Partage des ressources spatiales et trophiques au sein d'un peuplement de lézards insectivores des Jbilets centrales (Maroc occidental)

Spatial and trophic resource partitioning among seven sympatric insectivorous lizard species was investigated in arid area in the central Jbilet mountains (Western Morocco) during spring 1995 . Two foraging guilds are apparent: a specialist sit-and-wait (Agama impalearis, Tarentola mauritanica et Saurodactylus brosseti) and a generalist one (Eumeces algeriensis, Chalcides polylepis, Acanthodactylus erythrurus and Mesa/ina simoni). The studied !izard species differentiate from each other in substrate use relatively to their respective adaptive morphological traits. A. impalearis and T. mauritanica occur mainly in rocky areas, E. algeriensis and M. simoni appear mostly on rocky and pebbly-bare ground substrates, A. erythrurus and C. po/y/epis are found on sandy-pebbly substrates while S. brosseti occurs in pebbly soils. By contrast, there were large overlaps in the taxonomie composition of their diets which are numerically dominated by Formicidae, lsoptera, Coleoptera and Araneidae with different proportions according to lizard species. However, important prey-size differences between species allowed to reduce trophic overlap. A selectivity analysis of lizard diet revealed patterns of prey selection based on criteria inherent either to predator (foraging behaviour, morphological constraints) or prey (size, abundance and activity). Results suggest that spatial and trophic segregation along with taxonomie divergence make possible the coexistence of these lizard speciesLa différenciation des niches spatiale et trophique de sept espèces sympatriques de lézards insectivores a été étudiée dans un milieu aride des Jbilets centrales (Maroc occidental) durant le printemps 1995. Deux guildes ont été distinguées sur la base du mode d'acquisition des proies : la guilde des espèces chassant à l'affût (Agama impalearis, Tarentola mauritanica et Saurodactylus brosseti) et celle des espèces pratiquant la chasse extensive (Eumeces algeriensis, Chalcides polylepis, Acanthodactylus erythrurus et Mesalina simoni). Les espèces étudiées se séparent par une utilisation différentielle du substrat, vraisemblablement en relation avec leurs traits morphologiques spécifiques. A. impalearis et T mauritanica affectionnent essentiellement les terrains rocheux, E. algeriensis et M. simoni investissent surtout les substrats rocheux et caillouteux-terreux, A. erythrurus et C. polylepis fréquentent les substrats sableux ou terreux, tandis que S. brosseti peuple les biotopes à dominance caillouteuse ou pierreuse. En terme de composition taxinomique, il existe de forts recouvrements des spectres alimentaires des différentes espèces étudiées. Les principaux types de proies consommées sont les Formicidés, les Isoptères, les Coléoptères, et les Aranéides. Toutefois, les différences importantes de taille des proies ingérées par chacune des espèces, permettent de réduire les recouvrements des niches trophiques. La comparaison entre les régimes alimentaires observés et les ressources effectivement disponibles a permis de déceler des choix commandés par divers critères inhérents aussi bien aux prédateurs (stratégie de chasse, contraintes morphologiques) qu'à leurs proies (abondance, taille, activité). L'ensemble des résultats obtenus montre que les sept espèces de lézards different plus dans l'utilisation des microhabitats que dans l'exploitation de proies de tailles différentes. De plus, la divergence phylogénétique des espèces étudiées et leur différence de taille importante permettent de réduire les recouvrements de leurs niches écologiques ce qui favorise leur coexistence

New insights on phylogeography and distribution of painted frogs (Discoglossus) in northern Africa and the Iberian Peninsula

Painted frogs (Discoglossus) contain five to six species of Western Palearctic anurans that are mainly distributed in allopatry. We here provide the first comprehensive assessment of the phylogeography of the Moroccan species D. scovazzi and geographically characterize its contact zone with D. pictus in Eastern Morocco. Discoglossus scovazzi shows, in general, a weak phylogeographic structure across Morocco on the basis of mitochondrial DNA sequences of the cytochrome b gene, with only populations centered in the Atlas Mountains characterized by the presence of slightly divergent haplotypes. In eastern Morocco, all populations east of the Moulouya River were clearly assignable to D. pictus. This species was also found along the Mediterranean coast west of the Moulouya, in the cities of Nador and Melilla, suggesting that not the river itself but the wide arid valley extending along much of the river (except close to the estuary) acts as a possible distributional barrier to these frogs. No sympatry of D. scovazzi with D. pictus was observed, and all specimens were concordantly assigned to either species by DNA sequences of cytochrome b and of the nuclear marker RAG1. Species distribution models of the two taxa show largely overlapping areas of suitable habitat, and the two species’ niches are significantly more similar than would be expected given the underlying environmental differences between the regions in which they occur. Comparative data are also presented from the southern Iberian contact zone of D. galganoi galganoi and D. g. jeanneae. These taxa showed less clear-cut distributional borders, extensively shared RAG1 haplotypes, and had instances of sympatric occurrence on the basis of cytochrome b haplotypes, in agreement with the hypothesis of a yet incomplete speciation. In this wide contact zone area we found mitochondrial sequences containing double peaks in electropherograms, suggesting nuclear pseudogenes or (less likely) heteroplasmy, possibly related to the ongoing admixture among the lineagesPeer reviewe

