Ranking Of Species Research Articles

Late Holocene long arid phase in the Indian subcontinent as seen in shallow sediments of the eastern Arabian Sea

Multi-proxy record of benthic and planktic foraminifera, total organic carbon and carbon and oxygen isotope ratios from Core SK291/GC15, off the coast of Goa, eastern Arabian Sea reveals significant paleoceanographic and paleoclimatic turnovers during ~6000 to 1700 calibrated years before the Present (cal yr BP). Benthic foraminiferal census data was analyzed with multivariate techniques including factor and cluster analyses of highest ranked species from the studied core that enabled to identify seven biofacies. The record suggests centennial to millennial-scale changes in the surface conditions driven by monsoon-linked upwelling in the eastern Arabian Sea during the studied interval. Various benthic biofacies combined with isotope and planktic foraminiferal data suggest that depletion of dissolved oxygen and increase in organic productivity in the study area was caused by intense monsoonal upwelling since the middle Holocene. The results suggest that during 5400–4700 and 3000–2500 cal yr BP the southwest (SW) monsoon was strong leading to intense upwelling in the study area as reflected by increased Globigerina bulloides percentages. These were generally warmer intervals in the northern hemisphere. The SW monsoon significantly weakened (abrupt decrease in G. bulloides population) during 4700–3400 cal yr BP roughly coinciding with a long arid phase in the Indian subcontinent and a cold interval in Europe. Our record suggests an abrupt increase in SW monsoon intensity during ~3000 to 2500 cal yr BP, when a pronounced change in benthic biofacies is also noted that suggests a major shift in the sub-surface conditions. Our data document a prolong weak SW monsoon phase beginning at ~4600 cal yr BP, little earlier than 4.2 ka event, in the eastern Arabian Sea.

On the unranked topology of maximally probable ranked gene tree topologies.

A ranked tree topology is a tree topology with a temporal ordering of its coalescence events. Under the multispecies coalescent model, we consider ranked gene tree topologies realized along the branches of ranked species trees, where one gene copy is sampled for each species. Previous results have demonstrated that for almost all ranked species tree topologies with at least five species, there exists a set of branch lengths such that the maximally probable ranked gene tree topologies-those generated with the highest probability under the model-do not match the species tree ranked topology. Here, we focus on the agreement of a ranked species tree with its maximally probable ranked gene tree topologies in terms of their unranked topology, that is, disregarding the ordering of the coalescence events. We show that although the set of maximally probable ranked gene tree topologies for a ranked species tree can contain ranked trees with different unranked topologies, at least one of these maximal ranked gene tree topologies must have the same unranked topology as the species tree. Our results contribute to the study of the relationships between gene trees and species trees.

Multivariate analyses of the vegetation of the western Himalayan forests of Muzaffarabad district, Azad Jammu and Kashmir, Pakistan

Abstract Muzaffarabad district, Azad Jammu and Kashmir, Pakistan is part of the western Himalaya and rich in phytodiversity, but until now little was known about its plant diversity on larger spatial scale and vegetation composition through multivariate statistical tools. To fill this research gap, the whole district was ecologically explored for the collection of field data from August 2014 to July 2016. For vegetation studies, a total of 16 altitudinal transects comprising 110 sampling stations (samples) with 990 plots were studied by using a stratified random vegetation sampling method. Different multivariate statistical tools including Monte Carlo permutation test, Indicator species analysis, hierarchical clustering, ordination, variation partitioning and multi-response permutation procedures tests were used for the first time for the study area to elucidate the number of significant vegetation groups, ranking and placement of plant species in these groups, classification of vegetation units, detection of important gradients, importance of groups of environmental variables and pairwise compositional differences of the species groups respectively. The results showed that all the recorded 343 plant species belong to seven significant plant associations which were further placed into 5 major forest types. Out of the total 19 variables studied, CCA detected the significant contribution of the majority (simple effects: 12; unique effects: 8) of them. The latter (unique effects) in descending order included altitude, forest cover, deforestation, community maturity, forest density, latitude, slope aspect, and longitudinal variations. Similarly, variation partitioning results depicted that topography was the leading driver affecting vegetation distribution, followed by the biotic and edaphic factors. The forest edges, especially the sub-alpine ecosystem, were most diverse, supported higher tree density and also faced maximum deforestation pressure. Furthermore, rangelands in the temperate to alpine zones were affected by heavy overgrazing. Due to the disrupted local ecosystem functioning, the study area needs proper management and conservations plans to save its biodiversity wealth in this part of western Himalaya.

