Every year, the Coastal wetlands of North Africa support an important wintering waterbird population of many Palearctic and sub-Saharan species of various contrasting habitat requirements. In this study, we describe the habitat use by24 water-obligate species wintering in a coastal wetland of the Northeastern Algeria (the wetland of Lake Tonga), highlighting thereby the ecological mechanisms that support their coexistence and their resources partitioning. The analysis of resource exploitation (Relative frequency, Feinsinger niche breadth, Pianka niche overlap and Ivlev’s electivity indexes) showed that waterbird species inhabiting the lake wetland have several similarities in using the different habitat categories, which lead us to cluster them into 5 guilds (G1: one rails, two grebes and eight ducks; G2: five wading species and one gull; G3: three herons; G4: cormorants, mallards, and on gull; finally, G5: only one species Cattle egret (Bubulcus ibis).Almost all the species were specialists in resource utilization patterns (narrow niche breadths, both under 0.3) and therefore, vulnerable to fluctuations in resources, particularly the feeding habitats. Mean niche overlaps for all the pairs of species ranged from 0.05 to 0.68. The overall pattern in the community was higher niche overlaps between the species of a particular guild than those between other species. According to Ivlev’s electivity index, we found that only three microhabitats from seven were the most important for the discussed species, open water body was the most attractive, followed by meadows, muddy areas and floating- leafed vegetation. Similarities on habitat requirements derived from our region can provide important and optimal wetland management at multi-species assemblage level for this wetland and similar area around the African coast.

During two annual cycles (from September 2012 to August 2014), we analysed structural patterns (provided and compared data on diversity metrics) of bird assemblages in coastal wetlands of Northeastern Algeria. Annual and seasonal differences in relative species abundance were analysed from the viewpoint of diversity/dominance. Bird assemblages vary only in the number of species (35 recorded species during the wintering season against 23 during the breeding season). Values of the relative abundance in both seasons were similar, curves in the diversity/dominance diagram were analogous (not significantly different; both p > 0.05). Indeed, the seasonal structure of waterbird communities indicates highly dominated assemblages manifesting themselves in reduced species diversity and increased dominance of certain species. Simpson's index was never recorded below 0.50, thus indicating evidently lower evenness. The Eurasian Coot Fulica atra and the Little Grebe Tachybaptus ruficollis were highly dominant species together accounting for more than 50% of waterbird communities. This atypical organisation (highly dominated structure) is mainly due to anthropogenic or natural stresses. The marked decline in bird species diversity recorded during the study period (approximately two years long) may be of concern to wetland managers as causes and consequences of the increased number of widespread species and factors behind the increasing species diversity are likely to be felt in both seasons.

As rare and threatened species, ecological information about common waterbirds is needed to assess priorities for wetland management. In this study, we attempt to provide information about the spatial ecology and wintering behaviour of one of the most common species of the coastal Mediterranean wetland complex of northeastern Algeria, the Eurasian Wigeon Anas penelope. Over the three winters of the study the maximum number of recorded Eurasian Wigeon across all sites rose from 1,096 in 2010/11 to 1,397 in 2012/13. This represents a 27% increase over three years in the Guerbes-Sanhadja region. Among these wetland complex sites abundance varied markedly during the three wintering periods of study, being highest in Garaet Hadj-Tahar and Garaet Beni Mhamed (ranging from 300–700 individuals), and lowest in the remaining sites, which never exceeded 150 individuals. Bird abundance often peaked in January of each year and decreased as winter progressed. Wigeon have similar patterns of migration phenology among years at Garaet Hadj-Tahar and Garaet Beni Mhamed. At the remaining sites, they exhibited a different pattern. The multiple regression analysis for all seasons showed a marginally significant correlation between Wigeon abundance changes and three environmental variables of the wetland complex exclusively in the spring seasons (depth, vegetation and temporariness). A roosting area is identified as a functional role of the Guerbes-Sanhadja wetland complex for this anatid, since they spent all of the daytime sleeping, swimming (ranged from 30 to 40%), and resting (from 15 to 25%) in all winters. Despite their semi-permanent and unprotected status (apart from only three sites), these patched wetlands provide suitable conditions for this sensitive species, and therefore should receive the attention of wetland management.

telailia S., Boutabia L., khemis El-Hak M.D., Elafri a., Djebbari n.: Multi-annual and seasonal patterns of waterbird assemblages in a Mediterranean coastal lagoon (El Mellah lagoon) of northeastern algeria. Ekológia (Bratislava), vol. 36, no. 2, p. 146-158 , 2017. recently, Mediterranean coastal lagoons have raised considerable environmental concerns. Long-term studies of seasonal changes in waterbird assemblages are therefore extremely important in terms of ecological relevance and conservation of these sensitive ecosystems. an ornithological survey of four years was carried out in a typical costal wetland (El Mellah lagoon) of northeastern algeria. intra-seasonal comparison of waterbird assemblages (diversity indices) demonstrates clear changes between the wintering and the breeding periods. it seems that the first one was rich in term of species number than the second season (43 against 24). in contrast, the breeding seasons were more equilibrate (high values of Simpson, Shannon and evenness index). additionally, curves in the diversity/dominance diagram revealed that both wintering and breeding assemblages share the same characteristics of community structure, few dominant species (with intermediate relative abundance) and many rare species with the relative abundance lower than 0.1. invertebrates (25 species) and piscivorous (11 species) are the most abundant guilds over the four years of study (no significant differences among years have been calculated). The marked decline in bird species diversity recorded in this study (in comparison with previous studies) is mainly due to salinity oscillations (due to aquaculture activities) and may be of concern to wetland managers and it might be useful to provide some guidelines about the characteristics that coastal lagoons have to follow in the construction process to enhance the biodiversity.

