Déclin précipité du Triton de Poiret Pleurodeles poireti Gervais, 1835 et autres changements du statut des amphibiens de Numidie, Algérie du Nord-Est

The worldwide erosion of biological diversity has not spared amphibians which are amongst the most affected taxa with numerous extinct or near-extinct species. Our knowledge of the status and ecology of amphibians of Algeria is still limited whereas local natural habitats are fast disappearing under a strong anthropogenic pressure. Eighty two localities were sampled between 1996 and 2010, to survey the amphibian community within Numidia, North-Eastern Algeria. Nine species, three Urodeles (Pleurodeles poireti, Pleurodeles nebulosus and Salamandra algira and six Anurans (Bufo bufo spinosus, Bufo mauritanicus, Bufo viridis, Discoglossus pictus, Hyla meridionalis and Pelophylax saharicus) were found within the region. Results suggest a marked, rapid and unexplained crash of the Algerian Newt Pleurodeles poireti, a species endemic to a small area in and around Djebel Edough (Annaba). Information on the status (abundance and distribution) of each recorded taxon is provided and conservation measures are discussed in the light of an apparent local decline of Anurans and the vulnerability of three species (S. algira, P. nebulosus and B. bufo spinosus)La crise aiguë que traverse la biodiversité à l'échelle planétaire n'a pas épargné les amphibiens qui figurent parmi les taxons les plus touchés, illustrés par le déclin prononcé ou la disparition de plusieurs espèces. Notre connaissance du statut et de l'écologie des amphibiens d'Algérie reste limitée alors que les milieux naturels locaux subissent une pression anthropique intense qui ne fait que s'accroître et qui risque de s'exacerber sous l'effet du réchauffement climatique. Dans le but d'inventorier et d'évaluer le statut du peuplement d'amphibiens du complexe de zones humides de la Numidie, «point chaud» pour de nombreux taxons aquatiques et poche relictuelle afrotropicale, nous avons échantillonné 82 sites entre 1996 et 2010. Un total de neuf espèces dont trois Urodèles (Pleurodeles poireti Gervais, 1835, Pleurodeles nebulosus (Guichenot, 1850) et Salamandra algira Bedriaga, 1883) et six Anoures (Bufo bufo spinosus, Bufo mauritanicus Schlegel, 1841, Bufo viridis Laurenti, 1768, Discoglossus picrus Otth, 1837, HYla meridionalis Boettger, 1874 et Pelophylax saharicus Boulanger in Hartert, 1913) ont été inventoriées. Un fait marquant est le déclin net, rapide et inexpliqué du Triton de Poiret Pleurodeles poireti, espèce endémique à une région limitée au Djebel Edough et ses environs, au cours des dernières années. Le statut de trois espèces (S. algira, P. nebulosus and B. bufo spinosus) semble préoccupant au vu des pressions anthropogéniques qui s'exercent sur la Numidie qui abrite 82% des amphibiens d'Algérie

Distribution and assemblage structure of black flies of the western Aures Mountains, Algeria (Diptera: Simuliidae)

Besides their important ecological role in flowing waters, blackflies (Diptera: Simuliidae) may pose medical and veterinary risks. For seventeen months, we surveyed the blackflies of ten localities across the Aures Mountains, in the Saharan Atlas, Algeria, and recorded eight taxa (i.e. species, species groups or species complexes). High altitude sites were dominated by the Simulium ornatum (Meigen, 1818) group, whereas sites located on the southern slope of the Aures Mountains were occupied by the eurytopic Simulium velutinum (Santos Abreu, 1922) complex and the thermophilic, pollutant-tolerant Simulium ruficorne Macquart, 1838 ‘A’ morphotype.Co-inertia analysis was used to determine the relationship between a species’ abundance and habitat types. The co-inertia analysis revealed a likely co-structure between blackfly assemblages and measured environmental descriptors (water temperature, conductivity, current velocity, bed width, etc.) in sampled habitats. This confirmed the importance of altitude as a driver of blackfly distribution. Our results also showed that there has been an increase in anthropogenic pressures on the vulnerable freshwater biota of the Aures Mountains

The breeding ecology of Mallard Anas platyrhynchos at Lake Tonga, north-eastern Algeria

