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Climate-informed prioritization of marine biodiversity hotspots to support the implementation of the post-2020 biodiversity framework



Marine biodiversity exposed to prolonged and intense subsurface heatwaves
Publication . Fragkopoulou, Eliza; Sen Gupta, Alex; Costello, Mark John; Wernberg, Thomas; Araújo, Miguel B.; Serrao, Ester; De Clerck, Olivier; Assis, Jorge
Marine heatwaves (MHWs) are becoming increasingly common, with devastating ecosystem impacts. However, MHW understanding has almost exclusively relied on sea surface temperature with limited knowledge about their subsurface characteristics. Here we estimate global MHWs from the surface to 2,000 m depth, covering the period 1993-2019, and explore biodiversity exposure to their effects. We find that MHWs are typically more intense in the subsurface at 50-200 m and their duration increases up to twofold with depth, although with large spatial variability linked to different oceanographic conditions. Cumulative intensity (a thermal stress proxy) was highest in the upper 250 m, exposing subsurface biodiversity to MHW effects. This can be particularly concerning for up to 22% of the ocean, where high cumulative intensity overlapped the warm range edge of species distributions, thus being more sensitive to thermal stress. Subsurface MHWs can hence drive biodiversity patterns, with consequent effects on ecological interactions and ecosystem processes. The authors estimate the intensity, duration and number of global marine heatwaves from 1993 to 2019, from the surface to 2,000 m. They show generally higher intensity of marine heatwaves at 50-200 m, but increased duration with depth, and predict ocean regions of higher biodiversity exposure.
A global dataset of demosponge distribution records
Publication . Vafeiadou, Ariadni; Fragkopoulou, Eliza; Assis, Jorge
Biodiversity information in the form of species occurrence records is key for monitoring and predicting current and fu- ture biodiversity patterns, as well as for guiding conserva- tion and management strategies. However, the reliability and accuracy of this information are frequently undermined by taxonomic and spatial errors. Additionally, biodiversity in- formation facilities often share data in diverse incompatible formats, precluding seamless integration and interoperabil- ity. We provide a comprehensive quality-controlled dataset of occurrence records of the Class Demospongiae, which comprises 81% of the entire Porifera phylum. Demosponges are ecologically significant as they structure rich habitats and play a key role in nutrient cycling within marine ben- thic communities. The dataset aggregates occurrence records from multiple sources, employs dereplication and taxonomic curation techniques, and is flagged for potentially incorrect records based on expert knowledge regarding each species’ bathymetric and geographic distributions. It yields 417,626 records of 1,816 accepted demosponge species (of which 321,660 records of 1,495 species are flagged as potentially correct), which are provided under the FAIR principle of Find- ability, Accessibility, Interoperability and Reusability in the Darwin Core Standard. This dataset constitutes the most up- to-date baseline for studying demosponge diversity at the global scale, enabling researchers to examine biodiversity patterns (e.g., species richness and endemicity), and forecast
Bio‐ORACLE v3.0. pushing marine data layers to the CMIP6 earth system models of climate change research
Publication . Assis, Jorge; Fernández Bejarano, Salvador Jesús; Salazar, Vinícius W.; Schepers, Lennert; Gouvêa, Lidiane; Fragkopoulou, Eliza; Leclercq, Frederic; Vanhoorne, Bart; Tyberghein, Lennert; Serrao, Ester; Verbruggen, Heroen; De Clerck, Olivier
Motivation: Impacts of climate change on marine biodiversity are often projected with species distribution modelling using standardized data layers representing physical, chemical and biological conditions of the global ocean. Yet, the available data layers (1) have not been updated to incorporate data of the Sixth Phase of the Coupled Model Intercomparison Project (CMIP6), which comprise the Shared Socioeconomic Pathway (SSP) scenarios; (2) consider a limited number of Earth System Models (ESMs), and (3) miss important variables expected to influence future biodiversity distributions. These limitations might undermine biodiversity impact assessments, by failing to integrate them within the context of the most up-to-date climate change projections, raising the uncertainty in estimates and misinterpreting the exposure of biodiversity to extreme conditions. Here, we provide a significant update of Bio-ORACLE, extending biologically relevant data layers from present-day conditions to the end of the 21st century Shared Socioeconomic Pathway scenarios based on a multi-model ensemble with data from CMIP6. Alongside, we provide R and Python packages for seamless integration in modelling workflows. The data layers aim to enhance the understanding of the potential impacts of climate change on biodiversity and to support well-informed research, conservation and management. Main Types of Variable Contained: Surface and benthic layers for, chlorophyll-a, diffuse attenuation coefficient, dissolved iron, dissolved oxygen, nitrate, ocean temperature, pH, phosphate, photosynthetic active radiation, total phytoplankton, total cloud fraction, salinity, silicate, sea-water direction, sea-water velocity, topographic slope, topographic aspect, terrain ruggedness index, topographic position index and bathymetry, and surface layers for air temperature, mixed layer depth, sea-ice cover and sea-ice thickness. Spatial Location and Grain: Global at 0.05 degrees resolution. Time Period and GrainDecadal from present-day to the end of the 21st century (2000-2100). Major Taxa and Level of Measurement: Marine biodiversity associated with surface and epibenthic habitats. Software Format: A package of functions developed for Python and R software.
