Soil landscape development in the short-grass steppe ecosystem- assessing the vulnerability of soils to climate change

Background/Question/Methods

The contemporary landscapes of the short-grass steppe ecosystem possess a remarkably diverse soil mantle.  While spatial heterogeneity does indeed exist among soils in the short-grass steppe, the combined effects of vegetation and climate have created a uniquely spatial homogenous soil-landscape mosaic when compared to soil of other ecosystems. We identified dominate soil conditioning variables (state factors, Jenny1940) by combining Soil Survey Geographic data with geologic, geomorphic, and elevation data in northeastern Colorado, therefore isolating geographic areas where contributions of single state factor outrank the combined contribution of other factors. In water limited systems areas such as the short-grass steppe, three broad phases of soil development can be identified according to landscape age that we believe to be ecologically and biogeochemically significant. 

Results/Conclusions

In a similar fashion to Vitousek et al (2008) we identified  and characterized  functional pedologic phases within water limited SGS ecosystems in which soils are either 1) Aggrading or Building with regard to soil development, 2) are in an Intermediate or Equilibrium stage of soil development, and 3) Degrading or Declining in terms of soil development. This geographic approach to modeling pedologic and ecohydrologic dynamics identify regions where soil capacity to store water and nutrients at a relative maximum and are used as the basis for assessing ecosystem vulnerability.