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- Applying genomic approaches to delineate conservation strategies using the freshwater mussel Margaritifera margaritifera in the Iberian Peninsula as a modelPublication . Perea, S; Mendes, Sofia L.; Sousa-Santos, C.; Ondina, P.; Amaro, R.; Castro, J.; San-Miguel, E.; Lima, C. S.; Garcia, M.; Velasquez, V.; Garcia-Roves, P.; Fernández, D.; Araujo, R.; Sousa, V. C.; Reis, J.Efective conservation actions to counteract the current decline of populations and species require a deep knowledge on their genetic structure. We used Single Nucleotide Polymorphisms (SNPs) to infer the population structure of the highly threatened freshwater pearl mussel Margaritifera margaritifera in the Iberian Peninsula. A total of 130 individuals were collected from 26 locations belonging to 16 basins. We obtained 31,692 SNPs through Genotyping by Sequencing (GBS) and used this dataset to infer population structure. Genetic diversity given as observed heterozygosity was low. Pairwise FST comparisons revealed low levels of genetic diferentiation among geographically close populations. Up to 3 major genetic lineages were determined: Atlantic, Cantabrian and Douro. This structure suggests a close co-evolutionary process with brown trout (Salmo trutta), the primordial fsh host of this mussel in the studied area. Some sub-basins showed some genetic structuring, whereas in others no intrapopulation diferentiation was found. Our results confrm that genetic conservation units do not match individual basins, and that knowledge about the genetic structure is necessary before planning recovery plans that may involve relocation or restocking. The same reasoning should be applied to strictly freshwater species that are sessile or have restricted dispersal abilities and are currently imperiled worldwide.
- Conservation challenges imposed by evolutionary history and habitat suitability shifts of endangered freshwater mussels under a global climate change scenarioPublication . Reis, Joaquim; Perea, Silvia; Gama, Mafalda; Mendes, Sofia L.; Sousa, Vitor C.; Lima, Cristina S.; Banha, Filipe; Gil, Maria; Alvarez, Maria Garcia; Anastácio, P.M.; Santos, Carla Sousa; Araujo, RafaelClimate change and associated shifts in temperature and precipitation patterns have become an increasing concern as drivers of ongoing biodiversity loss. The Mediterranean region is particularly vulnerable, being both a biodiversity hotspot and a region very prone to desertification. Freshwater mussels are amongst the most threatened invertebrate taxa worldwide. Unio tumidiformis is an endemic and endangered species restricted to the southern Iberian Peninsula, living in temporary Mediterranean-type streams. Freshwater mussels need a fish host for successful larval transformation, meaning U. tumidiformis must belong to the genus Squalius. The main objective of this study was to evaluate the vulnerability of U. tumidiformis to climate change, by studying its population genetics and evolutionary history, its current and future habitat suitability, and that of its hosts. Genetic population structure and diversity were assessed using Single-Nucleotide Polymorphisms through Genotyping by Sequencing and used to infer species evolutionary history. The species potential distribution was modeled using an ensemble forecasting approach, and future shifts in habitat suitability were assessed with the projected climate data layers from Worldclim. Most populations showed extreme genetic differentiation (Fst up to 0.745), even from close neighboring ones. Upper Guadiana populations were more diverse and less differentiated. We hypothesize that U. tumidiformis originated in Upper Guadiana and followed the same colonization routes as their hosts with numerous founder effects and bottlenecks. Our results also predicted a reduction of 99% of climatically suitable areas for U. tumidiformis in the Iberian Peninsula until 2040. For the fish hosts, a maximum 42% reduction in suitable areas was estimated throughout the century, with remaining adequate habitats in the north. Our results suggest that difficult conservation options are necessary, prioritizing the preservation of populations, translocations to the northern area of its historical range and stream engineering to increase resilience to droughts.