Browse

1 - 10 of 764 items :

  • Geosciences x
  • Life Sciences x
Clear All
The assessment of the physicochemical quality of water intended for irrigation of Oued Méskiana (Oum El Bouaghi) Algeria

Abstract

The aquatic ecosystem of the Meskiana Valley (wilaya of Oum El Bouaghi) covers a large area with a permanent flow and a semi-arid climate characterized by a strong evapotranspiration. In order to determine the Physico-chemical quality, pollution and salinity of the water of the river of Meskiana and more particularly in its downstream part which is exposed to wastewater discharges, analyses were carried out at the level of three sampling points: witness, the upstream (before spill), downstream (after spill)). In order to prevent the risk of alkalization and salinization of soil, the sodium absorption rate (SAR) and the percentage of sodium were determined and represented on the Wilcox and Riverside diagram. The high concentrations of polluting chemical elements and excessive salinity obtained at the downstream site show a high risk of pollution and salinization.

Open access
Biodiversity, Distribution and Ecology of Testate Amoebae (Arcellinida and Euglyphida) from the Bulgarian Black Sea Coast and the related brackish lakes. A Synthesis

Abstract

The studies on the marine and freshwater testate amoebae of the Bulgarian Black Sea littoral and some related coastal brackish lakes are briefly reviewed. So far, a total of 184 species and subspecies of testate amoebae from 18 families and 45 genera from orders of Arcellinida and Euglyphida were published in national and international journals. The underground waters of the Bulgarian marine sand supralittoral are better studied than the related continental lakes. A total of about 45 species of marine interstitial testate amoebae are known, so far, and a big part of them were for the first time described from the Black Sea littoral. It’s interesting to note the presence in the marine underground waters of the Black Sea littoral of many freshwater testate amoebae also, considered by us as eurybionts. That is due of the low and variable salinity of the littoral Black Sea waters during the year. The presence of some psammobiotic testate amoebae as Psammonobiotus lineare and Corythionella georgiana in some related brackish lakes is also of ecological interest. The general conclusion of the present synthesis is that the testate amoebae fauna of the Bulgarian Black Sea coast and the related with it many brackish and freshwater littoral lakes is few known yet and need more active researches.

Open access
Breeding Biology of Booted Eagle Hieraaetus Pennatus (Gmelin, Jf, 1788): The First Study in North Africa

Abstract

Knowledge and study of breeding birds’ biology is essential to understand the dynamic, assess productivity and identify threats. The population of booted eagles (Hieraaetus pennatus) was studied during three consecutive breeding seasons (2013−2015) in the Chettabah forest. Each year, arrivals of Booted eagles are recorded during March (15 individuals in 2013, 12 in 2014 and 11 in 2015). For the three years of study, the mean breeding pair’s density was 1.23 ± 0.153/km2, incubation period ranged from 33 to 38 days, whilst the frequency distribution of clutch size was 67.6% for 2 eggs, 27% for 1 and 5.4% for 3. Amongst the 63 eggs monitored, 55 hatched. No significant variation in hatching rate was observed during the 3 years (90% in 2013, 76.19% in 2014 and 84% in 2015). The comparison of breeding parameters with those reported in Spain showed a noticeable similarity. Further investigations should be conducted to improve the provision of information to support sound management interventions of this North African population.

Open access
Changes in Snowbed Vegetation in the Western Carpathians Under Changing Climatic Conditions and Land Use in the Last Decades

Abstract

Snowbed vegetation is one of the most sensitive alpine vegetation type to the climate change, because shortened period of snow cover has essential impact on the snowbed environment. We focus on its changes in the Western Tatras, which is a part of the Western Carpathians (Slovakia). The assessment of changes in snowbed vegetation is based on the method of pair comparison. In 2016–2018, we resampled 21 historical phytocoenological relevés of Festucion picturatae and Salicion herbaceae alliances from 1974 and 1976. Historical data include 45 species, while recent data include 50 species. We observed a decrease in the frequency of species characteristic for snowbeds and, on the other hand, an increase in that for strong competitors, especially grasses and small shrubs from adjacent habitats. According to Ellenberg’s ecological indices, there is some increase in temperature and decrease in light ecological factors in snowbed habitats. In S. herbaceae data, a statistically significant increase in the average species number was observed with new species that penetrated from the adjacent habitats. Changes in species composition between historical and recent data are confirmed by Non-metric multidimensional scaling (nMDS) ordination diagram. Linear mixed-effect models showed big variability in factors that have impact on phytodiversity; nevertheless, temperature is the most significant factor.

Open access
Chemical Composition of the Essential Oil of Aerial Parts of Thymus ciliatus (Desf.)

