Ecological Health of Grasslands and Sagebrush Steppe on the Northern Yellowstone Range

Abstract

Native plant abundances within the grasslands and sagebrush steppe of the Northern Range decreased substantially during the 20th century and the degradation has continued during the 21st century. Forage production has declined precipitously, and ecological processes (i.e., water cycle, energy flow, and nutrient cycle) are impaired and degrading further. The declining health of Northern Range grasslands and sagebrush steppe is primarily caused by heavy grazing and browsing by bison and elk, not climatic changes. Excessive grazing and browsing is caused by modern-day management decisions that allowed bison and elk populations to become much larger than primeval times. National Park Service policy requires human intervention (i.e., active management) when human actions have impaired natural ecological processes or altered natural abundances of native plants and animals.