Structure et dynamique d’une population d’Agama impalearis (Sauria : Agamidae) dans les Jbilets centrales, Maroc

A population study of Agama impaleari was conducted during two consecutive years (1993-1994) in a Jujube bush site located in an arid area at the Jbilet Mountains (Western Morocco). Lizards of both sexes required approximatively one year to reach sexual maturity. One to two clutches were produced per breeding season (May-August) and clutch size was significantly correlated with maternal body size. The annual reproductive output was in average of 20 eggs per female per year and did not exhibit a significant difference between the two years of study. Population size showed important seasonal changes throughout the study period and absolute spring density estimates were of 15 and 11 ind/ha, respectively in 1993 and 1994. In the post-reproductive period (September) the population density (excluding hatchlings) markedly declined and was only of 4-5 ind/ha. After the completion of hatching period (July to early November), the densities of hatchlings were 11 and 13 ind/ha respectively in 1993 and 1994 compensing for the population losses. The annual turnover rate of the population did not exhibit a significant yearly change and was of 77 %. Adult survivorship after the reproductive activity varied between years and juvenile survival during the first year was estimated to be 35 %. Maximum longevity assessed by means of squelettochro-nology was 5 years.Une population d'Agama impaleari a été étudiée durant deux années consécutives (1993 et 1994) en milieu aride au niveau d’une steppe à jujubier localisée dans les Jbilets Centrales, Maroc occidental. La maturité sexuelle chez les individus des deux sexes est atteinte approximativement à l’âge d’un an. Une à deux pontes sont produites par saison de reproduction entre mai et août et le nombre d’œufs par ponte augmente de façon significative avec la taille corporelle des femelles. Le taux de fécondité qui est en moyenne de 20 œufs par femelle et par an ne diffère pas de façon significative d’une année à l’autre. La densité de la population a montré d’importantes fluctuations saisonnières au cours de la période d’étude et les densités absolues en mai étaient de 15 et 11 ind/ha, respectivement en 1993 et 1994. Au mois de septembre, juste après la saison de reproduction, cette densité chute à 4-5 ind/ha (nouveau-nés exclus). Au terme de la période des éclosions (juillet à début novembre), les densités des nouveau-nés étaient de 11 et 13 ind/ha, respectivement en 1993 et 1994, compensant ainsi la disparition des adultes. Le taux de renouvellement annuel de la population, 77 %, est élevé et reste constant d’une année à l’autre. Le taux de survie des adultes après la saison de reproduction varie d’une année à l’autre et celui des juvéniles durant leur première année d’existence est estimé en moyenne à 35 %. La longévité minimale observée, déterminée au moyen de la squelettochronologie, est de 5 années.Znari Mohammed, El Mouden El Hassan, Boumezzough Ali. Structure et dynamique d’une population d’Agama impalearis (Sauria : Agamidae) dans les Jbilets centrales, Maroc. In: Revue d'Écologie (La Terre et La Vie), tome 53, n°4, 1998. pp. 293-308

Partage des ressources spatiales et tropiques au sein d’un peuplement de lézards insectivores des Jbilets centrales (Maroc occidental)

