Analysis of Biological Soil Crust Mapping in the Mojave Desert, USA.

Biological soil crusts (BSCs) are critical ecological components in arid regions around the world.  These crusts form living, desert skin that reduces soil erosion, influences soil fertility, manages soil moisture/temperature, and prevents desertification.  BSCs are fragile resources, easily destroyed by physical disturbances and potentially impacted by climate change.

Despite their ecological importance, the environmental factors controlling BSC distribution in the Mojave Desert are poorly understood.  Furthermore, no predictive modeling technique exists for BSCs in Mojave landscapes.  Our investigation employs a novel, interdisciplinary approach to investigate BSC ecology and to develop a predictive model of BSC biotic potential.

We discuss initial results from various BSC mapping techniques (remote sensing indices, field-based mapping, and geomorphic mapping) and surface characterization.  Our data indicate the application of two remote sensing indices (Karnieli et al., 1997; Chen et al., 2005) with high resolution Quickbird ® multispectral imagery (2.44m) effectively delineate BSC density into three mapping units.  In contrast, our field-based map is divided into 10 mapping units reflecting BSC distribution, density, morphology, and species composition.  Field-based mapping further addresses surface characteristics that control soil stability and resistance to disturbance. 

Initial field data and mapping reveal geomorphology is a primary controlling factor in BSC distribution within the Mojave.  Because geomorphology largely determines soil characteristics that influence crust distribution, geomorphic maps could be incorporated into a BSC predictive model.   The science of BSCs is still in its infancy, with few conclusive answers regarding their biology.  Our interdisciplinary approach to BSCs bridges gaps between biology, ecology, soil science, hydrology, statistics, chemistry, geomorphology, GIS, and remote sensing.  Our research aids in understanding interrelationships between biological soil crusts, soils, geomorphology, and land stability.