Response of Nebraska Sand Hills Natural Vegetation to Drought, Fire, Grazing, and Plant Functional Type Shifts as Simulated by the Century Model

Authors

Jennifer Mangan, Digital Library for Earth System Education, University Corporation for Atmospheric Research
Jonathan T. Overpeck, University of Arizona, Tucson, Arizona
Robert S. Webb, University of Colorado, Boulder, and NOAA Climate Diagnostics Center, 325 N. Broadway, Boulder, CO
Carol Wessman, University of Colorado, Boulder, CO
Alexander Goetz, University of Colorado, Boulder, CO

Document Type

Article

Date of this Version

2004

Comments

Published in Climatic Change 63: 49–90, 2004. Copyright © 2004 Kluwer Academic Publishers. Used by permission.

Abstract

The Nebraska Sand Hills exist in a semi-arid climatic environment and the land surface is grassland growing on sandy soils. These soils have been periodically active throughout the Holocene, but are currently stabilized by the vegetation. However, a shift in climate could cause grassland death and eventual sand dune remobilization. Our studies used the CENTURY nutrient cycling and ecosystem model to investigate the impacts of drought, plant functional type, fire, grazing, and erosion on Nebraska Sand Hills vegetation and dune stability. Fire and grazing alone had little impact on the vegetation, but when combined with mild drought, biomass decreased. Overall biomass increased if one plant functional type was allowed to dominate the ecosystem. Addition of as little as 1 mm of erosion per year under current climate conditions decreases vegetation as much as a drought 20 percent drier than the worst of the 1930s drought years in Nebraska.