Spatial and trophic resource partitioning among seven sympatric insectivorous lizard species was investigated in arid area in the central Jbilet mountains (Western Morocco) during spring 1995. Two foraging guilds are apparent : a specialist sit-and-wait (Agama impalearis, Tarentola mauritanica et Saurodaclylus brosseti) and a generalist one (Eumeces algeriensis, Chalcides polylepis, Acanthodaclylus erythrurus and Mesalina simoni). The studied lizard species differentiate from each other in substrate use relatively to their respective adaptive morphological traits. A impalearis and T. mauritanica occur mainly in rocky areas, K algeriensis and M. simoni appear mostly on rocky and pebbly-bare ground substrates, A. erythrurus and C. polylepis are found on sandy-pebbly substrates while S. brosseti occurs in pebbly soils. By contrast, there were large overlaps in the taxonomic composition of their diets which are numerically dominated by Formicidae, Isoptera, Coleoptera and Araneidae with different proportions according to lizard species. However, important prey-size differences between species allowed to reduce trophic overlap. A selectivity analysis of lizard diet revealed patterns of prey selection based on criteria inherent either to predator (foraging behaviour, morphological constraints) or prey (size, abundance and activity). Results suggest that spatial and trophic segregation along with taxonomic divergence make possible the coexistence of these lizard species.La différenciation des niches spatiale et trophique de sept espèces sympatriques de lézards insectivores a été étudiée dans un milieu aride des Jbilets centrales (Maroc occidental) durant le printemps 1995. Deux guildes ont été distinguées sur la base du mode d’acquisition des proies : la guilde des espèces chassant à l’affût (Agama impalearis, Tarentola mauritanica et Saurodaclylus brosseti) et celle des espèces pratiquant la chasse extensive (Eumeces algeriensis, Chalcides polylepis, Acanthodaclylus erythrurus et Mesalina simoni). Les espèces étudiées se séparent par une utilisation différentielle du substrat, vraisemblablement en relation avec leurs traits morphologiques spécifiques. A. impalearis et T. mauritanica affectionnent essentiellement les terrains rocheux, E. algeriensis et M. simoni investissent surtout les substrats rocheux et caillouteux-terreux, A. erythrurus et C. polylepis fréquentent les substrats sableux ou terreux, tandis que S. brosseti peuple les biotopes à dominance caillouteuse ou pierreuse. En terme de composition taxinomique, il existe de forts recouvrements des spectres alimentaires des différentes espèces étudiées. Les principaux types de proies consommées sont les Formicidés, les Isoptères, les Coléoptères, et les Aranéides. Toutefois, les différences importantes de taille des proies ingérées par chacune des espèces, permettent de réduire les recouvrements des niches trophiques. La comparaison entre les régimes alimentaires observés et les ressources effectivement disponibles a permis de déceler des choix commandés par divers critères inhérents aussi bien aux prédateurs (stratégie de chasse, contraintes morphologiques) qu’à leurs proies (abondance, taille, activité). L’ensemble des résultats obtenus montre que les sept espèces de lézards diffèrent plus dans l’utilisation des microhabitats que dans l’exploitation de proies de tailles différentes. De plus, la divergence phylogénétique des espèces étudiées et leur différence de taille importante permettent de réduire les recouvrements de leurs niches écologiques ce qui favorise leur coexistence.Znari Mohammed, El Mouden El Hassan, Benfaida Hilal, Boumezzough Ali. Partage des ressources spatiales et tropiques au sein d’un peuplement de lézards insectivores des Jbilets centrales (Maroc occidental). In: Revue d'Écologie (La Terre et La Vie), tome 55, n°2, 2000. pp. 141-160

Fatal chytridiomycosis in the Moroccan midwife toad Alytes maurus and potential distribution of Batrachochytrium dendrobatidis across Morocco

Multiple threats, including emerging infectious diseases, are contributing to the extinction of amphibians worldwide. One of the most devastating diseases is the fatal amphibian skin disease chytridiomycosis caused by the fungus Batrachochytrium dendrobatidis (Bd). The presence of Bd in North Africa was described in 2011 and this included the distribution range of the endemic Moroccan midwife toad (Alytes maurus). Here we report new Bd positive occurrences across several distant regions of Morocco, augment the known number of infected species, and describe the first evidence of lethal chytridiomycosis in A. maurus. Although population declines in this species were not recorded, the family Alytidae has been identified as the most susceptible taxonomic group to chytridiomycosis of the Palearctic. An environmental niche model, taking into account new records of Bd in the country, confirms the Mediterranean coast and the Rif and Middle Atlas Mountains as very favourable areas for Bd. Our results suggest that the real impact of chytridiomycosis in North Africa is poorly understood, and that this continent cannot be identified as a region less impacted by chytridiomycosis, as was previously proposed.Peer reviewe

Age structure of a population of Barbarophryne brongersmai (Anura, Bufonidae) inhabiting an arid environment in the Central Jbilets (West-Morocco).

