methods: We compared patterns of leaf variation in a total of 2,934 leaves from 640 individuals corresponding to 68 populations of ten oak species using univariate and multivariate analyses. We also characterized the environmental conditions where each of the species occurred using the available geographical records and bioclimatic variables. Results: We found morphological overlap in leaf traits in oak species occurring in similar climatic environments. Additionally, oak species with a greater range of environmental distributions showed greater leaf shape morphological variation. Conclusions: The environment influenced the generation of similar leaf morphologies among oak species despite geographical distance and phylogenetic relationships.

The study was conducted in Endiras Forest, northwest Ethiopia, to evaluate the effects of environmental variables on the patterns of plant community formation. A systematic random sampling technique was used to collect vegetation data from 56 (20 m × 20 m) plots laid at 100 m intervals on ten transects. In each plot, the species encountered and its percent cover abundance were recorded, which was later transformed into a modified Braun-Blanquet scale. The composite soil samples collected from 15 cm × 15 cm subplots were examined for 13 soil parameters. Communities were determined using cluster analysis. The Shannon-Wiener index was employed to quantify species diversity. The relationships between species and environmental variables were evaluated using canonical correspondence analysis (CCA). Seventy-three woody plant species, distributed in 40 families, were documented. Fabaceae was found to be the most species-rich family (20.55%). Five communities were generated from the cluster analyses that vary in diversity. Nine environmental variables were found to be significant in determining patterns of community formation (P

Abstract: Aim: To determine the relationships between the functional trait composition of forest communities and environmental gradients across scales and biomes and the role of species relative abundances in these relationships. Location: Global. Time period: Recent. Major taxa studied: Trees. Methods: We integrated species abundance records from worldwide forest inventories and associated functional traits (wood density, specific leaf area and seed mass) to obtain a data set of 99,953 to 149,285 plots (depending on the trait) spanning all forested continents. We computed community‐weighted and unweighted means of trait values for each plot and related them to three broad environmental gradients and their interactions (energy availability, precipitation and soil properties) at two scales (global and biomes). Results: Our models explained up to 60% of the variance in trait distribution. At global scale, the energy gradient had the strongest influence on traits. However, within‐biome models revealed different relationships among biomes. Notably, the functional composition of tropical forests was more influenced by precipitation and soil properties than energy availability, whereas temperate forests showed the opposite pattern. Depending on the trait studied, response to gradients was more variable and proportionally weaker in boreal forests. Community unweighted means were better predicted than weighted means for almost all models. Main conclusions: Worldwide, trees require a large amount of energy (following latitude) to produce dense wood and seeds, while leaves with large surface to weight ratios are concentrated in temperate forests. However, patterns of functional composition within‐biome differ from global patterns due to biome specificities such as the presence of conifers or unique combinations of climatic and soil properties. We recommend assessing the sensitivity of tree functional traits to environmental changes in their geographic context. Furthermore, at a given site, the distribution of tree functional traits appears to be driven more by species presence than species abundance.

Summary: Plants possess a large variety of nonacquisitive belowground organs, such as rhizomes, tubers, bulbs, and coarse roots. These organs determine a whole set of functions that are decisive in coping with climate, productivity, disturbance, and biotic interactions, and have been hypothesized to affect plant distribution along environmental gradients.We assembled data on belowground organ morphology for 1712 species from Central Europe and tested these hypotheses by quantifying relationships between belowground morphologies and species optima along ecological gradients related to productivity and disturbance. Furthermore, we linked these data with species co‐occurrence in 30 115 vegetation plots from the Czech Republic to determine relationships between belowground organ diversity and these gradients.The strongest gradients determining belowground organ distribution were disturbance severity and frequency, light, and moisture. Nonclonal perennials and annuals occupy much smaller parts of the total environmental space than major types of clonal plants. Forest habitats had the highest diversity of co‐occurring belowground morphologies; in other habitats, the diversity of belowground morphologies was generally lower than the random expectation.Our work shows that nonacquisitive belowground organs may be partly responsible for plant environmental niches. This adds a new dimension to the plant trait spectrum, currently based on acquisitive traits (leaves and fine roots) only. [ABSTRACT FROM AUTHOR]

Understanding why some, but not other, plant communities are vulnerable to alien invasive species is essential for predicting and managing biological invasions. Darwin proposed two seemingly contradictory hypotheses on how native‐invader relatedness influences invasion success, emphasizing, respectively, the importance of environmental filtering and competition between natives and invaders. Despite much recent empirical research on this topic, reconciling these two hypotheses, known as Darwin's naturalization conundrum, remains a challenge.Using plot‐level data from natural forests along elevational transects covering strong environmental gradients, we examined whether the invasion of the globally invasive species crofton weed (Ageratina adenophora) can be explained by environmental filtering and/or competition from closely related species linked to environmental gradients.Abundant precipitation, warm temperatures, open canopies and postfire environments facilitated A. adenophora invasion, whereas resident taxonomic richness suppressed its invasion. Importantly, we found that invader‐resident relatedness had a strong negative effect on invader cover under resource scarcity conditions (e.g. low water availability), but not under non‐resource environmental stress gradients (e.g. low temperature).Synthesis and applications. Our results suggest that the impact of species phylogenetic relatedness on invasion success varies distinctly along resource versus non‐resource environmental gradients. These results help to reconcile Darwin's naturalization conundrum, thereby improving the ability to predict the success of alien plant invasions in a changing world. Our study stresses the need to consider adjusting forest species composition to strengthen their resistance to invasion, while taking into account resource and non‐resource environmental gradients, particularly after wildfires. [ABSTRACT FROM AUTHOR]

