Innovative approaches are needed to gather the data required for robust ecological site concept and state and transition model development. While expert knowledge plays an important role in developing ecological site descriptions (ESDs), coupled soil-vegetation data sets are required for refining and testing of ESD concepts. Often, ESD development is data limited, particularly in less intensively managed landscapes. Digital soil mapping approaches and historical aerial photos can help fill some of these data gaps. We present here a new approach for gathering the requisite data needed to analyze current vegetation-soil relationships and, most importantly, how vegetation-soil relationships have changed over the past 60 years in response to climate and management. The study area for this demonstration project is a 51,919 acre Colorado Plateau shrub and grassland ecosystem in southern Utah. Existing soil maps and associated ESDs suggest two potential reference communities are present in the study area (Wyoming big sagebrush and Fourwing saltbush). However, these two ecological sites are nearly identical in soil and landscape attributes. The goal of this effort was to evaluate if soil and/or landscape attributes differentiate these two sites or if the two communities are simply alternative states of the same site in this climate setting. The approach used was to create high resolution raster maps of soil properties and evaluate study area vegetation change using a combination of field data and object oriented image analysis of historical aerial photos. Analysis of vegetation change and overlaid soil property maps suggest these two ecological sites can be distinguished based on soil-depth. Additionally, raster maps of soil properties combined with these refined ESD concepts allowed for predictions of sub-map unit ecological site distribution. Results suggest digital soil mapping coupled with spatially explicit data on vegetation change can be used to refine ecological site concepts in data poor areas.
Oral presentation and poster titles, abstracts, and authors from the Society for Range Management (SRM) Annual Meetings and Tradeshows, from 2013 forward.