An ecological survey of Laro-limicolae in Northeastern Algeria

Study Extent

The study was carried out at three Ramsar wetlands in the El-Kala National Park, located in the extreme north eastern Algeria (fig. 1): 1) Lake Tonga (36° 51’ N/ 8°29’ E), a large shallow exorheic lake with an area of 2,700 ha and an average depth of 1 m. It is fed by three tributaries: the El-Hout wadi from the southeast, the El-Eurg wadi from the east, and the Messida Channel from the north (fig. 1). Due to the richness and diversity of its habitats, it is a renowned wintering and breeding site for a multitude of waterbird species, some of which are rare and declining in range, such as the white-headed duck Oxyura leucocephala and the marbled teal Marmaronetta angustirostris (Boumezbeur, 1993; Lazli et al., 2011a, 2011b, 2012; Menasria and Lazli, 2017; Mecif et al., 2020; Gherib et al., 2021). 2) Lake Oubeïra (36° 50’ N/ 8°23’ E), an endorheic freshwater lake with an area of 2,200 ha and an average depth of 2.15 m (fig. 1). With a typical spatial organisation of belt vegetation, it is considered a wintering and nesting site, hosting numerous species, such as the Greylag Goose Anser anser, the Great Cormorant Phalacrocorax carbo and several shorebird species, such as the Pied avocet Recurvirostra avosetta, the black-winged stilt Himantopus himantopus, the little ringed plover Charadrius dubius and the Eurasian bittern Botaurus stellaris (DGF, 2002; Lazli et al., 2018). 3) - El-Mellah lagoon (36° 53’ N / 8° 19’ E), the only lagoon on the Algeria coast, connected to the sea by a 900 meter channel. It has a surface area of 860 ha and is ranked fifth largest among the 14 North African lagoons (Baba Ahmed, 2008). This lagoon is not only fueled by marine waters, which are partly responsible for its brackish nature, but also by the gentle waters of two wadis: R'guibet and Boularoug (fig. 1).

Sampling

To assess richness and abundance of Laro-limicolae species in the three Ramsar sites we made bi-weekly visits from September to August 2014/2015 and from September to August 2015/2016. We conducted a total of 192 counts. At each visit, the sites were systematically covered, following a course chosen in advance (fig. 1). Censuses of avian populations were carried out from various points to allow the most exhaustive count of species and their numbers. Observations of Laro-limicolae were made from 8:00 h to 16:00 h using a telescope (Kowa™ 20 x 60). Because we were able to count the birds at short range it was easy to determine the exact number of birds and their species using the scanning sampling protocol.

Quality Control

Laro-limicolae phenology and ecology were measured using the following ecological indices: (1) total abundance, that is, the total number of birds that visited site on a given day; (2) specific richness, that is, the number of species observed at a given visit; and (3); the Shannon-Weaver diversity index, that is a way to measure the diversity of a species in a community (this index was calculated according to the formula H' = ΣPi ln Pi, where Pi is the proportion of each specie in the sample, and (4) equitability index, is a way to measure the evenness of species in a community (this index is calculated as: E = H'/ln(S), where S is the total number of unique species and when E is close to 1; the diversity observed reflects an abundance distribution close to equilibrium (Legendre and Legendre, 1979; Shannon and Weaver, 1949).

Method steps

1. Phenological status observed: (1) resident; observed throughout the year; (2) wintering; observed only in the winter; (3) migratory breeders; observed only in breeding season; (4) wintering/breeding, observed during winter and breeding season. Statistical data analysis To perform comparisons between years we used a Chi-square test and a multivariate factor analysis (CFA)). Statistical analyses were applied using R- version software. 4.3.1 (R Core Team, 2023).

1. Charadriiformes
   rank: order
2. Glareolidae
   rank: family
3. Haematopodidae
   rank: family
4. Recurvirostridae
   rank: family
5. Scolopacidae
   rank: family
6. Charadriidae
   rank: family
7. Laridae
   rank: family

The study was carried out at three Ramsar wetlands in the El-Kala National Park, located in the extreme north eastern Algeria: 1) Lake Tonga (36° 51’ N/ 8°29’ E), a large shallow exorheic lake with an area of 2,700 ha and an average depth of 1 m. It is fed by three tributaries: the El-Hout wadi from the southeast, the El-Eurg wadi from the east, and the Messida Channel from the north. Due to the richness and diversity of its habitats, it is a renowned wintering and breeding site for a multitude of waterbird species, some of which are rare and declining in range, such as the white-headed duck Oxyura leucocephala and the marbled teal Marmaronetta angustirostris (Boumezbeur, 1993; Lazli et al., 2011a, 2011b, 2012; Menasria and Lazli, 2017; Mecif et al., 2020; Gherib et al., 2021). 2) Lake Oubeïra (36° 50’ N/ 8°23’ E), an endorheic freshwater lake with an area of 2,200 ha and an average depth of 2.15 m. With a typical spatial organisation of belt vegetation, it is considered a wintering and nesting site, hosting numerous species, such as the Greylag Goose Anser anser, the Great Cormorant Phalacrocorax carbo and several shorebird species, such as the Pied avocet Recurvirostra avosetta, the black-winged stilt Himantopus himantopus, the little ringed plover Charadrius dubius and the Eurasian bittern Botaurus stellaris (DGF, 2002; Lazli et al., 2018). 3) - El-Mellah lagoon (36° 53’ N / 8° 19’ E), the only lagoon on the Algeria coast, connected to the sea by a 900 meter channel. It has a surface area of 860 ha and is ranked fifth largest among the 14 North African lagoons (Baba Ahmed, 2008). This lagoon is not only fueled by marine waters, which are partly responsible for its brackish nature, but also by the gentle waters of two wadis: R'guibet and Boularoug.