Carlos Cano-Barbacil

Aim: Oceanic islands host exceptional biodiversity and endemism but are highly vulnerable to biological invasions. We aimed to identify non‐native species with high potential to invade the Canary Islands within the next decade and to prioritise them based on their environmental and socioeconomic risks. Location: The Canary Islands, Macaronesia, northeastern Atlantic Ocean. Methods: We applied a structured horizon scanning protocol with a global scope. A panel of 37 experts assessed 823 species across five thematic groups (marine species, freshwater animals, terrestrial vertebrates, terrestrial invertebrates and plants) by scoring their likelihood of arrival, establishment and impacts. Impacts were evaluated separately as environmental and socioeconomic. Agreement and consistency among experts were quantified, and two consensus‐based ranked lists were developed. Results: Although agreement in expert scores was relatively low, species rankings showed high consistency. A total of 94 species were identified as priorities for prevention based on environmental impacts (12 very high risk, 82 high risk), while 49 species were prioritized for socioeconomic impacts (2 very high, 47 high). Environmental risks were dominated by lizards, snakes and freshwater fish, whereas socioeconomic risks were mainly concentrated on insects. Environmental and socioeconomic impact scores were only weakly related, underscoring the value of independent evaluation. Main Conclusions: This study provides a horizon scanning explicitly focused on the Canary Islands, with separate assessments of environmental and socioeconomic risks. Our results highlight taxonomic groups that warrant urgent attention, show that invasion risk patterns vary depending on the spatial and contextual scale of assessment and provide a proactive tool to support surveillance, early warning systems and biosecurity measures. By anticipating future threats, this work contributes methodological and applied advances with broad relevance for conservation biogeography and invasive species management in island ecosystems.

We argue that contemporary scientific systems progressively constrain high-risk and conceptually innovative research while being increasingly structured around short funding cycles, productivity-based evaluation criteria and risk-averse frameworks that favour predictable and non-transformative research outputs. Drawing on recent empirical literature, we show how such systems can place disproportionate pressure on early-career researchers by incentivizing safe, tractable and easily evaluated outputs. Structural academic mechanisms such as peer review and funding, escalating publication costs and institutional inequalities interact with precarious employment and hierarchical dependencies. In this environment, we contend that strategic conformity becomes a rational career path. This risks suppressing creativity and critical thinking precisely at the stage when scientific independence could otherwise emerge. Consequently, the probability of substantive contributions by early-career researchers is declining, while talent may increasingly abandon academia or cluster within a limited number of well-resourced institutions and national systems. By adopting a systems-level perspective, we argue that scientific creativity is not merely an individual trait but an emerging property of a supportive academic landscape and that maintaining or restoring it may require substantial structural reforms. These include promoting stable research pathways, decentralized decision-making and evaluation frameworks that better recognize collaboration, originality, persistence and nonlinear career trajectories. Without systemic change, we risk stifling the potential of early-career researchers to go beyond the confines of existing methods and approaches and deliver transformative advances. This would limit their capacity to meaningfully change our understanding of the world or benefit society, with impacts that fall short of their potential.

Introduction: The circum-Mediterranean region is a global biodiversity hotspot, hosting a highly distinctive freshwater fauna with a high degree of endemism and conservation concern. However, these ecosystems are increasingly threatened by biological invasions, particularly by non-native fish species, which represent a major driver of biodiversity loss. Objective: This study aims to compile a comprehensive and updated inventory of non-native inland fish species across the circum-Mediterranean region and to identify the main taxonomic, biogeographical, and socio-environmental drivers shaping their distribution. Methodology: We conducted an extensive review of the scientific literature, online databases (including EASIN, GISD, and CABI), and technical reports to compile records of non-native fish species across inland and transitional waters of Mediterranean-climate basins. Analyses focused on species composition, taxonomic representativeness, introduction pathways, native regions, and the relationship between species richness and selected environmental and socio-economic variables. Results: A total of 151 non-native fish species were recorded across the study area. Italy, Spain, Bosnia and Herzegovina, France, and Croatia exhibited the highest numbers of established species. Taxonomic representation was uneven, with Salmoniformes and Esociformes overrepresented among established non-native species, while Siluriformes and Characiformes were underrepresented. Most introductions originated from Europe, Asia, and North America, primarily through intentional releases and escape events. Non-native species richness was positively correlated with gross domestic product, precipitation, and the number of dams, highlighting the role of economic development and habitat modification in facilitating invasions. Conclusions: Biological invasions by non-native fishes are widespread across the Mediterranean basin and are strongly driven by human activities and environmental conditions. The high invasion levels observed in this biodiversity hotspot pose a significant threat to endemic freshwater faunas. These findings underscore the need for coordinated transnational management strategies, stricter regulation of introduction pathways, and prioritization of high-risk species to mitigate further impacts.

