Check list of waterbirds at Wadi Djedi in Ziban Oasis – Algeria

Check list of waterbirds at Wadi Djedi in Ziban Oasis–Algeria. This pioneering work is the first to document the aquatic avifauna community of the Wadi Djedi in the Ziban region in southeast of Algeria. We present results obtained through the monthly counts of waterbirds conducted from September 2013 to September 2016. On this wetland we recorded 36 species of water birds representing 11 families. The Anatidae family was the most numerous, with 11 species. From among all the species, 18 were wintering species, nine were visitors, eight were sedentary breeding species (including the ruddy shelduck Tadorna furruginea and Kentish plover Charadrius alexandrines) and one species was migratory nesting (the white stork Ciconia ciconia). Two species (the teal marbled Marmaronetta angustirostris and ferruginous duck Aythya nyroca) are listed as Vulnerable on the IUCN Red List of endangered species. Data published through GBIF (doi:10.15470/6m0dyq)


Introduction
North Africa has a great variety of wetlands that are wintering and stopover sites for several Palearctic migratory birds (Fishpool and Evans, 2001). Algeria contains a wide variety of wetlands that are major staging posts and wintering grounds for migrating birds (Stevenson et al., 1988).
Waterbirds are an important component of the biotic community of aquatic ecosystems (Green and Elmberg, 2014). In the Algerian Sahara, waterbirds are relatively well known due to data collected by several ornithologists in the past (Heim de Balsac and Mayaud 1962;Ledant et al., 1981;Isenmann and Moali, 2000). These early works were based on observations recorded intermittently in a few wetlands.
Few studies have been performed to determine the ecological importance and especially the ornithological value of Wadi Djedi. Here we present the preliminary data of our waterbird survey aiming to evaluate the status of species using this wetland.

Study area
The Ziban oasis is located in the east of Algeria, south of the Aurès Mountains (5º 44' 00'' N, 35º 51' 00'' E). The region is characterized by the arid Mediterranean climate. The average maximum temperature is 41.38 ºC in August and the minimum temperature during January is 8.26 ºC. Precipitation averaged about 128 mm over the last ten years (2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014). Wadi Djedi in the Ziban oasis is one of the largest Saharan rivers. It originates in the Saharan Atlas Mountains at an altitude of about 1,400 m and it flows for about approximately 480 km from west to east ( fig. 1). During the rainy season (winter), the river helps to raise the water level of Chott Melrhir (Ballais, 2010). The flora is dominated by Tamarix gallica, Atriplex halimus, Phragmites australis, Typha elephantina and Juncus maritimus.

Data acquisition
This study was undertaken through monthly bird counts from September 2013 to September 2016 using binoculars and a telescope KOWA (20 × 60). Surveys were conducted at three stations on the edges of the Wadi ( fig. 2) to obtain consistent data. Individual counts were conducted when the numbers of birds present was small. When more than 200 birds were present, total numbers were estimated by dividing the flock into small equal blocks (50-200 birds according to flock size) and counting the number of blocks (Blondel, 1975). This latter method is that most commonly used in the winter counts of waterfowl (Lamotte and Bourlière, 1969). The bird community was sampled by performing counts of waterbirds from vantage points with unlimited distance (Blondel, 1975;Legendre and Legendre, 1979). Three sampling points were chosen for the bird count.

Results
The study revealed that the waterbird community of this wetland is composed of 36 species belonging to 11 families (table 1; GBIF dataset (Doi:10.15470/6m0dyq)). The Anatidae Family with 11 species was found to be the richest in species number, followed by Scolopacidae (nine species), and Ardeidae (four species). Four families were doubleton (two species): Rallidae, Recurvirostridae, Threskiornithidae and Charadriidae. Singleton families, that is, those represented by a single species, were Phalacrocoraciidae, Ciconiidae, Phoenicopteridae and Accipitridae ( fig. 3).

Anatidae
Eleven duck species were noted ( fig. 3, fig. 5). Three species were resident breeders: mallard Anas platyrhynchos, ruddy shelduck Tadorna ferruginea and shelduck Tadorna tadorna. Five   The three remaining species were migrants: Northern pintail Anas acuta, gadwall Anas strepera and garganey Anas querquedula (table 1). The maximum count of Anatidae recorded at the study site (all species included) was over 2,000 individuals.

Ardeidae
Four species were observed, only one of which, the great egret Ardea alba, was a migrant species. The others were wintering species: cattle egret Bubulcus ibis, little egret Egretta garzetta, and grey heron Ardea cinerea. They were poorly represented and usually seen on shallow shorelines.

Scolopacidae
Nine species of this small wader family were observed. Four were migrant species: common snipe Gallinago gallinago, dunlin Calidris alpina, sandpiper Tringa stagnatilis, and common redshank Tringa tetanus. These four species were mainly observed only once or twice during the study period, especially during their post-breeding passage. Five wintering species were noted: spotted redshank Tringa erythropus, common greenshank Tringa nebularia, little stint Calidris minuta, green sandpiper Tringa ochropus, and common sandpiper Actitis hypoleucos.

Rallidae
Only two species of the Rallidae family were observed: the common coot Fulica atra and the common moorhen Gallinula chloropus. Both are resident breeders in the area and seen during the breeding period in the boundary waters next to the site containing the Phragmites. Egg fragments and nests with eggs found in the vegetation confirmed the breeding success of this species.

Recurvirostridae
Two resident breeder species were found from this family, the tow black-winged stilt Himantopus himantopus and avocet Recurvirostra avosetta. They were observed almost throughout the year in fluctuating numbers; breeding pairs were observed during June and July. Eggs and chicks found on 15 May 2016 confirmed the breeding success of this species.

Threskiornithidae
The Eurasian spoonbill Platalea leucorodia and the glossy ibis Plegadis falcinellus have wintering status in the region. These species are generally present in the site in very small numbers, not exceeding 20 individuals for either species (table 1).

Charadriidae
For this family, two species were found; the ringed plover Charadrius hiaticula (migrant species) and the kentish plover Charadrius alexandrines (resident breeder species). Both have a sedentary status. Their presence was confirmed after breeding pairs were observed in April and May 2016 when nests with two and three eggs were found in the northern border of the site.  (table 1).

Ciconiidae
The white stork Ciconia ciconia (migratory breeder) is an anthropophilic species. It nests voluntarily in the cities and the villages where it chooses high points to build its nest. They were regularly observed feeding in the wetland, from January till August. A maximum of 87 individuals was recorded at the site on 4 October 2013 (table 1).

Phoenicopteridae
The greater flamingo Phoenicopterus roseus (wintering species) is a characteristic species of salt wetlands. It was regularly observed in high numbers from September until the end of May. The highest number of birds, 280, was recorded in January 2014 (table 1).

Accipitridae
The Western marsh-harrier Circus aeruginosus (wintering species) was the only species observed from this family. It was seen throughout winter, from November to April. Low numbers were recorded in the southern part of the Wadi.

Discussion
Anatidae was the most abundant family in terms of richness and number, with 11 species and a maximum abundance exceeding 2,000 individuals from the total species combined in December and January 2013. Except for Scolopacidae, with nine species detected, all other families were poorly represented.
Breeding was confirmed for some species, such as the ruddy shelduck Tadorna ferruginea, which had not been reported previously in the Wadi Djedi. Reproduction of this species had been reported previously in the valley of Oued Righ in the south of Ziban by Nouidjem et al. (2016). Species of greatest conservation concern, listed as Endangered Species in the category (VU) of the IUCN Red List (Birdlife International, 2004), were the marbled teal Marmaronetta angustirostris and the ferruginous duck Aythya nyroca.