More than iso/anisohydry: Hydroscapes integrate plant water use and drought tolerance traits in 10 eucalypt species from contrasting climates

Abstract The iso/anisohydric continuum describes how plants regulate leaf water potential and is commonly used to classify species drought response strategies. However, drought response strategies comprise more than just this continuum, incorporating a suite of stomatal and hydraulic traits. Using a common garden experiment, we compared and contrasted four metrics commonly used to describe water use strategy during drought in 10 eucalyptus species comprising four major ecosystems in eastern Australia. We examined the degree to which these metrics were aligned with key stomatal and hydraulic traits related to plant water use and drought tolerance. Species rankings of water use strategy were inconsistent across four metrics. A newer metric (Hydroscape) was strongly linked to various plant traits, including the leaf turgor loss (TLP), water potential at stomatal closure (Pgs90), leaf and stem hydraulic vulnerability to embolism (PL50 and Px50), safety margin of hydraulic segmentation (HSMHS), maximum stomatal conductance (gsmax) and Huber value (HV). In addition, Hydroscape was correlated with climatic variables representing the water availability at the seed source site. Along the continuum of water regulation strategy, species with narrow Hydroscapes tended to occupy mesic regions and exhibit high TLP, PL50 and Px50 values and narrow HSMHS. High gsmax recorded in species with broad hydroscapes was also associated with high HV. Despite a fourfold difference in Hydroscape area, all species closed their stomata prior to the onset of hydraulic dysfunction, suggesting a common stomatal response across species that minimizes embolism risk during drought. Hydroscape area is useful in bridging stomatal regulation, hydraulic architecture and species drought tolerance, thus providing insight into species water use strategies. A plain language summary is available for this article.

Variation in plant functional traits is best explained by the species identity: Stability of trait‐based species ranking across meadow management regimes

Abstract It is commonly assumed in trait‐based studies that plant functional traits are species‐specific, being more variable among species than among different environmental conditions. If the environment affects traits, it is assumed that species react in a similar direction and conserve the functional distances. The rank of species based on the trait values is then unchanged, which justifies the use of species trait averages from database values. Such assumptions of species specificity are, however, increasingly disputed by studies showing overall high intraspecific trait variability. To test the species specificity and ranking stability of functional traits, we sampled plant individuals of almost all species (66 in total) within each plot of a long‐term (19 years) land use management experiment, which comprised a factorial combination of fertilization, mowing and removal of the dominant species Molinia caerulea in an oligotrophic wet meadow in the Czech Republic. Plant individuals were measured for eight commonly used traits: height, leaf dry matter content (LDMC), specific leaf area (SLA), leaf δ13C content, leaf carbon content, leaf δ15N content and leaf nitrogen content. Height, LDMC and SLA were also extracted from the LEDA trait database for comparison. Species identity consistently explained the largest portion of trait variability (40%‐68%). Land use managements had a considerably lower effect (0.4%–9% of explained trait variability for individual traits). The species trait averages computed for each land use management regime separately were mutually correlated, showing the stable trait‐based species ranking. Ranking stability of species trait averages was observed despite land use management changing absolute trait values and despite the tremendous intraspecific trait variability (causing substantial overlap of trait values for different species). For all treatments, our measured species averages for LDMC and SLA were also stably ranked with species averages from the LEDA database. Synthesis. Our results showed that species conserve the functional distances in different environmental conditions from where they were measured. Species trait averages can describe general trends in functional composition, although averaging reduces the ecologically interesting information of the intraspecific trait variability. A plain language summary is available for this article.

Modelling the fire propagation from the fuel bed to the lower canopy of ornamental species used in wildland–urban interfaces

South-eastern France is strongly affected by wildfires mostly occurring in the wildland–urban interfaces (WUIs). A WUI fire is often initiated in dead surface fuel, then can propagate to shrubs and trees when the lower canopy is close to (or touches) the ground. Whereas a previous study assessed the fire propagation from the fuel bed to the lower canopy of different species used as ornamental vegetation in this region, the objectives of the current work consisted of checking if the modelling of this fire propagation was possible using WFDS (Wildland–Urban Interface Fire Dynamical Simulator) in comparing experimental and modelling results. Experimental and modelling constraints (i.e. branch geometric definition, branch motion due to convection) showed differences in some of the recorded data (such as time to ignition, ignition temperature, mass loss and maximum temperature), but comparisons of variation in mass loss and temperature over time showed that modelling the fire propagation at the scale of a branch was possible if the branch fuel-moisture content remained lower than 25%. For both experiments and modelling, the ranking of species according to their branch flammability highlighted identical groups of species.

