Based on secular fixed_site data in the artificial sand_fixing vegetation district at the southeast fringe of the Tengger Desert, the formative characteristics of soil microbiotic crusts and its influences on vegetati...Based on secular fixed_site data in the artificial sand_fixing vegetation district at the southeast fringe of the Tengger Desert, the formative characteristics of soil microbiotic crusts and its influences on vegetation dynamics were analyzed. Once sand barrier and artificial vegetation have stabilized the surface of the sifting sand, could form aeolian deposition crust and then evolve into algae_dominated crust. Such processes result from the interactions of physical effects of atmospheric dust and silt deposition on sand surface, sinking and raindrop impact, and soil microorganism activities. Under the condition of less than 200 mm precipitation, the presence of microbiotic crust changes the soil hydraulic conductivity, alters the temporal and spatial distribution of the limited precipitation in sand layer and leads to the decline of deep_rooted shrubs. The development of microbiotic crust and subsurface soil affects the plant growth and seed rain distribution, as a result, the diversity of plant species gradually tend to become saturated and finally affects the vegetation stability.展开更多
Groundwater in Egypt plays an important role in the country＇s water budget. South Western desert represent an arid of desert biome within world＇s net-work of the biosphere reserves. In this study, the plant wild veg...Groundwater in Egypt plays an important role in the country＇s water budget. South Western desert represent an arid of desert biome within world＇s net-work of the biosphere reserves. In this study, the plant wild vegetation were surveyed in Abu Tartur mining area located in the Southern part of Western depending essentially on the seepage from water line tubes which supplies water demands at Abu Tartur. The vegetation-environment relationships in Abu Tartur are described. Data sets （42 species in 38 plots） beside the pip-line enriched from 13 wells were analyzed, using multivariate procedures, i.e., two-way indicator species analysis （TW1NSPAN）, detrended correspondence analysis （DCA） and detrended canonical correspondence analysis （CCA）, to produce a classification of plant communities in the studied areas and to examine the relationships of that plant communities to certain edaphic factors. Five plant communities were identified. Astragalus vogelii, Chenopodium murale, Citrullus colocynthis, Fagonia arabica, Farsetia aegyptia, Hyoscyamus muticus, Morettia philaeana, Cynodon dactylon, Trichodesma africana, Tarnarix nilotica, Senna italica, Schouwia purpurea, Salsola volkensii and Phragmites australis were common in the study area. Phytochemical survey for nitroprpionic compounds in some taxa belonging to Fabaceae family showed the absence of these toxic compounds by using GC/MS analysis. Also some phytochemical components ofAstragalus vogalii were extracted and identified by GC/MS spectra. A biological activity, in this regard was the screening of methanol extracts for some wild taxa of Abu Tartur against natural Tetranychus urticae as acricidal activity and the methanol extracts of some taxa give high mortality results, like Farsetia aegyptia （86.6%） and Fagonia arabica Burm. f. （70.0%）.展开更多
The local plant resources adapted to the desert harsh geomorphologicl environment are a landmark that characterizes the Saharan region： erg, dunes, and wadis. This work emphasizes on some results obtained through a s...The local plant resources adapted to the desert harsh geomorphologicl environment are a landmark that characterizes the Saharan region： erg, dunes, and wadis. This work emphasizes on some results obtained through a study conducted in 2011, based on surveys and field observations in the Tidikelt oases （in Salah, wilaya of Tamenrasset） which is implanted in the south of Algeria. The objective was the study of traditional herbal medicine using the spontaneous medicinal herbs, which constitute one of the socio-cultural aspects of Saharan society in Algeria. Traditional medicine is one reflect of the knowledge and how to live of the local population. Desert people know the various herbs ＇Achebe＇, and its nomenclature. They indicated their site or places of local presence, as well as its own peculiarities and their uses. Our goal is to contribute in enhancing the interest of valorization of these plants in the therapeutic and eventually industrial uses. For that, we need to integrate this perspective into local economic development policies valuing the diversity of plant resources from Tidikelt in the Algerian Sahara.展开更多
The current study focuses on the contribution of the dromedary in the preservation and increase of spontaneous flora through seeds transfer by endozoochory. Thus dromedary faeces have been collected in selected area o...The current study focuses on the contribution of the dromedary in the preservation and increase of spontaneous flora through seeds transfer by endozoochory. Thus dromedary faeces have been collected in selected area of region of Ghardaia （Northern Algeria Sahara）, since it is one of the three known cameline rangelands during the four successive seasons of the years 2009-2010, in order to examine their seed contents. Our investigation allowed us to invento 1,832 seeds representing 33 different types varying according to the seasons of harvest. The biggest density of seeds was present in summer with 986 seeds, against 424 seeds in winter, 366 seeds in fall and 56 seeds in spring, and of the same way, the biggest number of types was present in summer with 30 types, consistent of the fall season with 26 types, and arrived then the season of winter with 20 types and the one of spring with five types. The gotten results allowed us to appreciate the ecological role of this animal in the desertic ecosystem in the dissemination and the proliferation of the seeds of the spontaneous flora in its fragile and hostile desert environment to the survival of the seeds enveloped in its faeces.展开更多
文摘Based on secular fixed_site data in the artificial sand_fixing vegetation district at the southeast fringe of the Tengger Desert, the formative characteristics of soil microbiotic crusts and its influences on vegetation dynamics were analyzed. Once sand barrier and artificial vegetation have stabilized the surface of the sifting sand, could form aeolian deposition crust and then evolve into algae_dominated crust. Such processes result from the interactions of physical effects of atmospheric dust and silt deposition on sand surface, sinking and raindrop impact, and soil microorganism activities. Under the condition of less than 200 mm precipitation, the presence of microbiotic crust changes the soil hydraulic conductivity, alters the temporal and spatial distribution of the limited precipitation in sand layer and leads to the decline of deep_rooted shrubs. The development of microbiotic crust and subsurface soil affects the plant growth and seed rain distribution, as a result, the diversity of plant species gradually tend to become saturated and finally affects the vegetation stability.
