Spatial variation of mercury contamination in yellow-legged gulls (Larus michahellis) in the Western Mediterranean.

Mercury (Hg) is a global pollutant of major concern in marine and coastal environments. In the Mediterranean Sea, Hg concentrations in biota are higher than in other seas, even when seawater concentrations are similar. Seabirds, as marine top predators, can reflect Hg contamination on a large spatial scale.

Among-colony variation in plastic ingestion by Yellow-legged gulls (Larus michahellis) across the western Mediterranean basin.

The Mediterranean region is both a hotspot for biodiversity and for the accumulation of plastic pollution. Many species are exposed to this pollution while feeding, including a wide diversity of seabirds. Our objective was to investigate spatial variation in the quantity and types of plastic ingested by Yellow-legged gulls using information obtained from regurgitated pellets collected in 11 colonies.

Long-term Exposure to Industrial Chemical Contamination Affects the Magnitude of Predator-induced Immunosuppression in a Free-living Passerine.

Industrial chemical contamination is known to have immuno-toxic effects on birds. It may also interfere with natural stressful conditions to further disrupt the immune responses, but these possible interactive effects are still poorly documented in free-living birds. Using the phytohaemagglutinin skin-swelling test, we assessed how the T-cell mediated immune response varied according to the perceived risk of predation in hybrid sparrows, Passer domesticus × Passer hispaniolensis, originating from two sites differentially impacted by industrial chemical contamination, in southern Tunisia.

Experimental evidence of increased carcass removal along roads by facultative scavengers.

Investigating the spatial response of scavenging behaviors to roads may help in understanding the relevance of this overlooked ecosystem service. Roads can provide suitable foraging sites for scavengers, whether they are obligate or facultative. However, only a few studies have investigated the impact of roads on the spatial distribution of scavenging behavior, and most of them focused on areas inhabited by species-rich communities of obligate scavengers.

Behavioral fever in Bosk's fringe-toed lizards (Acanthodactylus boskianus) living in an industrial area in south-eastern Tunisia.

As an indicator of physiological state of lizards, thermoregulatory behavior has been proposed as an assessment tool of environmental contamination, particularly in desert ecosystems where lizards represent a major biological component. Although pesticide contamination has been shown to induce behavioral fever in lizards, the possible pyrogenic effect of heavy metals has received less attention. The objective of this study was to provide data on this issue by using Bosk's fringe-toed lizards (Acanthodactylus boskianus) living in a metal-contaminated industrial area in south-eastern Tunisia as a study model.

Prioritizing the provision of urban ecosystem services in deprived areas, a question of environmental justice.

The distribution of urban ecosystem services (UES) is often uneven across socioeconomic groups, leading to environmental justice issues. Understanding the distribution of UES across a landscape can help managers ensure an equitable distribution of services. While many past studies have focused on the distribution of green spaces in relation to socioeconomic variables, this research analyzes the distribution of UES provided by these green spaces.

Decreased Cell-Mediated Immune Response in Bosk's Fringe-Toed Lizards (Acanthodactylus boskianus) Inhabiting an Industrialized Area in Southern Tunisia.

Lizards increasingly are recognized as suitable contaminant biomonitors in terrestrial ecosystems. Previously, we have shown that Bosk's fringe-toed lizards (Acanthodactylus boskianus) living close to the Gabès-Ghannouche industrial complex for fertilizer and acid production in southern Tunisia were contaminated by heavy metals. However, the impact of this contamination on lizard health parameters has not been investigated.

Flaviviruses in migratory passerines during spring stopover in a desert oasis.

Bird migration has long been hypothesized as the main mechanism for long-distance dispersal of flaviviruses, but the role of migratory birds in flaviviruses spillover is not well documented. In this study, we investigated the eco-epidemiology of West Nile virus (WNV) and Usutu virus (USUV) in trans-Saharan passerines during their spring stopover in southern Tunisian oases. To do, we combined oral swab analysis and serological tools to assess whether migratory birds could be reaching these stopover sites while infectious or have been previously exposed to viruses.

Exposure of yellow-legged gulls to along the Western Mediterranean coasts: Tales from a sentinel.

Efficiently tracking and anticipating the dynamics of infectious agents in wild populations requires the gathering of large numbers of samples, if possible at several locations and points in time, which can be a challenge for some species. Testing for the presence of specific maternal antibodies in egg yolks sampled on the colonies could represent an efficient way to quantify the exposure of breeding females to infectious agents, particularly when using an abundant and widespread species, such as the yellow-legged gull (). We used such an approach to explore spatio-temporal patterns of exposure to , a pathogenic protozoan responsible of toxoplasmosis in humans and other warm-blooded vertebrates.

Diversity, prevalence and host specificity of avian parasites in southern Tunisian oases.

Oases are semi-natural woodlots surrounded by an inhospitable desert environment. This insular-like habitat system is known to support a mixture of sedentary and migratory bird species originating from different areas. However, little is known about the interactions between these birds and parasites.

Reproductive effects in hybrid sparrow from a polluted area in Tunisia: Oxidative damage and altered testicular histomorphology.

Air pollution is a threat for human health and wildlife. The aim of this study is to assess the pathophysiological changes and the oxidative-antioxidative status in testicular tissues of 40 Hybrid sparrows collected from four areas in Gabès city, one of the most polluted areas in Tunisia. The testis histopathological analysis revealed alterations in birds from Ghannouche, the polluted area.