Riassunto -Andamento temporale e uso complementare di una zona umida mediterranea (Tonga, Nord-est Algeria) da parte degli uccelli acquatici migranti e residenti.Abbiamo effettuato una descrizione quantitativa sull'uso di una zona umida mediterranea (Tonga, nord-est dell'Algeria) da parte di 22 specie di uccelli acquatici (11 residenti e 11 migratori paleartici) durante il periodo di fine-estate inizio-inverno, analizzando anche la loro gestione del tempo diurno e le relative principali caratteristiche del paesaggio. Le analisi delle analogie nella gestione del tempo da parte degli uccelli (analisi del clustering gerarchico) ha mostrato 4 gruppi di specie associati a 4 attività principali: nutrimento principalmente nelle ore diurne (11 specie), dormire (6), nuotare (3) e riposare (2). Le specie residenti (aironi e rallidi) hanno mostrato un tempo di nutrimento maggiore rispetto alle specie migratorie (anatre tuffatrici, gabbiani e cormorani). Dal periodo di fine-estate a quello di inizio-inverno le abitudini dei migratori cambiano, mentre i residenti si comportano uniformemente durante le ore diurne e durante il corso della stagione. L'utilizzo di questa zona umida naturale in maniera complementare da parte di una gran numero di uccelli acquatici (residenti e migratori) è favorita principalmente dalla presenza di numerosi tipi di habitat. Abbiamo constatato che sono 3 le principali unità ecologiche più utilizzate come habitat di foraggiamento tra podicipedidae Bonaparte, rallidi, anatre, gabbiani ed aironi: corpo idrico aperto, piane tidali e prati allagati. Al contrario, vegetazione a foglie galleggianti ed emergente alta erano le categorie di habitat più comuni usate nelle attività di riposo, soprattutto da cormorani ed aironi. I dati raccolti sui requisiti di comportamento di questi uccelli acquatici possono essere utilizzati per la conservazione e la corretta gestione di questa e di altre zone umide costiere mediterranee.Parole chiave: comportamento diurno, microhabitat, metodo di coordinamento, periodo stagionale, uccelli acquatici. Abstract -We carried out a quantitative description of the use of a Mediterranean wetland (Tonga, North-east Algeria) by 22 waterbirds species (11 residents and 11 Palaearctic migrants) during late summerwintering period, also analyzing their species-specific diurnal time budgets and the main related features of the landscape. The analyses of similarity in time budgets across birds (hierarchal Cluster Analysis) showed four clusters of species associated with four major activities: day time mostly feeding (11 species), sleeping (6), swimming (3) and resting (2). Residents (herons and Rails) showed a higher feeding time when compared to migrants (diving ducks, Gulls and Cormorants). From late summer to winter the time budget activity change in migrants; in contrast residents behave uniformly among daytime and at the course of the season. The use of this natural wetland in a complementary way by a high number of waterbirds (residents and migrants), is principally promoted by the ex...

Understanding the factors affecting escape behaviour in waterbirds can be useful in the management of human disturbances. A common measure of escape response is flight initiation distance (FID), the distance at which an approaching intruder disturbs an individual bird enough to make it move away. Here, we analyse the escape behaviour of a set of waterbirds for the first time within a North African context. We tested (one-way ANOVA and general linear model) how FID varied with the area where waterbirds were temporal scale, distance at which the observer start approaching to the sampled birds, body size, flock size, species composition of the flock and foraging activity of the sampled birds. We collected 866 individual FIDs for 19 waterbird species wintering at two north Algerian wetlands (the Mekhada marsh, RAMSAR site, El-taref District and the Sebkhet El-Mahmel, unprotected wetland, Khenchela District). The obtained FIDs ranged from 32.6 m in smaller species as the Kentish plover Charadrius alexandrines to 167 m in larger ones as the ruddy shelduck Tadorna ferruginea. The obtained models stated that differences in the absolute levels of FIDs were mostly related to starting distance (Effect size = 0.62), to which is added a relatively little effect of wetland status, taxonomic differences, temporal scale, body size, flock size, species composition of the flock and bird activity. More specifically, FID was lower in smaller and homospecific groups at early winter in the protected wetland. Reserve managers in North Africa could use species and context-specific FIDs in delineating appropriate buffer areas and in the design of management initiatives aimed at minimising eventual potential threat due to human disturbance and guaranteeing animal welfare and wildlife.

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