Abstract Forests play a crucial role in mitigating climate change as primary terrestrial carbon sinks. While some studies suggest that global warming enhances forest productivity, a growing body of evidence highlights detrimental impact primarily driven by increased water stress. Yet the extent to which positive effects of climate change offset its negative impacts on tree species productivity remains unclear at large spatial extents. We assessed forest growth and mortality for the 21 most abundant tree species in Europe using National Forest Inventory data from more than 50,000 plots and 700,000 trees to disentangle the relative importance of climate and forest structure. Specifically, we examined how vapor pressure deficit (VPD) anomalies across species’ climatic edges and stand developmental stages affect forest growth and mortality occurrence and intensity (i.e. whether mortality occurred and the amount of basal area lost). Then, we aggregated the responses across species and separately for broad-leaved and needle-leaved species to assess whether forest growth and mortality differed between major functional groups. Although the importance of forest growth and mortality drivers varied markedly among species, climate had a stronger influence on mortality than on growth, particularly in needle-leaved species. Forest growth declined and mortality increased along VPD anomaly in most species and forests studied. Responses were most pronounced at arid species’ edges in early-stage broad-leaved forests and at wet edges in late-stage needle-leaved forests, where differences between functional groups were also highest. We evidence the need to parametrise species-specific models of forest growth and mortality across large spatial extents to better understand and predict effects of climate change on forest productivity. In addition, our results emphasize the importance of improving the understanding of forest mortality processes given the strong influence of climate on mortality, while also further studying vulnerable populations to climate change in arid edges of species distributions.

Theory predicts that selection against maladaptive hybridization leads to divergence of sexual characters in co-occurring closely related species. Consequently, signal disparity should be greater between sympatric vs. allopatric lineage pairs. However, this pattern may also result from species sorting or the greater evolutionary age of sympatric pairs. We used species pairs comparisons to examine the existence of acoustic divergence in a Neotropical montane radiation, the Rhinocryptidae, whose members tend to occupy different elevational ranges. Most rhinocryptids exhibit conservative morphology and are only differentiated by song attributes. Our results show that sympatric species pairs that overlap in elevation exhibited overall greater song divergence compared to allopatric species pairs after controlling for morphological differences, age and phylogenetic effects. Song divergence decreased when excluding sympatric pairs that do not overlap in elevation, suggesting that selection for improved species identification between co-occurring (syntopic) species accentuates signal differentiation. Comparative evolutionary models of signal differentiation over time revealed a similar pattern, which suggests that sexual selection in syntopy might have driven reproductive character displacement in this radiation. We conclude that selection against the production of unfit hybrids could favor acoustic traits that reliably signal species identity in tropical environments where many taxa are poorly differentiated by visual attributes.

Context Global change is leading to more frequent and intense tree damage and mortality events. Drought-induced tree mortality is occurring worldwide leading to broad-scale events, but the spatial patterns of tree damage and mortality, their underlying drivers and their variation over time is largely unknown. Objectives We investigated the spatial patterns of tree damage and mortality across Mediterranean forests of the Iberian Peninsula, the underlying effects of stand structure and climate, and how the spatial patterns and relationships with underlying drivers changed over time. Methods We used the Spanish Forest Inventory to analyse the autocorrelation in tree damage and mortality across forest types, hurdle-gamma models to quantify the effect of stand structure and climate on tree damage and mortality, and cross-correlograms to assess their spatial dependence and its change over time. Results We observed a greater magnitude and a stronger autocorrelation in tree damage than mortality, with positive aggregation up to 20 kms. There was a spatial dependence between tree damage and mortality with their drivers, with spatial aggregation increasing with water availability, drought intensity and stand structure. The spatial dependence of tree damage and mortality with the underlying drivers increased over time, particularly for drought intensity. Conclusions Our results suggest that the combined effect of intense competition and drought could favour more extensive die-off and tree mortality events, providing key information for identifying vulnerable areas and the planning of adaptation measures.

