The aim of this work was to provide evidence on the presence of microplastics (MPs) in regurgitated Yellow-legged Gull pellets (n = 18) from Sfax salina (south-eastern Tunisia). This artificial area is subject to high anthropogenic pressure and hosts Yellow-legged Gulls, which are at the top of the trophic chain and can be used as sentinel species to monitor litter in the environment, including plastic pollution. The total number of MPs found in the samples was 309, 63.8 % fibres (4.95 ± 3.51 MPs/g) and 36.2 % fragments (2.87 ± 1.74 MPs/g). Micro-FTIR analysis evidenced that a large proportion of the fibres was attributed to artificial cellulose (40.7 %). Ethylene vinyl acetate (EVA) and polyethylene (PE) were found in the fragments.

Climate change significantly impacts avian morphological and reproductive phenologies, particularly influencing the distribution of endemic species with restricted ranges. This study explores the potential distributional shifts of the Levaillant’s Woodpecker, endemic to North Africa, in response to climate change. We employed ecological niche modeling to assess its range dynamics during historical periods (Last Interglacial, Last Glacial Maximum, and mid-Holocene), the present, and projected future scenarios (2050 and 2070). The analysis incorporated 68 occurrence records of the species and 15 bioclimatic variables. Our findings indicate a current equilibrium between the woodpecker and its climatic environment. Historically, the species experienced a marked range contraction during the Last Interglacial, followed by a significant expansion in the Last Glacial Maximum. The mid-Holocene distribution closely resembled the present range. Future projections, however, suggest a decline in Levaillant’s Woodpecker populations, with a shift towards higher altitude forests as a response to global warming impacts on their existing habitats. This study highlights the critical need for awareness about global warming and its potential threats to biodiversity, particularly forest avifauna.

We investigated ecological factors that influence the presence of nests of Levaillant’s Woodpecker Picus vaillantii in the Aurès Mountains of northeastern Algeria. Surveys carried out during the breeding season in 2018 and 2019, using point counts combined with extensive nest searching around each point at 72 random stations, allowed us to detect 44 nests against 28 unoccupied points. Using data on trees, deadwood, snags, canopy cover at the nest site, and elevation, we developed models reflecting landscape structure and forest composition. The results indicate that P. vaillantii prefers nesting in high-altitude forests and in dense canopies with high elevation. This reflects the importance of the forest composition, which is related to altitude, and the landscape structure, represented by the canopy cover, for the breeding of this species.

Abstract Levaillant’s Woodpecker Picus vaillantii is a primary cavity nester endemic to the forests of northern Africa, including the cedar forest in Aures Mountains. This species, as like all woodpeckers, is important for the integrity of ecosystems, especially since it provides nesting cavities and contributes to the availability of habitats for several secondary cavity nesters that cannot dig their own nests. To characterize for the first time the Levaillant’s Woodpecker’s nest cavities and to test the effect of local climatic conditions on the sizes and orientations of these cavities in Aures cedar forests of north-eastern Algeria surveys were carried out in 2018 and 2019 breeding seasons using the point count method to search for the nests of the Levaillant’s Woodpecker. Based on measures realized on a total of 52 available nest cavities, results reveal entrances with a dominance of round shapes (94.2%) compared to oval shapes. The mean height and width values ​​of the cavity entrances were 7.26 ± 1.51 cm and 7.11 ± 1.44 cm. The depth of the internal chamber and its width were estimated at 35.42 ± 7.82 cm and 17.95 ± 4.01 cm respectively. Unlike the average values ​​of the volumes of the internal chamber, those relating to the entrance area and orientation vary significantly according to altitude and climatic conditions. Indeed, when climbing towards the summits, the cavities widen and turn to the west-southwest. This behavior of the Levaillant’s woodpecker seems to help it to benefit from maximum sunshine at high altitudes and to avoid predators and competitors more abundant at medium low altitudes.