Relationships among leaf flammability attributes and identifying low-leaf-flammability species at the wildland–urban interface

Leaf flammability is a multidimensional plant functional trait with emerging importance for wildfire risk management. Understanding relationships among leaf flammability attributes not only provides information about the properties of leaves as fuels in the wildland–urban interface (WUI), it can also offer an effective way to identify low-leaf-flammability species. We examined relationships between leaf ignitibility, sustainability and combustibility among 60 plant species of the WUI of eastern Australia. We found that leaf ignitibility and sustainability worked in opposition to each other as dimensions of flammability. Species with leaves that were slow to ignite were those with leaves that sustained burning for the longest, whereas species with leaves that were fast to ignite had leaves that burned for the shortest periods of time. Low leaf combustibility was related to short leaf burning sustainability but not to ignitibility. We created an overall leaf flammability index (OLFI) to rank species on emergent properties of ignitibility, sustainability and combustibility attributes in combination. We found that low-leaf-flammability species with low OLFI values had small leaf area, high leaf mass per area and high leaf water content. Our findings have implications for species selection for green firebreaks in the WUI.

How do lianas and vines influence competitive differences and niche differences among tree species? Concepts and a case study in a tropical forest

AbstractLianas and other climbing plants are structural parasites of trees, generally reducing host tree survival, growth, and reproduction, yet their influences on the outcome of competition among tree species have remained largely unexplored.We propose that there are three distinct components to liana–tree interactions:prevalence, defined as the proportion of infested trees;load, defined as the mean liana cover on infested trees; andtolerance, defined as the effect of a given level of infestation on tree population growth rates. We introduce a new metric that integrates these components, the lianaburden, defined as the total effect of lianas on per capita population growth rates given current prevalence, load, and tolerance. Using these metrics, we quantify variation among 33 co‐occurring tropical tree species in liana–tree interactions and its relation with shade‐tolerance.The focal tree species vary strongly in liana prevalence, load, tolerance, and burden. Interspecific variation in tolerance is the largest contributor to interspecific variation in burden. Species rankings of per capita population growth rates under current liana infestation levels differ somewhat from rankings under liana‐free conditions, and differ strongly from rankings under uniformly high liana infestation. Thus, lianas alter competitive hierarchies to benefit tree species that are relatively tolerant of and/or resistant to lianas. Among the focal tree species, shade‐tolerance is positively correlated with liana tolerance and prevalence, but largely unrelated to load and burden, meaning shade‐tolerance does not predict which species are competitively disadvantaged by lianas. We describe a variety of mechanisms by which lianas may potentially increase or decrease niche differences among tree species, including interactions with spatial and temporal environmental niche partitioning, and potential differences among tree species in relative vulnerability to different liana species.Synthesis. Lianas, like other natural enemies, can in principle alter competitive hierarchies and niche structure of co‐occurring tree species, and our analyses suggest such influences are substantial in our focal tropical tree community and likely many other tree communities as well. Quantifying these effects requires a more comprehensive approach including analyses and modelling of dynamics of liana–tree interactions and their variation with tree and liana species identities.

Relationship Between the Vegetation Community and Soil Nutrient and Enzyme Activity During the Restoration of Abandoned Land in the Loess Hilly Region

The trends of and relationships among the plant community, soil nutrients, and four soil enzymes were investigated after being abandoned for 10, 15, 20, 30, and 45 years to reveal the soil properties during the restoration in the Loess Hilly Region. The results indicate the following ranking of dominant plant community species:Artemisia scoparia→Lespedeza dahurica+Artemisia sacrorum→Artemisia giraldii+irons Artemisia annua→Bothriochloa flaccidum+Artemisia selengensis. The ranking reflects an increase along the chronosequence of abandoned land. Moreover, the ratio of the total species of Compositae, Poaceae, and Leguminosae decreases from 66.67% to 50% and then increases up to 75%. The SOC, TN, TP, AN, AP, and four enzyme activity types (ALP, CAT, UE, and SC) increase but respond differently to restoration, while the stoichiometric ratio fluctuates. In contrast to the number of plant families, genus, species, and plant diversity, Compositae, Poaceae, and Leguminosae have major effects on the soil nutrient and enzyme activity, which explains the total variation of 72.8%, 69.1%, and 66.0%, respectively. The effects of these three families on the soil enzymes are greater than that on soil nutrients. Poaceae and Leguminosae have a positive effect on the nutrient and enzyme activity, while the family Compositae has a negative effect. Overall, the changes of dominant species of grassland communities during restoration significantly affect the soil enzyme and thereby are responsible for the soil nutrient dynamics.

