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Rapid anthropogenic climate change is driving threatened biodiversity one step closer to extinction. Effects on native biodiversity are determined by an interplay between species' exposure to climate change and their specific ecological and life-history characteristics that render them even more susceptible. Impacts on biodiversity have already been reported, however, a systematic risk evaluation of threatened marine populations is lacking. Here, we employ a trait-based approach to assess the risk of 90 threatened marine Mediterranean species to climate change, combining species' exposure to increased sea temperature and intrinsic vulnerability. One-quarter of the threatened marine biodiversity of the Mediterranean Sea is predicted to be under elevated levels of climate risk, with various traits identified as key vulnerability traits. High-risk taxa including sea turtles, marine mammals, Anthozoa and Chondrichthyes are highlighted. Climate risk, vulnerability and exposure hotspots are distributed along the Western Mediterranean, Alboran, Aegean, and Adriatic Seas. At each Mediterranean marine ecoregion, 21%-31% of their threatened species have high climate risk. All Mediterranean marine protected areas host threatened species with high risk to climate change, with 90% having a minimum of 4 up to 19 species of high climate risk, making the objective of a climate-smart conservation strategy a crucial task for immediate planning and action. Our findings aspire to offer new insights for systematic, spatially strategic planning and prioritization of vulnerable marine life in the face of accelerating climate change., (© 2022 The Authors. Global Change Biology published by John Wiley & Sons Ltd.)

The Barcelona Convention (BC) aims at biodiversity conservation in the Mediterranean Sea, including in its Annex II a list of threatened species that need protection. This study aimed to assess existing scientific effort and knowledge on the invertebrate species of BC Annex II, through a systematic literature review. For the 52 invertebrates of Annex II, 1285 relevant articles were included in the review. Georeferenced records were retrieved from 183 additional articles and online databases (GBIF and WoRMS). For thirty species, <10 articles were retrieved; three species were not included in any study. The dominant research topic in the literature was 'physiology/growth' (22.5 %), followed by 'ecology' (20.1 %) and 'distribution/habitat' (17.1 %); only 6.6 % of the studies focused on 'population assessment'. Research focus substantially varied by phylum and species. Fisheries were the main threat reported, followed by natural impacts, pollution, climate change, and coastal development. An evident lack of records from the southern Mediterranean coastline was attributed to the low research effort. Population trends were reported for only 23 species. A declining trend was commonly reported (148 cases), with only three studies reporting an increase and another three reporting stable populations. The critically endangered bivalve Pinna nobilis was the species with the most records of declining populations. No conservation action was proposed for most (31) BC Annex II species. Our analyses further revealed significant coverage gaps in several species within the current marine protected areas. Despite increasing regional collaboration, most of the BC Annex II invertebrate species are understudied, with knowledge gaps compromising conservation efforts. [Display omitted] • Knowledge gaps compromise conservation efforts in the Mediterranean Sea. • Literature was systematically reviewed for 52 protected invertebrates. • For most species information was scarce with no population assessments. • For species assessed, a declining population trend was most commonly reported. • Fisheries, natural impacts, pollution and climate change were top-ranking threats. [ABSTRACT FROM AUTHOR]

For species with temperature-dependent sex determination (TSD) there is the fear that rising temperatures may lead to single-sex populations and population extinction. We show that for sea turtles, a major group exhibiting TSD, these concerns are currently unfounded but may become important under extreme climate warming scenarios. We show how highly female-biased sex ratios in developing eggs translate into much more balanced operational sex ratios so that adult male numbers in populations around the world are unlikely to be limiting. Rather than reducing population viability, female-biased offspring sex ratios may, to some extent, help population growth by increasing the number of breeding females and hence egg production. For rookeries across the world (n = 75 sites for seven species), we show that extreme female-biased hatchling sex ratios do not compromise population size and are the norm, with a tendency for populations to maximize the number of female hatchlings. Only at extremely high incubation temperature does high mortality within developing clutches threaten sea turtles. Our work shows how TSD itself is a robust strategy up to a point, but eventually high mortality and female-only hatchling production will cause extinction if incubation conditions warm considerably in the future. [ABSTRACT FROM AUTHOR]