Trypanosomiasis is widely distributed in African and Asian camel livestock. It is among the major constraint to camel production and causes serious economic losses. The disease control and management required knowledge about its impact on animal health. Objectives: The present study aims to confirm T. evansi infection in studied animals and to determine the modifications of haematological parameters in infected camels compared to non-infected ones. Methods: A total of 241 dromedary camels were randomly selected. Parasitological and serological tests were performed to confirm the infection. Haematological parameters (Red Blood cell Count, White Blood Cells, haemoglobin concentration, Packed Cell Volume, Mean Cell Volume, Mean Cell Haemoglobin, Mean Cell Haemoglobin Concentration, Red cell Distribution Width and White Blood cell Count) were automatically analysed, differential leukocyte counts was manually carried out and morphological abnormalities of erythrocytes were recorded. Results: Trypanosoma evansi infection was confirmed in 3.6% of animals by microscopy and in 57.3% by serology. In seropositives camels, the most important haematological alterations were microcytic hypochromic anaemia, neutrophilia, monocytosis, eosinophilia and anisocytosis. Conclusion:On the basis of these findings, haematological parameters, markedly affected in T. evansi infection, are good biomarkers for the diagnosis and monitoring of the disease. They may be used for planning control programs to reduce its impact on camel livestock production

Tunisia's Ichkeul Lake is among the most productive ecosystems in the Mediterranean, with a great regional value thanks to its diversity of habitats. It is an important overwintering area for waterfowl species. It is a RAMSAR wetland, a National Park, a UNESCO World Heritage, and a Biosphere Reserve. This review paper provides a broad overview of the climatic, hydraulic, biogeochemical features, bio-resources, and bio-productivity of the Lake. The interconnectivity between the different environmental components of the lake is presented, highlighting the main characteristics of this vital ecosystem. Its ecosystem consists of a permanent lake bordered by temporary marshes. It is connected to the Mediterranean Sea via Bizerte Lagoon under a typical semi-arid to sub-humid bio-climate with wet and dry seasons. The winter rainfall fills up the rivers and lake with freshwater that overflows into the Tinja River. In summer, high evaporation reduces the water level and allows seawater to enter the wetland from Bizerte Lagoon. The ecosystem is threatened by pollution, the damming of its main rivers, and climate change. The unsustainable water management has resulted in fundamental environmental modifications, as evidenced by the large variation in the salinity, water level, productivity of water plants, and the decline in venue and stop-overs of waterbirds. The current situation is a warning that indicates a general perturbation of the resources of this particular site and of Tunisian wetlands in general, especially that the Mediterranean region has been designated as a climate change hotspot. Accurate hydrological management is needed to boost the physical functioning of the ecosystem, and to gain deeper knowledge of the different phases of the water cycle and its relationship to other long-term environmental cycles for sustainable water management strategies in the most water-scarce region in the world.

Levaillant's Woodpecker is an endemic species of the forests of north-western Africa. Through the cavities it digs, its presence is essential for the existence of other cavity nesters. However, despite its importance to its ecosystems, there are not much data dealing with its ecology and especially its habitats. To describe these habitats, we investigated nest-sites characteristics of Levaillant's Woodpecker Picus vaillantii in the Aures forest massifs of north-eastern Algeria, during two breeding seasons 2018 and 2019. Using the point count method, we detected 45 occupied nesting cavities, unevenly distributed over the formations, dominated by Atlas cedar (73.3%), Holm oak (13.3%), and Aleppo pine (4.4%). Results showed high utilisation of live trees (71.1%) with healthy crowns (75.5%). Findings also revealed that the species favoured tree trunks (77.7%) as nesting support and that the determination of the nest height was strongly dependent on the height of the nesting tree. Nest height and tree diameter at this height varied significantly among tree species. Nests were higher in Aleppo pine, however, tree diameters at nest positions were lower in this species, compared with other tree species. These results on the ecology of Levaillant's Woodpecker can serve to fill the information gap in the ornithological knowledge of the Aures forests areas and provide important information for the conservation of the species in the context of forest management practices.