Ethnomedicinal Practices in Kilikhar, Mongar

This study records medicinal plants used in different treatment by the local healer at Kilikhar Chiwog of Mongar Dzongkhag, Bhutan. A total of 61 different medicinal plants were recorded from 52 species identified belonging to 37 different families. Preference ranking of plant species helped to validate the efficacy of the plants used for treating diseases. It is also observed that a single plant species is used to treat single to multiple diseases.

Beauty ranking of mammalian species kept in the Prague Zoo: does beauty of animals increase the respondents' willingness to protect them?

Aesthetic preferences for animals correspond with the species' presence in the worldwide zoos and influence the conservation priorities. Here, we investigated the relationship between the willingness of respondents to protect mammals and some attributed characteristics such as their aesthetic beauty. Further, several methodological aspects of measuring mammalian beauty were assessed. Animal beauty was associated not only with the respondents' willingness to protect the species but also with its attributed dangerousness and usefulness. We found that the most preferred animals were carnivores and ungulates, whilst smaller species of rodents and afrosoricids were unpopular. The main characteristics determining that an animal will be ranked as beautiful were complex fur pattern and body shape. We demonstrated that the position of mammalian species along the 'beauty' axis is surprisingly stable, no matter the form (illustrations vs photographs), context of stimulus presentation (several number of stimuli per family vs one randomly selected species per family), or the method of beauty evaluation (relative order vs Likert's scale).

Ranking crop species using mixed treatment comparisons.

The mixed treatment comparison (MTC) method has been proposed to combine results across trials comparing several treatments. MTC allows coherent judgments on which of the treatments is the most effective. It produces estimates of the relative effects of each treatment compared with every other treatment by pooling direct and indirect evidence. In this article, we explore how this methodological framework can be used to rank a large number of agricultural crop species from yield data collected in field experiments. Our approach is illustrated in a meta-analysis of yield data obtained in 67 field studies for 36 different bioenergy crop species. The considered dataset defines a network of comparisons of crop species. We introduce several Bayesian MTC models based on baseline treatment contrasts and evaluate the practical advantages of these models to produce yield ratio estimates. We explore the consistency of some estimates by node-splitting and compare our results to those obtained with a classical two-way linear mixed model. Results reveal that the model showing the lowest deviance information criterion (DIC) includes both study random effects and study-specific residual variances. But all the tested models including study random effects lead to similar yield ratio estimates. The proposed Bayesian framework allows an in-depth analysis of the uncertainty in the species ranking.

Biodiversity of Bali Banana (Musaceae) and its Usefulness

Banana (Musa spp.) is one the most important agriculture commodities in Indonesia. Archeological and molecular evidences suggest that speciation of this herb occurred in Indonesia, leading to the high diversity in the archipelago. In Bali Island, banana is not only sought for food but as well as for their symbolic role in religious and cultural ceremonies. However, the high demand for bananas in Bali is not yet supported by the adequate production of local farms. This presented study aimed to investigate the diversity of banana cultivars or sub-species in Bali and its usefulness to determine preferable cultivars to cultivate. We recorded and characterized 43 banana cultivars in 10 villages that represent the 8 regencies and 1 city of Bali province. Out of the 43 cultivars, 7 were highly used and at least one cultivar was discovered in each of the studied village. The presence of these cultivars in the study areas were confirmed by site visit and characterization of the fruits. Among the highly ranked cultivars or species, only biu kayu is unique to Bali as it was not found in the closest provinces of East Java and Madura. Hence, the results suggested that to improve the cultivation and production of these 7 highly used cultivars could be an appropriate solution to meet Bali demand of bananas. Furthermore, cultivating biu kayu would also help conservation effort since this cultivar is also currently listed as a rare genetic resource.