The increasing availability of contemporary climate databases calls for comparative studies testing their performance in ecological modelling. We evaluated how contemporary climate data sources interact with the modelling algorithm and affect the predictive accuracy of Species Distribution Models (SDMs). We modelled the distribution of 37 woody plants in the Iberian Peninsula using three global climate databases: WorldClim (WC), CHELSA (CH) and MERRAclim (MER); a regional climate database (the Iberian Climate Atlas, ICA), and three modelling algorithms: Generalized Linear Models (GLMs), Generalized Additive Models (GAMs), and Partial Least Squared Regressions (PLSRs). The predictive capacity of the models was estimated by performing an external evaluation while controlling for extrapolation issues. The climate database source variable and its interaction with the modelling algorithm variable showed significant effects on a model's predictive performance. Post hoc tests revealed that MER produced the lowest discrimination capacity scores, especially using GLMs as algorithm. PLSR models were significantly better than GLMs when MER was used. GAMs and PLSR models with MER were significantly worse than some ICA and CH models but not worse than any of the WC models. These results indicate that contemporary climate data sources need to be considered as a seedbed of uncertainty in SDMs and that poorly flexible algorithms are unable to deal with suboptimal data. CH is a reliable global climate database and PLSR is a technique worth considering in SDMs. The best practice is to select the most accurate climate data available and to choose the algorithm based on the purpose of the study and on context-dependent technical details.

Alien species constitute one of the main threats to freshwater ecosystems, negatively impacting biodiversity, economy, biosecurity and ecosystem services. Predicting the arrival and spread of alien species is of paramount importance to prevent new introductions and control the expansion and establishment of already introduced species. We modelled the distribution of four freshwater invaders in Great Britain, using environmental and anthropogenic predictors, to help focus management actions. The species grouped different taxa including signal crayfish ( Pacifastacus leniusculus ), the marsh frog ( Pelophylax ridibundus ), the red-eared slider ( Trachemys scripta ) and the pike-perch ( Sander lucioperca ). The modelling approach accounted for methodological limitations and implemented two evaluations, a temporal evaluation using data corresponding to 70% of the oldest records to calibrate models and the remaining 30% for evaluation using various performance metrics (the common AUC, TSS and also null models) and an independent evaluation using the most recent range expansion of the species in the last six years. The distribution of the species was facilitated by multiple environmental and anthropogenic predictors. Road density was the second most important predictor of the occurrence of signal crayfish and red-eared slider preceded by the distance to ports and isothermality for each species respectively. Human population density was the most important predictor of marsh frog presence whereas pike-perch was mostly related to the proximity of boat ramps and precipitation regimes. Our distribution models were accurate and predicted the most recent range expansion of all of the species, highlighting their usefulness for preventing alien species spread and the value of using historical projections, usually available for non-native species, to calibrate and evaluate Species Distribution Models.

Understanding public attitudes toward invasive species is crucial to curtail the reasons for their introduction and to increase the effectiveness of control measures. A questionnaire was distributed in three European countries (Italy, Spain and United Kingdom) to evaluate public attitudes on the problems posed by invasive species, their perception of the impacts and their willingness to introduce and support management actions. People whose occupations are not nature related or who practice gardening as a main outdoor activity, represent the highest risk groups relating to the introduction of invasive species. Ecosystem damage and species extinctions were the main concerns for people, and signal crayfish and zebra mussel were the species of most concern. People firstly supported control and eradication followed by awareness resulting in increasing public awareness as management measures. This information can feed into educational, prevention and eradication campaigns promoting the necessary socio-cultural changes to prevent the negative impacts of invasive species.

Lumpfish are a commercially significant marine fish that are harvested in roe fisheries and used as cleaner fish in salmon farming, however, little is known of the environmental factors shaping the ecological niche of the species at global scale. As captive reared lumpfish are sensitive to warm water, the geographic distribution of wild populations may change as sea temperatures rise under expected climate change. After investigating the ecological niche of the lumpfish using Species Distribution Models, we found that nitrate concentration, ice cover, diffuse attenuation, and temperature predicted the probability of lumpfish occurrence. Through modelling distribution under expected climate change forecasts within a realistic scenario, we found reduced probability of lumpfish occurrence in areas which currently support roe harvest and cleaner fish industry. Future conservation of the species and fisheries management should account for changes in lumpfish distribution as the range shifts northward.