Abstract

The essential oil of the aerial parts of Thymus ciliatus (Desf.) belonging to the Lamiaceae family, was obtained by steam distillation and analyzed by GC-FID and GC-MS. 75 components were identified corresponding to 95.57% of the total oil. The major constituents of the oil were: elemol (6.80%), carvacrol (5.86%), γ-muurolene (5.18%), β-sesquiphellandrene (5.09%), bicyclogermacrene (5.04%), β-pinene (4.49%) and curcumene (4.20%), together with other compounds at relatively low levels: 1,8-cineol (3.66%), β-eudesmol (2.92%), β-bisabolene (2.81%), β-silinene (2.75%), camphor (2.64%), germacrone (2.34%), α-zingiberene (2.12%), δ-cadinene (2.08%), caryophyllene oxide (1.90%), spathulenol (1.88%), □-caryophyllene (1.88%), ar-turmerone (1.79%), α-pinene (1.52%), limonene (1.52%), selina-4,11-diene (1.46%), curzerenone (1.41%), germacrone B (1.37%), bornyl acetate (1.31%), β-farnesene (1.28%), borneol (1.23%), myrtenal (1.16%), zingiberenol (1.15%) and sabinene (1.13%). These results differ from those of previous studies reported on this species collected from other regions of Algeria and Morocco.

Open access
Ethnobotanical study of Belezma National Park (BNP) plants in Batna: East of Algeria

Abstract

The present work focuses on an ethnobotanical study of medicinal plants in the Belezma National Park (BNP), which is located in Batna city. It was conducted to precise on the medicinal plants in the park and gathers all the information on the therapeutic practice used by the local inhabitants of the study area. Using 300 questionnaire cards, ethnobotanical surveys of BNP were conducted during two campaigns (2017 and 2018). The obtained results allowed us to identify 50 medicinal plants used by the population of the region, which are divided into 27 families and 46genus.

The obtained results show both leaves and stems are mostly used for diseases’ treatment in the form of a decoction with a rate of 42.34%. For the treated diseases, the digestive disorders occupy the first place with a rate of 34.01%, followed by uro-genital diseases with a rate of 17.56%, 11.20% for respiratory diseases, 11.84% for orthopedic diseases and 6.23% for cardiovascular.

The founded results could be a database for research on phytochemistry and pharmacology for the national medicinal flora and the population of the BNP region. Also, they constitute a very valuable source of information.

Open access
Fitting Competing Models of the Population Abundance Distribution: Land Snails from Nikopol Manganese Ore Basin Technosols

Abstract

This paper examines the temporal dynamics of terrestrial mollusks of the Nikopol manganese ore basin technosols. The research was carried out at the Research Centre of the Dnipro Agrarian and Economic University in Pokrov (Ukraine). Sampling was carried out in 2012–2014 on four variants of artificial soil: formed on red-brown clays, on loess-like loams, on gray-green clays, and on humus-rich layer. The distribution of the number of individuals in a mollusk population was described by broken stick, Motomura, log-normal, Zipf, and Zipf-Mandelbrot models. It was shown that the series of models that best describe mollusk abundance distribution is specific for a particular species and technosols type and generally is invariant over time.

Open access
Floristic Distribution According to the Edaphic Parameters of a Steppe Zone, Case of Study: The Nature Reserve “El-Mergueb” M’sila, Algeria

Abstract

The natural site of El-Mergueb, is one of the specific steppe ecosystem, that occupies an area of 16,481 ha; it is among the particular ecosystems in Algeria and is unique in northern Africa. It is located in the geographical limit of the Tell Atlas and the Saharan Atlas. It is at an altitude of 550 to 800 m, with a typically arid climate. The faunistic and floristic richness, quite specifically, contains species protected and classified in the IUCN: Chlamydotis and Gazella, as well as an autochthonous plant diversity: Stipa, Pistacia and Ziziphus. This study is based on the analysis of the vegetation by characterizing the associated soil type through the monitoring of the Eco-pedological relation during two seasons in three years: 2015−2016−2017. Nine soil profiles with a collection of twenty-one samples for each station of experimentation were collected. The results thus obtained showed that the content of the parameters analyzed is between low and average of the three stations. The average of the floristic analysis of the study area made it possible to define 34 botanical families spread over 69 botanical genus and 275 species. The analysis and the description of a natural space is important to establish a typology which is that is the basis for the development of management plans to conserve this category of protected areas. The FAC (Factorial Analysis of Correspondence) is relative to the individualization and the typology for three sequences, which corresponds to the groups (A), (B) and (C) also for the places in arid climate variants with very cold winters.

Open access
Green-extraction of essential oil of the species Ruta chalepensis L.: gas chromatography-mass spectroscopy-infra red analysis and response surface methodology optimization

Abstract

The objective of the present study was the optimization of the parameters affecting the hydrodistillation of Ruta chalepensis L. essential oil using response surface design type Box-Behnken. After an appropriate choice of three parameters, 15 experiments were performed leading to a mathematical second-degree model relating the response function (yield of essential oil) to parameters and allowing a good control of the extraction process. The realization of the experiments and data analysis was carried out by response surface methodology (RSM). A deduced second-order polynomial expression was used to determine the optimal conditions necessary to obtain a better essential oil yield. These optimized operating conditions were: a granulometry of 2 mm, a condensation-water flow rate of 3.4 mL/min and an extraction time of 204 min. Analysis of variance (ANOVA) indicates that the generated second-order polynomial model was highly significant with R2=0.9589 and P<0.006. The gas chromatography-mass spectrometry analysis of essential oil extracted from the Ruta chalepensis L. aerial parts revealed the presence of 2-undecanone, 2-nonanone and 2-decanone as major components.

Open access