An ecosystem service-disservice ratio: Using composite indicators to assess the net benefits of urban trees

Considering ecosystem disservices (EDS) of urban forests alongside the services (ES) can lead to better-informed decisions about tree species selection and placement in cities. Finding a common assessment framework, that does not rely on a financial model, can be tricky, and many studies consider, but do not include, EDS in their tree appraisals. Compound indicators represent a means to neatly combine disparate ecosystem data into one meaningful metric. In this study quantitative field measurements, model outputs, and categorical data relating to some of the major ES and EDS of the urban forest of Meran, Italy, were successfully compressed into a single unit, overcoming epistemological boundaries surrounding different urban ecosystem valuation methods. Several methods of compound indicator construction were considered and uncertainty and sensitivity analysis carried out on the species rankings which were produced. Significant differences in ES/EDS provision were observed between trees on public and private land. Spatial analysis revealed hotspots of high ES provision and low EDS provision, and vice versa. With correct use, compound indicators can stand alongside other methods of measuring and valuing positive and negative aspects of urban ecosystems.

Sensitivity of native and alien freshwater bivalve species in Europe to climate‐related environmental factors

AbstractWhile native freshwater bivalve species are declining, several alien bivalve species have become invasive, thereby impacting ecosystem functioning and services. These biodiversity changes can be attributed to deteriorated water quality, hydro‐morphological alterations, and the overarching effect of global change. Therefore, a systematic assessment of the sensitivity of freshwater bivalve species nowadays occurring in European inland waters to environmental factors is urgent. The present study reviewed 493 relevant papers, resulting in 8405 data entries on presence–absence of bivalve species in relation to environmental factors that are affected by global change (i.e., water temperature, water depth, oxygen availability, and flow velocity). From these worldwide field data, minimum and maximum values measured in their habitat and water bodies were selected. In addition, data on laboratory‐derived tolerance ranges were collected. Subsequently, novel species sensitivity distributions (SSDs) were derived for each environmental factor using field‐based occurrence data and laboratory‐derived tolerance ranges, respectively. Species sensitivity distributions for maximum habitat temperature significantly differed between native and alien species. The latter occurred in habitats with higher maximum water temperatures than native species. The increase in water temperatures by global warming will affect a higher percentage of native species than alien species. The ranking of species based on their sensitivity for various environmental factors shows that vulnerable and endangered species have a higher overall sensitivity and are likely to be more affected by climate change. Invasive alien species were found to have a lower overall sensitivity and are thus less affected by climate change further aiding to their invasive nature. The available SSDs allow the ranking of freshwater bivalve species sensitivity to environmental stressors, the prediction of their potential occurrence in freshwater habitats, and the evaluation of management measures to optimize their biodiversity and ecosystem services.

English

The present study was conducted for the conservation and management of vegetation in a socio-ecological mountain landscape through assessment of floristic composition, community types and structure of woody species in the Wabe River catchment of the Gurage Mountains in Ethiopia. The preferential sampling technique was applied to collect floristic and vegetation structure data, and within each plot, woody species diameter at breast height (DBH) was measured. R statistical software was used to analyze the vegetation cluster, diversity and structure. As a result of the heterogeneous nature of the catchment vegetation, the optimum number of six clusters (community types) were identified which were named through high ranked species. The majority of the community types had high diversity indexes and equitability or evenness. Most of the species had lower DBH classes and frequency. Besides, the important value index (IVI) for most of the species showed high value. This information facilitated for sustaining the biodiversity through identification of high plant diversity spot community types to be protected, degraded vegetation areas to be rehabilitated and fragmented vegetation areas to establish ecological connectivity. Further studies on the ecosystem services provided by the vegetation could be important for understanding their value and to advance the planning and management mechanisms.   Key words: Community type, floristic composition, diversity, equitability, structure, important value index (IVI), landscape planning. &nbsp

Global near infrared spectroscopy models to predict wood chemical properties of Eucalyptus

Global near infrared spectroscopy models (multiple-species, multiple-sites) were developed to predict chemical properties of Eucalyptus wood. The sample data set included 186 samples from four data sets (five species) originating from six countries: Eucalyptus urophylla from Argentina, Colombia, Venezuela, and South Africa; Eucalyptus dunnii from Uruguay; Eucalyptus globulus and Eucalyptus nitens from Chile; and Eucalyptus grandis from Colombia. The 186 samples were all preselected from larger collections of 400 to nearly 1800 samples to represent the range of chemical and spectral variation in each data set. The chemical traits modeled were total lignin, insoluble lignin, soluble lignin, syringyl–guaiacyl ratio (S/G), glucose, xylose, galactose, arabinose, and mannose. Single-species models and global multiple-species models were developed for each chemical constituent. For the global model, the R2cv for total lignin, insoluble lignin and syringyl–guaiacyl ratio were 0.95, 0.96, and 0.86, respectively. An alternate expression of the syringyl–guaiacyl relationship (S/(S+G)) resulted in better near infrared calibrations (e.g., for the global model, R2cv = 0.95). The global models for sugar content were also very good, but were slightly inferior to those for the lignin related traits, with R2cv = 0.74 for glucose, 0.89 for xylose, and from 0.72 to 0.91 for the minor sugars. To investigate the utility of the global models to predict chemical traits for species not included in the calibration, three-species calibrations were used to predict each trait in a fourth species data set. The prediction fit statistics ranged from excellent to poor depending on the species and trait, but in general the predictions would be at least moderately useful for most species-trait combinations. For some species-trait combinations with poor initial predictions from the global model, the inclusion of 10 samples from the “new” species into the calibration global model improved the fit statistics substantially. The global calibrations will be useful in tree breeding programs to rank species, families, and clones for important wood chemical traits.

