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Aim: The aim was to determine reef connectivity and future coral cover levels under global scenarios of coral bleaching loss and potential recovery. Location: Global coral reefs. Time period: Present‐day to 2100. Major taxa studied: Scleractinian coral. Methods: We used a global coral larval dispersal model that describes population connectivity among reefs at a resolution of ⅙° × ⅙° (c. 18 km × 18 km) cells. To simulate different patterns of bleaching events, we ran three scenarios at different levels of coral reef habitat loss followed by a reseeding of coral larvae from surviving reefs to simulate recovery. Results: We found a total of 604 distinct reef networks, but more than half of the world's reef cells are contained in six large coral reef networks (294–5,494 cells), whereas the rest form smaller networks. In the bleaching scenario where previously identified predicted climate refugia were maintained, initial connectivity was largely preserved even when 71% of global coral reef habitat was lost, but the relict reef cells were unable to reseed even 50% of former coral reef habitat because many of the relict reefs are in the same networks as each other. In scenarios where refugia were lost first or with random loss, less of the initial connectivity was maintained, but more widespread reseeding was possible because more reef cells within smaller networks were maintained. Main conclusions: Our findings highlight the importance of maintaining functional coral reef habitat outside of predicted climate refugia to sustain connectivity globally, and suggest an important role for "stepping stone" reefs between the climate refugia. Without attention to these issues of habitat loss and connectivity, much of global coral reef habitat might not be reseeded without human intervention. [ABSTRACT FROM AUTHOR]

As human activities on the world's oceans intensify, mapping human pressure is essential to develop appropriate conservation strategies and prioritize investments with limited resources. Here, we map six human (nonclimatic) pressures on coral reefs using the latest quantitative data on fishing, water pollution (nitrogen and sediments), coastal population, industrial development, and tourism. Using a percentile approach to rank different stressors, we identify the top‐ranked local pressure and estimate a cumulative pressure index for 54,596 global coral reef pixels at 0.05° (∼5 km) resolution. We find that coral reefs are exposed to multiple intense local pressures: fishing and water pollution (nutrients and sediments) are the most common top‐ranked pressures worldwide (in 30.8% and 32.3% of reef cells, respectively), although each pressure was ranked as a top pressure in some locations. We also find that local pressures are similar inside and outside a proposed global portfolio of coral reef climate refugia, suggesting that even potential climate refugia have high levels of local human pressure that require effective management. Our findings and datasets provide the best available information that can ensure local pressures are effectively managed across the world's coral reefs. [ABSTRACT FROM AUTHOR]

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Climate change can affect the habitat resources available to species by changing habitat quantity, suitability and spatial configuration, which largely determine population persistence in the landscape. In this context, dispersal is a central process for species to track their niche. Assessments of the amount of reachable habitat (ARH) using static snap‐shots do not account, however, for the temporal overlap of habitat patches that may enhance stepping‐stone effects. Here, we quantified the impacts of climate change on the ARH using a spatio–temporal connectivity model. We first explored the importance of spatio–temporal connectivity relative to purely spatial connectivity in a changing climate by generating virtual species distributions and analyzed the relative effects of changes in habitat quantity, suitability and configuration. Then, we studied the importance of spatio–temporal connectivity in three vertebrate species with divergent responses to climate change in North America (grey wolf, Canadian lynx and white‐tailed deer). We found that the spatio–temporal connectivity could enhance the stepping‐stone effect for species predicted to experience range contractions, and the relative importance of the spatio–temporal connectivity increased with the reduction in habitat quantity and suitability. Conversely, for species that are likely to expand their ranges, spatio–temporal connectivity had no additional contribution to improve the ARH. We also found that changes in habitat amount (quantity and suitability) were more influential than changes in habitat configuration in determining the relative importance of spatio–temporal connectivity. We conclude that spatio–temporal connectivity may provide less biased and more realistic estimates of habitat connectivity than purely spatial connectivity. [ABSTRACT FROM AUTHOR]