文摘Groundwater in Egypt plays an important role in the country＇s water budget. South Western desert represent an arid of desert biome within world＇s net-work of the biosphere reserves. In this study, the plant wild vegetation were surveyed in Abu Tartur mining area located in the Southern part of Western depending essentially on the seepage from water line tubes which supplies water demands at Abu Tartur. The vegetation-environment relationships in Abu Tartur are described. Data sets （42 species in 38 plots） beside the pip-line enriched from 13 wells were analyzed, using multivariate procedures, i.e., two-way indicator species analysis （TW1NSPAN）, detrended correspondence analysis （DCA） and detrended canonical correspondence analysis （CCA）, to produce a classification of plant communities in the studied areas and to examine the relationships of that plant communities to certain edaphic factors. Five plant communities were identified. Astragalus vogelii, Chenopodium murale, Citrullus colocynthis, Fagonia arabica, Farsetia aegyptia, Hyoscyamus muticus, Morettia philaeana, Cynodon dactylon, Trichodesma africana, Tarnarix nilotica, Senna italica, Schouwia purpurea, Salsola volkensii and Phragmites australis were common in the study area. Phytochemical survey for nitroprpionic compounds in some taxa belonging to Fabaceae family showed the absence of these toxic compounds by using GC/MS analysis. Also some phytochemical components ofAstragalus vogalii were extracted and identified by GC/MS spectra. A biological activity, in this regard was the screening of methanol extracts for some wild taxa of Abu Tartur against natural Tetranychus urticae as acricidal activity and the methanol extracts of some taxa give high mortality results, like Farsetia aegyptia （86.6%） and Fagonia arabica Burm. f. （70.0%）.
文摘The local plant resources adapted to the desert harsh geomorphologicl environment are a landmark that characterizes the Saharan region： erg, dunes, and wadis. This work emphasizes on some results obtained through a study conducted in 2011, based on surveys and field observations in the Tidikelt oases （in Salah, wilaya of Tamenrasset） which is implanted in the south of Algeria. The objective was the study of traditional herbal medicine using the spontaneous medicinal herbs, which constitute one of the socio-cultural aspects of Saharan society in Algeria. Traditional medicine is one reflect of the knowledge and how to live of the local population. Desert people know the various herbs ＇Achebe＇, and its nomenclature. They indicated their site or places of local presence, as well as its own peculiarities and their uses. Our goal is to contribute in enhancing the interest of valorization of these plants in the therapeutic and eventually industrial uses. For that, we need to integrate this perspective into local economic development policies valuing the diversity of plant resources from Tidikelt in the Algerian Sahara.
文摘The current study focuses on the contribution of the dromedary in the preservation and increase of spontaneous flora through seeds transfer by endozoochory. Thus dromedary faeces have been collected in selected area of region of Ghardaia （Northern Algeria Sahara）, since it is one of the three known cameline rangelands during the four successive seasons of the years 2009-2010, in order to examine their seed contents. Our investigation allowed us to invento 1,832 seeds representing 33 different types varying according to the seasons of harvest. The biggest density of seeds was present in summer with 986 seeds, against 424 seeds in winter, 366 seeds in fall and 56 seeds in spring, and of the same way, the biggest number of types was present in summer with 30 types, consistent of the fall season with 26 types, and arrived then the season of winter with 20 types and the one of spring with five types. The gotten results allowed us to appreciate the ecological role of this animal in the desertic ecosystem in the dissemination and the proliferation of the seeds of the spontaneous flora in its fragile and hostile desert environment to the survival of the seeds enveloped in its faeces.
