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Aim: Regional taxonomic diversity (species richness) is strongly influenced by a joint effect of the current processes (habitat and energy availability) and historical legacies (past climate and geography), but it is still unclear how those historical and current environmental drivers have shaped the functional diversity of species assemblages. Major taxa studied: Freshwater fish. Location: Global. Time period: 1960s–2000s. Methods: We combined the spatial occurrences over 2,400 river basins world‐wide and the functional traits measured on 10,682 freshwater fish species to quantify the relative role of the habitat, climate and historical processes on the current global fish functional diversity. To avoid any correlation between taxonomic diversity and functional diversity, we controlled for differences in the number of species (species richness) between rivers. Functional diversity was considered through three complementary facets: functional richness, functional dispersion and functional identity. Results: The habitat‐related variables explained most of the gradient in functional richness, verifying the habitat size–diversity hypothesis. In contrast, the historical climate–geography legacies markedly imprinted the functional dispersion and functional identity patterns, leading to a balanced influence of the current and historical processes. Indeed, the distribution of morphological traits related to fish dispersal was explained largely by the glaciation events during the Quaternary, leading to strong latitudinal gradients. Main conclusions: This study provides new insights into the role of historical and current environmental determinants on the functional structure of fish assemblages and strengthens the proposal that the independence of facets of functional diversity from the species richness makes them essential biodiversity variables to understand the structure of communities and their responses to global changes. [ABSTRACT FROM AUTHOR]

Aim: Fisheries ecosystems are subject to long‐term shifts in food web structure as a result of exploitation and environmental change. These shifts can be gradual and unresolved by decadal‐scale time series. The aim of our study was to determine long‐term legacy effects of overexploitation and changes to the composition of basal organic matter sources on the trophic structure of marine food webs. Location: New Zealand. Time period: Approximately 1250 AD to the present; the complete history of human occupation in New Zealand. Major taxa studied: Mesopredatory fishes. Methods: We used whole tissue (δ13C and δ15N) and amino acid‐specific (δ15NAA) stable isotope analyses of bone collagen and muscle tissue from five fishes spanning the period of human occupation of New Zealand to resolve the bioenergetic consequences of long‐term shifts in food web structure. Stable isotope analysis of amino acids provided the basis for resolution of changes in trophic level in the absence of information on δ15N at the base of the food web during pre‐industrial times. Results: Our analyses indicate likely declines in the contribution of organic matter derived from kelps in four species, and intraspecific increases in trophic levels in three species of the five fishes studied between European colonization (AD 1650–1800) and the present‐day regime of industrialized fishing and environmental change (AD 1953–2018), but little change during the prehistoric time period spanning early Māori occupation (AD 1250–1450) to European colonization. Analysis of the bioenergetic costs of the observed shifts in food web structure indicate a 179% increase in basal organic matter requirements to support mesopredatory fish. Main conclusions: These data provide a rare case study on the consequences of legacy effects of exploitation and environmental change for bioenergetics of fish communities relevant to ongoing changes in global marine ecosystems. Overexploitation and decline in kelp forests have inflated the bioenergetic costs of these fisheries. [ABSTRACT FROM AUTHOR]

Aim: We tested whether there is a strong effect of species interactions on assembly of local lake fish communities, in addition to environmental filters and dispersal. Location: Seven hundred and seventy‐two European lakes and reservoirs. Time period: 1993–2012. Major taxa studied: Nineteen species of freshwater fishes. Methods: We applied a latent variable approach using Bayesian Markov chain Monte Carlo algorithms (R package "BORAL"). We compared the contributions of six environmental predictors and the spatial organization of 772 European lakes in 209 river basins on the presence/absence of the 19 most frequent fish species and on the biomass and mean mass of the six dominant species. We inspected the residual correlation matrix for positive and negative correlations between species. Results: Environmental (50%) and spatial (10%) predictors contributed to the presence/absence assembly of lake fish communities, whereas lake size and productivity contributed strongly to the biomass and mean mass structures. We found highly significant negative correlations between predator and prey fish species pairs in the presence/absence, biomass and mean mass datasets. There were more significantly positive than negative correlations between species pairs in all three datasets. In addition, unmeasured abiotic predictors might explain some of the correlations between species. Main conclusions: Strong effects of species interactions on assembly of lake fish communities are very likely. We admit that our approach is of a correlational nature and does not generate mechanistic evidence that interactions strongly shape fish community structures; however, the results fit with present knowledge about the interactions between the most frequent fish species in European lakes and they support the assumption that, in particular, the mean masses of fish species in lakes are modified by species interactions. [ABSTRACT FROM AUTHOR]