En mayo de 2017 la Organización Meteorológica Mundial reconoció como estación centenaria de observación a largo plazo el Observatorio Meteorológico de El Retiro, situado en la localidad de Madrid, por su serie climatológica de más de cien años. En este trabajo se hace un breve repaso histórico del Observatorio de El Retiro, cuyo origen daría lugar a la actual Agencia Estatal de Meteorología (AEMET), y se analizan las series históricas de temperatura, precipitación, número de días cálidos, noches tropicales y días con helada, con el objetivo de detectar posibles tendencias. Durante sus algo más de 130 años de existencia la temperatura media anual del aire en superficie ha experimentado una variación positiva de 2 °C, con respecto a la que había a comienzos del siglo XX. Además, se han confirmado aumentos significativos en el número de días cálidos y de noches tropicales de un 120,8% y un 520,6%, respectivamente; mientras que el número de días con helada ha disminuido un 32,3% durante el periodo de estudio. Por el contrario, la precipitación anual acumulada no muestra un cambio significativo a lo largo del mismo periodo.

The circum-Mediterranean region is a global biodiversity hotspot, home to a highly distinctive freshwater fauna with a large proportion of endemic species, many of which are threatened. These ecosystems are increasingly impacted by biological invasions, particularly by non-native fishes. Here, we provide a comprehensive, updated inventory and analysis of non-native fishes recorded in inland waters across all countries bordering the Mediterranean Sea, based on an extensive review of scientific literature, databases and technical reports. A total of 151 non-native fish species were recorded in circum-Mediterranean inland waters, with Italy, Spain, Bosnia and Herzegovina, France and Croatia exhibiting the highest numbers of established species. Certain orders, such as Salmoniformes and Esociformes, were significantly overrepresented among established non-native species, whereas others, including Siluriformes and Characiformes, were underrepresented. Most introductions came from other European countries, Asia and North America, primarily through escapes or intentional releases. Non-native fish species richness showed a strong positive correlation with gross domestic product, precipitation and the number of dams, underscoring the influence of economic development and habitat availability as key drivers of species establishment. We also discuss the implications for regional biodiversity conservation and highlight the need for coordinated transnational strategies.

The ongoing biodiversity crisis, marked by global wildlife declines and high extinction rates that undermine ecosystem function and essential ecosystem services, is also evident in European marine ecosystems, where coastal birds have experienced marked population losses due to overfishing, habitat degradation, pollution, and decades of hunting. Despite conservation efforts and the establishment of protected areas, many species remain threatened. Numerous studies have assessed long-term population trends of individual coastal bird species; however, research addressing changes at the community level across broad temporal and spatial scales remains limited. Here, we used a large-scale database of 308 time series of coastal bird communities collected between 1957 and 2024 across the Baltic Sea, the North Sea, and the Western Mediterranean Sea to assess how abundance, taxonomic and functional diversity have changed over the past decades, and to evaluate the effect of conservation areas on coastal bird communities.Our results showed overall increases in taxonomic richness (1.7% per year on average), taxonomic diversity (1.4%), abundance (2.7%), functional richness (4.1%) and functional evenness (0.7%) of coastal bird communities. However, trends were highly variable across sites, including 4.5% of them experiencing significant declines in species richness, 5.2% in taxonomic diversity, and 13.3% in abundance. Although these overall increases were similar across the three regions studied, they were not uniform within them. For example, recovery in the Western Mediterranean Sea occurred primarily between 1970 and 2000, while in the Baltic Sea, increases have occurred since 1995. Our results also showed the relevance of conservation areas for coastal birds, especially those strictly protected (i.e., IUCN Categories of Protected Areas Ia, Ib or II). However, we also found that some non-protected sites are recovering at rates similar to—or even exceeding—those observed in strictly protected areas.Despite overall improving trends, many coastal bird communities continue to face persistent declines due to site-specific stressors and broader pressures such as overfishing, bycatch, habitat degradation, and climate change. Ensuring long-term conservation success will require not only well-managed protected areas and strict conservation policies but also strengthened monitoring, international collaboration, and adaptive strategies across European seas.

Freshwater salinization is an emerging threat impacting approximately one‐third of the world's freshwater bodies. However, the salinity tolerance of many inland fishes remains understudied, despite being a crucial factor in determining species distributions and fitness. We updated and analysed a comprehensive global database of experimental salinity tolerance, compiled from 128 sources, to investigate geographical and taxonomic biases in research on the salinity tolerance of inland fishes. Additionally, we examined how salinity tolerance relates to fish traits and how experimental data align with field‐reported salinity levels. Experimental data on salinity tolerance was available for < 1% of the world's inland fishes, with data severely lacking from diverse tropical regions and species‐rich orders such as Characiformes and Siluriformes. Most salinity tolerance studies focused on relatively large and widely distributed species from North America, Europe and Oceania and certain orders such as Acipenseriformes, Centrarchiformes, Cyprinodontiformes or Lepisosteiformes. Our results showed that fish salinity tolerance was strongly associated with fish habitat type, taxonomy, aspects of morphology, migratory behaviour and the experimental approach used (direct vs. gradual). Our results also showed significant, though sometimes weak relationships between field‐reported salinity levels and experimental estimates. Improved understanding of fish salinity tolerance will be essential for assessing impacts of freshwater salinization and forecasting the invasion potential of non‐native species.

