نتایج جستجو برای: arid lut desert
تعداد نتایج: 33098 فیلتر نتایج به سال:
Knowledge of genetic structure and patterns of connectivity is valuable for implementation of effective conservation management. The arid zone of Australia contains a rich biodiversity, however this has come under threat due to activities such as altered fire regimes, grazing and the introduction of feral herbivores and predators. Suitable habitats for many species can be separated by vast dist...
Previous studies have found that urbanization often decreases net primary production (NPP), an important integrative measure of ecosystem functioning. In arid environments, however, urbanization may boost productivity by introducing highly productive plant communities and weakening the coupling of plant growth to naturally occurring cycles of water and nutrients. We tested these ideas by compar...
Since the early 20th century, “desert reclamation” has been synonymous with large-scale waterworks and irrigation. These techniques have made it possible to produce abundant crops in arid or semi-arid environments. The costs have often been externalized, with increased environmental productivity in the new croplands counterbalanced by increased aridity elsewhere. In this paper I consider whose ...
Rates of nitrogen (N) deposition have increased in arid and semiarid ecosystems, but few studies have examined the impacts of long-term N enrichment on ecological processes in deserts. We conducted a multiyear, nutrient-addition study within 15 Sonoran Desert sites across the rapidly growing metropolitan area of Phoenix, Arizona (USA). We hypothesized that desert plants and soils would be sensi...
[1] In semi-arid areas, multiple equilibrium states of an ecosystem (e.g., grassland and desert) are found to coexist, and the transition from grassland to desert is often abrupt at the boundary. A simple ecosystem model is developed to provide the biophysical explanation of this phenomenon. The model has three variables: living biomass, wilted biomass, and soil wetness. The moisture index, whi...
To study life in the Mars-like Atacama Desert of Chile we have created a robot, Zoë, and conducted three seasons of technical and scientific experiments. We describe Zoë’s exploration algorithms and architecture and assess a total of six months of long distance survey traverses. To date Zoë has navigated autonomously over 250 km. Its average distance per autonomous traverse is 672 m with 75 tra...
Nayband is a historical village in South Khorasan, which is located on the western edge of the desert. The adjacency of the village to the caravan route, its strategic position, and the existence of water resources and fertile lands have led to the formation of its texture. The harsh climatic conditions of the region and the existence of miscreants and bandits in the historical periods, while c...
In arid and semi-arid grassland, many models hypothesize that desertification leads to the replacement of grassland by shrubland vegetation; however, the theoretical interpretations are open to debate. Therefore, a field study was conducted in the Guinan desertified grassland of the Qinghai-Tibet plateau, North-west China, to test the hypotheses on a regional scale. We used four field sites to ...
Bioarchaeology and biogeochemistry can elucidate aspects of individual life histories that are often lost in the archaeological record. Here, we use stable and radiogenic isotope analyses of enamel, bone and hair to reconstruct paleodiet and paleomobility in an adult male interred along a pre-Columbian route connecting the northern Chilean coast to the inland Loa River Valley. Although this wel...
Since about 30 % of the land surface are covered with arid and desert conditions of soil, bright grounds and their aerosol emissions are of essential importance for the investigation of general aerosol impact in climate. Therefore retrievals of aerosol properties from spaceborne platforms need to include retrieval approaches, working over this conditions. An approach to retrieve aerosol propert...
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