Aims: Contemporary climate change and biological invasions are two main drivers of biodiversity redistribution. Interactive effects between these drivers have been reported in a variety of studies, yet results are conflicting. Some studies find that contemporary climate change facilitates the spread and success of non‐native species, especially those with broad physiological tolerances. Other studies conclude that non‐natives are vulnerable to current and future changes in climatic conditions. Given that most studies have focused on terrestrial species, here we contribute to this debate by analysing responses of marine native and non‐native fauna and flora to key climate‐related stressors, namely increased temperature (warming) and decreased salinity (freshening). Location: Global. Time period: 2002–2019. Major taxa studied: Marine benthic macrophytes and invertebrates. Methods: We conducted a meta‐analysis of experiments investigating the performance (e.g. growth, survival and reproduction) of benthic species in response to warming and freshening. Results: We found that non‐native species tended to respond positively to elevated temperature, whereas the performance of native species declined. Similarly, decreased salinity negatively affected the biological processes of native species, but non‐natives showed neutral or negative overall responses to freshening. Main conclusions: We find evidence that non‐native species outperform natives under a wide variety of warming and freshening conditions. The growth and reproduction of non‐natives are enhanced by warmer temperatures, and thus ocean warming is expected to facilitate future spread and success of non‐native species. Increased freshening along future coastal areas, however, will likely have a negative impact in both native and non‐native species and thus is expected to be a driver of significant change in coastal marine ecosystems. Our comprehensive analysis highlighted the need to expand our understanding of climate change effects beyond warming and specifically, studies focusing on salinity changes. [ABSTRACT FROM AUTHOR]

Aim: Geographical gradients of vertebrate species richness are determined jointly by evolutionary and environmental factors. Support for these factors comes mostly from tetrapods and, recently, marine fishes, but their validity and relative importance in freshwater fishes is not well understood. Here, we describe the species richness gradient for the major component of the viviparous freshwater fishes of the Americas, the poeciliids, and test the effects of evolutionary and environmental factors on this pattern. Location: The Americas. Time period: Approximatley 56–0 Ma. Major taxa studied: Poeciliidae (Teleostei: Cyprinodontiformes). Methods: We constructed geographical ranges for 93% (256) of poeciliids to describe and evaluate their species richness gradient. Evolutionary factors (evolutionary time and speciation rate) were derived from a recent phylogeny. Environmental factors were represented as basin area, topographical heterogeneity, energy, climate seasonality and past climatic stability. We tested the influence of these factors with a piecewise structural equation model (pSEM). Results: The distribution of Poeciliidae is biased to the Atlantic coast, with species richness showing a bimodal latitudinal gradient, peaking in middle latitudes near the Tropics of Cancer and Capricorn, and exhibiting the highest richness in Middle America. The pSEM showed that this species richness pattern was influenced positively by evolutionary time and past climatic stability and negatively by climate seasonality. Main conclusion: The species richness gradient of Poeciliidae has been shaped by the interplay of evolutionary time in addition to current and historical climate. Indeed, regions with high poeciliid richness were those containing by ancient lineages, supporting the time‐for‐speciation effect, and that have experienced low historical stability in temperature and currently show low temperature seasonality. Conversely, species‐poor regions contained younger lineages and experienced greater temperature seasonality. Our study highlights the need to assess jointly the evolutionary, historical and climatic drivers of species richness in order to unravel the causes of diversity gradients. [ABSTRACT FROM AUTHOR]