Global change is reshaping biological communities, leading to shifts in community composition, species distributions and species realized niches. These processes are especially relevant in freshwater ecosystems, where vertebrate declines are particularly severe and dispersal is naturally constrained by drainage basins. Using data from 204 sampling sites across the Iberian Peninsula, the majority of which were located in the northern regions, particularly the Basque Country and Catalonia, we quantified temporal shifts in freshwater fish species occupancy, realized niches and their relationships with species traits between 2001–2010 and 2015–2024. We combined monitoring data, environmental variables, species traits and complementary statistical approaches, including the within outlying mean index (WitOMI), an ordination method that quantifies niche metrics such as marginality and breadth. No significant changes were detected in mean species occupancy or niche parameters between periods. However, this apparent stability masks species‐specific dynamics. Increases in occupancy were observed in fast life‐cycle species. Similarly, declines in niche marginality were predominantly associated with habitat generalists and species with low fecundity but with a long reproductive season, while changes in niche breadth were only weakly and negatively associated with omnivory and body elongation. Overall, our results suggest a modest reorganization of Iberian freshwater fish communities driven by the expansion of generalist species and declines in specialists. These trends are consistent with ongoing biotic homogenization and highlight the importance of integrating species distributions, niche dynamics and functional traits to better understand biodiversity responses to global change and to inform conservation planning and adaptive management strategies.

The Anthropocene is characterised by a continuous human‐mediated reshuffling of the distributions of species globally. Both intentional and unintentional introductions have resulted in numerous species being translocated beyond their native ranges, often leading to their establishment and subsequent spread – a process referred to as biological invasion. Biological invasions are associated with profound changes in the composition, structure, and functioning of recipient ecosystems, plus substantial financial losses and disruptions to society, culture, and human well‐being. These ecological, economic, and socio‐cultural impacts are interrelated, ubiquitous, and detrimental, yet they are often subjectively perceived or inaccurately quantified. Persistent knowledge gaps remain, however, which limit our understanding of the complex and multifaceted causes and mechanisms of invasion impacts. To overcome these gaps and comprehensively capture all related facets pertaining to the nature and diversity of invasion impact, this scoping review of academic studies, grey literature, and expert reports provides a conceptual model for interpreting invasion impacts, structured around three interrelated pillars: impact domains, challenges in the study of impacts, and available risk‐ and impact assessments. We initially explore the various mechanisms and consequences of ecological, economic, and socio‐cultural invasion impacts and their temporal dynamics, substantiating these with relevant empirical examples. We then review common challenges and fallacies in studying invasion impacts, including context specificity and inter‐comparability of impact magnitudes, challenges associated with quantifying non‐ecological impacts, and research biases, before synthesising how risks are analysed and impacts assessed, and how these assessments ultimately inform management decisions. Our review underscores the multifaceted and complex nature of invasion impacts, and that effectively addressing biological invasions requires more than isolated, reactive interventions; it calls for globally coordinated, proactive action underpinned by reliable scientific knowledge, sincere political commitment, and broad public engagement. Drawing on nearly a century of literature and global expert contributions, this work offers a comprehensive, nuanced, and timely overview of the potential consequences of biological invasions, providing a valuable foundation for informing future research directions, management interventions, and policy development.

Marine ecosystems have been historically impacted by human activities, leading to significant declines in biodiversity. Despite conservation efforts and the establishment of protected areas over recent decades, many marine species remain threatened. Here, we used a large‐scale database of 308 time series of coastal bird communities collected between 1957 and 2024 across three European regional seas to assess how abundance, taxonomic and functional diversity have changed over the past decades, and to evaluate the effect of conservation areas on coastal bird communities. Our results showed overall increases in taxonomic richness (1.7% per year on average), taxonomic diversity (1.4%), abundance (2.7%), functional richness (4.1%) and functional evenness (0.7%) of coastal bird communities. Although these overall increases were similar across the three seas investigated, they were not uniform within them. Recovery in the Western Mediterranean Sea occurred primarily between 1970 and 2000, while in the Baltic Sea, increases have occurred since 1995. For the Baltic Sea, we also found that taxonomic and functional richness, along with total abundance, are increasing more rapidly in wintering compared to breeding communities. Besides the overall mean increases, trends were highly variable across sites, including 4.5% of them experiencing significant declines in species richness, 5.2% in taxonomic diversity, and 13.3% in abundance. This site‐scale variability underscores the need for targeted conservation strategies that address local challenges. Our results also showed the relevance of conservation areas for coastal birds, especially those strictly protected. However, the effectiveness of protection depends on additional factors beyond the formal protection status alone. As some anthropogenic pressures persist, additional conservation actions are needed to ensure that marine bird communities continue to recover, but also to maintain stability in those populations that may have reached their carrying capacity.