Understanding soil water dynamics and transport of nutrients is challenging in tropical rainforests due to the uniqueness of several properties related to soils, vegetation and seasonality that make relating patterns found in temperate environments to tropical sites difficult. We address the need for better edaphic characterization in tropical environments by investigating soil water percolation rates and chemistry across topographic, soil texture and seasonal gradients in a mature tropical rainforest in Central Amazonia, Brazil. We utilized a passive wick flux meter (e.g., drainage lysimeter) to directly measure real-time percolation fluxes at 60-cm depth, and to sample a suite of chemical species across plateau, slope and valley topographic positions. We found percolation flux volume and chemical exports generally increase with decreasing elevation and clay content, which was lowest in the valley. Daily percolation flux was observed to be 2.39 ± 0.44 in plateau, 3.01 ± 0.50 in slope and 6.16 ± 0.83 mm in valley. Most solutes were present in small amounts of <1 mg L-1, such as PO43-, Fe2+/Fe3+ and Mn2+; however, NO3- concentrations were >20 mg L-1, even exceeding 100 mg L-1 in the valley. Based on additional isotopic analysis, we speculate high NO3- concentrations are partially an artefact of root decomposition following installation of the flux meters. The empirical relationships we show among percolation volume and nutrient exports under varying topographies and soil textures can improve Earth System Model performance by better constraining ecohydrological relationships to nutrient fluxes, which can in-turn better illuminate the important factors that govern their behaviour. [ABSTRACT FROM AUTHOR]

Coral reefs globally face unprecedented challenges from anthropogenic stressors, necessitating innovative approaches for effective assessment and management. Molecular biomarkers, particularly those related to protein expressions, provide a promising avenue for diagnosing coral health at the cellular level. This study employed enzyme-linked immunosorbent assays to evaluate stress responses in the coral Porites lobata along an environmental gradient in Maunalua Bay, Hawaii. The results revealed distinct protein expression patterns correlating with anthropogenic stressor levels across the bay. Some proteins, such as ubiquitin and Hsp70, emerged as sensitive biomarkers, displaying a linear decrease in response along the environmental gradient, emphasizing their potential as indicators of stress. Our findings highlighted the feasibility of using protein biomarkers for real-time assessment of coral health and the identification of stressors. The identified biomarkers can aid in establishing stress thresholds and evaluating the efficacy of management interventions. Additionally, we assessed sediment and water quality from the inshore areas in the bay and identified organic contaminants, including polycyclic aromatic hydrocarbons and pesticides, in bay sediments and waters. [ABSTRACT FROM AUTHOR]

Common distributional patterns have provided the foundations of our knowledge of Neotropical biogeography. A distinctive pattern is the "circum‐Amazonian distribution", which surrounds Amazonia across the forested lowlands south and east of the basin, the Andean foothills, the Venezuelan Coastal Range, and the Tepuis. The underlying evolutionary and biogeographical mechanisms responsible for this widespread pattern of avian distribution have yet to be elucidated. Here, we test the effects of biogeographical barriers in four species in the passerine family Thamnophilidae by performing comparative demographic analyses of genome‐scale data. Specifically, we used flanking regions of ultraconserved regions to estimate population historical parameters and genealogical trees and tested demographic models reflecting contrasting biogeographical scenarios explaining the circum‐Amazonian distribution. We found that taxa with circum‐Amazonian distribution have at least two main phylogeographical clusters: (1) Andes, often extending into Central America and the Tepuis; and (2) the remaining of their distribution. These clusters are connected through corridors along the Chaco–Cerrado and southeastern Amazonia, allowing gene flow between Andean and eastern South American populations. Demographic histories are consistent with Pleistocene climatic fluctuations having a strong influence on the diversification history of circum‐Amazonian taxa, Refugia played a crucial role, enabling both phenotypic and genetic differentiation, yet maintaining substantial interconnectedness to keep considerable levels of gene flow during different dry/cool and warm/humid periods. Additionally, steep environmental gradients appear to play a critical role in maintaining both genetic and phenotypic structure. [ABSTRACT FROM AUTHOR]

Questions: Annual species have evolved sets of germination cues that are thought to be predictive of the post‐germination environment. In naturally patchy environments, germination microsites often vary considerably in the amount of light they receive and in the diurnal temperature fluctuations they experience. However, whether species' differential germination responses to light and temperature are associated with their spatial patterns of occurrence remains largely untested. Location: Mediterranean‐climate woodlands in Southwest Western Australia. Methods: We surveyed species' occurrences in annual plant communities in 150 quadrats across gradients of canopy cover and litter cover. Nineteen species recorded in this survey were then included in a germination experiment that manipulated (1) Light vs Dark (12 h light or continuous dark) approximating seeds near the soil surface vs those covered by litter and (2) Cold vs Warm temperature regimes (7/18°C and 7/24°C) approximating diurnal fluctuations experienced in shaded vs sun‐exposed microsites, respectively. Results: In the germination experiment, six species had highest germination probabilities in the Light treatment (regardless of temperature), five in Cold + Light, one in Warm + Light, two were indifferent to the treatments, and four did not germinate at all. Binomial linear mixed‐effects models showed that species' maximum responses to light and temperature did not explain their spatial distributions along canopy cover and litter cover gradients, contrary to theoretical expectations of germination being a strong driver of species' occurrences. Conclusions: Despite variation in species' responses to experimental treatments, no association was found with their field microsite associations. Germination strategies in our system were wider than expected for Mediterranean systems. Our results support that germination cues are not strong drivers of microhabitat associations in this system. [ABSTRACT FROM AUTHOR]

Understanding how environmental conditions and plant functional variation are mutually related is critical to improving our comprehension of plant adaptations. In this context, our knowledge of the interlinks between plant functional, spectral and genetic traits and environmental filters is still very limited, especially for wetland species. To gain new insights on this topic, a multidimensional dataset, centred on the widespread macrophyte species Nuphar lutea, was assembled by collecting data on functional traits (including spectral traits), genetic metrics and environmental determinants from 28 plots spanning north‐central Italy. A strong environmental filter acts on all traits (morphological, biochemical, spectral and the genetic diversity metrics) resulting in significant local control over trait patterns, exemplified by the discrimination value of water electrical conductivity. This is further reinforced by the key contribution of sediment variables in explaining traits variation. Site‐specific environmental conditions were reflected in different patterns of genetic diversity, suggesting a long‐term effect of environmental filters on genotypes as well. High water conductivity – in our study sites indicative of long‐term hydrogeological settings – is linked to more acquisitive behaviour in N. lutea and a progressive reduction in its genetic diversity, while high nutrients availability in sediments promotes higher leaf traits performance. This study better explores how high variability in leaf traits reinforces current genetic and mechanistic knowledge about competitive strategies in the key aquatic plant N. lutea, by testing the effectiveness of a novel integrative approach to assess multiple sources of plant functional variation. [ABSTRACT FROM AUTHOR]

