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Genetic variability of red swamp crayfish reveals its invasion process

Patterns of genetic diversity in invasive populations can be modulated by a range of factors acting at different stages of the invasion process, including the genetic composition of the source population(s), the introduction history (e.g. propagule pressure), the environmental suitability of recipient areas, and the features of secondary introductions. The North American red swamp crayfish, Procambarus clarkii, is one of the most widely introduced freshwater species worldwide. It was legally introduced into Spain twice, near the city of Badajoz in 1973 and in the Guadalquivir marshes in 1974. Thereafter the species rapidly colonised almost the entire Iberian Peninsula. Seven nuclear microsatellites were used to describe the genetic diversity and structure of 28 locations distributed across the Iberian Peninsula and to explain the expansion process of the red swamp crayfish. Additionally, the relationship between environmental suitability and genetic diversity of the studied locations were analysed. The red swamp crayfish had a clear spatial genetic structure in the Iberian Peninsula, probably determined by the two independent introduction events in the 1970s, which produced two main clusters separated spatially, one of which was dominant in Portugal and the other in Spain. The human-mediated dispersal process seemed to have involved invasion hubs, hosting highly genetically diverse areas and acting as sources for subsequent introductions. Genetic diversity also tended to be higher in more suitable environments across the Iberian Peninsula. These results showed that the complex and human-mediated expansion of the red swamp crayfish in the Iberian Peninsula has involved several long- and short-distance movements and that both ecological and anthropogenic factors have shaped the genetic diversity patterns resulting from this invasion process. Early detection of potential invasion hubs may help to halt multiple short-distance translocations and thus the rapid expansion of highly prolific invasive species over non-native areas. informacion[at] Acevedo-Limón et al (2020) Historical, human, and environmental drivers of genetic diversity in the red swamp crayfish (Procambarus clarkii) invading the Iberian Peninsula. Freshwater Biology. Doi 10.1111/fwb.13513
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Turning up the heat on global hotspots of marine biodiversity

Turning up the heat on global hotspots of marine biodiversity

The year 2016 has been the hottest on record, reflecting a generally rising trend in the Earth's temperature. Understanding the global distribution of these changes is extremely important to be able to assess the threats that local ecosystems must face. Is this trend the same everywhere around the world? How can this be determined in an environment as remote, vast and inaccessible as the ocean? This study determined that there are places where the temperature increase and associated environmental changes have been much greater than elsewhere. Remote sensing data gathered over more than 30 years from a whole constellation of satellites orbiting our planet and imaging its surface allowed the authors to look at our planet from the right perspective. This information was used to determine how the temperature, productivity and currents of our oceans have changed over the last three decades for the entire planet. Climate-driven environmental changes were found, not surprisingly, not evenly distributed. However, by overlaying the areas affected by climate-driven change with areas of high biodiversity, particularly vulnerable areas of ocean located near the poles and the equator were identified. For instance, the North Sea, between America and Europe, and all the marine areas connected by the Labrador Current have experienced one of the largest global increases in ocean temperature. Near the equator, there has been a large increase in the velocity of marine currents. All of these changes are likely to affect the marine organisms living in those places. This study contributes to the international effort to mitigate the causes and consequences of climate change. Ramírez et al (2017) Climate impacts on global hotspots of marine biodiversity. Sci Adv 3 e1601198 DOI: 10.1126/sciadv.1601198