Abstract Levaillant’s Woodpecker Picus vaillantii is a primary cavity nester, endemic to the forests of northern Africa, including the cedar forest in Aurès Mountains. This species, similar to all woodpeckers, is important for the integrity of ecosystems, especially as it provides nesting cavities and contributes to the availability of habitats for several secondary cavity nesters that cannot excavate their hollows. This work aim to characterise the Levaillant’s Woodpecker’s nest cavities and to test the effect of local climatic conditions on the size and orientation of these cavities. Surveys were carried out in the breeding seasons of 2018 and 2019 using the point count method to search for the nests. Based on nest measurements conducted on a total of 52 available nest cavities, our results reveal that entrances are dominated by round shapes (94.2%) as compared to oval shapes. The mean height and width values of the cavity entrances were found to be 7.26 ± 1.51 centimetres and 7.11 ± 1.44 centimetres. The depth of the internal chamber and its width were estimated to be 35.42 ± 7.82 centimetres and 17.95 ± 4.01 centimetres, respectively. Unlike the average values of the volumes of the internal chamber, those relating to the entrance area and orientation vary significantly according to altitude and climatic conditions. Indeed, when climbing towards the summits, the cavities widen and turn to the west-southwest. This behaviour of the Levaillant’s Woodpecker seems to help it to benefit from maximum sunshine at high altitudes and to avoid predators and competitors more abundant at medium or low altitudes.

Camels are the most adapted species to the harsh ecosystems of the African continent where they represent 80% of world's population. However, they can be susceptible to many pathogens such as Trypanosoma evansi. This parasite is widely distributed in Africa and represents a real threat to animal health and production. In Tunisia, despite its importance, this disease is underestimated and only a few data are available. The present study aims to investigate the prevalence of the disease by combining microscopic and serological tests. A cross-sectional study was conducted on 307 dromedary camels randomly selected from Southern Tunisia. Collected blood samples were microscopically examined and tested with Card Agglutination Trypanosomiasis Test to detect anti-T. evansi antibodies. The microscopic and serological prevalence were estimated at 2.93 and 62.54%, respectively. Microscopic examination showed morphological features of T. evansi. All positives samples were collected from aged males (>5 years old). Seroprevalence was similar for both sexes but it was higher in dry season and in the southwest of Tunisia. The present study revealed high prevalence of T. evansi infection among dromedary camels. This highlights the need for adequate control measures based on the detection and treatment of infected animals and vector control. We recommend investigating the prevalence of infection in other domestic animals living in the same environment.

The increased incidence of antibiotic-resistant Enterobacteriaceae is a public health problem worldwide. The aim of this study was to analyze the potential role of wild birds, given their capacity of migrating over long distances, in the spreading of carbapenemase, extended-spectrum β-lactamase (ESBL), and acquired-AmpC beta-lactamase-producing Enterobacteriaceae in the environment. Fecal and pellet samples were recovered from 150 wild birds in seven Tunisian regions and were inoculated in MacConkey-agar plates for Enterobacteriaceae recovery (one isolate/animal). Ninety-nine isolates were obtained and acquired resistance mechanisms were characterized in the five detected imipenem-resistant and/or cefotaxime-resistant isolates, by PCR and sequencing. The following ESBL, carbapenemase, and acquired-AmpC beta-lactamase genes were detected: blaCTX-M-15 (two Escherichia fergusonii and one Klebsiella oxytoca isolates), blaKPC-2 (one K. oxytoca), blaKPC-3 (one E. fergusonii), blaACT-36, and blaACC-2 (two K. oxytoca, four E. fergusonii, and two E. coli). The IncFIIs, IncF, IncFIB, IncK, IncP, and IncX replicons were detected among these beta-lactamase Enterobacteriaceae producers. The blaKPC-2, tetA, sul3, qnrB, and cmlA determinants were co-transferred by conjugation from K. oxytoca strain to E. coli J153, in association with IncK and IncF replicons. Our results support the implication of wild birds as a biological vector for carbapenemase, ESBL, and acquired-AmpC-producing Enterobacteriaceae.

This study aimed to observe the type of asymmetry exhibited by Porcellio laevis sampled from 15 sites belonging to Tunisian industrialized areas. Physicochemical parameters such as pH, organic matter and CaCO3 contents were measured in soils. Moreover, Cd, Pb, Zn, and Cu concentrations were determined in both soils and woodlice. Additionally, 10 metrical traits were measured to evaluate the type of asymmetry on individuals: the basis, the second and the third articles of the antenna, the first article of the flagellum of the antenna and the merus, the carpus, and the propodus of the sixth and the seventh pereopods. Among the 531 measured individuals, 432 exhibited fluctuating asymmetry (FA) while the remaining individuals exhibited antisymmetry or directional asymmetry. The data obtained were analyzed using a multivariate statistical analysis. Contrary to our hypothesis, the results showed that individuals from contaminated sites have a low FA level, whereas those from uncontaminated sites have a high FA level, particularly females but with some exceptions. Variations in FA level in the traits and populations studied and its usefulness as a stress indicator were discussed.