The Wallacean shortfall refers to the knowledge gap in biodiversity distributions. There is still limited knowledge for freshwater fish species despite the importance of focusing conservation efforts towards this group due to their alarming extinction risk and the increasing human pressure on freshwater ecosystems. Here, we addressed the Wallacean shortfall for freshwater fish faunas across Europe by using the completeness indicator derived from species accumulation curves to quantify the fish sampling efforts. The multiple potential drivers of completeness that were previously related to the sampling efforts for other species (i.e., population density, nature reserves, or distance to cities) were tested using a 10 × 10 km2 grid resolution, as well as environmental (e.g., climatic) factors. Our results suggested that although there was an overall spatial pattern at the European level, the completeness was highly country-dependent. Accessibility parameters explained the sampling efforts, as for other taxa. Likewise, climate factors were related to survey completeness, possibly pointing to the river conditions required for fish sampling. The survey effort map we provide can be used to optimize future sampling, aiming at filling the data gaps in undersampled regions like the eastern European countries, as well as to account for the current bias in any ecological modeling using such data, with important implications for conservation and management.

Differences between climatic databases have been reported to alter the spatial predictions of species distribution models (SDM). In the present study, the global WorldClim v.2 database (WC) and the regional Iberian Climate Atlas (ICA) were compared in the geographical context of the Iberian Peninsula. Six climatic variables were considered: BIO1, BIO5 and BIO6 (temperature-related variables) and BIO12, BIO13 and BIO14 (precipitation-related variables). We performed regression analyses between values for each pair of homologous variables and generated quantile–quantile plots to compare the distribution of ranges within 10 × 10 grid cells. Pearson correlations were used to determine whether absolute differences between homologue variables were related to elevation. We modelled the occurrence of 48 woody plant species using either WC or ICA variables, and tested for differences in the estimated suitability values, discrimination power and importance of variables. Precipitation values varied considerably between databases, with WC variables reaching lower maximum and less variable values than ICA. Regarding temperature values, BIO1 had the highest correlation value between both datasets, whereas we observed substantial differences in the case of BIO5, which showed consistently lower values in WC than in ICA. Higher discrepancies between datasets, especially for temperature variables, were found in high elevation areas. As regards distribution models, the climate data source affected estimated suitability values, discrimination capacity and estimated variable importance. In addition, the rarer the species, the higher the uncertainty associated with the climate source. Climate data source is another uncertainty factor to add to all those that have already been highlighted in SDM.

Freshwater ecosystems rank among the most endangered ecosystems in the world and are under increasing threat from aquatic invasive species (AIS). Understanding the range expansion of AIS is key for mitigating their impacts. Most approaches rely on Species Distribution Models (SDMs) to predict the expansion of AIS, using mainly environmental variables, yet ignore the role of human activities in favouring the introduction and range expansion of AIS. In this study, we use five SDM algorithms (independently and in ensemble) and two accuracy measures (TSS, AUC), combined with a null modelling approach, to assess the predictive performance of the models and to quantify which predictors (environmental and anthropogenic from the native and introduced regions) best explain the distribution of nine freshwater invasive species (including fish, arthropods, molluscs, amphibians and reptiles) in a large island (Great Britain), and which species characteristics affect model performance. Our results show that the distribution of invasive species is difficult to predict by SDMs, even in cases when TSS and AUC model accuracy values are high. Our study strongly advocates the use of null models for testing SDMs performance and the inclusion of information from the native area and a variety of both human-related and environmental predictors for a more accurate modelling of the range expansion of AIS. Otherwise, models that only include climatic variables, or rely only on standard accuracy measures or a single algorithm, might result in mismanagement of AIS.

The interplay between niche conservatism and niche evolution has been suggested to play a key role in shaping the biogeographical history of a given clade. Here, we integrate climatic data associated with the distribution range of 86 diprotodontid species and their phylogenetic relationships in order to examine the evolutionary dynamics of ecological niches of Diprotodontia and explore the link between diversification, niche evolution, and trends in biodiversity over space in this iconic group. Both mean annual temperature (MAT) and annual precipitation (AP) best-fitted punctuated modes of evolution indicate that climatic niche evolution in diprotodonts is speciational. Among-clade variation in rates of climatic niche evolution was correlated with variation in rates of lineage diversification, which reinforces the view that rapid shifts in climatic niches promote speciation. We found that both climatic attributes, AP and MAT, exhibited a pattern according to which species richness progressively declined along a gradient from ancestral to derived climatic conditions and, in turn, it was negatively correlated to niche breadth. However, correlation between niche breadth and niche position was not similar for both climatic traits, as these differ with respect to the relative position of the zone colonized by the most recent common ancestor within its corresponding axis. Diprotodontia diversity decreased while phylogenetic clustering increased, suggesting that niche conservatism associated with ancestral climate probably drives most of variation in species richness in this region. Our study shows that the diversification of diprotodontid marsupials appears to have occurred against a background of moderate phylogenetic niche consevatism, which largely determines the current distribution of this group.