Aim: To determine the relationships between the functional trait composition of forest communities and environmental gradients across scales and biomes and the role of species relative abundances in these relationships. Location: Global. Time period: Recent. Major taxa studied: Trees. Methods: We integrated species abundance records from worldwide forest inventories and associated functional traits (wood density, specific leaf area and seed mass) to obtain a data set of 99,953 to 149,285 plots (depending on the trait) spanning all forested continents. We computed community‐weighted and unweighted means of trait values for each plot and related them to three broad environmental gradients and their interactions (energy availability, precipitation and soil properties) at two scales (global and biomes). Results: Our models explained up to 60% of the variance in trait distribution. At global scale, the energy gradient had the strongest influence on traits. However, within‐biome models revealed different relationships among biomes. Notably, the functional composition of tropical forests was more influenced by precipitation and soil properties than energy availability, whereas temperate forests showed the opposite pattern. Depending on the trait studied, response to gradients was more variable and proportionally weaker in boreal forests. Community unweighted means were better predicted than weighted means for almost all models. Main conclusions: Worldwide, trees require a large amount of energy (following latitude) to produce dense wood and seeds, while leaves with large surface to weight ratios are concentrated in temperate forests. However, patterns of functional composition within‐biome differ from global patterns due to biome specificities such as the presence of conifers or unique combinations of climatic and soil properties. We recommend assessing the sensitivity of tree functional traits to environmental changes in their geographic context. Furthermore, at a given site, the distribution of tree functional traits appears to be driven more by species presence than species abundance. [ABSTRACT FROM AUTHOR]

Intraspecific trait variation is a key feature that enables species to occur in heterogeneous landscapes. We studied Clusia grandiflora and Anacardium occidentale traits over a forest-dune gradient on the Brazilian Amazon coast (restinga). C. grandiflora showed a drought-avoidance strategy, storing water in its leaves, whereas A. occidentale showed conservative resource use in leaves, evidenced by its high dry-matter content and acquisitive resource in wood, showing lower wood density. Only A. occidentale changed its trait values through the forest-dune gradient, showing more conservative leaves in dunes and shrublands, despite a lower wood density than in forest. Leaf and wood traits are likely to be decoupled among Amazon coastal trees and their responses to environmental gradients are species-specific. [ABSTRACT FROM AUTHOR]

The juxtaposition of climatic zones in tropical mountains is considered one of the leading causes of the high diversity of tropical mountains; high peaks block oceanic winds, causing mid-elevation peaks of precipitation and diversity. Also, historically wind-protected valleys may harbor high species richness because of climate stability. Despite this knowledge, the elevational patterns of many taxa and their drivers remain unsolved. We aimed to describe the spatial patterns of ants’ diversity in the Jamapa River watershed in Mexico based on species distribution models of 253 ant species. Moreover, we intend to understand the relationship between ant diversity with the current climatic conditions and historical climatic stability. The watershed includes maximum elevations of 5636, 4282, and 2500 m from south to north and is exposed to the oceanic northeastern winds. Elevational patterns of species richness were consistent with theoretical predictions but changed south (mid-elevation peaks) to north (monotonic decrease) in the watershed. Species richness was positively associated with mean annual temperature and precipitation seasonality. Climatically stable sites harbored high species richness below 2100 m of elevation but low species richness above 2400 m, while the beta diversity showed the opposite pattern. We observed that present climatic conditions and historical climatic stability were essential drivers of ant diversity in the Jamapa River watershed. Elevational patterns of species richness were concordant with theoretical expectations. They changed from a monotonic decrease of diversity to marked mid-elevation peaks of species richness, presumably associated with the maximum height of the mountains.

Central African rainforests are predicted to be disproportionately affected by future climate change. How species will cope with these changes is unclear, but rapid environmental changes will likely impose strong selection pressures. Here we examined environmental drivers of genomic variation in the central African puddle frog (Phrynobatrachus auritus) to identify areas of elevated environmentally-associated turnover. We also compared current and future climate models to pinpoint areas of high genomic vulnerability where allele frequencies will have to shift the most in order to keep pace with future climate change. Neither physical landscape barriers nor the effects of past Pleistocene refugia influenced genomic differentiation. Alternatively, geographic distance and seasonal aspects of precipitation are the most important drivers of SNP allele frequency variation. Patterns of genomic differentiation coincided with key ecological gradients across the forest-savanna ecotone, montane areas, and a coastal to interior rainfall gradient. Areas of greatest vulnerability were found in the lower Sanaga basin, the southeastern region of Cameroon, and southwest Gabon. In contrast with past conservation efforts that have focused on hotspots of species richness or endemism, our findings highlight the importance of maintaining environmentally heterogeneous landscapes to preserve genomic variation and ongoing evolutionary processes in the face of climate change.

