Suchergebnisse

Anthropogenic habitats may function as a refuge for some species, including freshwater mussels (Bivalvia, Unionida). In this study we assessed possible differences in density, size and condition index of the Moroccan freshwater pearl mussel Pseudunio marocanus (Pallary, 1918), formerly Margaritifera marocana, colonizing anthropogenic (sāqya=irrigation canal) and natural (Bouhlou River) habitats in Morocco. Results showed that the individuals colonizing the irrigation canal located on the left bank have a significantly higher density and condition index when compared to natural conditions, but no differences were found regarding size. Since this species is listed as critically endangered by the IUCN, being also considered among the 100 most endangered organisms in the planet, the presence of P. marocanus in anthropogenic habitats has high conservation importance. In fact, and despite no Moroccan freshwater pearl mussels were found on the irrigation canal located in the right bank, the one located on the left bank present stable conditions for the settlement of juveniles and, if managed carefully, for the future survival of the species. However, local authorities reported frequent dredging and cleaning activities by local farmers on this sāqya without any special attention devoted to Moroccan freshwater pearl mussels (or any other species) conservation. Therefore, the results reported here can be used by scientists, managers, politicians and local people to promote future management actions that enhance the Moroccan freshwater pearl mussel protection and guarantee their future survival, including on anthropogenic habitats. ; This study was conducted within the scope of project «Biodiversity and conservation of the critically endangered freshwater mussels in Morocco: ecogeographic, genetic and physiological information», funded by Mohamed bin Zayed Species Conservation Fund (Reference 15256799) and project «Breeding the most endangered bivalve on Earth: Margaritifera marocana», funded by IUCN SOS save our species fund (Reference 2015B-015). MLL was supported by the Portuguese Foundation for Science and Technology (FCT) grant number SFRH/BD/ 115728/2016. We acknowledge Joana Garrido Nogueira for the help preparing the Figures. We also acknowledge the editor Dr. Amanda Bates and three anonymous referees for the helpful suggestions. ; info:eu-repo/semantics/publishedVersion

The freshwater pearl mussel Margaritifera marocana (Pallary,) is an endemic species of Morocco being listed as critically endangered and it stands among the world's 100 most threatened species. An extensive survey was performed in the Sebou basin (total area of approximately 40,000 km2), covering 26 different sites. Margaritifera marocana was found only in four sites limited to a small tributary (Oued (=River) Bouhlou). This population has a very restricted distribution (no more than 4 km of river length) but appears stable with recent recruitment, since small specimens were found. Genetic analyses were performed, showing that this population has a similar diversity to that found in the River Laabid (Oum Er Rbia basin), but represents a distinct conservation unit that should be managed independently. Although this study adds a new population to the current known distribution of M. marocana, urgent conservation measures (e.g. extension of the Tazzekka National Park; better management of river flow; increase of the riparian vegetation in some stretches; establishment of national and international legislation, and engagement of local citizens) are needed given the species' restricted distribution, its rarity, and the numerous threats that impair its future survival. ; This study was conducted within the scope of the project 'Biodiversity and conservation of the critically endangered freshwater mussels in Morocco: ecogeographic, genetic and physiological information', funded by Mohamed bin Zayed Species Conservation Fund (Reference 15256799), the project 'Breeding the most endangered bivalve on Earth: Margaritifera marocana', funded by IUCN SOS Save our Species fund (Reference 2015B‐015), and by the Portuguese Foundation for Science and Technology (FCT) under grants SFRH/ BPD/108445/2015 (EF) and SFRH/BD/115728/2016 (MLL). ; info:eu-repo/semantics/publishedVersion

The IUCN Red List assessments are essentially based on population trends and range, namely Area of Occupancy (AOO) and Extent of Occupancy (EOO). Range estimations are based on fixed grids, but this is likely inappropriate for species living in river networks. Furthermore, AOO and EOO are measured using the whole hydrographic network, therefore disregarding temporary sections, which is particularly problematic in arid and semi-arid regions. Here we mapped the permanent hydrographic network of Morocco using satellite imagery, complemented with field surveys to collect samples for molecular analyses of the five freshwater mussel species present and assess their distribution. The phylogeographic patterns are described for each species and used to identify priority areas and evolutionary significant units for conservation. Permanent hydrographic river sections represent only 18.3% of the whole hydrographic network. A north-to-south gradient of genetic diversity, species richness and distribution range was found, being coherent with water availability and river intermittence. Isolated evolutionary units were detected in southern basins that should also receive particular attention in conservation planning. We propose the mean river width multiplied by the extent of the river network as the best and the most adequate way to estimate both EOO and AOO. Given the worldwide degradation of freshwater systems and biodiversity, an accurate (re)assessment of species conservation status supported with maps of intermittent water bodies will be essential for prioritizing and guiding conservation actions and management plans, especially in arid and semi-arid regions. ; This work was partially supported by the Portuguese Foundation for Science and Technology (FCT) under grant SFRH/BD/115728/2016 (MLL) and grant SFRH/BD/137935/2018 (AGS). This research was developed under ConBiomics: the missing approach for the Conservation of freshwater Bivalves Project N° NORTE-01-0145- FEDER-030286, co-financed by COMPETE 2020, Portugal 2020 and the European Union through the ERDF, and by FCT through national funds. This study was additionally conducted within the scope of project "Biodiversity and conservation of the critically endangered freshwater mussels in Morocco: ecogeographic, genetic and physiological information", funded by Mohamed bin Zayed Species Conservation Fund (Reference 15256799) and project "Breeding the most endangered bivalve on Earth: Margaritifera marocana", funded by IUCN SOS save our species fund (Reference 2015B-015). Official capture and sampling licenses were issued by the Université Cadi Ayyad (Faculté des Sciences, Semlalia, Marrakech, Maroc). ; info:eu-repo/semantics/publishedVersion