Aim: Understanding patterns and drivers of phylogenetic beta diversity in a region is important to understanding the origin and maintenance of the regional species diversity and variation in species diversity between local sites. Here we used a phylogenetic beta diversity metric quantifying deep evolutionary histories to explore geographical and ecological patterns of phylogenetic beta diversity in angiosperm assemblages across China. Location: China. Taxon: Flowering plants (angiosperms). Methods: China was divided into 100 × 100 km grid cells. Species composition in each grid cell was documented. We used a basal‐weighted metric (Dpw) to quantify phylogenetic beta diversity among angiosperm assemblages with two sampling approaches (neighbourhood approach and pairwise approach). Dpw was related to latitude and climatic conditions of angiosperm assemblages and to geographical and climatic distances between angiosperm assemblages across China. Results: We found that the southeastern portion of China has much higher Dpw than the northwestern portion of China. The line of high versus low values of Dpw across China is generally consistent with the line of 500‐mm precipitation per year. Our study shows that precipitation is associated with Dpw more strongly than temperature, and Dpw decreases with latitude, particularly in the eastern part of China. Main conclusions: The emergence of the observed pattern of basal‐weighted phylogenetic beta diversity is at least partly because the southeastern portion of China retains a large number of Tertiary relicts, making it a biogeographical museum, whereas many Tertiary relicts went extinct from the northwestern portion of China, particularly the Tibetan Plateau, due to the uplift of the plateau and the Himalayas, which makes the region a biogeographical grave for Tertiary relicts. [ABSTRACT FROM AUTHOR]

Aim: Higher temperatures increase the metabolic rate of ectothermic organisms up to a certain level and make them grow faster. This temperature‐sensitivity of growth is frequently used to predict the long‐term effects of climate warming on ectotherms. Yet, realized growth also depends on ecological factors and evolutionary adaptation. Here we study whether faster growth is observed along temperature clines within and between marine fish species from polar to tropical regions. Location: Global. Time period: The sampling or publication year is for 718 observations before 1980, 1,073 observations between 1980 and 2000, and 390 observations after 2000 (for 336 observations no year was recorded). Major taxa studied: Marine teleost fish and elasmobranchs. Methods: The effects of temperature on fish growth are studied using 2,517 growth observations, representing 771 species in 165 marine ecoregions. The effects of temperature are presented with a Q10, describing relative increase in the rate of growth for each 10 °C increase. Results: We find weak within‐ and between‐species effects of temperature on growth. The typical within‐species effect of temperature has a Q10 of 1.1. The between‐species effect is a little higher (Q10 = 1.4, or Q10 = 1.2 when corrected for phylogenetic relationships). When analysed per fish guild, growth responses vary from nearly independent of temperature in large demersals (Q10 = 1.1) to positive in small pelagics (Q10 = 1.6) and elasmobranchs (Q10 = 2.3). Average growth is higher in ecoregions with high primary production. Main conclusion: The change in average growth along temperature clines is weaker than predicted by metabolic theory, suggesting that the metabolic predictions are not sustainable in an ecosystem context. The long‐term response of fish to the increase in temperature associated with climate change may hence be shaped more by local environmental and ecological dynamics than by the physiological temperature response of the species currently present. [ABSTRACT FROM AUTHOR]

Aim: We examined the diversity–biomass relationship in stream fish communities and quantified direct and indirect effects of abiotic variables on this relationship. Location: France. Time period: 1992–2012. Major taxa studied: Stream fishes. Methods: We analysed the relationship between biodiversity (species richness and functional diversity) and fish community biomass at 1,357 stream sites distributed throughout France. We used piecewise path analysis to quantify effects of abiotic and biodiversity variables on biomass and assess relative contributions of native and non‐native species on the diversity–biomass relationship. Results: Biodiversity showed a direct positive relationship with biomass after controlling for sampling effort, and direct effects of biodiversity variables on community biomass exceeded those of climate and physical habitat variables. Our analysis indicates that positive effects of species richness on biomass exceeded those of functional diversity. Indirect effects of abiotic variables mediated by biodiversity metrics indicated that biomass increased in warmer, lowland habitats. Human impact had no effect on native biodiversity but had a positive effect on non‐native biodiversity. Main conclusions: We provide evidence that direct effects of biodiversity on community biomass outweigh those of abiotic variables in riverine fish communities, but resource partitioning alone is unlikely to drive the effects of biodiversity on biomass in this system. Quantification of the relative roles of anthropogenic impacts, biodiversity and environmental context in the regulation of ecosystem functioning will be necessary to understand the potential consequences of ongoing global change. [ABSTRACT FROM AUTHOR]