AbstractInterspecific competition is thought to play a key role in determining the coexistence of closely related species within adaptive radiations. Competition for ecological resources can lead to different outcomes from character displacement to, ultimately, competitive exclusion. Accordingly, divergent natural selection should disfavor those species that are the most similar to their competitor in resource use, thereby increasing morphological disparity. Here, we examined ecomorphological variability within an Australo‐Papuan bird radiation, the Acanthizidae, which include both allopatric and sympatric complexes. In addition, we investigated whether morphological similarities between species are related to environmental factors at fine scale (foraging niche) and/or large scale (climate). Contrary to that predicted by the competition hypothesis, we did not find a significant correlation between the morphological similarities found between species and their degree of range overlap. Comparative modeling based on both a priori and data‐driven identification of selective regimes suggested that foraging niche is a poor predictor of morphological variability in acanthizids. By contrast, our results indicate that climatic conditions were an important factor in the formation of morphological variation. We found a significant negative correlation between species scores for PC1 (positively associated to tarsus length and tail length) and both temperature and precipitation, whereas PC2 (positively associated to bill length and wing length) correlated positively with precipitation. In addition, we found that species inhabiting the same region are closer to each other in morphospace than to species outside that region regardless of genus to which they belong or its foraging strategy. Our results indicate that the conservative body form of acanthizids is one that can work under a wide variety of environments (an all‐purpose morphology), and the observed interspecific similarity is probably driven by the common response to environment.

Aquatic Invasive Alien Species (AIAS) are increasing due to the synergistic effects of climate change and habitat destruction. AIAS can heavily impact biodiversity and human health, causing a loss of ecosystem services; therefore, their control and management have now become a priority, particularly in the light of the new EU regulation 1143/2014 on invasive alien species. The main research goal of the Innovative Training Network Marie Skłodowska-Curie Aquainvad-ED is to exploit the application of innovative tools and the power of citizen science for early detection, control and management of AIAS. Eight early stage researchers are involved in Aquainvad-ED, engaged in four main research themes: (1) development and application of novel methods for early detection of AIAS; (2) identification of vectors of introduction and pathways of dispersal; (3) impacts of freshwater and marine invaders; and (4) risk assessment and control of AIAS. In order to develop multidisciplinary approaches to address these issues, the fellows are working within an international consortium (UK, Spain, Italy) composed of scientists and conservation practitioners from three universities (Swansea University, Universidad de Oviedo, Università degli Studi di Firenze), one technological institute (AZTI), two governmental agencies (Natural Resources Wales and Cardiff Harbour Authority), one NGO (Wye & Usk Foundation) and five SMEs working in fundamental and applied aspects of AIAS (Neoalgae, Natural Applications, NEMO, Ecohydros, and Itinera C.E.R.T.A).

The Australasian marsupial family Dasyuridae exhibits one of the most spectacular species-level diversity of any marsupial group. The existence of such exceptional species and phenotypic diversity is commonly attributed to ecological opportunity (EO). According to the EO hypothesis, organisms freed from the burden of competition may undergo an initial burst in diversification and morphological evolution. Subsequently, as accessible niches become occupied, rates of diversification should slow through time. We examined the dynamics of lineage and phenotypic diversification to test whether Dasyuridae diversified in a classic adaptive radiation. We found that patterns of both lineage diversification and phenotypic (body mass) disparity exhibited an early burst as predicted by the EO model. Three historical events may have spurred this radiation: the extinction of thylacinids, the emergence of the New Guinean cordillera, and the spread of arid habitats as evidenced by the existence of phylogenetic clustering in these regions. In contrast to previous studies carried out on continent-wide systems, our results support a niche-filling scenario with an early-burst signal strong enough to be detected. This study shows that the diversification of Dasyuridae conforms fully to the postulates of the EO hypothesis and thus it constitutes a 'classic' adaptive radiation.