Eucalyptus afforestation may affect stream ecosystems, but the magnitude of these effects on water quality and biota in subtropical lowland streams is little understood. We evaluated the potential effects of Eucalyptus afforestation on water quality and macroinvertebrate assemblage. Water quality parameters and macroinvertebrate assemblages were sampled in summer and winter in 30 streams covering an afforestation gradient (from 0.05 to 96% of the catchment area) and tested their relationship. We analyzed the taxa density distribution in afforestation and water parameters using the Thresholds Indicator Taxa Analyses (TITAN). Nutrient concentrations, conductivity, and total dissolved solids showed positive responses to the increase of afforestation, but the responses varied among seasons. Macroinvertebrate metrics showed negative (Ephemeroptera-Trichoptera-Plecoptera (EPT), sensitive families, scrapers), and positive (Chironominae, Oligochaeta) responses to the afforestation. Densities of sensitive taxa (mostly EPT) decrease with an increase in Eucalyptus afforestation, which is also related to water quality and possibly to habitat changes attributed to afforestation management. The use of water quality parameters in combination with macroinvertebrates assemblage contributes to managing these streams under catchment afforestation. [ABSTRACT FROM AUTHOR]

We evaluated whether ecological thresholds could be detected along gradients of disturbances by using larval Odonata genera. Morphological, physiological, and behavioral differences between Odonata suborders may be reflected in different thresholds to anthropogenic disturbance. Therefore, we hypothesized that larval Zygoptera genera would have narrower ecological thresholds in response to increased levels of stream disturbance and would be considered sensitive to anthropogenic disturbances, and the opposite for larval Anisoptera genera, which would have wider ecological thresholds and would be considered tolerant to anthropogenic disturbances. We assessed 30 larval Odonata genera collected from 186 headwater stream sites in the Neotropical Savanna. Threshold Indicator Taxa Analysis detected ecological thresholds in seven Odonata genera (Argia, Brechmorhoga, Cacoides, Gomphoides, Phyllocycla, Progomphus and Hetaerina) revealing them as robust bioindicators (purity and reliability ≥ 0.85). Most Zygoptera were associated with less-disturbed sites and most Anisoptera were associated with more-disturbed sites, but not all genera corresponded to this pattern. Therefore, we recommend using Odonata larvae at the genus-level, versus the suborder level, for constructing improved biomonitoring tools and obtaining more accurate impact assessments of neotropical stream sites. [ABSTRACT FROM AUTHOR]

There has been limited research on the abiotic and biotic factors affecting the prevalence of phago-mixotrophy (prevMixo) among nanophytoplankton across freshwater ecosystems. In recent years, large-scale sampling campaigns like the EPA-National Lakes Assessment and the NSERC LakePulse survey have generated surface water community composition data for hundreds of lakes across North America, covering large environmental gradients. We present results from our analyses of the nanophytoplankton community data from these two surveys, focusing on a taxonomic comparison of the mixoplankton communities across ecoregions and multivariate analyses of the environmental drivers of the prevMixo. We identified potentially phago-mixotrophic taxa in the majority of sites and across all ecozones sampled. Lake trophic state was identified as the main predictor of nanophytoplankton resource-acquisition strategy assemblages, with lower prevalence and diversity of mixoplankton communities in more eutrophic lakes. Lake trophic state also controlled the composition of the mixoplankton community and increased total phosphorus levels were associated with a loss of mixoplankton diversity. This study represents the most comprehensive assessment of the prevMixo in lake nanophytoplankton communities to date spanning hundreds of sites and a dozen ecozones. [ABSTRACT FROM AUTHOR]

The study was conducted in Endiras Forest, northwest Ethiopia, to evaluate the effects of environmental variables on the patterns of plant community formation. A systematic random sampling technique was used to collect vegetation data from 56 (20mx20 m) plots laid at 100m intervals on ten transects. In each plot, the species encountered and its percent cover abundance were recorded, which was later transformed into a modified Braun-Blanquet scale. The composite soil samples collected from 15 cmx15 cm subplots were examined for 13 soil parameters. Communities were determined using cluster analysis. The Shannon-Wiener index was employed to quantify species diversity. The relationships between species and environmental variables were evaluated using canonical correspondence analysis (CCA). Seventy-three woody plant species, distributed in 40 families, were documented. Fabaceae was found to be the most species-rich family (20.55%). Five communities were generated from the cluster analyses that vary in diversity. Nine environmental variables were found to be significant in determining patterns of community formation (P < 0.05). Organic matter, pH, and altitude, highly correlated with CCA axis 1, largely shaped the community formation patterns. Various patterns of community formation demonstrate the need to design different conservation measures. [ABSTRACT FROM AUTHOR]

Context: The dynamics of a plant population are influenced by both biotic and abiotic factors that interfere with the phenotype of the individual, indicating how species develop in the occupied environment. Riparian plant species are subject to environmental fluctuations, such as periodic flooding regimes and severe droughts, which may result from climate change. Aims: The aim of this study was to evaluate the morphological growth responses of individuals of Inga vera subsp. affinis (DC.) T.D.Penn. in controlled drought and flooding conditions by observing variations in functional traits using controlled experiments. Methods: Individuals were subjected to partial flooding and dry periods, and functional traits, such as leaf area, root height and dry mass, were analysed. The difference between treatments was tested using unifactorial statistical analysis of variance (ANOVA). Key results: Fifteen-day-old individuals of Inga vera subsp. affinis kept under flooding conditions showed lower root height and dry mass compared to plants exposed to drought treatment; 50-day-old plants under flooding conditions also presented lower root dry mass than did plants in drought treatment, maintaining the result after the resilience period. Conclusions: Root dry mass was the most affected variable in individuals of Inga vera subsp. affinis under flooding conditions, even after the recovery period. In general, plants in the control and drought treatments did not differ significantly considering the analysed variables. Implications: Given the current climate change conditions, an increase in the frequency and duration of extreme events, such as floods and droughts, is expected. Thus, understanding how phenotypical traits of species already adapted to flooding conditions behave under water stress and waterlogged conditions for longer periods of time is essential to explain plant responses and predict future survival scenarios for the species. Photograph of a seedling of a tropical riparian tree, Inga vera subsp. affinis. The study of the ecology of native species in tropical environments offers a range of information about the development of forests, including more specific characteristics such as variations that can occur within a single species. Trees are very well adapted to this type of environmental variation such as flooding, but species can show very resilient responses and development to times of drought in these environments, even at young ages, demonstrating the importance of preservation and management of tropical native forests. Photograph by Rosana Feitosa. [ABSTRACT FROM AUTHOR]

