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- 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.
- Against all odds: a tale of marine range expansion with maintenance of extremely high genetic diversityPublication . Robalo, Joana; Francisco, Sara M.; Vendrell, Catarina; Lima, Cristina S.; Pereira, Ana; Brunner, Benedikt P.; Dia, Mamadou; Gordo, L. S.; Castilho, RitaThe displacement of species from equatorial latitudes to temperate locations following the increase in sea surface temperatures is among the significant reported consequences of climate change. Shifts in the distributional ranges of species result in fish communities tropicalisation, i.e., high latitude colonisations by typically low latitude distribution species. These movements create new interactions between species and new trophic assemblages. The Senegal seabream, Diplodus bellottii, may be used as a model to understand the population genetics of these invasions. In the last decades, this species has undergone an outstanding range expansion from its African area of origin to the Atlantic coast of the Iberian Peninsula, where now occurs abundantly. Mitochondrial and nuclear markers revealed a striking high haplotypic nucleotide and genetic diversity values, along with significant population differentiation throughout the present-day geographical range of the Senegal seabream. These results are not consistent with the central-marginal hypothesis, nor with the expectations of a leptokurtic distribution of individuals, as D. bellottii seems to be able to retain exceptional levels of diversity in marginal and recently colonised areas. We discuss possible causes for hyperdiversity and lack of geographical structure and subsequent implications for fisheries.
- Foraging behaviour and diet of Brown boobies Sula leucogaster from Tinhosas Islands, Gulf of GuineaPublication . Correia, Edna; Catry, Paulo; Sinclair, Frazer; Santos, Yodiney dos; Robalo, Joana; Lima, Cristina S.; Granadeiro, José PedroSeabirds are a highly threatened group, yet the foraging ecology of several species remains poorly understood. Brown boobies breed in all oceans in the tropical region and are common across their range. In Tinhosa Grande (São Tomé and Príncipe), this species breeds in one of the largest colonies of seabirds in the east tropical Atlantic. We studied the foraging ecology of Brown boobies from this colony during the chick-rearing period. Thirty-three birds were tracked with GPS loggers and their diet was analysed from 11 regurgitations, using traditional and DNA barcoding techniques for prey identifcation. A total of 127 completed foraging trips were identifed, 89% of which lasted less than 24 h. Females performed signifcantly longer trips and both sexes foraged preferentially over deep oceanic waters. The diet of Brown boobies included juvenile fsh and squid (Sthenoteuthis pteropus), comprising mostly fsh species whose juvenile phases live in the pelagic environment, and only migrate to coastal waters when adults. The most frequent of those prey found was Flying gurnard (Dactylopterus volitans). The relevance of such prey shows that Brown booby conservation depends not only on the management of their foraging areas and breeding sites but also on the correct management of the coastal adjacent areas that support the adult individuals of some of their prey. Our results suggest that the areas closest to the colony do not have available resources for these birds to feed on and that Brown boobies may be associate with subsurface marine predators or with sargassum patches to forage.