Print PagePrescribed fire is a commonly used management tool to prevent or limit the encroachment of single-leaf piñon pine (Pinus monophylla) and Utah juniper (Juniperus osteosperma) in to sagebrush (Artemisia tridentata) communities within the Great Basin of the Western United States. The consequences of woody plant encroachment are typically a significant loss of grass and forb cover and diversity and an increase in susceptibility to wildfire and invasion by cheatgrass (Bromus tectorum), a non-native annual grass. However, successfully increasing native grass and forb diversity through natural regeneration following prescribed fire depends on seed dispersal from adjacent unburned communities, the impact of the fire intensity and duration on survival of soil seed banks and below ground root systems of perennial forbs and grasses, and sufficient precipitation during the subsequent growing season. We studied natural regeneration following an August 2009 prescribed fire in a sagebrush community with approximately 49 percent total plant cover, 5.6 percent of cover contributed by P. monophylla and J. osteosperma and none by B. tectorum.
Results/Conclusions
Diversity in the unburned sagebrush community consisted of 72 native species, including 26 annual forbs, 30 perennial forbs, six perennial grasses, six shrubs and two trees. We also documented that sagebrush understory diversity and cover were significantly less than canopy interspaces. The fire destroyed all aboveground biomass, killed most woody perennial species and significantly reduced diversity and cover. Diversity in the burned area was dominated by two annual forbs with the continued exclusion of cheatgrass. Most perennial grasses re-sprouted after the fire, but not until late summer. We will continue to record regeneration over the next three growing seasons and also access the impact of the fire on soil hydrologic properties and susceptibility to erosion.