Migrating birds have been implicated in pathogen dissemination over long distances. The lack of data on the intestinal microbiota of birds makes these animals a promising path in order to understand their potential role in the transmission of antibiotic-resistant bacteria. This study aimed to investigate the diversity of enterococcal species, and to analyse the antimicrobial-resistant phenotypes/genotypes, as well as the genetic lineages of isolates obtained from faecal and pellet samples of colonial wild birds in Tunisia. Seventy-nine enterococci were recovered from 150 wild birds, after inoculation of samples in Slanetz–Bartley agar, and were identified as E. faecalis (n = 53), E. faecium (n = 19) and E. casseliflavus (n = 7). Antimicrobial susceptibility was tested, and the following rates of resistance were found: tetracycline (46.8%); erythromycin (34.2%); chloramphenicol (8.8%); gentamicin and streptomycin (2.5–3.8%); ciprofloxacin, trimethoprim–sulfamethoxazole and kanamycin (12.7–21%); and ampicillin and linezolid (0%). The tet(M), tet(L), erm(B), erm(C), aac(6′)-Ie–aph(2″)-Ia and cat genes were detected in most tetracycline-, erythromycin-, gentamicin- and chloramphenicol-resistant enterococci, respectively. Three vancomycin-resistant E. faecalis isolates were detected, two with the vanA gene (into Tn1546) and one with the vanB2 gene (into Tn5382); these isolates showed different sequence types determined by multi-locus sequence typing (ST9, ST16 and a new ST848). Seven E. casseliflavus isolates harbouring the intrinsic vancomycin resistance mechanism vanC2 were obtained. The gelE, ace, agg, esp and hyl virulence genes were detected among vanA/vanB2 enterococci. This study provides insight into the possible role of wild birds in the spread of certain antimicrobial resistance genes, particularly vanA/vanB2. To the authors’ knowledge, this is the first report of vanB2-containing enterococci in Africa.

We propose a simple ecological index to monitor wetlands, based on interannual changes in waterbird numbers and the hydro-ecological characteristics of their wintering sites. This new method provides a simple tool applicable to most types of wetlands in northern Africa with comparable waterbird species and hydrological attributes. Scores of this ecological index are calculated through a four-steps approach: (1) discriminate prospected sites into different associations based on their hydro-ecological characteristics; (2) compute indicator values for each waterbird species considered to quantify the strength of species-habitat relationships in each wetland associations; (3) calculate the relative rate of temporal change in indicator species abundances between two sampling events (in our example 2001-2013 and 1970/2000); (4) compute the weighted sum across species of the product of these two metrics within a given wetlands association. The application of our index to the monitoring of Tunisian wetlands suggests the degradation of wintering lagoons and salt pans and coastal environments. Nevertheless, applying the index in floodplains and garaets tends to indicate improved overwintering conditions, especially for man-tolerant waterbird species. Our new index targets environmental stakeholders seeking for an efficient tool for biodiversity monitoring.

Waterbirds as an ecological indicator for monitoring wetlands : an application to Tunisia. We propose a simple ecological index to monitor wetlands, based on interannual changes in waterbird numbers and the hydro-ecological characteristics of their wintering sites. This new method provides a simple tool applicable to most types of wetlands in northern Africa with comparable waterbird species and hydrological attributes. Scores of this ecological index are calculated through a four-steps approach : (1) discriminate prospected sites into different associations based on their hydro-ecological characteristics ; (2) compute indicator values for each waterbird species considered to quantify the strength of species-habitat relationships in each wetland associations ; (3) calculate the relative rate of temporal change in indicator species abundances between two sampling events (in our example 2001-2013 and 1970/ 2000) ; (4) compute the weighted sum across species of the product of these two metrics within a given wetlands association. The application of our index to the monitoring of Tunisian wetlands suggests the degradation of wintering lagoons and salt pans and coastal environments. Nevertheless, applying the index in floodplains and garaets tends to indicate improved overwintering conditions, especially for man-tolerant waterbird species. Our new index targets environmental stakeholders seeking for an efficient tool for biodiversity monitoring.

