Browsing by Author "Araújo, Miguel B."
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- Global biodiversity patterns of marine forests of brown macroalgaePublication . Fragkopoulou, Eliza; Serrao, Ester; De Clerck, Olivier; Costello, Mark J.; Araújo, Miguel B.; Duarte, Carlos M.; Krause‐Jensen, Dorte; Assis, JorgeAim Marine forests of brown macroalgae create essential habitats for coastal species and support invaluable ecological services. Here, we provide the first global analysis of species richness and endemicity of both the kelp and fucoid biomes. Location Global. Time period Contemporary. Major taxa studied Marine forests of brown macroalgae, formed by kelp (here defined as orders Laminariales, Tilopteridales and Desmarestiales) and fucoid (order Fucales), inhabiting subtidal and intertidal environments. Methods We coupled a large dataset of macroalgal observations (420 species, 1.01 million records) with a high-resolution dataset of relevant environmental predictors (i.e., light, temperature, salinity, nitrate, wave energy and ice coverage) to develop stacked species distribution models (stacked SDMs) and yield estimates of global species richness and endemicity. Results Temperature and light were the main predictors shaping the distribution of subtidal species, whereas wave energy, temperature and salinity were the main predictors of intertidal species. The highest regional species richness for kelp was found in the north-east Pacific (maximum 32 species) and for fucoids in south-east Australia (maximum 53 species), supporting the hypothesis that these regions were the evolutionary sources of global colonization by brown macroalgae. Locations with low species richness coincided between kelp and fucoid, occurring mainly at higher latitudes (e.g., Siberia) and the Baltic Sea, where extensive ice coverage and low-salinity regimes prevail. Regions of high endemism for both groups were identified in the Galapagos Islands, Antarctica, South Africa and East Russia. Main conclusions We estimated the main environmental drivers and limits shaping the distribution of marine forests of brown macroalgae and mapped biogeographical centres of species richness and endemicity, which largely coincided with the expectation from previous evolutionary hypotheses. The mapped biodiversity patterns can serve as new baselines for planning and prioritizing locations for conservation, management and climate change mitigation strategies, flagging threatened marine forest regions under different climate change scenarios.
- Kelp forest diversity under projected end‐of‐century climate changePublication . Assis, Jorge; Fragkopoulou, Eliza; Gouvêa, Lidiane; Araújo, Miguel B.; Serrao, EsterAim: Future climate change threatens marine forests across the world, potentially disrupting ecosystem function and services. Nonetheless, the direction and intensity of climate-induced changes in kelp forest biodiversity remain unknown, precluding well-informed conservation and management practices. Location: Global. Methods: We use machine-learning models to forecast global changes in species richness and community composition of 105 kelp forest species under contrasting Shared Socioeconomic Pathway (SSP) scenarios of climate change (decade 2090-2100): one aligned with the Paris Agreement and another of substantially higher emissions. Results: A poleward and depth shift in species distributions is forecasted, translating into similar to 15% less area in the extent of the global biome, coupled with marked regional biodiversity changes. Community composition changes are mostly projected in the Arctic, the Northern Pacific and Atlantic, and Australasia, owing to poleward range expansions and wide low latitude losses. Main Conclusions: By surpassing the Paris Agreement expectations, species reshuffling may simplify and impair ecosystem services in numerous temperate regions of Australasia, Southern Africa, Southern America and the Northern Atlantic, and in the tropical Pacific, where complete species losses were projected without replacement. These estimates, flagging threatened regions and species, as well as refugial areas of population persistence, can now inform conservation, management and restoration practices considering future climate change.
- Marine biodiversity exposed to prolonged and intense subsurface heatwavesPublication . Fragkopoulou, Eliza; Sen Gupta, Alex; Costello, Mark John; Wernberg, Thomas; Araújo, Miguel B.; Serrao, Ester; De Clerck, Olivier; Assis, JorgeMarine 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.
- Oceanographic connectivity explains the intra-specific diversity of mangrove forests at global scalesPublication . Gouvêa, Lidiane; Fragkopoulou, Eliza; Cavanaugh, Kyle; Serrao, Ester; Araújo, Miguel B.; Costello, Mark John; Westergerling, E. H. Taraneh; Assis, JorgeThe 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.
- Seagrass biodiversity under the latest‐generation scenarios of projected climate changePublication . Gouvêa, Lidiane; Fragkopoulou, Eliza; Araújo, Miguel B.; Serrao, Ester A.; Assis, JorgeAimThe potentially cascading consequences of climate changes on redistribution of habitat-forming species, like seagrasses, remain a major research gap. Empirical demonstrations of local population changes are increasingly reported without a globally integrated predictive framework as a leading testable hypothesis. Therefore, here, we aimed to estimate changes in species richness, community composition, and areas of climatic refugia under future climate scenarios.LocationGlobal scale.Time PeriodPresent-day conditions (from 2010 to 2020) and for three Shared Socioeconomic Pathway (SSP) scenarios of future climate change (from 2090 to 2100).Major Taxa StudiesSeagrasses (plantae).MethodsWe coupled seagrass occurrences with environmental predictors (temperature, salinity, nitrate, wave energy, and ice) in stacked species distribution modelling.ResultsModels estimated a present global extent of 917,169 km2 with high species richness in Temperate Australasia, Indo-Pacific, and Temperate North Pacific. Future projections predicted widespread spatial redistribution, with Arctic expansions, losses in lower latitudes, and deeper vertical ranges, while globally maintaining the area extent occupied worldwide by seagrass species (only 5% of change). Species richness increased poleward under more drastic scenarios (SSP3-7.0 and SSP5-8.5), with losses in tropical zones (30oN to 30oS). Local climatic refugia are retained in all scenarios but decrease under higher emissions. Additionally, even where seagrass species remain, widespread community composition changes were predicted.Main ConclusionsOur findings serve as baselines to inform, anticipate, and mitigate cascading consequences of shifts in seagrass ecosystems that provide essential services for humanity.
- Trophic convergence of marine vertebrate communities worldwidePublication . González-Trujillo, Juan David; Assis, Jorge; Serrao, Ester A.; Costello, Mark John; Fragkopoulou, Eliza; Mendoza, Manuel; Araújo, Miguel B.Biogeographic regions arise due to constraints on species ranges, fostering lineage divergence as a result. Yet, convergent evolution means that evolutionary distinct lineages can share similar characteristics when subjected to similar environmental conditions. The ecological convergence of distinct regions has been demonstrated in terrestrial communities, but it remains uncertain if marine systems exhibit similar patterns, given the greater ease of dispersal in the ocean. Using information on the dietary preferences of marine vertebrates, we develop an ocean regionalization that groups regions with similar trophic communities, describing how species are organized into trophic guilds and how guilds overlap with one another. Six types of trophic communities emerge globally, largely explained by temperature, productivity, and depth. Regions with analogous environments support similar numbers of species with analogous feeding strategies, even if the species do not share the same evolutionary origins. These findings support the notion that independently evolving sets of marine species can converge into functionally analogous trophic communities when exposed to similar environmental conditions. They also provide a benchmark for studying the functional consequences of global environmental change.