Ecosystem consequences of regional pinyon mortality

Abstract

Pinyon-juniper (Pinus edulis - Juniperus spp.) woodlands in the American Southwest have expanded in many areas since the late Nineteenth century. Woodland expansion has occurred in both, extent and increasing stand density. Expansion of woodlands has been attributed to reduced fire frequency, increased ungulate grazing, and changes in climate. These increases of woody vegetation have been shown to alter nutrient cycling, fire dynamics, and vegetation patterns across the landscape which can have large-scaled impacts on ecosystem function. Recently, pinyon-juniper woodlands and the American Southwest have experienced nearly a decade of continuous drought, beginning in the mid-1990s. In 2002 severe drought caused a bark beetle outbreak (Ips confusus) in pinyon pine, causing high levels of pinyon mortality throughout the region. This persistent drought has caused wide spread mortality among pinyons, and to a lesser extent, junipers.

Citation

Clifford, Michael J. 2008. Ecosystem consequences of regional pinyon mortality. Flagstaff, AZ: Northern Arizona University. 65 p. Thesis.