This field survey was carried out to understand whether the organization of waterbird communities differed between both wetland types such as natural and artificial ones. We counted yearly from 2001/2002 to 2010/2013 in Northern Tunisia all wintering species occurred at 28 natural sites and 20 artificial ones. For each waterbird group we considered the mean values of four ecological parameters such as species richness, abundance, density and Shannon diversity. Our results clearly showed that waterbirds globally preferred natural sites. Indeed, from a mean of about 200.500 birds per year and a total of 95 species, of about 183.000 birds per year and 94 species were counted at natural wetlands. Thirty five species exclusively used natural wetlands, whereas only one species used exclusively artificial ones. Shannon diversity and species richness values of different waterbird groups were significantly higher in natural wetlands. Based on densities, mean values calculated for ducks and coots, and diving birds were significantly higher in artificial wetlands, whereas, for shorebirds and gulls, and herons mean values were significantly higher in natural wetlands. Globally, wetland variables determining the distribution of waterbird groups differed within both wetland types. In Fact, the Multiple Regression Analysis identified surface area as an important independent variable that controlled positively mean densities of ducks and coots, and diving birds within natural wetlands and controlled negatively their mean densities within artificial ones. Our results were rather striking for Northern Tunisia and they may not be applicable to other regions where there are available differences in surface areas. This field survey is of fundamental biological interest and is essential to the development of a conservation program and future researches.

Ecological diagnosis of the Ichkeul National Park (Tunisia) after dams building : the case of waterbirds. The Ichkeul National Park (INP) has been ratified as a National Park (1980), a Biosphere Reserve under UNESCO's Man and the Biosphere Program (1977), and a Wetland of International Importance under the Ramsar Convention (1980), and subsequently has been inscribed on the World Heritage List (1980). However, this area is actually threatened by three dams which can retain up to 75 % of the inflow freshwater. According to this situation, fundamental modifications of different components of the INP were recognized. The modification of the hydrological parameters and the response of waterbird community to dam building have been specifically assessed in the present paper. Across 2001-2004, the salinity of the lake ranged from an average of 21 g l(-1) in winter to 37 g l(-1) in summer with an annual average of 27 g l(-1). This latest value was more than two times that recorded before the dams were built. Thus, the densities of Potamogeton and Scirpus populations were dramatically decreased, reducing the available food of herbivorous waterbirds, notably ducks and coots. They were restricted each year to within the mouths of rivers and covered a small area in September before disappearing by the end of October and November. Concerning waterbird communities, a total of 71 species were counted. The commonest species that accounted for more than 54 % of the total abundance of the waterbird communities were : Common Coot (21 %), Common Pochard (16 %), Eurasian Wigeon (12 %) and Greater Flamingo (5 %). The most abundant trophic groups were herbivores (11 species and 75 V. of the total abundance of waterbird communities), filterers (3 species and 5 %), vertebrate consumers (14 species and 3 %) and insectivores (26 species and 9 %). Subordinate ones were invertebrates-vertebrates consumers (8 species and 1 %), invertebrates-herbivores (6 species and 5 %) and omnivores (3 species and 2 %). The total species richness varied significantly among months. It ranged from 39 to 41 species, between November and December, and the minimum from 12 to 14 species, during June and July. Species abundance also varied significantly between months with a peak during November and December of about 50 000 individuals. The lowest species abundance values were recorded in July and August with an abundance of about 1500 to 3000 individuals. The INP constitutes a very important area during the autumn migration and wintering periods and provides a habitat for a large range of groups of wintering., waterbirds, notably herbivorous species. Thus, the competition for resources may be higher in winter than in summer. The total number of species is still decreasing from 93 species (1966-1985) and 90 species (1982-1994) to 71 species in 2001-2004. This variation is most likely dependent on the variation of the number of sporadic species visiting the site than due to the local conditions. The annual density of all waterbird communities decreased dramatically of about 40% after the building of dams. This condition was mainly caused by the decreasing number of herbivores. Indeed, they presented the lowest peak abundance estimations obtained since the beginning of waterbird counts in the park. There were about 120 000 birds in 1963-1983, 90 000 birds in 1984-1992, 121 000 birds in 1993-1994, but 60 000 in the present assessment. We support the hypothesis that freshwater diversion and increasing salinity caused severe depletion of Potamogeton and Scirpus, ad therefore, a worrying reality of the feeding condition for this trophic group. Furthermore, the intensive pressure of feeding exercised by the herbivorous species on wetland production has been identified as having a negative local effect on the Potamogeton population dynamics mainly when the productivity of the Ichkeul National Park was low. From those results, it is suggested that dams built upstream of the Ichkeul National Park caused significant changes to the abundance of waterbird community.