Global efforts to halt biodiversity loss mandate the establishment of protected areas. In the face of habitat loss and climate uncertainty, large-scale networks of protected areas connected by corridors are needed to increase the dispersal and persistence potential of biota. For example, the recent European Biodiversity Strategy for 2030 defines clear targets for identifying, establishing and integrating ecological corridors, as part of a Trans-European Nature Network. Here, we examined whether rivers could serve as such corridors, facilitating landscape connectivity (i.e. extent to which landscape facilitates or impedes species movement, exchange of genes, natal dispersal and metapopulation dynamics) among protected areas hosted within different countries in the Balkan Peninsula, southeastern Europe. To quantitatively address this question, we calculated the proportion of the river network enclosed within a protected area per country to detect patterns of protection coverage and explored the degree to which spatial connections between 1878 protected areas are supported by the river network. Acknowledging that dams hinder instream continuity, we further quantified potential loss of connections between protected areas caused by the existence of already implemented or planned dam projects upon critical river habitats of endangered fish species. Our results highlight that Balkan rivers have great potential in providing the spatial connections needed to establish landscape connectivity between most of protected areas in the region. Still, heedless hydropower growth and dissimilarities in river protection between neighboring countries remain key challenges for the evolution of a relative framework. Transnational cooperation and systematic planning of infrastructure development could be the only efficient steps towards supporting the establishment of a river-based network to reconstruct connectivity between protected areas and meet biodiversity goals. [ABSTRACT FROM AUTHOR]

Abstract: Recent studies have provided theoretical and empirical evidence about the importance of hatchling production for sea turtle population dynamics. Therefore, understanding the effect of nesting habitat loss as a factor leading to hatchling reduction is essential in order to establish conservation plans for the recovery of sea turtle populations. In the present study, we developed a method to quantify habitat loss and link it with hatchling production. We used data for loggerhead sea turtles (Caretta caretta) collected at Sekania nesting beach, western Greece, to describe biological and behavioral attributes of nesting individuals. Spatial characteristics of the nesting site were analyzed and alternative scenarios of habitat loss were examined. We then used circle-packing technique to evaluate the impact of an increasingly reduced available nesting area on the spatial distribution of nests. An increased number of nests within the study site resulted in density-dependent processes regulating hatchling production. Under the different scenarios, we evaluated the risk of the laying nests exceeding the estimated carrying capacity of the nesting beach. Our results clearly demonstrated the need to apply direct and efficient conservation measures at Sekania nesting site to minimize further habitat loss from human-related processes and a rising sea level. The approach developed evaluates the effect of habitat loss upon nesting by linking it with quantifiable processes (density dependence), providing a conservation tool to guide planning decisions towards the conservation of the sea turtle population. [Copyright &y& Elsevier]

Freshwater ecosystems are threatened worldwide, with 1/3 of freshwater species being under extinction risk. Yet, systematic conservation planning has received little attention as a means to prioritize freshwater conservation areas. Here, we develop a comprehensive approach to spatially delineate key areas for freshwater conservation across Europe, considering directed-connectivity, climate change and human-related disturbances. We assess the adequacy of the current reserve network in protecting European freshwater ecosystems and provide guidelines for expansion. We conducted 13 prioritization scenarios for 18,300 sub-basins across Europe, accounting for the distribution of 1,668 freshwater species. Connectivity properties, metrics of climatic stability and human induced pressures were incorporated into the spatial prioritization framework. We highlight the critical importance of specific regions in Central and Southern Europe, the Mediterranean Basin, and parts of the Balkan Peninsula for future freshwater conservation efforts. However, our analysis also reveals the complete inadequacy of the current reserve network, as protected sub-basins only cover 4 % of the study area and encompass on average only 3 % of freshwater species distributions. In contrast, expanding current reserves to cover the top 17 % of high priority areas across Europe could substantially improve the overall coverage of species distributions, reaching an average of 61.5 % for all freshwater species and even exceeding 93.1 % for species of conservation interest (critically endangered, endangered and vulnerable species). The priority freshwater conservation network derived from the analysis provides specific spatial recommendations to help achieve conservation goals if the current reserve network is appropriately expanded. • Freshwater species are at risk worldwide and conservation planning is overlooked. • A new comprehensive approach prioritizes key areas for European freshwaters. • Critical regions for conservation exist in Central Europe and the Mediterranean. • Current reserves are inadequate covering only 4 % of Europe's freshwater ecosystems. • Expanding reserves can result in a 20-fold increase in species coverage within PAs. [ABSTRACT FROM AUTHOR]