Utilizing a multi-index decision analysis method to overall assess forage yield and quality of C3 grasses in the western Canadian prairies

Seasonal dynamic of forage quality and yield has a major impact on livestock production. A sound evaluation on quality and quantity of forage is useful for cost-effective utilization of forage. However, forage quality and yield can vary with forage species, harvest seasons and yearly climate conditions. To improve forage use efficiency, a field experiment (2008–2010) was conducted in Swift Current, Saskatchewan, Canada. Dry matter yield and quality indicators (fiber, protein, digestibility and minerals) were measured for nine cool-season grasses harvested in June, August and October. The interrelationships and attributes among quality indicators were determined by principal component analysis (PCA) and the weights of quality indicators were calculated by entropy weight (EW) method. To synthesize different attribute indicators into a comprehensive index that reflects quality ranking of different forage species, an integrated multi-index decision analysis method, i.e., PCA-based TOPSIS with EW, was used in this paper. The evaluation process and results showed that the interrelation patterns and positive or negative attributes for quality indicators were consistent with years and harvest seasons, whereas the rankings of most grasses in yield and comprehensive quality varied with years and harvest seasons. According to the yearly and seasonal rankings of forage quality and yield, flexible production tactics and adaptive management techniques should be considered within the western Canadian prairie region. For instance, Northern wheatgrass (Agropyron dasystachyum) can be recommended to be mixed with high quality forages due to its high yield in any harvest season. Meadow bromegrass (Bromus Riparius) can be recommended to be mixed with high yield forages due to its high quality in summer and fall. These findings will provide valuable information for forage breeders, and livestock and forage managers to maximize grass utilization efficiency while balancing yield and quality.

Misleading prioritizations from modelling range shifts under climate change

AbstractAimConservation planning requires the prioritization of a subset of taxa and geographical locations to focus monitoring and management efforts. Integration of the threats and opportunities posed by climate change often relies on predictions from species distribution models, particularly for assessments of vulnerability or invasion risk for multiple taxa. We evaluated whether species distribution models could reliably rank changes in species range size under climate and land use change.LocationConterminous U.S.A.Time period1977–2014.Major taxa studiedPasserine birds.MethodsWe estimated ensembles of species distribution models based on historical North American Breeding Bird Survey occurrences for 190 songbirds, and generated predictions to recent years given c. 35 years of observed land use and climate change. We evaluated model predictions using standard metrics of discrimination performance and a more detailed assessment of the ability of models to rank species vulnerability to climate change based on predicted range loss, range gain, and overall change in range size.ResultsSpecies distribution models yielded unreliable and misleading assessments of relative vulnerability to climate and land use change. Models could not accurately predict range expansion or contraction, and therefore failed to anticipate patterns of range change among species. These failures occurred despite excellent overall discrimination ability and transferability to the validation time period, which reflected strong performance at the majority of locations that were either always or never occupied by each species.Main conclusionsModels failed for the questions and at the locations of greatest interest to conservation and management. This highlights potential pitfalls of multi‐taxa impact assessments under global change; in our case, models provided misleading rankings of the most impacted species, and spatial information about range changes was not credible. As modelling methods and frameworks continue to be refined, performance assessments and validation efforts should focus on the measures of risk and vulnerability useful for decision‐making.

On the Species Structure of a Competitive Marine Community

Some examples of marine animal and plant communities with a structure determined by competitive inter-species relationships are discussed. It has been shown that the ranked species structure of these communities obeys a geometric progression, whose coefficient does not differ significantly from the constant exp(–1) = 0.368. A relationship between a certain parameter of this progression and the species diversity of a community has been found.