International audienceWe estimated age structure and some life-history traits in a population of Barbarophryne brongersmai at the northern border of the distribution area of this species by using skeletochronology to establish individual age and age at sexual maturity. Maturity was reached at 2-4 years in males and 3-5 years in females, which was late relatively to small body size. Longevity was estimated to be 12 and 8 years for males and females, respectively, whereas mean body size is 45.6 mm in both sexes. However, this estimate suffers from small sample size in females. We did not detect a positive relationship between age and size, suggesting that adult individuals cease growing after maturity. Conversely, body size varied within an age class, suggesting great variability of growth rate among individuals during the juvenile stage. Collectively, these traits characterize a life history strategy that could be an evolutionary response to habitat unpredictability in arid regions

Dimorphisme sexuel et cinétique de croissance et de maturation chez Testudo g. graeca, dans les Jbilets centrales, Maroc

Sexual dimorphism, growth and maturation patterns of Testudo g. graeca in the Central Jbilets, Morocco. — Sexual size dimorphism and the growth and maturation patterns were studied in the Mediterranean Spur-thighed Tortoise (Testudo g. graeca), in the central Jbilets mountains (western Morocco). The number and width of scute growth annuli were respectively used as indicators of age at sexual maturity and of juvenile growth rates. Males reach their sexual maturity earlier than females but juvenile growth rates do not differ between sexes. Thence, when reaching sexual maturity males are smaller than females. However, important age and size inter-individual variations were observed at maturity. In both sexes, precocious individuals show high juvenile growth rates but reach a smaller body size at maturity than late individuals. Therefore, sexual maturity depends on juvenile growth rates. The important individual variations in age and size at maturity could reflect the plasticity of individual growth and maturation in response to changing environmental conditions.Le dimorphisme sexuel de taille (DST) et ses relations avec les patterns de croissance et de maturation ont été étudiés chez la Tortue mauresque (Testudo g. graeca), dans les Jbilets centrales (Maroc occidental). L’âge de maturité sexuelle et les taux de croissance ont été estimés à partir du nombre et de la largeur des anneaux de croissance ornant les écailles épidermiques de la carapace. La maturité sexuelle est plus précoce chez les mâles que chez les femelles bien qu’aucune différence du taux de croissance juvénile ne soit détectable selon le sexe. Les mâles atteignent ainsi à maturité sexuelle une taille plus petite que celle des femelles. Toutefois, il existe d’importantes variations individuelles dans l’âge et la taille à maturité. Chez les deux sexes, plus un individu montre une croissance juvénile rapide, plus il atteint la maturité sexuelle précocement et présente alors une taille plus faible. L’âge d’acquisition de la maturité sexuelle semble ainsi essentiellement déterminé par la cinétique de croissance juvénile. Les variations individuelles importantes d’âge et de taille observées à la maturité sexuelle semblent refléter la plasticité de croissance et de maturation que présentent les individus en réponse aux conditions variables du milieu.Ben Kaddour Khalid, El Mouden El Hassan, Slimani Tahar, Lagarde Frédéric, Bonnet Xavier. Dimorphisme sexuel et cinétique de croissance et de maturation chez Testudo g. graeca, dans les Jbilets centrales, Maroc. In: Revue d'Écologie (La Terre et La Vie), tome 60, n°3, 2005. pp. 265-278

Occurrence of Batrachochytrium dendrobatidis in the Tensift region, with comments on its spreading in Morocco

The chytrid fungus Batrachochytrium dendrobatidis (Bd) is a generalist pathogen that affects many amphibian species and is responsible of chytridiomycosis onset, considered as the main causes of species extinctions and populations declines worldwide. The chytrid fungal pathogen has been first described in North Africa in 2011. The present work reported the first survey on Bd prevalence and intensity in the Tensift region of Morocco. The survey has been conducted on 11 different localities by collecting skin swabs and tissue samples of 97 individuals. Using a quantitative Polymerase Chain Reaction (qPCR) protocol, low-intensity of Bd infection has been detected in the area of study. In fact, the chytrid fungal pathogen has been identified in 10 individuals distributed in six of the 11 sites investigated, placing the 95% confidence interval for overall prevalence at 5.5-19.6%. The survey confirmed the occurrence of Bd at both high and low altitude localities, on four species out of seven known to inhabit the region and added two additional species (Pelophylax saharicus and Sclerophrys mauritanica) to the list of Bd susceptible amphibians in Morocco. The present records extended Bd distribution more than 400 km in the South of Morocco, indicating that the chytrid fungal pathogen is more widespread in the country than previously thought.This research was supported by Project [ICGVSA] founded by the Hassan II Academy of Sciences and Technology. The Portuguese National Funds through FCT (Foundation for Science and Technology) support the Investigator FCT grant to AC (IF/00209/2014)