Distribution of waterbird communities in North-Eastern Algeria

Understanding how bird species interact with local environmental conditions is fundamental to grasping habitat preferences and their effects on species distribution. This study examined the influence of abiotic factors on waterbird assemblages across three wetlands within the Sidi Fredj Complex (Souk Ahras, northeastern Algeria): Mkimen Marsh, Medjen Djedj and Medjen Bouhsane. Monthly bird surveys were conducted from July 2018 to July 2019, combined with water quality measurements at each site. A suite of multivariate analyses including Principal Component Analysis (PCA), Canonical Correspondence Analysis (CCA), Redundancy Analysis (RDA) and Non-Metric Multidimensional Scaling (NMDS) was applied to explore species environment relationships. My results showed that environmental variation significantly structured bird community composition. Mkimen, characterized by higher pH, salinity, dissolved oxygen, chloride, nitrate and nitrite, supported high species richness and was dominated by taxa such as the Little Egret (Egretta garzetta), Mallard (Anas platyrhynchos), White Stork (Ciconia ciconia), Yellow-legged Gull (Larus michahellis) and Grey Heron (Ardea cinerea). It also exhibited significantly higher diversity and evenness indices compared to the other sites. In contrast, the Green Sandpiper (Tringa ochropus) and Black-throated Diver (Gavia arctica) showed strong affinities for higher dissolved oxygen and chloride levels at Medjen Djedj. Medjen Bouhsane, characterized by lower temperature and phosphorus levels, favored species such as the Northern Pintail (Anas acuta), Northern Shoveler (Anas clypeata), Eurasian Coot (Fulica atra), Great Cormorant (Phalacrocorax carbo), Great Crested Grebe (Podiceps cristatus), Common Moorhen (Gallinula chloropus) and Eurasian Teal (Anas crecca). These findings highlight that waterbird species respond in species-specific ways to environmental gradients, although ecologically similar species often share habitat preferences. The strong associations between bird presence and physico-chemical conditions underscore the role of waterbirds as effective bioindicators of wetland health. This study also confirms the importance of incorporating habitat heterogeneity and environmental variability into conservation strategies. Understanding these ecological relationships is essential for preserving waterbird diversity in Mediterranean wetland ecosystems facing increasing anthropogenic pressures.