Heavy metal accumulation in lizards living near a phosphate treatment plant: possible transfer of contaminants from aquatic to terrestrial food webs.

We investigated the accumulation of heavy metals in Bosk's fringe-toed lizards (Acanthodactylus boskianus) living in Gabès region (southeastern Tunisia), in relation to habitat, diet, and distance from the Gabès-Ghannouche factory complex of phosphate treatment. More specifically, we compared the concentrations of cadmium, lead, and zinc in the stomach contents and samples of the liver, kidney, and tail from lizards living in four sites corresponding to different combinations of habitat (coastal dunes vs backshore) and distance from the factory complex (<500 vs 20 km). Examination of stomach contents showed that lizards living on the coastal dunes mainly feed on littoral amphipods, while those living in the backshore feed exclusively on terrestrial invertebrates.

Condition and Health of Rufous Bush Robin (Cercotrichas galactotes) Nestlings in a Polluted Oasis Habitat in Southern Tunisia.

We investigated whether the proximity to the Gabès-Ghannouche factory complex of phosphate treatment, in south-eastern Tunisia, was associated with notable changes in the condition and health of Rufous bush robin (Cercotrichas galactotes) nestlings hatched in the neighbouring oasis habitat. Results demonstrated that excrements of nestlings hatched in one oasis close to the factory complex contained higher concentrations of lead and zinc than the excrements of nestlings from one oasis situated 20 km away. Furthermore, when effects of age and nestling number in the nest were controlled, nestlings hatched near the factory complex showed reduced tarsus length, rectrix length, haematocrit level and haemoglobin concentration, but higher levels of fluctuating asymmetry compared to those from the more distant oasis.

Egg sampling as a possible alternative to blood sampling when monitoring the exposure of yellow-legged gulls (Larus michahellis) to avian influenza viruses.

We explored whether antibody detection in egg yolks could serve as an alternative to antibody detection in plasma samples when monitoring yellow-legged gulls (Larus michahellis) for exposure to avian influenza viruses (AIVs). We tested female plasma and eggs for anti-AIV antibodies and used the data we obtained to check whether the two sample types yielded the same antibody status (positive or negative) and to compare the antibody prevalence estimated from the blood data with that estimated from the yolk data. Our results showed that sampling one egg per clutch, regardless of that egg's position in the laying sequence, is sufficient to provide an unbiased estimate of antibody prevalence across clutches.

Circulation of a Meaban-like virus in yellow-legged gulls and seabird ticks in the western Mediterranean basin.

In recent years, a number of zoonotic flaviviruses have emerged worldwide, and wild birds serve as their major reservoirs. Epidemiological surveys of bird populations at various geographical scales can clarify key aspects of the eco-epidemiology of these viruses. In this study, we aimed at exploring the presence of flaviviruses in the western Mediterranean by sampling breeding populations of the yellow-legged gull (Larus michahellis), a widely distributed, anthropophilic, and abundant seabird species.

Maternal antibody transmission in relation to mother fluctuating asymmetry in a long-lived colonial seabird: the yellow-legged gull Larus michahellis.

Female birds transfer antibodies to their offspring via the egg yolk, thus possibly providing passive immunity against infectious diseases to which hatchlings may be exposed, thereby affecting their fitness. It is nonetheless unclear whether the amount of maternal antibodies transmitted into egg yolks varies with female quality and egg laying order. In this paper, we investigated the transfer of maternal antibodies against type A influenza viruses (anti-AIV antibodies) by a long-lived colonial seabird, the yellow-legged gull (Larus michahellis), in relation to fluctuating asymmetry in females, i.

Breeding performance of passerines in a polluted oasis habitat in southern Tunisia.

We investigated the breeding performance of passerines nesting in the oases close to Gabès city, one of the most industrialised areas in Tunisia, in relation to habitat pollution. Using data on nest survival, clutch size and chick productivity of four insectivorous passerine species, we assessed whether the proximity to Gabès-Ghannouche factory complex of phosphate treatment was associated with reduced breeding performance. Our results show evidence of decreased breeding performance near the factory complex, but this decrease was more perceptible when comparing one oasis situated at the vicinity of the factory complex (polluted oasis) with one control oasis situated tens of kilometres faraway, than when comparing sites situated hundreds of metres apart within the polluted oasis.

Prevalence of influenza A antibodies in yellow-legged gull (Larus michahellis) eggs and adults in southern Tunisia.

Investigating the prevalence of anti-influenza A viruses (AIV) antibodies in wild birds can provide important information for the understanding of bird exposure to AIV, as well as for prevention purposes. We investigated AIV exposure in nature by measuring the prevalence of anti-AIV antibodies in the nests and adults of an abundant and anthropophilic waterbird species common around the Mediterranean sea, the yellow-legged gull (Larus michahellis). Sampling took place in two colonies located in the gulf of Gabès in southern Tunisia: Sfax and Djerba.

Distribution-abundance relationship for passerines breeding in Tunisian oases: test of the sampling hypothesis.

The positive relationship between local abundance and distribution of species is a widely recognized pattern in community ecology. However, it has been suggested that this relationship can simply be an artefact of sampling because locally rare species are less detectable then locally abundant ones, and hence their distribution can easily be underestimated. Here, we use count data to investigate the relationship between distribution and abundance of passerines breeding in a sample of oases from southern Tunisia, and we provide a test of the sampling artefact hypothesis.