Vascular plant species (VP) and bryophytes (B) constitute a significant portion of forest biodiversity and respond to both management intensity and natural disturbances within forests. In this study, we investigated the cross-taxa congruence between understorey VP and B at both diversity and composition levels across a wide range of sustainably managed forests in Slovenia. The taxonomic and functional characteristics of the selected plant groups were studied, with a particular emphasis on ground-dwelling species. We employed a trait-based approach to examine the functional characteristics. On average, the species richness of B in sustainably managed temperate forests increased with the corresponding number of VP. Furthermore, a moderate positive correlation in species composition between the studied groups of ground-dwelling organisms was also observed. The ground-dwelling VP and B were congruent in terms of trait-based composition, which was influenced by soil reaction and nutrients and light availability, while trait-based diversity was only slightly similar in response to moisture. A negative correlation between the composition of stress-tolerant VP and B hemeroby was found, indicating forest environments with a low level of disturbance. This is likely due to the sustainable management of Slovenian forests, where climate change and natural disturbances have intensified in recent years. A cross-taxon comparison of the two groups at four different levels, namely taxonomic-based diversity and composition and trait-based diversity and composition, revealed varying degrees of congruence. It is therefore important to monitor the status and temporal trends of both groups from different aspects to draw reliable conclusions. [ABSTRACT FROM AUTHOR]

Abstract Common distributional patterns have provided the foundations of our knowledge of Neotropical biogeography. A distinctive pattern is the “circum‐Amazonian distribution”, which surrounds Amazonia across the forested lowlands south and east of the basin, the Andean foothills, the Venezuelan Coastal Range, and the Tepuis. The underlying evolutionary and biogeographical mechanisms responsible for this widespread pattern of avian distribution have yet to be elucidated. Here, we test the effects of biogeographical barriers in four species in the passerine family Thamnophilidae by performing comparative demographic analyses of genome‐scale data. Specifically, we used flanking regions of ultraconserved regions to estimate population historical parameters and genealogical trees and tested demographic models reflecting contrasting biogeographical scenarios explaining the circum‐Amazonian distribution. We found that taxa with circum‐Amazonian distribution have at least two main phylogeographical clusters: (1) Andes, often extending into Central America and the Tepuis; and (2) the remaining of their distribution. These clusters are connected through corridors along the Chaco–Cerrado and southeastern Amazonia, allowing gene flow between Andean and eastern South American populations. Demographic histories are consistent with Pleistocene climatic fluctuations having a strong influence on the diversification history of circum‐Amazonian taxa, Refugia played a crucial role, enabling both phenotypic and genetic differentiation, yet maintaining substantial interconnectedness to keep considerable levels of gene flow during different dry/cool and warm/humid periods. Additionally, steep environmental gradients appear to play a critical role in maintaining both genetic and phenotypic structure.

Coral reefs globally face unprecedented challenges from anthropogenic stressors, necessitating innovative approaches for effective assessment and management. Molecular biomarkers, particularly those related to protein expressions, provide a promising avenue for diagnosing coral health at the cellular level. This study employed enzyme-linked immunosorbent assays to evaluate stress responses in the coral Porites lobata along an environmental gradient in Maunalua Bay, Hawaii. The results revealed distinct protein expression patterns correlating with anthropogenic stressor levels across the bay. Some proteins, such as ubiquitin and Hsp70, emerged as sensitive biomarkers, displaying a linear decrease in response along the environmental gradient, emphasizing their potential as indicators of stress. Our findings highlighted the feasibility of using protein biomarkers for real-time assessment of coral health and the identification of stressors. The identified biomarkers can aid in establishing stress thresholds and evaluating the efficacy of management interventions. Additionally, we assessed sediment and water quality from the inshore areas in the bay and identified organic contaminants, including polycyclic aromatic hydrocarbons and pesticides, in bay sediments and waters.

Aim: Biodiversity is known to affect ecosystem functioning, and environmental stress may influence the relationships between biodiversity and ecosystem functions (BEF). However, it is still unknown how the relationship between biodiversity and ecosystem multifunctionality (BEMF) varies with the environment at regional scale. We aimed to explore the change of BEMF relationship across environmental gradients in boreal and temperate forest ecosystems, and to identify the main impact mechanisms on EMF. Methods: Based on a data set collected in Northeastern China, we quantified EMF by calculating the average of six individual functions, defined species richness and functional diversity as community diversity, and defined the community-weighted means of functional traits as functional composition. We used multifactorial linear regression to assess the effect of biodiversity indices across environmental gradients on BEMF, and used structural equation models to identify the relationships among impact factors and EMF. Results: Community diversity and functional composition, as well as their interactions with environmental gradients, were jointly influencing the EMF. In the boreal forests, functional composition was the dominant driver of EMF. In the temperate forests, community diversity became the dominant factor impacting EMF. Main conclusions: The results imply that BEMF relationship changes with environmental conditions. EMF is mainly influenced by the community functional traits of the dominant species (mass ratio effect) in the boreal forests. In the temperate forests, greater community diversity leads to greater resource utilization and thus greater EMF (niche complementarity effect).

We analyzed the two main drivers (climate and land uses) shaping the composition of small mammal communities at 16 localities situated in the confluence of the Mediterranean and Eurosiberian regions (Barcelona, Spain). The study area represents a land use and land cover gradient showing urbanization and crop intensification in the lowlands and forest encroachment in mountain areas. We identified 2458 small mammal individuals of 12 different species from barn owl (Tyto alba) pellets. Three open-land species (Microtus duodecimcostatus, Crocidura russula, and Mus spretus) and one forest/generalist species (Apodemus sylvaticus) were dominant in the diet, accounting for 93% of prey. In order to disentangle the effects of both main drivers on the small mammal community, we used partial constrained ordination techniques, which allowed us to determine the pure effects (and shared effects) of the environmental factors. Land use predictors explained 33.4% of the variance (mostly crops), followed by 23.4% of the variance explained by the geo-climatic variables (mostly rainfall), and an additional 24.8% of the variance was shared by both groups of predictors, totaling 81.6% of environmental variance. The remaining 18.4% of variance was unexplained by environmental matrices. This pattern was consistent with expected associations of species and biotic influences at small spatial scales and highlighted that the number of species increased from the crops in the lowlands towards the highlands covered by deciduous and coniferous forests.