Abstract: Genetic variation, as a basis of evolutionary change, allows species to adapt and persist in different climates and environments. Yet, a comprehensive assessment of the drivers of genetic variation at different spatial scales is still missing in marine ecosystems. Here, we investigated the influence of environment, geographic isolation, and larval dispersal on the variation in allele frequencies, using an extensive spatial sampling (47 locations) of the striped red mullet (Mullus surmuletus) in the Mediterranean Sea. Univariate multiple regressions were used to test the influence of environment (salinity and temperature), geographic isolation, and larval dispersal on single nucleotide polymorphism (SNP) allele frequencies. We used Moran's eigenvector maps (db‐MEMs) and asymmetric eigenvector maps (AEMs) to decompose geographic and dispersal distances in predictors representing different spatial scales. We found that salinity and temperature had only a weak effect on the variation in allele frequencies. Our results revealed the predominance of geographic isolation to explain variation in allele frequencies at large spatial scale (>1,000 km), while larval dispersal was the major predictor at smaller spatial scale (<1,000 km). Our findings stress the importance of including spatial scales to understand the drivers of spatial genetic variation. We suggest that larval dispersal allows to maintain gene flows at small to intermediate scale, while at broad scale, genetic variation may be mostly shaped by adult mobility, demographic history, or multigenerational stepping‐stone dispersal. These findings bring out important spatial scale considerations to account for in the design of a protected area network that would efficiently enhance protection and persistence capacity of marine species. [ABSTRACT FROM AUTHOR]

Summary: Spatial differences in environmental selective pressures interact with the genomes of organisms, ultimately leading to local adaptation. Landscape genomics is an emergent research area that uncovers genome–environment associations, thus allowing researchers to identify candidate loci for adaptation to specific environmental variables. In the present study, we used latent factor mixed models (LFMMs) and Moran spectral outlier detection/randomization (MSOD‐MSR) to identify candidate loci for adaptation to 10 environmental variables (climatic, soil and atmospheric) among 43 515 single nucleotide polymorphisms (SNPs) from 202 accessions of the model legume Medicago truncatula. Soil variables were associated with a large number of candidate loci identified through both LFMMs and MSOD‐MSR. Genes tagged by candidate loci associated with drought and salinity are involved in the response to biotic and abiotic stresses, while those tagged by candidates associated with soil nitrogen and atmospheric nitrogen, participate in the legume‐rhizobia symbiosis. Candidate SNPs identified through both LFMMs and MSOD‐MSR explained up to 56% of variance in flowering traits. Our findings highlight the importance of soil in driving adaptation in the system and elucidate the basis of evolutionary potential of M. truncatula to respond to global climate change and anthropogenic disruption of the nitrogen cycle. [ABSTRACT FROM AUTHOR]

Aim To study the combined effects of climate change on connectivity between marine protected areas ( MPAs) and larval supply to the continental shelf. Location The Mediterranean Sea, where sea surface temperatures are expected to strongly increase by the end of the 21st century, represents an archetypal situation with a dense MPA network but resource overexploitation outside. Methods Using an individual-based mechanistic model of larval transport, forced with an emission-driven regional climate change scenario for the Mediterranean Sea, we explored the combined effects of changes in hydrodynamics, adult reproductive timing and larval dispersal on the connectivity among MPAs and their ability to seed fished areas with larvae. Results We show that, over the period 1970-2099, larval dispersal distances would decrease by 10%, the continental shelf area seeded with larvae would decrease by 3% and the larval retention fraction would increase by 5%, resulting in higher concentration of larvae in smaller areas of the continental shelf. However, connectance within the MPA network would increase by 5% as more northern MPAs would become suitable for reproduction with increasing temperatures. We also show that the effects of changes in adult reproductive timing and larval dispersal on connectivity patterns are additive. Main conclusions Climate change will influence connectivity and the effectiveness of MPA networks, and should receive more attention in future conservation planning and large-scale population dynamics. [ABSTRACT FROM AUTHOR]

Abstract: Extreme climatic events like the 2003 summer heatwave and inappropriate land management can threaten the existence of rare plants. We studied the response of Eryngium alpinum, a vulnerable species, to this extreme climatic event and different agricultural practices. A demographic study was conducted in seven field sites between 2001 and 2010. Stage-specific vital rates were used to parameterize matrix population models and perform stochastic projections to calculate population growth rates and estimate extinction probabilities. Among management regimes, spring grazing and land abandonment decreased vital rates and population growth, while autumn grazing and late mowing had positive effects on population viability. The 2003 heatwave reduced fecundity rates and survival rates. Only spring grazed sites presented considerable extinction risk. Stochastic projections showed that an increased frequency of 2003-like events may exacerbate extinction risk, but extinction probability depends mainly on land management regimes. To better conserve E. alpinum populations, we recommend conversion of presently spring grazed and abandoned sites to late mowing or autumn grazing. [Copyright &y& Elsevier]