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This study aims to determine the relationships likely to exist between the edaphic variables and the abundance of oak species in the Edough forest of the commune of Seraidi (North East of Algeria), a humid bioclimatic stage where rainfall is abundant. In order to characterize the properties of the soils of the Edough forest (Seraidi) and to verify the usefulness of the fractionation of organic matter in a forest ecosystem, we have established a prospecting sampling plan based on a topographic background of the superposition of the different plant groups. In this context, the approach we adopted consisted on three main steps (i) a stratified sampling of the soil, (ii) the determination of the different strata of vegetation, (iii) describing the soil on which these plant formations settle and develop. Our results revealed that the soils of the Edough forest are acidic to very acidic and non-saline. It is also characterized by clayey texture that is not very permeable, with a high rate of organic matter, which controls the buffering capacity of the soil. The characterization of the soils allowed determining three types of plant formations and thus three types of soils where pedogenesis is under direct control of the supply of organic matter. The relationship between the soil and the vegetation in this forest is clearly close. It is mainly controlled by the supply of organic matter, which shows a significant dynamic and evolution. On the other hand, the climatic conditions and the type of plant formations have a capital role in the mineralization of the existing organic matter.

To study the vegetation cover of a given region, we often call for the study of pollen rain. This method allows the inventory of vegetation to be carried out during a given period. The objective of this study is to design the plant inventory of a site in the city of Annaba, the Christian Cemetery, based on pollen analysis. The Cemetery is a favorable place, par excellence, for the development of foam pads. These are excellent sensors for pollen and spore diversity. The latter are well preserved in their leaves thanks to a suitable acidity and humidity. Four representative samples of the spatial variability of the cemetery's environment and flora were used. The results obtained show that the foam pads are, on the one hand, very developed and on the other hand very rich in pollen which are in perfect state of conservation. Pollen analysis has shown a great diversity in flora, in particular51 taxa belonging to 41 families, 28 tree species and 23 non-tree species. The pollen of Poaceae is the most dominant in the four samples, followed by the pollens of the species: Pinus sylvestris, Cupressus sempervirens, Quercu ssuber, Olea europeae and Myrica sp. The majority of the plant species existing in the plant cover of the site are manifested by the abundance of their pollens in the moss pads. The presence of "foreign" pollens has been noted in relation to different species which are not included in the cemetery's floristic inventory. The use of pollen analysis helps to define the relationships that exist between the plant inventory making up the plant cover and pollen rain. This approach to determining highly pollen-producing species in protected urban areas could be used as a predictive model, by the Ministry of Health, of periods conducive to allergies in humans. [ABSTRACT FROM AUTHOR]

Résumé: La gestion des déchets solides est l'un des problèmes les plus difficiles à gérer par les pays en développement qui souffrent de graves problèmes de pollution causés par la production de grandes quantités de déchets. En Algérie, la mise en décharge est considérée comme la filière principale d'élimination des déchets. Le pays compte plus de 3 200 décharges sauvages implantées à travers le territoire national. Les résultats obtenus ont montré que la majorité des déchets sont constitués de métaux et de plastiques (29 et 30 %). Ces derniers sont considérés comme sources majeures de pollution des sols et de l'eau, car ils peuvent être des générateurs de polluants persistants tels que les métaux lourds qui ont des conséquences néfastes pour l'environnement. Cependant, ces déchets peuvent être récupérés et valorisés. Les déchets organiques, textiles et papiers considérés comme biodégradables correspondant à plus de 27 % du poids de la composition des déchets, et présentent un fort potentiel de récupération. Les autres déchets (verre et déchets de construction) représentent de faibles portions considérées comme banales et peuvent être récupérés et réutilisés. De l'analyse de ces résultats, il ressort que la décharge de Kef Oum Teboul recèle un fort potentiel de récupération et recyclage, et ses dépotoirs, qui abritent une biodiversité riche et diversifiée, doivent être protégés. Solid waste management is a significant problem for developing countries. The large quantities of waste produced cause serious pollution. In Algeria, landfills are the main waste disposal sites, with more than 3,200 illicit dumps throughout the country. This study focuses on the Kef Oum Teboul landfill, in far northeastern Algeria. The objective of the study was to examine the impact of this dump on the receiving environment. We took 41 waste samples for qualitative and quantitative evaluation, then studied the physicochemical characteristics of the soils under the waste. The results show that most of the waste consisted of metals (29%) and plastics (30%). These are major sources of soil and water pollution because they can generate persistent pollutants such as heavy metals, which have adverse consequences for the environment. But these wastes can be recovered and recycled. Biodegradable organic waste, textile, and paper, with a high recovery potential, account for more than 27% of the composition of the waste by weight. Other waste (glass and construction waste) is found in small quantities that are considered harmless and can be recovered and reused. The analysis of these results indicates that the Kef Oum Teboul landfill has a high recovery and reuse potential and that these sites, with their rich and diversified biodiversity, should be protected. [ABSTRACT FROM AUTHOR]