As biodiversity loss accelerates globally, understanding environmental influence over biodiversity-ecosystem functioning (BEF) relationships becomes crucial for ecosystem management. Theory suggests that resource supply affects the shape of BEF relationships, but this awaits detailed investigation in marine ecosystems. Here, we use deep-sea chemosynthetic methane seeps and surrounding sediments as natural laboratories in which to contrast relationships between BEF proxies along with a gradient of trophic resource availability (higher resource methane seep, to lower resource photosynthetically fuelled deep-sea habitats). We determined sediment fauna taxonomic and functional trait biodiversity, and quantified bioturbation potential (BPc), calcification degree, standing stock and density as ecosystem functioning proxies. Relationships were strongly unimodal in chemosynthetic seep habitats, but were undetectable in transitional 'chemotone' habitats and photosynthetically dependent deep-sea habitats. In seep habitats, ecosystem functioning proxies peaked below maximum biodiversity, perhaps suggesting that a small number of specialized species are important in shaping this relationship. This suggests that absolute biodiversity is not a good metric of ecosystem 'value' at methane seeps, and that these deep-sea environments may require special management to maintain ecosystem functioning under human disturbance. We promote further investigation of BEF relationships in non-traditional resource environments and emphasize that deep-sea conservation should consider 'functioning hotspots' alongside biodiversity hotspots.

The objective of this study was to determine the critical thermal minimum [CTmin], critical thermal maximum [CTmax], and thermal tolerance range of A. mellifera at three different elevations located in the Mexican Transition Zone: 11; 1,324, and 3,304 m.a.s.l. In general, we found that the CTmin of A. mellifera was lower at the site with the highest elevation (i.e., they tolerate colder temperatures). At the same time, the CTmax remained constant across the three studied elevations, revealing higher plasticity for cold tolerance rather than heat. Moreover, we did not find evidence that the body mass of the individuals was associated with their thermal tolerance at any of the three sampled elevations. Our findings suggest processes of local adaptation of A. mellifera populations in environmentally contrasting sites, allowing them to expand their range of distribution, which could be useful in predicting responses to future environmental change.

Secondary metabolites such as antioxidants are critical components that protect seeds from stress damage during seed development, desiccation, and ex-situ storage. Antioxidants are essential determinants of seed quality, longevity, and persistence. Understanding the environmental factors that regulate the accumulation, content, and function of antioxidant pools in sea oat seeds is critical for gene banking and understanding the environmental impacts on seed quality. Germination, viability, and Trolox Equivalent Antioxidant Capacity (TEAC) were analyzed on seeds from 18 sea oat populations from the US Atlantic and Gulf of Mexico coasts. We first assessed baseline TEAC, followed by TEAC performed on imbibed seeds for 36 h at 35/25°C during the day and night, respectively. Then, we analyzed the relationship of the antioxidant pools from these 18 sea oat populations to sampling site environmental classifications. Higher baseline antioxidants were common in regions with extreme environmental conditions corresponding to sea oat populations growing at latitudinal extremes characterized by warmer and colder temperatures. Baseline antioxidants did not correlate with prevailing seed germination. However, higher concentrations of antioxidants following imbibition were associated with poor seed germination in warmer conditions. Our results indicate that climatic conditions and environmental components associated with temperatures and precipitation may largely influence the innate pool of antioxidants in sea oat seeds. Also, a high amount of antioxidants following sea oat seed imbibition suggest seed damage or poor viability influenced by environmental stress conditions during seed development.

Savannas cover one‐fifth of the Earth's surface, harbour substantial biodiversity, and provide a broad range of ecosystem services to hundreds of millions of people. The community composition of trees in tropical moist forests varies with climate, but whether the same processes structure communities in disturbance‐driven savannas remains relatively unknown. We investigate how biodiversity is structured over large environmental and disturbance gradients in woodlands of eastern and southern Africa. We use tree inventory data from the Socio‐Ecological Observatory for Studying African Woodlands (SEOSAW) network, covering 755 ha in a total of 6780 plots across nine countries of eastern and southern Africa, to investigate how alpha, beta, and phylogenetic diversity varies across environmental and disturbance gradients. We find strong climate‐richness patterns, with precipitation playing a primary role in determining patterns of tree richness and high turnover across these savannas. Savannas with greater rainfall contain more tree species, suggesting that low water availability places distributional limits on species, creating the observed climate‐richness patterns. Both fire and herbivory have minimal effects on tree diversity, despite their role in determining savanna distribution and structure. High turnover of tree species, genera, and families is similar to turnover in seasonally dry tropical forests of the Americas, suggesting this is a feature of semiarid tree floras. The greater richness and phylogenetic diversity of wetter plots shows that broad‐scale ecological patterns apply to disturbance‐driven savanna systems. High taxonomic turnover suggests that savannas from across the regional rainfall gradient should be protected if we are to maximise the conservation of unique tree communities. [ABSTRACT FROM AUTHOR]