This article aims at studying wintering waterbirds in Tunisian coastal lagoons in order to support effective conservation measures. Species number and abundance of wintering waterbirds were assessed in January, each year from 2002 to 2007, in 10 lagoon sites belonging to four different lagoon systems. We counted 76 species and on average more than 120,000 birds per year, which represented more than 25% of the national population sizes. The most abundant taxonomic groups were waterfowls and waders, which also represented the highest species number. In general, the six most abundant bird species comprised collectively more than 77% of all birds counted. Considering all the studied lagoon systems collectively, for 13 species the lagoon systems should be considered as of international importance according the Ramsar Convention as they support regularly more than 1% of the populations. Only the lagoon system of the North held regularly more than 20,000 birds. The species abundances and species richness varied significantly among year and among lagoon systems. Based on our results we proposed priority conservation measures, these ecosystems being of major importance for wintering birds, at both national and international level.

Ecological diagnosis of the Ichkeul National Park (Tunisia) after dams building : the case of waterbirds. The Ichkeul National Park (INP) has been ratified as a National Park (1980), a Biosphere Reserve under UNESCO’s Man and the Biosphere Program (1977), and a Wetland of International Importance under the Ramsar Convention (1980), and subsequently has been inscribed on the World Heritage List (1980). However, this area is actually threatened by three dams which can retain up to 75 % of the inflow freshwater. According to this situation, fundamental modifications of different components of the INP were recognized. The modification of the hydrological parameters and the response of waterbird community to dam building have been specifically assessed in the present paper. Across 2001– 2004, the salinity of the lake ranged from an average of 21 g l−1 in winter to 37 g l−1 in summer with an annual average of 27 g l−1. This latest value was more than two times that recorded before the dams were built. Thus, the densities of Potamogeton and Scirpus populations were dramatically decreased, reducing the available food of herbivorous waterbirds, notably ducks and coots. They were restricted each year to within the mouths of rivers and covered a small area in September before disappearing by the end of October and November. Concerning waterbird communities, a total of 71 species were counted. The commonest species that accounted for more than 54 % of the total abundance of the waterbird communities were : Common Coot (21 %), Common Pochard (16 %), Eurasian Wigeon (12 %) and Greater Flamingo (5 %). The most abundant trophic groups were herbivores (11 species and 75 % of the total abundance of waterbird communities), filterers (3 species and 5 %), vertebrate consumers (14 species and 3 %) and insectivores (26 species and 9 %). Subordinate ones were invertebrates-vertebrates consumers (8 species and 1 %), invertebratesherbivores (6 species and 5 %) and omnivores (3 species and 2 %). The total species richness varied significantly among months. It ranged from 39 to 41 species, between November and December, and the minimum from 12 to 14 species, during June and July. Species abundance also varied significantly between months with a peak during November and December of about 50 000 individuals. The lowest species abundance values were recorded in July and August with an abundance of about 1500 to 3000 individuals. The INP constitutes a very important area during the autumn migration and wintering periods and provides a habitat for a large range of groups of wintering waterbirds, notably herbivorous species. Thus, the competition for resources may be higher in winter than in summer. The total number of species is still decreasing from 93 species (1966-1985) and 90 species (1982-1994) to 71 species in 2001-2004. This variation is most likely dependent on the variation of the number of sporadic species visiting the site than due to the local conditions. The annual density of all waterbird communities decreased dramatically of about 40 % after the building of dams. This condition was mainly caused by the decreasing number of herbivores. Indeed, they presented the lowest peak abundance estimations obtained since the beginning of waterbird counts in the park. There were about 120 000 birds in 1963-1983, 90 000 birds in 1984-1992, 121 000 birds in 1993-1994, but 60 000 in the present assessment. We support the hypothesis that freshwater diversion and increasing salinity caused severe depletion of Potamogeton and Scirpus, and therefore, a worrying reality of the feeding condition for this trophic group. Furthermore, the intensive pressure of feeding exercised by the herbivorous species on wetland production has been identified as having a negative local effect on the Potamogeton population dynamics mainly when the productivity of the Ichkeul National Park was low. From those results, it is suggested that dams built upstream of the Ichkeul National Park caused significant changes to the abundance of waterbird community.

