Historical and modern disturbance regimes, stand structures, and landscape dynamics in piñon-juniper vegetation of the western united states

William H. Romme, Craig D. Allen, John D. Bailey, William L. Baker, Brandon T. Bestelmeyer, Peter M. Brown, Karen S. Eisenhart, M. Lisa Floyd, David W. Huffman, Brian F. Jacobs, Richard F. Miller, Esteban H. Muldavin, Thomas Swetnam, Robin J. Tausch, Peter J. Weisberg

Research output: Contribution to journalArticle

188 Citations (Scopus)

Abstract

Piñon-juniper is a major vegetation type in western North America. Effective management of these ecosystems has been hindered by inadequate understanding of 1) the variability in ecosystem structure and ecological processes that exists among the diverse combinations of piñons, junipers, and associated shrubs, herbs, and soil organisms; 2) the prehistoric and historic disturbance regimes; and 3) the mechanisms driving changes in vegetation structure and composition during the past 150 yr. This article summarizes what we know (and don't know) about three fundamentally different kinds of piñon-juniper vegetation. Persistent woodlands are found where local soils, climate, and disturbance regimes are favorable for piñon, juniper, or a mix of both; fires have always been infrequent in these woodlands. Piñon-juniper savannas are found where local soils and climate are suitable for both trees and grasses; it is logical that low-severity fires may have maintained low tree densities before disruption of fire regimes following Euro-American settlement, but information is insufficient to support any confident statements about historical disturbance regimes in these savannas. Wooded shrublands are found where local soils and climate support a shrub community, but trees can increase during moist climatic conditions and periods without disturbance and decrease during droughts and following disturbance. Dramatic increases in tree density have occurred in portions of all three types of piñon-juniper vegetation, although equally dramatic mortality events have also occurred in some areas. The potential mechanisms driving increases in tree density-such as recovery from past disturbance, natural range expansion, livestock grazing, fire exclusion, climatic variability, and CO2 fertilization-generally have not received enough empirical or experimental investigation to predict which is most important in any given location. The intent of this synthesis is 1) to provide a source of information for managers and policy makers; and 2) to stimulate researchers to address the most important unanswered questions.

Original languageEnglish (US)
Pages (from-to)203-222
Number of pages20
JournalRangeland Ecology and Management
Volume62
Issue number3
DOIs
StatePublished - May 2009

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stand structure
Western United States
disturbance
vegetation
climate
savannas
woodlands
savanna
shrubs
woodland
shrub
soil
fire severity
Juniperus
fire regime
ecosystem management
vegetation structure
information sources
ecosystem structure
shrublands

Keywords

  • Climate
  • CO2
  • Drought
  • Fire
  • Grazing
  • Range expansion
  • Tree infill
  • Tree invasion

ASJC Scopus subject areas

  • Management, Monitoring, Policy and Law
  • Nature and Landscape Conservation
  • Animal Science and Zoology
  • Ecology

Cite this

Romme, W. H., Allen, C. D., Bailey, J. D., Baker, W. L., Bestelmeyer, B. T., Brown, P. M., ... Weisberg, P. J. (2009). Historical and modern disturbance regimes, stand structures, and landscape dynamics in piñon-juniper vegetation of the western united states. Rangeland Ecology and Management, 62(3), 203-222. https://doi.org/10.2111/08-188R1.1

Historical and modern disturbance regimes, stand structures, and landscape dynamics in piñon-juniper vegetation of the western united states. / Romme, William H.; Allen, Craig D.; Bailey, John D.; Baker, William L.; Bestelmeyer, Brandon T.; Brown, Peter M.; Eisenhart, Karen S.; Floyd, M. Lisa; Huffman, David W.; Jacobs, Brian F.; Miller, Richard F.; Muldavin, Esteban H.; Swetnam, Thomas; Tausch, Robin J.; Weisberg, Peter J.

In: Rangeland Ecology and Management, Vol. 62, No. 3, 05.2009, p. 203-222.

Research output: Contribution to journalArticle

Romme, WH, Allen, CD, Bailey, JD, Baker, WL, Bestelmeyer, BT, Brown, PM, Eisenhart, KS, Floyd, ML, Huffman, DW, Jacobs, BF, Miller, RF, Muldavin, EH, Swetnam, T, Tausch, RJ & Weisberg, PJ 2009, 'Historical and modern disturbance regimes, stand structures, and landscape dynamics in piñon-juniper vegetation of the western united states', Rangeland Ecology and Management, vol. 62, no. 3, pp. 203-222. https://doi.org/10.2111/08-188R1.1
Romme, William H. ; Allen, Craig D. ; Bailey, John D. ; Baker, William L. ; Bestelmeyer, Brandon T. ; Brown, Peter M. ; Eisenhart, Karen S. ; Floyd, M. Lisa ; Huffman, David W. ; Jacobs, Brian F. ; Miller, Richard F. ; Muldavin, Esteban H. ; Swetnam, Thomas ; Tausch, Robin J. ; Weisberg, Peter J. / Historical and modern disturbance regimes, stand structures, and landscape dynamics in piñon-juniper vegetation of the western united states. In: Rangeland Ecology and Management. 2009 ; Vol. 62, No. 3. pp. 203-222.
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