Anticipating global change impact on natural vegetation, especially in poorly researched systems, requires an understanding of the environmental factors that most strongly influence the organisation of plant communities at different scales. The environmental relations of plant communities in the Drakensberg mountains of South Africa remain poorly researched. This study investigated the influence of selected environmental determinants on the dominant species of plant community organisation in this area. In order to provide an overview of the influence of the environment on botanical composition and plant diversity, this study, conducted as four discrete exercises, investigated the interplay of altitude, aspect and slope on the abundance of selected species, and to examine the influence of latitude, geological substrate and local topography on species composition. Plant diversity showed no pattern of response to investigated environmental variables. Species composition was related to temperature and solarradiation variables. High altitude sites facing east were distinct for non-graminoid species. Altitude and latitude exerted a pronounced effect on species composition, confounded by longitude and precipitation gradients. Geological substrate, in concert with slope steepness and orientation, influenced composition, restricting the abundance but not distribution of some grasses. Highly individualistic responses were found for C3, C4, and non-graminoid species in relation to altitude, slope and aspect. Slope and aspect mediate the effects of altitude and hence temperature for some species. This study has demonstrated the complexity of drivers influencing species and compositional distribution in the Drakensberg and permits a preliminary consideration of potential changes in the composition and dominance structure of mid-elevation grasslands in response to climate change. The dominant grass species were widespread across environmental gradients, occupying currently warm, cool, moist and dry habitats. Hence, we predict that these mid-elevation C4 grasslands will persist in the face of current patterns of climate change provided they are not unduly impacted by other global change threats such as altered fire regimes and nutrient deposition. This prediction is, however, unlikely to apply to the herbaceous dicotyledons and non-graminoid monocotyledons, a component which contributes 78% towards species richness. This study could not make a critical assessment of the non-graminoid species owing to their low frequency of occurrence and low abundance in our plot-based sampling approach. Further monitoring and a targeted sampling approach is is required in future. [ABSTRACT FROM AUTHOR]

Canopy soils can be important to forest nutrient cycling, hydrology, and biodiversity, but the factors determining their distribution and properties are largely unknown. We surveyed canopy soils across gradients of temperature and precipitation in six primary forests in Costa Rica. We used solid-state 13C nuclear magnetic resonance (NMR) and mass spectrometry (MS) to understand how the composition of canopy soil organic matter varies within and across sites. Climate, particularly fog, appears to drive canopy soil abundance across forests, while tree size determines canopy soil abundance within a forest. Canopy soil chemistry mostly varied within sites, though temperature was associated with the carbon (C) to nitrogen ratio, total dissolved nitrogen, and alkyl-C abundance, while fog explained some of the variation in dissolved organic carbon and O-alkyl C abundance. This study is the first-ever glimpse into large- and small-scale drivers of canopy soil abundance and biochemical composition. Our results highlight the importance of tree size and fog in determining the quantity and quality of canopy soil organic matter, suggesting that canopy soil stocks may be particularly vulnerable to climate and land use change. Identifying how multi-scale factors influence canopy organic matter processes will enhance our ability to identify and predict how environmental change might affect the abundance and chemistry of canopy soils and thus biodiversity that they support.

Reductions in a limiting nutrient might be expected to necessitate compromises in the functional traits that depend on that nutrient; yet populations existing in locations with low levels of such nutrients often do not show the expected degradation of functional traits. Indeed, logperch (Percina caprodes), pumpkinseed sunfish (Lepomis gibbosus) and yellow perch (Perca flavescens) residing in low‐calcium water in the Upper St. Lawrence River were all previously found to maintain levels of scale calcium comparable to those of conspecific populations in high‐calcium water. Yet it remains possible that the maintenance of one functional trait (i.e., scale calcium) under nutrient‐limited (i.e., low calcium) conditions could come at the expense of maintaining other functional traits that depend on the same nutrient. The present study therefore examines other calcium‐dependent traits, specifically skeletal element sizes and bone densities in the same fish species in the same area. Using radiographs of 101 fish from the three species across four locations (two in high‐calcium water and two in low‐calcium water), this new work documents multi‐trait "homeostasis" along the gradient of water calcium. That is, no effect of calcium regime (low‐calcium vs. high‐calcium) was detected on any of the measured variables. Further, effect sizes for the skeletal traits were very low − lower even than effect sizes previously documented for scale calcium. These results thus show that native fishes maintain phenotypic stability across a suite of functional traits linked to calcium regulation, perhaps pointing to an "organismal‐level homeostasis" scenario rather than a "trait‐level homeostasis" scenario. [ABSTRACT FROM AUTHOR]

Closely related, ecologically similar species often segregate their distributions along environmental gradients of time, space, and resources, but previous research suggests diverse underlying causes. Here, we review reciprocal removal studies in nature that experimentally test the role of interactions among species in determining their turnover along environmental gradients. We find consistent evidence for asymmetric exclusion coupled with differences in environmental tolerance causing the segregation of species pairs, where a dominant species excludes a subordinate from benign regions of the gradient but is unable to tolerate challenging regions to which the subordinate species is adapted. Subordinate species were consistently smaller and performed better in regions of the gradient typically occupied by the dominant species compared with their native distribution. These results extend previous ideas contrasting competitive ability with adaptation to abiotic stress to include a broader diversity of species interactions (intraguild predation, reproductive interference) and environmental gradients, including gradients of biotic challenge. Collectively, these findings suggest that adaptation to environmental challenge compromises performance in antagonistic interactions with ecologically similar species. The consistency of this pattern across diverse organisms, environments, and biomes suggests generalizable processes structuring the segregation of ecologically similar species along disparate environmental gradients, a phenomenon that we propose should be named the competitive exclusion–tolerance rule. [ABSTRACT FROM AUTHOR]

