Browsing by Author "Benaissa, Hassan"
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- Alarming decline of freshwater trigger species in western Mediterranean key biodiversity areasPublication . Nogueira, Joana Garrido; Sousa, Ronaldo; Benaissa, Hassan; De Knijf, Geert; Ferreira, Sónia; Ghamizi, Mohamed; Gonçalves, Duarte V.; Lansdown, Richard; Numa, Catherine; Prié, Vincent; Riccardi, Nicoletta; Seddon, Mary; UrbaÅ„ska, Maria; Valentini, Alice; Vikhrev, Ilya; Varandas, Simone; Teixeira, Amílcar; Lopes-Lima, Manuel; Nogueira J.G.Theidentification of key biodiversity areas (KBA) was initiated by the International Union for Conservation of Nature in 2004 to overcome taxonomic biases in the selection of important areas for conservation, including freshwater ecosystems. Since then, several KBAs have been identified mainly based on the presence of trigger species (i.e., species that trigger either the vulnerability and or the irreplaceability criterion and thus identify a site as a KBA). However, to our knowledge, many of these KBAs have not been validated. Therefore, classical surveys of the taxa used to identify freshwater KBAs (fishes, molluscs, odonates, and aquatic plants) were conducted in Douro (Iberian Peninsula) and Sebou (Morocco) River basins in the Mediterranean Biodiversity Hotspot. Environmental DNA analyses were undertaken in the Moroccan KBAs. There was a mismatch between the supposed and actual presence of trigger species. None of the trigger species were found in 43% and 50% of all KBAs surveyed in the Douro and Sebou basins, respectively. Shortcomings of freshwater KBA identification relate to flawed or lack of distribution data for trigger species. This situation results from a misleading initial identification of KBAs based on poor (or even inaccurate) ecological information or due to increased human disturbance between initial KBA identification and the present. To improve identification of future freshwater KBAs, we suggest selecting trigger species with a more conservative approach; use of local expert knowledge and digital data (to assess habitat quality, species distribution, and potential threats); consideration of the subcatchment when delineating KBAs boundaries; thoughtful consideration of terrestrial special areas for conservation limits; and periodic field validation.
- Alarming decline of freshwater trigger species in western Mediterranean key biodiversity areasPublication . Nogueira, Joana Garrido; Sousa, Ronaldo; Benaissa, Hassan; De Knijf, Geert; Ferreira, Sónia; Ghamizi, Mohamed; Gonçalves, Duarte V.; Lansdown, Richard; Numa, Catherine; Prié, Vincent; Riccardi, Nicoletta; Seddon, Mary; Urbańska, Maria; Valentini, Alice; Vikhrev, Ilya; Varandas, Simone; Teixeira, Amílcar; Lopes‐Lima, ManuelThe identification of key biodiversity areas (KBA) was initiated by the International Union for Conservation of Nature in 2004 to overcome taxonomic biases in the selection of important areas for conservation, including freshwater ecosystems. Since then, several KBAs have been identified mainly based on the presence of trigger species (i.e., species that trigger either the vulnerability and or the irreplaceability criterion and thus identify a site as a KBA). However, to our knowledge, many of these KBAs have not been validated. Therefore, classical surveys of the taxa used to identify freshwater KBAs (fishes, molluscs, odonates, and aquatic plants) were conducted in Douro (Iberian Peninsula) and Sebou (Morocco) River basins in the Mediterranean Biodiversity Hotspot. Environmental DNA analyses were undertaken in the Moroccan KBAs. There was a mismatch between the supposed and actual presence of trigger species. None of the trigger species were found in 43% and 50% of all KBAs surveyed in the Douro and Sebou basins, respectively. Shortcomings of freshwater KBA identification relate to flawed or lack of distribution data for trigger species. This situation results from a misleading initial identification of KBAs based on poor (or even inaccurate) ecological information or due to increased human disturbance between initial KBA identification and the present. To improve identification of future freshwater KBAs, we suggest selecting trigger species with a more conservative approach; use of local expert knowledge and digital data (to assess habitat quality, species distribution, and potential threats); consideration of the subcatchment when delineating KBAs boundaries; thoughtful consideration of terrestrial special areas for conservation limits; and periodic field validation.
- Fish hosts of the critically endangered Unio foucauldianus Pallary, 1036 (Mollusca: Unionidae)Publication . Benaissa, Hassan; Teixeira, Amílcar; Lopes-Lima, Manuel; Sousa, Ronaldo; Varandas, Simone; Rassam, Hanane; Ghamizi, MohamedUnio foucauldianus Pallaiy, 1936 (Unionidae) is a critically endangered freshwater mussel, with a small geographical distribution restricted to Morocco. As many other unionids, the life cycle of this species includes an obligatoiy parasitic phase using fish as hosts. Therefore, the knowledge of fish hosts is essential to develop any efficient conservation strategy devoted to this species. In this study, we used two approaches to assess the fish hosts of Unio foucauldianus: determination of infestation rates of fishes under natural conditions through a monthly (from January to June) sampling in Laabid (Oum Er Rbia basin) and N'Fis (Tensift basin) Rivers and laboratorial trials to assess metamorphose rates using different fish species from both rivers. The natural infestation offish showed a peak ofinfestation in May and juveniles only metamorphosed in the following native fish species: Luciobarbus ksibi (Boulenger, 1905), Carasobarbus fritschü (Günther, 1874), Luciobarbus zayanensis (Doadrio, Casal-López & Yahyaoui, 2016), Labeobarbus maroccanus (Günther, 1874) and Luciobarbus magniatlantis (Pellegrin, 1919). Given the increasing pressure on native fish species due to human activities, including the increased number ofnon-native fish introductions that did not function as hosts of U. foucauldianus, urgent conservation measures are needed to mitigate some of the threats on native ichthyofauna. Only an integrated framework comprising knowledge ofthe freshwater mussel biology and their native fish hosts can help th e conservation of U. foucauldianus in Morocco.
