Development and evaluation of an ecohydrology soil-moisture model to aid in understanding semi-arid ecosystem dynamics

摘要

This paper presents a simple soil-water (ecohydrologic) model developed in STELLA modeling environment. The model development was framed by previous work in both the rangeland science and ecohydrology disciplines and was calibrated to four locations of diverse soils and climate across Texas, USA. Overall, the model calibration procedure showed that the model is fairly well behaved compared to the available observed data at each location. Exploratory and sensitivity analyses showed some expected patterns of behavior that illustrate the model is sensitive to some extreme conditions and that the directional impacts of the changes followed a logical progression. However, there are several model components, particularly the biomass stock and the plant-soil related feedbacks on infiltration and runoff were not well parameterized and need to be improved before intended applications. Future work includes extending this model to include a feedback loop impact component [after Hayward and Boswell (2014), Model behavior and the concept of loop impact: A practical method. System Dynamics Review 30(1-2), 29-57] to better understand the water dynamics in semi-arid environments arising from climate and grazing management changes as well as developing a teaching tool for rangeland, soils, and/or modeling courses.