Oceanographic connectivity explains the intra-specific diversity of mangrove forests at global scales
Publication . Gouvêa, Lidiane; Fragkopoulou, Eliza; Cavanaugh, Kyle; Serrao, Ester; Araújo, Miguel B.; Costello, Mark John; Westergerling, E. H. Taraneh; Assis, Jorge
The distribution of mangrove intra-specific biodiversity can be structured by historical demographic processes that enhance or limit effective population sizes. Oceanographic connectivity (OC) may further structure intra-specific biodiversity by preserving or diluting the genetic signatures of historical changes. Despite its relevance for biogeography and evolution, the role of oceanographic connectivity in structuring the distribution of mangrove's genetic diversity has not been addressed at global scale. Here we ask whether connectivity mediated by ocean currents explains the intra-specific diversity of mangroves. A comprehensive dataset of population genetic differentiation was compiled from the literature. Multigenerational connectivity and population centrality indices were estimated with biophysical modeling coupled with network analyses. The variability explained in genetic differentiation was tested with competitive regression models built upon classical isolation-by-distance (IBD) models considering geographic distance. We show that oceanographic connectivity can explain the genetic differentiation of mangrove populations regardless of the species, region, and genetic marker (significant regression models in 95% of cases, with an average R-square of 0.44 +/- 0.23 and Person's correlation of 0.65 +/- 0.17), systematically improving IBD models. Centrality indices, providing information on important stepping-stone sites between biogeographic regions, were also important in explaining differentiation (R-square improvement of 0.06 +/- 0.07, up to 0.42). We further show that ocean currents produce skewed dispersal kernels for mangroves, highlighting the role of rare long-distance dispersal events responsible for histori- cal settlements. Overall, we demonstrate the role of oceanographic connectivity in structuring mangrove intra-specific diversity. Our findings are critical for mangroves' biogeography and evolution, but also for management strategies considering climate change and genetic biodiversity conservation.
Trans-Arctic asymmetries, melting pots and weak species cohesion in the low-dispersal amphiboreal seaweed Fucus distichus
Publication . Neiva, J.; Assis, Jorge; Fragkopoulou, Eliza; Pearson, Gareth; Raimondi, Peter T.; Anderson, Laura; Krause-Jensen, Dorte; Marbà, Núria; Want, Andrew; Selivanova, Olga; Nakaoka, Masahiro; Grant, W. Stewart; Konar, Brenda; Roleda, Michael Y.; Sejr, Mikael K.; Paulino, Cristina; Serrao, Ester
Amphiboreal taxa are often composed of vicariant phylogroups and species complexes whose divergence and phylogeographic affinities reflect a shared history of chronic isolation and episodic trans-Arctic dispersal. Ecological filters and shifting selective pressures may also promote selective sweeps, niche shifts and ecological speciation during colonization, but these are seldom considered at biogeographical scales. Here we integrate genetic data and Ecologic Niche Models (ENMs) to investigate the historical biogeography and cohesion of the polymorphic rockweed Fucus distichus throughout its immense amphiboreal range, focusing on trans-Arctic asymmetries, glacial/interglacial dynamics, and integrity of sympatric eco-morphotypes. Populations were sampled throughout the Pacific and the Atlantic, from southern rear-edges to the high-Arctic. They were genotyped for seven microsatellites and an mtDNA spacer, and genetic diversity and structure were assessed from global to local scales. ENMs were used to compare niche divergence and magnitude of post-glacial range shifts in Pacific versus Atlantic sub-ranges. Haplotypic and genotypic data revealed distinct and seemingly isolated Pacific vs Arctic/Atlantic gene-pools, with finer-scale regional sub-structuring pervasive in the Pacific. MtDNA diversity was highly structured and overwhelmingly concentrated in the Pacific. Regionally, Alaska showed the highest intra-population diversity but the lowest levels of endemism. Some sympatric/parapatric ecotypes exhibited distinct genotypic/haplotypic compositions. Strikingly, niche models revealed higher Pacific tolerance to maximum temperatures and predicted a much more consolidated presence in the NE Atlantic. Glacial and modern ranges overlapped extensively in the Pacific, whereas the modern Atlantic range was largely glaciated or emerged during the Last Glacial Maximum. Higher genetic and ecogeographic diversity supports a primary Pacific diversification and secondary Atlantic colonization, also likely reflecting the much larger and more stable climatic refugia in the Pacific. The relic distribution and reduced ecological/morphological plasticity in the NE Atlantic are hypothesized to reflect functional trans-Arctic bottlenecks, recent colonization or competition with congeners. Within the Pacific, Alaska showed signatures of a post-glacial melting pot of eastern and southern populations. Genetic/ecotypic variation was generally not sufficiently discontinuous or consistent to justify recognizing multiple taxonomic entities, but support a separate species in the eastern Pacific, at the southern rear-edge. We predict that layered patterns of phylogeographic structure, incipient speciation and niche differences might be common among widespread low-dispersal amphiboreal taxa.

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Fundação para a Ciência e a Tecnologia

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