- Fish hosts of the freshwater mussel Unio foucauldianus Pallary, 1936Publication . Benaissa, Hassan; Teixeira, Amílcar; Lopes-Lima, Manuel; Sousa, Ronaldo; Varandas, Simone; Rassam, Hanane; Ghamizi, MohamedThe life cycle of Unio foucauldianus Pallary, 1936, a critically endangered freshwater mussel species (Bivalvia: Unionida), includes a parasitic phase using fish as hosts. Therefore, to develop more efficient conservation strategies it is essential to know which are the suitable fish hosts of U. foucauldianus. In this study, two approaches were used to assess the fish hosts of U. foucauldianus: the determination of infestation rates of fishes under natural conditions through monthly sampling (from January to June) in the Laabid River (Oum Rbia basin) and the N'Fis River (Tensift basin), and artificial infestation in laboratory trials using fish species from both rivers. The natural infestation of fish was detected from February to June, with a peak in May. Fully metamorphosed juveniles were only detected in native fish species, i.e. Luciobarbus ksibi (Boulenger, 1905), Carasobarbus fritschii (Günther, 1874), Luciobarbus zayanensis Doadrio, Casal‐lopez & Yahyaoui, 2016, Labeobarbus maroccanus (Günther, 1874), and Luciobarbus magniatlantis (Pellegrin, 1919). The two non‐native fish species used do not function as effective hosts. Given the increasing human pressure on native fish species in the Mediterranean biodiversity hotspot, including the increased number of non‐native fish introductions, urgent conservation measures are discussed for this and other freshwater mussel species.
- Freshwater conservation assessments in (semi-)arid regions: testing river intermittence and buffer strategies using freshwater mussels (Bivalvia, Unionida) in MoroccoPublication . Gomes-dos-Santos, André; Froufe, Elsa; Gonçalves, Duarte V.; Sousa, Ronaldo; Prié, Vincent; Ghamizi, Mohamed; Benaissa, Hassan; Varandas, Simone; Teixeira, Amílcar; Lopes-Lima, ManuelThe 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.
- Oued Bouhlou: a new hope for the Moroccan pearl musselPublication . Sousa, Ronaldo; Teixeira, Amílcar; Santos, André; Benaissa, Hassan; Varandas, Simone; Ghamizi, Mohamed; Prié, Vincent; Froufe, Elsa; Lopes-Lima, ManuelThe 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.
- Preliminary data on fish hosts and their conservation importance for the critically endangered Pseudunio marocanus (Pallary, 1918)Publication . Benaissa, Hassan; Ghamizi, Mohamed; Teixeira, Amílcar; Sousa, Ronaldo; Rassam, Hanane; Varandas, Simone; Lopes-Lima, ManuelPseudunio marocanus (Pallary, 1918) is an endemic species of Morocco and is considered one of the world’s 100 most threatened species. The life cycle of this critically endangered freshwater mussel remains unknown. However, knowledge about the discharge period of its larvae and its ecological fish hosts is crucial to adopt more effective conservation strategies. Given this information gap, monitoring the presence of P. marocanus glochidia in fish from the Laabid River was carried out from January to May 2019 to determine the larvae discharge period. Two different approaches were used to assess the fish hosts of P. marocanus: (i) the determination of glochidia infestation rates of fishes in situ through monthly (from January to May) sampling in the Laabid River (Oum Er Rbia basin); and (ii) artificial infestation in laboratory trials using four fish species. A peak in glochidia discharge was observed at the end of February. Fully metamorphosed juveniles were detected in all native fish species, i.e. Luciobarbus ksibi (Boulenger, 1905), Carasobarbus fritschii (Günther, 1874), Luciobarbus zayanensis Doadrio, Casal-lopez and Yahyaoui, 2016, and Pterocapoeta maroccana Günther, 1874. For the first time, the glochidia discharge period and the fish hosts of P. marocanus were determined, and this information is vital to implement future conservation measures (i.e. propagation, reinforcement of populations, possible reintroductions of P. marocanus, careful management of river flow by upstream dams, and the prohibition of fishing activities during the critical glochidia discharge period). Given the increasing human pressure on freshwater habitats and biodiversity in Morocco, it is essential to preserve the native ichthyofauna to conserve this rare pearl mussel species.
- Refuge in the sāqya: Irrigation canals as habitat for one of the world's 100 most threatened speciesPublication . Sousa, Ronaldo; Teixeira, Amílcar; Benaissa, Hassan; Varandas, Simone; Ghamizi, Mohamed; Lopes-Lima, ManuelAnthropogenic 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.