This paper reviews the predictions and management implications of two current paradigms in the ecology and management of arid and semi-arid rangelands. The equilibrium model stresses the importance of biotic feedbacks such as density-dependent regulation of livestock populations and the feedback of livestock density on vegetation composition, cover and productivity. Range management under this ...

Desertification is the degradation of land in arid and semi-arid areas. Nowadays, lack of water and desertification are extreme problems for plant survival and growth in the arid and semi-arid areas of the world. It becomes increasingly important as to how to let the plant absorb moisture more effectively for keeping growth strong. We synthesized superabsorbent polymers (SAPs) with carbohydrate...

Hydrological processes and their spatial distribution directly are relevant to climate, topography, geology, and land use in the watershed. Therefore, use of a model whit integrity and high performance for simulating the process in deferent watersheds is very important. In this study was assessment performance of semi-distributed SWAT model in simulating hydrology processes in three watersheds ...

BACKGROUND Desiccation resistance shapes the distribution of terrestrial insects at multiple spatial scales. However, responses to drying stress have been poorly studied in aquatic groups, despite their potential role in constraining their distribution and diversification, particularly in arid and semi-arid regions. METHODS We examined desiccation resistance in adults of four congeneric water...

Improving the capability of land-surface process models to simulate soil moisture assists in better understanding the atmosphere-land interaction. In semi-arid regions, due to limited near-surface observational data and large errors in large-scale parameters obtained by the remote sensing method, there exist uncertainties in land surface parameters, which can cause large offsets between the sim...

soil biodiversity is the origin of considerable goods for maintenance and extension of above ground biodiversity and environmental soundness. this study was carried out in shirvan, mashhad and gonabad, three regions of razavi and northern khorasan provinces, to determine soil characteristics and biodiversity in natural systems of arid and semi-arid regions. in each studied system, 10 locations ...