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.

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.

Laboratory observations on rearing experiment of Odonata serve to answer many evolutionary and ecological questions. In order to evidences the role of species parental habitat provenience in the development behaviour of their offspring, we surveyed several life history traits of two rearing populations of Sympetrum meridionale (Anisoptera: Sympetrinae), coming from two different habitats across north-eastern Algeria. The first one is a RAMSAR wetland called ‘Mekhada’ (a perennial water body), and the second one is a temporary pond located at “Maouna” Mountain (1400 m altitude). Overall, the development patterns of the two populations of dragonflies vary with the type of habitat the parental generation of the species occupy (Factorial ANCOVA: all p < 0.05). Firstly, egg mortality was very low in dragonfly population inhabiting the RAMSAR wetland compared of those belonging to Maouna Mountain. Secondly new-borne larvae stemming from females inhabiting the Mekhada wetland develop more slowly than did those coming from the “Maouna” Mountain pond. Finally, larvae of Sympetrum meridionale stemming from females inhabiting the temporary wetland were heavier than those inhabiting the perennial wetland. Such studies will ads considerably to our understanding of the mechanisms that are responsible for possible effects of environmental changes on life history traits of dragonflies across the southern part of their distribution range.