Biodiversity of Amphipoda Talitridae in Tunisian Wetlands

Although wetlands were remarkable habitats with their fauna and flora diversity, few studies have been devoted to the study of amphipod biodiversity in this ecosystem type. The amphipod communities of six wetland types belonging to 117 stations were studied with respect to species composition, abundance and their relationship with environmental parameters. Amphipods were collected during spring. At each station, eight quadrats of 50 × 50 cm2 were randomly placed. Animals were preserved in alcohol at 70°C. In the laboratory, the specimens collected were identified and counted. Physicochemical parameters (organic matter, particle size, heavy metals) of sampled soils were determined. The results showed that the highest species richness was observed in lagoons with the presence of eight species namely Orchestia montagui, Orchestia gammarellus, Orchestia mediterranea, Orchestia stephenseni, Orchestia cavimana, Platorchestia platensis, Deshayesorchestia deshayesii and Talitrus saltator, whereas in the hill lakes and dams banks, no specimens were collected. The biodiversity of amphipod species depends on climatic (temperature, humidity) and edaphic (organic matter, particle size, heavy metals) factors

Bioaccumulation of heavy metals in the terrestrial isopod Porcellionides pruinosus in the vicinity of Gabes-Ghannouch industrial complex

ACLThe current study reports the effects of heavy metals issued from the emissions of phosphate and their bioaccumulation in the soils, leaf litter, and the terrestrial isopod Porcellionides pruinosus in the vicinity of Gabes-Ghannouch industrial complex. Cd, Pb, Zn, and Cu concentrations were measured in soils, leaf litter, and P. pruinosus individuals, collected from four stations located at different distances from the factory. Results showed that heavy metal concentrations in soils varied from one site to another and did not reflect those measured in individuals. In contrast, a positive correlation was found between the isopods’ body length and the distance from the pollution source, revealing the isopod sensitivity to the soil metal concentrations. The bioaccumulation factor was calculated using soil and leaf litter as a solid support with the aim of ordering the metal accumulation in P. pruinosus for each site. Overall, P. pruinosus could be defined as a macroconcentrator of Cd, Zn, and Cu (BAF>2) and as a deconcentrator of Pb (BAF<1)

Effects of Heavy Metals Artificial Contamination on Porcellio laevis (Latreille, 1804) (Crustacea: Isopoda: Oniscidea)

ACLThis study aimed at determining the competition of cadmium (Cd), lead (Pb), zinc (Zn) and copper (Cu) on their assimilation, on the food consumption and the growth of terrestrial isopod Porcellio laevis. Individuals were exposed to artificially contaminated litter of Quercus for 4 weeks and were weekly weighed. At the end of the experiment, the concentration of Cd, Pb, Zn and Cu in individuals were measured by atomic absorption spectrometry. Biological parameters such as growth, and bioaccumulation factor (BAF) were calculated and results from the various treatments were compared. Depending on metals, weight loss or gain were recorded for isopods during the four weeks of exposure. A weight loss was measured on individuals exposed to Cd-contaminated litter whereas a weight gain was highlighted for those exposed to the Zn-contaminated litter. BAF values revealed that P. laevis was macroconcentrator of Zn and Cu and deconcentrator of Cd and P

Measure of environmental stress on Porcellio laevis Latreille, 1804 sampled near active Tunisian industrial areas

ACLThis 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

Zoological Studies / Biodiversity of Talitridae family (Crustacea, Amphipoda) in some Tunisian coastal lagoons

Background Although wetlands were remarkable habitats with their fauna and flora diversity, few studies have been devoted to the study of amphipod distribution in this type of environment. To study both qualitatively and quantitatively amphipod community, surveys were conducted during the spring season in ten coastal lagoons ranging from subhumid to arid bioclimatic stage. At each station, eight quadrats of 5050 cm were randomly placed. Amphipods were preserved in alcohol 70C. In the laboratory, the specimens collected were identified and counted. Meanwhile, analyses of organic matter, particle size, and heavy metals from the soil taken from each station were made. Results A total of 1,340 specimens of amphipods were collected, and eight species belonging to Talitridae family were identified. Species richness ranges from one species collected in the supralittoral zone of El Bcherliya (Ghar El Melh lagoon) and eight species in the supralittoral zone of Bizerte lagoon. In this last station, the relative abundance of amphipods was significantly higher (36.04%, N=483). In addition, the diversity indices of Simpson, Shannon-Weaver, and equitability shows that the highest species diversity characterizes this same station while the community was more balanced in opposite El Boughaz (Ghar El Melh lagoon) (J″=0.996). Conclusions The spatial distribution of different amphipod species depends on edaphic (heavy metals, granulometry, organic matter) and climatic (temperature, humidity) factors.(VLID)242534

Temporal and spatial distribution of dorcas and slender‐horned gazelles in a Saharan habitat

Saharan ungulates have suffered from poaching across their range leading to population declines. Low abundance and habitat inaccessibility have limited the availability of empirical data on desert ungulate ecology in the wild. Our objective was to evaluate temporal and spatial distribution, and home-range sizes of wild dorcas gazelles (Gazella dorcas) and slender-horned gazelles (Gazella leptoceros) under natural conditions using observations from 14,398 camera-days collected between April 2019 and October 2021 in the 7,700-ha fenced area of Jbil National Park (Jbil NP), Tunisia. We individually identified gazelles in Jbil NP using unique horn morphology. Both gazelle species exhibited nocturnal activity patterns in summer, but diurnal activity patterns dominated in winter. We also detected both species more frequently in the plains than in mountains. Water presence was influential in determining distribution only for dorcas gazelles. Minimum convex polygons (MCPs) were 2,062 ha for both the male and female of the most frequently detected dorcas gazelle pair and 1,527 ha for another solitary male. For slender-horned gazelles, MCPs were 2,280 ha and 2,041 ha, respectively, for a male and a female detected in Jbil NP. The decline and rarity of gazelles in the Sahara Desert have limited the sample size of our observed populations. Our study provides hitherto unknown data on wild populations of rapidly declining gazelle species and contributes to ongoing conservation efforts.</p

Heavy Metals Assessment and Their Effects on the Hepatopancreas in Orchestia montagui (Amphipoda, Talitridae)

International audienc

Ecotoxicological effects of trace element contamination in talitrid amphipod Orchestia montagui Audouin, 1826

International audienc