Estimating the total number of wintering waterbirds in Tunisia : period 2001/2002 to 2006/2007 Over the past decades, many waterbird populations have undergone rapid changes in numbers as well as in distribution. These continuing changes make it necessary to update population estimates on a regular basis. From this point of view, a regular mid-winter survey of wintering waterbirds was carried out in Tunisian wetlands. The overall objective of this paper is to record wintering population sizes for the period 2001–2002 to 2006-2007 and to identify waterbird indicator species relative to these Tunisian ecosystems. The preliminary analysis of the collected information enabled us to define the size and the actual status of wintering waterbird populations in Tunisia. A total richness of 106 species (3 common, 18 frequent and 85 rare ones), belonging to 23 families and 10 orders, was identified. The most abundant species, which accounted for about 90 % of the total abundance, were : Calidris alpina (18.7 %), Phoenicopterus ruber (13.6 %), Aythya ferina (11.4 %), Fulica atra (10.7 %), Tringa totanus (5.9 %), Larus michahellis (5.2 %), Larus genei (3.9 %), Anas penelope (3.7 %), Calidris minuta (3.5 %), Anas clypeata (2.2 %), Larus ridibundus (2.0 %), Charadrius alexandrinus (1.9 %), Phalacrocorax carbo (1.6 %), Vanellus vanellus (1.4 %), Pluvialis squatarola (1.3 %), Anas platyrhynchos (1.3 %), Anas crecca (1.3 %) and Numenius arquata (1.1 %). With an average of about 427 300 birds per year, Tunisian wetland areas play an important role in waterbird populations conservation due to their large habitats, high productivity and geographical position connecting European and African continents. Considering the Ramsar Criterions, a total of 20 sites appear as internationally important. Indeed, 3 sites individually and regularly held more than 20 000 birds and should be classified as internationally important : Kneiss islands (72 368 birds per year), Ichkeul National Park (91 587 birds per year), and sebkhat Sejoumi (29 276 birds per year). Together, these wetlands host about 45 % of the total national population sizes. Three other sites are also potentially important, recorded as hosting more than 20 000 wintering birds at least once : Kerkennah islands (16 608 birds per year), Jerba island (14 962 birds per year) and sebkhat Ariana (19 122 birds per year). The 1 % threshold for use in Ramsar Convention was met for 14 species (Sterna sandvicensis, Larus genei, Platalea leucorodia, Grus grus, Charadrius alexandrinus, Phoenicopterus ruber roseus, Pluvialis squatarola, Calidris minuta, Calidris alpina, Tringa totanus, Anser anser, Anas penelope, Aythya ferina and Fulica atra) and was exceeded in 10 wetlands. Among all species, 6 are globally threatened (Marmaronetta angustirostris, Aythya nyroca, Oxyura leucocephala, Gallinago media, Limosa lapponica and Larus audouinii) and were regularly observed in 10 sites. Application of the global ANOVA Kurskal-Wallis test to data relative to species richness, mean abundance and Hill (N1 and N2) diversity values reveals highly significant differences between the 8 wetland classes. However, the spatial organization of aquatic birds doesn’t reflect any clear gradient. The ANOSYM test discriminates two major associations : artificial versus natural habitats. The latter are themselves organized into 3 sub-associations according to permanence of water and marine influences. Despite these important carrying capacities of Tunisian wetlands, natural factors and human exploitation have greatly modified many of these ecosystems through habitat loss and fragmentation. Thus, it appears essential to use appropriate strategies, like indicator species method, to enhance the value of these areas for waterbird species, which are very sensitive to habitat changes. In the present case, based on the SIMPER analyses method, 15 species are indicators of the wetland status : Phoenicopterus ruber, Charadrius alexandrinus, Calidris alpina, Larus michahellis, Ardea cinerea, Bubulcus ibis, Ciconia ciconia, Vanellus vanellus, Grus grus, Phalacrocorax carbo, Larus genei, Fulica atra, Tachybaptus ruficollis, Aythya ferina, Podiceps cristatus and Anas platyrhynchos. Besides their fundamental interest and importance, results of the present study can be essential to the application of conservation programs.

