Secondary Succession in the Sagebrush Semidesert 66 Years After Fire in the Great Basin, USA

• Published in: Natural areas journal Vol. 36; no. 2; pp. 187 - 193
• Format: Journal Article
• Language: English
• Published: Natural Areas Association 01.04.2016
• Subjects: annual grasslands; Artemisia; basins; Bromus tectorum; ecology canyon; ecosystems; fire regime; grasses; historical ecology; indigenous species; invasive species; long-term data; monitoring; plant communities; secondary succession; shrublands; species diversity; state-and-transition models; W. Dwight Billings; wildfires; wildlife habitats; United States
• ISSN: 0885-8608; 2162-4399
• DOI: 10.3375/043.036.0211

The invasive annual grass Bromus tectorum (cheatgrass) creates multiple challenges as it spreads across the Great Basin, fueling repeated wildfires and dominating large expanses of land that were once sagebrush shrublands. The replacement of shrublands by annual grasslands has been widespread and much research has focused upon loss of wildlife habitat, altered fire regimes, and degraded ecosystem function. Monitoring of short-term plant community reassembly occurs in these systems, but considerably less is known about the long-term succession of native plant communities after fire. Using repeated measures in time over a 66-year period, we examined the species composition of two shrubland sites in the Great Basin. The sites burned completely in 1947 and density data on herbaceous species were reported one year and 41 years after the fire. At both sampling intervals, B. tectorum and other annual invasive species, dominated the sites. Our resampling 25 years later found B. tectorum no longer maintained dominance on the north-facing site and native grasses were common. The south-facing site still contained a high density of B. tectorum, but it was four times less abundant than in previous years. Our results are consistent with the few studies using historical data that show, in some instances, desert shrublands can transition out of an annual dominated state into a native perennial state over decadal time scales without intervention. This study highlights the importance of repeated long-term studies for improving development of restoration plans and state-and-transition models, as community trajectories may not be apparent for more than five decades following disturbance.