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Abstract: There are currently only two places in Portugal were native Artemia parthenogenetica can still be found. All other known populations have been eradicated by the invasive species Artemia franciscana, which has caused great losses of Artemia biodiversity in the Mediterranean region. The diploid strains found at the Portuguese salines are therefore of high conservation value. This study aims to assess the survival of these native A. parthenogenetica strains and of A. franciscana under a variety of environmental conditions. The effects of water temperature and salinity, of photoperiod and food supply (shortage) were studied in an experimental setup. The Portuguese parthenogenetic Artemia populations showed great variability in their physiological response to different abiotic conditions, suggesting possible local adaptations in response to different selective pressures experienced. For most of the conditions studied A. franciscana outcompeted the Artemia strain from Aveiro, whereas the strain from Rio Maior was more resistant than the A. franciscana under conditions that were similar to its local habitat. Strain-specific resistance to chemical conditions, related to pollution, are appointed as a potential cause why A. franciscana did not successfully invade Aveiro saline. The saline of Rio Maior has possibly not yet been invaded due to the fitness of its local Artemia strain in combination with its inland location. [Copyright &y& Elsevier]

Rivers are amongst the most threatened ecosystems in Europe. To prevent further degradation and to improve their ecological status, effective mitigation and restoration actions are needed. Those actions are primarily based on the precision of the ecological assessment results. This study aims to assess the ecological status of two small Mediterranean rivers-the Âncora (AR) and the Ferreira (FR) rivers-through the analysis of biological (benthic macroinvertebrates and macrophytes), physico-chemical and hydromorphological quality elements. Specific objectives were to analyse variations of biotic and abiotic parameters amongst rivers, and amongst seasons and sites within each river, to confirm adequate temporal windows to develop the monitoring surveys. Results showed that only one AR site achieved a good ecological status in spring and summer, while the other sites presented a moderate ecological status in all seasons. FR sites had a moderate to bad ecological status in all seasons. Both rivers showed high levels of nutrients, particularly during spring and summer, and were found quite altered in terms of floristic composition of the riparian communities. The riparian forest and the forbs fringe were dominated by several alien woody species and nitrophilous communities, respectively. Based on a multidisciplinary approach, this study provides an in-depth description of the ecological status of two small Mediterranean rivers located in sites of European interest, as well as a sound basis for the management of the aquatic environments. Mitigation of diffuse pollution and restoration of the riparian zones are a priority to improve their ecological status.