Populations located at the rear-edge of a species’ distribution may have disproportionate ecological and evolutionary importance for biodiversity conservation in a changing global environment. Yet genetic studies of such populations remain rare. This study investigates the evolutionary history of North-African low latitude marginal populations of Alnus glutinosa Gaertn., a European tree species that plays a significant ecological role as a keystone of riparian ecosystems. We genotyped 551 adults from 19 populations located across North Africa at 12 microsatellite loci and applied a coalescent-based simulation approach to reconstruct the demographic and evolutionary history of these populations. Surprisingly, Moroccan trees were tetraploids demonstrating a strong distinctiveness of these populations within a species otherwise known as diploid. Best-fitting models of demographic reconstruction revealed the relict nature of Moroccan populations that were found to have withstood past climate change events and to be much older than Algerian and Tunisian populations. This study highlights the complex demographic history that can be encountered in rear-edge distribution margins that here consist of both old stable climate relict and more recent populations, distinctively diverse genetically both quantitatively and qualitatively. We emphasize the high evolutionary and conservation value of marginal rear-edge populations of a keystone riparian species in the context of on-going climate change in the Mediterranean region. [ABSTRACT FROM AUTHOR]

Abstract: The phytoecological study of the alder forests of north-east Algeria shows that these habitats with boreal affinities harbour very high species richness (>400 species) and complex structures, which suggest their ancient origin. They correspond phytosociologically to two syntaxa, the Campanulo alatae-Alnenion glutinosae (riparian alder forests) and the Rusco hypophylli-Alnetum glutinosae (peat-forming alder carrs), respectively. Their degraded state and their regressive dynamics, observed during the 14 years of the study, reveal their precarious situation and their rapid ongoing decline under the influence of human-induced uncontroled disturbances (cutting, burning, draining, dumping…). With regard to their ecological, historical and patrimonial importance, the alder forests of Algerian Numidia should be urgently protected, with the aim of assuring the perennity of their exceptional floristic corteges. [ABSTRACT FROM AUTHOR]

The study was aimed to assess the ecotoxicological impact of anthropogenic activities on soil quality by using the land snail Helix aspersa as a bioindicator. Soil samples and snails were collected from several sites of northeast Algeria during spring and winter, 2017. All sites were chosen in this study for the reason of their proximity to industrial factories as a potential source of heavy metal soil contamination. The concentration of heavy metals in soil samples was analyzed using the X-ray Fluorescence (XRF) spectrometer (Thermo Scientific Model Niton FXL 950) since the three metals of the highest levels in soil samples were examined in Helix aspersa hepatopancreas and feet by means of the atomic absorption spectrophotometry. Also, the highest levels of heavy metals were noticed during spring in Helix aspersa of the closest sites to the potential sources of pollution. These results are correlated with the physico-chemical characteristics of soil (texture, organic matter, pH Water, conductivity, limestone, and porosity) in each site. [ABSTRACT FROM AUTHOR]

Populations located at the rear-edge of a species’ distribution may have disproportionate ecological and evolutionary importance for biodiversity conservation in a changing global environment. Yet genetic studies of such populations remain rare. This study investigates the evolutionary history of North-African low latitude marginal populations of Alnus glutinosa Gaertn., a European tree species that plays a significant ecological role as a keystone of riparian ecosystems. We genotyped 551 adults from 19 populations located across North Africa at 12 microsatellite loci and applied a coalescent-based simulation approach to reconstruct the demographic and evolutionary history of these populations. Surprisingly, Moroccan trees were tetraploids demonstrating a strong distinctiveness of these populations within a species otherwise known as diploid. Best-fitting models of demographic reconstruction revealed the relict nature of Moroccan populations that were found to have withstood past climate change events and to be much older than Algerian and Tunisian populations. This study highlights the complex demographic history that can be encountered in rear-edge distribution margins that here consist of both old stable climate relict and more recent populations, distinctively diverse genetically both quantitatively and qualitatively. We emphasize the high evolutionary and conservation value of marginal rear-edge populations of a keystone riparian species in the context of on-going climate change in the Mediterranean region. [ABSTRACT FROM AUTHOR]

The phytoecological study of the alder forests of north-east Algeria shows that these habitats with boreal affinities harbour very high species richness (> 400 species) and complex structures, which suggest their ancient origin. They correspond phytosociologically to two syntaxa, the Campanulo alatae-Alnenion glutinosae (riparian alder forests) and the Rusco hypophylli-Alnetum glutinosae (peat-forming alder carrs), respectively. Their degraded state and their regressive dynamics, observed during the 14 years of the study, reveal their precarious situation and their rapid ongoing decline under the influence of human-induced uncontroled disturbances (cutting, burning, draining, dumping…). With regard to their ecological, historical and patrimonial importance, the alder forests of Algerian Numidia should be urgently protected, with the aim of assuring the perennity of their exceptional floristic corteges., (Copyright © 2010 Académie des sciences. Published by Elsevier SAS. All rights reserved.)

The study of two pollen sequences from El-Kala marshes allowed the reconstruction of the regional vegetation history supported by eight radiocarbon dates. Pollen assemblages from Bourdim site were dominated by local input of Alnus and Salix, while regional vegetation was characterized by scattered Quercus suber forests with a well-developed Erica arborea matorral. While the vegetation dynamics recorded at Bourdim is recent (Late Holocene), the majority of the pollen diagram from Garaat El-Ouez is contemporaneous to the Late Pleniglacial and is characterized by open woodlands with Pinus, Poaceae and several heliophilous herbs. The significant values of Cedrus pollen identified in this period indicate that the region of El-Kala most probably played the role of a refugium for this tree., (Copyright © 2010 Académie des sciences. Published by Elsevier SAS. All rights reserved.)