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

Saudi Arabia diverse landforms include saltmarshes, sand dunes, desert plains, desert pavements, ancient lava fields, and mountains. Climate is influenced by winter Polar and summer Tropical Continental air masses. Tropical Maritime air affects southwestern regions during summer. Climate depends also on location and altitude with hot humid coastal areas, hot dry deserts, hyper-arid desert pavements and lava fields, and temperate mountainous regions. Climate exhibits spatiotemporal patterns reflecting north-south gradients of temperature, rainfall, evapotranspiration, and aridity. Vast latitudinal range and steep altitudinal gradient create temperature variations, affect rainfall seasonality and distribution, and influence dry season duration. Distribution of plant communities and species reflects multitudinous interactions between climate and plant traits, physiology, and chorology. Species exhibiting C3 photosynthesis inhabit cool northern regions and temperate southwestern mountains, species with C4 photosynthesis inhabit hot low-lying regions, and arido-active succulents with crassulacean acid metabolism dominate hyper-arid desert pavements and lava fields. Plant distribution also relates to species chorology with Euro-Siberian, Irano-Turanian, and Mediterranean chorotypes dominating cool northern regions and temperate southwestern mountains, while Saharo-Sindian, Sudano-Zambezian, and Tropical chorotypes dominating hot southern regions. Plant communities and species occurring in different habitats are described in relation to their traits, physiology, and chorology. Nature reserves and phytodiversity hotspots are considered with special reference to endemic, rare, endangered, and invasive species. An environmental perspective is also given in relation to anthropogenic pressures and positive directives of Saudi Vision 2030. [ABSTRACT FROM AUTHOR]

The conservation of biodiversity and ecosystem sustainability is essential for human well-being. An important tool for addressing this issue is ecological indicators. This overview document examines recent studies covering the period 2018–2022 that use the values of the Landolt indicator as one of the analysis methods. The total number of records examined was 8910. After excluding irrelevant, inconsistent and duplicate records, 91 records were selected. The selection criteria were the presence of the English abstract and a digital object identifier (DOI). We chose the VOSviewer software for data analysis and visualization. The analysis of research geography, types of plant communities under research, research topics, the network of co-authorship and relationship papers, as well as the publication activity and citation rate of the authors, is carried out. The results revealed that the geography of using Landolt indicator values is quite wide, while they are more often used in Switzerland, Italy and Russia. The most important and frequently cited studies were carried out in the context of large international projects, confirming the importance of scientific cooperation in the development of environmental indicators. The Landolt indicator values showed effectiveness in the study of forests, bogs, riparian vegetation, a coarse quarry waste dump, and in assessing the urban environment. At the same time, the vegetation dynamics and influence of various factors on plants were studied most often. It was revealed that Landolt indicator values can serve as an effective universal method that integrates many aspects of the environment and allows for a comprehensive multicriteria analysis of environmental factors, habitat stability, vegetation diversity and dynamics for different plant communities at different spatial scales over a wide geographical area. This is confirmed by the high citation rate of the papers. We recommend the Landolt indicator values for a wider use, including in the monitoring of ecosystems and individual species for their conservation and sustainable management. In order to achieve this goal, it is necessary to extend the network of relationships between the authors, which is not very well developed at the moment. The research results obtained are useful for the further successful development not only of the Landolt indicator values but also of environmental indicators in general. [ABSTRACT FROM AUTHOR]

Both abiotic and biotic conditions may be important for biodiversity. However, their relative importance may vary among different diversity dimensions as well as across spatial scales. Spiders (Araneae) offer an ecologically relevant system for evaluating variation in the relative strength abiotic and biotic biodiversity regulation. We quantified the relative importance of abiotic and biotic conditions for three diversity dimensions of spider communities quantified across two spatial scales. Spiders were surveyed along elevation gradients in northern Sweden. We focused our analysis on geomorphological and climatic conditions as well as vegetation characteristics, and quantified the relative importance of these conditions for the taxonomic, phylogenetic, and functional diversity of spider communities sampled across one intermediate (500 m) and one local (25 m) scale. There were stronger relationships among diversity dimensions at the local than the intermediate scale. There were also variation in the relative influence of abiotic and biotic conditions among diversity dimensions, but this variation was not consistent across spatial scales. Across both spatial scales, vegetation was related to all diversity dimensions whereas climate was important for phylogenetic and functional diversity. Our study does not fully support stronger abiotic regulation at coarser scales, and conversely stronger abiotic regulation at more local scales. Instead, our results indicate that community assembly is shaped by interactions between abiotic constrains in species distributions and biotic conditions, and that such interactions may be both scale and context dependent. [ABSTRACT FROM AUTHOR]

To elucidate the effects of environmental heterogeneity on diversity, composition, and degree of overlap between free-living (FL) and particle-attached (PA) bacteria, we sampled large, shallow, eutrophic Lake Taihu, China across gradients spanning riverine inflow, cyanobacterial blooms, and the open limnetic area. Using high-throughput sequencing of the 16S rRNA gene, we show that (i) bacterial communities near riverine inflow had high α-diversity and a high degree of overlap between FL and PA lifestyles, (ii) communities in cyanobacterial blooms have reduced α-diversity within the PA lifestyle, and (iii) communities from the limnetic area had the lowest bacterial α-diversity within the FL lifestyle and a medium degree of overlap between the FL and PA lifestyles. Redundancy analysis showed that the variation of the FL bacterial community was shaped by suspended solids and total phosphorous, while the variation of the PA bacterial community was shaped by suspended solids, dissolved oxygen, and the percentage of organic matter in suspended solids. This study highlights the importance of environmental heterogeneity, riverine input, cyanobacterial blooms, and nutrient status on the spatial distribution patterns of FL and PA bacterial communities in freshwater lakes. [ABSTRACT FROM AUTHOR]

Fish assemblages and environmental variables were studied in 155 lake and pond sites on the east edge of Europe (Tatarstan Republic). The main aim of the work was to describe and identify patterns of fish distribution in lakes from a poorly studied region of Europe. The impact of environmental factors on fish species and communities was analyzed with regression and ordination methods. Fish assemblages, probability of occurrences, and abundance of many fish species were very different between our results at the eastern edge of Europe and those reported from further west in the continent. The size (area) of lakes was the main environmental variable (positively) influencing total abundance, the total number of fish species, and the Shannon diversity index. The probability of occurrence of more than half of the fish species was related to the area and bottom substrate, either on its own or in combination with elevation and water depth. For the first time at this eastern edge of Europe, means and standard deviations for fish species along basic environmental gradients were estimated. The latter were highly variable between species. [ABSTRACT FROM AUTHOR]