Ecological theories of adaptive radiation predict that ecological opportunity (EO) stimulates cladogenesis through entry into a novel environment and/or release of competition pressures. Due to its dynamic paleoclimatic and geological history, the Australo‐Papuan region constitutes an opportune scenario to study patterns of diversification in relation to the colonization of new ecological niches. Here, we employ a comparative framework using the Australasian robins (Petroicidae) as a model system to test whether the diversification of this bird family fulfils a niche‐filling process as predicted by the EO model, and to test whether the observed morphological similarity is described by a pattern of phylogenetic niche conservatism (PNC) or convergence. Although we detected an early‐burst, we did not find a slowdown in speciation or morphological evolution as expected in a niche‐filling scenario. Divergence in tarsus length and tail length (PC1) was consistent with a multi‐peak model, in which PC1 represents a convergent trait among distantly related clades sharing the same foraging strategy. Our study thus shows that convergence rather than PNC seems to explain the existence of morphological similarity across independent lineages in the Petroicidae. We also found a low level of PNC regarding annual variations in temperature and precipitation, which is in agreement with the hypothesis that diversification within the Petroicidae involved repeated radiations. We suggest two non‐mutually exclusive hypotheses to explain the overall lack of density‐dependent cladogenesis. First, the extreme spatial and temporal heterogeneity of this region may have generated a pattern of repeated ecological opportunity over time and, second, this family may not yet have reached equilibrium diversity.

Species Distribution Models (SDMs) have been reported as a useful tool for the risk assessment and modeling of the pathways of dispersal of freshwater invasive alien species (IAS). Environmental DNA (eDNA) is a novel tool that can help detect IAS at their early stage of introduction and additionally improve the data available for a more efficient management. SDMs rely on presence and absence of the species in the study area to infer the predictors affecting species distributions. Presence is verified once a species is detected, but confirmation of absence can be problematic because this depends both on the detectability of the species and the sampling strategy. eDNA is a technique that presents higher detectability and accuracy in comparison to conventional sampling techniques, and can effectively differentiate between presence or absence of specific species or entire communities by using a barcoding or metabarcoding approach. However, a number of potential bias can be introduced during (i) sampling, (ii) amplification, (iii) sequencing, or (iv) through the usage of bioinformatics pipelines. Therefore, it is important to report and conduct the field and laboratory procedures in a consistent way, by (i) introducing eDNA independent observations, (ii) amplifying and sequencing control samples, (iii) achieving quality sequence reads by appropriate clean-up steps, (iv) controlling primer amplification preferences, (v) introducing PCR-free sequence capturing, (vi) estimating primer detection capabilities through controlled experiments and/or (vii) post-hoc introduction of “site occupancy-detection models.” With eDNA methodology becoming increasingly routine, its use is strongly recommended to retrieve species distributional data for SDMs.

Aquatic Invasive Alien Species (AIAS) are increasing due to the synergistic effects of climate change and habitat destruction. AIAS can heavily impact biodiversity and human health, causing a loss of ecosystem services; therefore, their control and management have now become a priority, particularly in the light of the new EU regulation 1143/2014 on invasive alien species. The main research goal of the Innovative Training Network Marie Sklodowska-Curie Aquainvad-ED is to exploit the application of innovative tools and the power of citizen science for early detection, control and management of AIAS. Eight early stage researchers are involved in Aquainvad-ED, engaged in four main research themes: (1) development and application of novel methods for early detection of AIAS; (2) identification of vectors of introduction and pathways of dispersal; (3) impacts of freshwater and marine invaders; and (4) risk assessment and control of AIAS. In order to develop multidisciplinary approaches to address these issues, the fellows are working within an international consortium (UK, Spain, Italy) composed of scientists and conservation practitioners from three universities (Swansea University, Universidad de Oviedo, Universita degli Studi di Firenze), one technological institute (AZTI), two governmental agencies (Natural Resources Wales and Cardiff Harbour Authority), one NGO (Wye & Usk Foundation) and five SMEs working in fundamental and applied aspects of AIAS (Neoalgae, Natural Applications, NEMO, Ecohydros, and Itinera C.E.R.T.A).