The breeding ecology of Mallard Anas platyrhynchos was investigated at Lake Tonga, north-eastern Algeria, which is at the southern edge of the species’ range in the Western Palearctic. Breeding was mainly carried out in stumps of alder carr (Alnus glutinosa) that border the northern limit of the lake. The breeding season was relatively short, spanning two months. Laying occurred mainly in April but continued until end of May. The average clutch size was 8.4 ± 1.9 eggs (N = 19 clutches) with 10 eggs being the modal clutch. The overall nesting success was 54% (N = 29 clutches), whereas predation accounted for most nest failure (76%). As often happens in arid climates and instable habitats, breeding outcome was significantly and negatively related to egg-laying date with precocious nests conferring better survival to eggs. In contrast, nest predation was positively associated with a deferred laying date. Seven cases of interspecific brood parasitism were recorded, all involving the Mallard and the Ferruginous Duck Aythya nyroca, with both species acting as either a host or a parasite. Nests in dense vegetation were more likely to harbour this interspecific interaction.Keywords: Anatidae, brood parasitism, clutch size, North Africa, reproduction, waterbirds, wetland

Large branchiopods (Branchiopoda: Anostraca, Notostraca and Spinicaudata) from the salt lakes of Algeria

We conducted a survey of large branchiopods (Crustacea, Branchiopoda) of the major salt lakes of Algeria, particularly those of the eastern Hauts Plateaux. The aim of the survey was to complement a previous survey that focused on the freshwater habitats of Numidia, northeast Algeria. The study revealed 8 species, with one taxon new to Algeria and North Africa (Chirocephalus salinus). Data on the status, phenology and habitats of collected and previously known species are presented for 19 taxa. The distribution of many species has been greatly extended and the co-occurrence of Artemia tunisiana and Branchinella spinosa has been recorded. The studied salt lakes, owing to a large production of fairy shrimps, support a great number of wintering and breeding waterbirds, but are subject to increasing human pressure

Phenology, nest-site selection and breeding success of a North African colony of the yellow-legged gull, Larus michahellis

Gulls are good biological models to investigate anthropogenic changes affecting the environment. We studied the breeding ecology of a monospecific colony of yellow-legged gulls, Larus michahellis on the Algerian island of Srigina, during three consecutive years (2009–2011) and attempted to identify factors influencing breeding parameters. Most nests (71%) were located in medium range of vegetation cover (20–80%). Egg-laying started in early March and extended to early May with egg-laying peaking at end of March. Mean clutch size varied significantly between years from 2.8 ± 0.4 (2009) to 2.4 ± 0.8 (2011) with clutches exhibiting a seasonal decrease in mean egg volume. Hatching success was relatively low compared with studies carried out in southern Europe and an average of 1.5 chicks survived to 20 days. Colony size decreased steadily during the study period, dropping by 28.4%. Such decline may be due to breeding dispersal by adults following poor breeding performances. Predation by feral cats (Felis silvestris catus), presumed to be the main cause of chick mortality, may be adversely impacting breeding success and could lead to the virtual extirpation of the yellow-legged gull and other breeding birds from the island.Key words: Laridae, seabirds, yellow-legged gull, reproductive ecology, predation, NorthAfrica

Nesting ecology of Ferruginous Duck Aythya nyroca in north-eastern Algeria

The status of waterbirds breeding in protected areas in North Africa needs constant monitoring because of a naturally fluctuating environment and permissive attitudes towards illegal activities likely to negatively affect population dynamics of threatened species. We present the results of a study conducted at a protected site, Lake Tonga, north-eastern Algeria, on a breeding population of Ferruginous Duck Aythya nyroca, a Near-Threatened duck subjected to considerable pressure from egg-pilfering and illegal hunting. Two distinct habitats within the lake were used by Ferruginous Duck: an Alder carr (Alnus glutinosa) and floating islets across the lake. The mean clutch size was 9.51 ± 1.84 eggs (N = 51 clutches) with hatching rate of 80.7% for successful clutches. Breeding success was low (37%) with predation (33%) and clutch desertion (17%) accounting for the majority of failed nests. The probabilities of nest failure and nest desertion increased with a delayed onset of egg laying. Predation was not significantly associated with egg laying date and vegetation cover, but late breeders nesting in dense vegetation seemed to suffer less predation. Conspecific brood parasitism was positively associated with nest size, whereas interspecific brood parasitism was marginally associated with water depth. We discuss different hypotheses concerning nest desertion, and argue that illegal hunting and disturbance may best explain why birds desert their nests.Keyword: Anatidae, anthropogenic pressure, breeding success, North Afric