Aim: β‐diversity is often measured through incidence‐based dissimilarity indices, such as the Simpson and Sørensen indices. Multiple‐site versions of these indices, which have been recently developed, enhance the accountability of global heterogeneity relative to the original formulations. However, they are known to be sensitive to the number of sites, which hinders the comparison of β‐diversity between two populations of unequal sizes. Moreover, the populations are never completely measured and the dissimilarity must be estimated from a sample of sites. Innovation: In this study, we propose adapted multiple‐site versions of the Simpson, Sørensen and nestedness indices that are population size‐independent as well as estimators of these indices. The properties of the indices and their estimators were tested through simulation studies. These simulation studies show that the adapted indices were population size‐independent. The estimators and their estimated standard errors were nearly unbiased for moderate sample sizes (n ≥ 25). Main conclusions: These estimators of these adapted multiple‐site dissimilarity indices now make it possible to compare the β‐diversity of two populations of unequal sizes. [ABSTRACT FROM AUTHOR]

Aim: To determine which morphological characteristics make a fish species a good candidate for introduction and establishment, we tested whether (a) introduced species differ in morphology from non‐introduced species (species only existing in native areas and not introduced to new areas) in each donor assemblage (biogeographic realm fauna); (b) within the introduced species, the morphology of established species (self‐sustaining introduced species) differs from that of the non‐established species; (c) within the established species, those exported out of their native realm have more extreme morphological traits than those translocated within their native realm. Major taxa studied: Freshwater fish. Location: Global. Time period: 1960s–2010s. Methods: We used a global database of freshwater fishes from the six realms. Ten morphological traits were measured on 9,150 species. Principal component analysis was conducted to combine the 10 traits into a multidimensional morphospace. We used permutational multivariate analysis of variance (PERMANOVA) and permutational analysis for the multivariate homogeneity of dispersions (PERMDISP2) to compare the distribution of species groups in the morphospace and Kolmogorov–Smirnov tests to compare their distributions on principal component (PC) axes. Results: The morphology of introduced species differed from that of non‐introduced species in all the six biogeographic realms. Among introduced species, established species had more extreme morphological traits than non‐established species in most realms. Among established species, exported species had more extreme morphological traits than translocated species. Main conclusions: Morphological differences between introduced and non‐introduced species was driven by an anthropogenic trait selection for fisheries and angling, leading to the preference for the introduction of predators with large and laterally compressed bodies. Established species represent a small subset of introduced species morphologies, with established species having more extreme morphological traits than their non‐established counterparts. Established fish have morphologies more adapted to lentic waters, and this trend was more marked for species exported to other realms than for species translocated within their native realm. [ABSTRACT FROM AUTHOR]

Motivation: I describe the GIS that is based on a new database of zooplankton collected by Juday net with a 0.1 m2 opening (0.168 mm mesh). Main types of variables contained: The average density (in milligrams per cubic metre) of plankton and their different constituents in 1° trapeziums. Location: Chukchi, Bering, Okhotsk, Japan/East seas and Pacific Ocean. Time period: 1984–2013. Taxa studied: All mesofauna; > 214 species of holo‐ and meroplankton. Methods: GIS creation, data analysis and literature review. Software format: Any that is capable of working with shapefiles. Results: Maps of the spatio‐temporal distribution of plankton with various taxonomic groups and dimensions were compiled and analysed. Based on these maps and on the literature, a hypothesis was made regarding the negative correlation of the zooplankton size with temperature. It was also revealed that some fluctuations in the abundance of plankton in the Bering Sea and the ocean are in phase, whereas in the Sea of Okhotsk and the Sea of Japan the fluctuations are fully out of phase. In particular, during the transition from the light to the dark time of the day in the Sea of Okhotsk and the Sea of Japan, the density of plankton almost everywhere throughout the epipelagic zone increases; however, in the Bering Sea and the ocean, over large parts of the water area, it decreases. This means that the common practice by trophologists of attempting to replace the day‐time catch in plankton nets with the night‐time catches to assess the food reserves for fish will yield significantly different results in these waters. Main conclusion: This unique GIS could be useful to planktonologists, ichthyologists, hydrobiologists, trophologists, ecologists, biogeographers and modellers for understanding patterns and drivers of plankton diversity and biomass variations at large scales. Unfortunately, owing to lack of funding, it has not been brought to the levels of species, size classes and developmental stages that could be available in the final release. [ABSTRACT FROM AUTHOR]