arid and semi-arid areas, due to the sensitive, have variable ecosystems, so continuous assessment and monitoring of the environment is required for most of managerial and adjustment practices. vegetation is one of the most important assessment tools and used as a criterion for evaluation and monitoring of ecosystem functions. in this study, for the first time in the country, we have evaluated ...

Ecologists and conservationists have long assumed that large grazers, including bison (Bison bison), did not occur in post-Pleistocene southwestern North America. This perception has been influential in framing the debate over conservation and land use in the northern Chihuahuan Desert. The lack of an evolutionary history of large grazers is being used to challenge the validity of ranching as a...

John Rawls rejects prejusticial conceptions of distributive desert on the grounds that such conceptions are immoral and impractical. Prejusticial understandings of desert claim that desert can be understood prior to and independently of justice in social institutions, and take legitimate desert claims to provide standards for evaluating social arrangements. Some philosophers have interpreted Ra...

We define the geographical distributions of mitochondrial DNA (mtDNA) lineages embedded within a broadly distributed, arid-dwelling toad, Bufo punctatus. These patterns were evaluated as they relate to hypothesized vicariant events leading to the formation of desert biotas within western North America. We assessed mtDNA sequence variation among 191 samples from 82 sites located throughout much ...

Rainfall events can be characterized as "pulses", which are discrete and variable episodes that can significantly influence the structure and function of desert ecosystems, including shifts in aboveground net primary productivity (ANPP). To determine the threshold and hierarchical response of rainfall event size on the Normalized Difference Vegetation Index (NDVI, a proxy for ANPP) and the diff...

[1] To determine the location of the potential dust source regions and to evaluate the dust emission frequencies over the arid and semiarid areas of China and Mongolia (35.5 N–47 N; 73 E–125 E), we established a map of Z0 from the composition of protrusion coefficient (PC) derived from the POLDER-1 bidirectional reflectance distribution function (BRDF). Using a =4 =4 resolution Z0 data set, we ...

a knowledge of soil surface conditions, especially desert crust, salt crust and desert varnish is useful for improving classification of remotely sensed data. desert crust can generate high levels of reflectance, similar to those areas with high salt concentration and non-saline soil. therefore, soil surface crusts might bias thematic remote sensing of soils. in this study, we evaluated the eff...