Estimating the total number of wintering waterbirds in Tunisia: period 2001/2002 to 2006/2007. - Over the past decades, many waterbird populations have undergone rapid changes in numbers as well as in distribution. These continuing changes make it necessary to update population estimates on a regular basis. From this point of view, a regular mid-winter survey of wintering waterbirds was carried out in Tunisian wetlands. The overall objective of this paper is to record wintering population sizes for the period 2001-2002 to 2006-2007 and to identify waterbird indicator species relative to these Tunisian ecosystems. The preliminary analysis of the collected information enabled us to define the size and the actual status of wintering waterbird populations in Tunisia. A total richness of 106 species (3 common, 18 frequent and 85 rare ones), belonging to 23 families and 10 orders, was identified. The most abundant species, which accounted for about 90 % of the total abundance, were : Calidris alpina (18.7 %), Phoenicopterus ruber (13.6 %), Aythya ferina (11.4 %), Fulica atra (10.7 %), Tringa totanus (5.9 %), Larus michahellis (5.2 %), Larus genei (3.9 %),Anas penelope (3.7 %), Calidris minuta (3.5 %), Anus clypeata (2.2 %), Larus ridibundus (2.0 %), Charadrius alexandrinus (1.9 %), Phalacrocorax carbo (1.6 %), Vanellus vanellus (1.4 %), Pluvialis squatarola (1.3 %), Anas platyrhynchos (1.3 %), Anas crecca (1.3 %) and Numenius arquata (1.1 %). With an average of about 427 300 birds per year, Tunisian wetland areas play an important role in waterbird populations conservation due to their large habitats, high productivity and geographical position connecting European and African continents. Considering the Ramsar Criterions, a total of 20 sites appear as internationally important. Indeed, 3 sites individually and regularly held more than 20 000 birds and should be classified as internationally important : Kneiss islands (72 368 birds per year), Ichkeul National Park (91 587 birds per year), and sebkhat Sejoumi (29 276 birds per year). Together, these wetlands host about 45 % of the total national population sizes. Three other sites are also potentially important, recorded as hosting more than 20 000 wintering birds at least once : Kerkennah islands (16 608 birds per year), Jerba island (14 962 birds per year) and sebkhat Ariana (19 122 birds per year). The 1 % threshold for use in Ramsar Convention was met for 14 species (Sterna sandvicensis, Lams genei, Platalea leucorodia, Grus grits, Charadrius alexandrinus, Phoenicopterus ruber roseus, squatarola, Calidris minuta, Calidris Tringa totanus, Anser anser, Anas penelope, Aythya ferina and Fulica atra) and was exceeded in 10 wetlands. Among all species, 6 are globally threatened (Marmaronetta angustirostris, Aythya nyroca, Ottawa leucocephala, Gallinago media, Limosa lapponica and Larus audouinii) and were regularly observed in 10 sites. Application of the global ANOVA Kurskal-Wallis test to data relative to species richness, mean abundance and Hill (NI and N2) diversity values reveals highly significant differences between the 8 wetland classes. However, the spatial organization of aquatic birds doesn't reflect any clear gradient. The ANOSYM test discriminates two major associations : artificial versus natural habitats. The latter are themselves organized into 3 sub-associations according to permanence of water and marine influences. Despite these important carrying capacities of Tunisian wetlands, natural factors and human exploitation have greatly modified many of these ecosystems through habtat loss and fragmentation. Thus, it appears essential to use appropriate strategies, like indicator species method, to enhance the value of these areas for waterbird species, which are very sensitive to habitat changes. In the present case, based on the SIMPER analyses method, 15 species are indicators of the wetland status : Phoenicopterus ruber, Charadrius alexandrinus, Calidris alpina, Larus michahellis, Ardea cinerea, Bubulcus ibis, Ciconia ciconia, Vanellus vanellus, Grus grits, Phalacrocorax carbo, Lams genei, Fulica atra, Tachybaptus ruficollis, Aythya ferina, Podiceps cristatus and Anas platyrhynchos. Besides their fundamental interest and importance, results of the present study can be essential to the application of conservation programs.