Late-summer Fire Provides Long-term Control of the Invasive Old World Bluestem (Bothriochloa ischaemum)

Charlotte M. Reemts^1,*, Carla Picinich², and Thomas A. Greene³

¹Texas Chapter of The Nature Conservancy, Austin, TX 78701. ²Natural and Cultural Resources Management Branch, Fort Hood Military Reservation, Fort Hood, TX 76544. ³Apache-Sitgreaves National Forest, Springerville, AZ 85938. *Corresponding author.

Southeastern Naturalist,Volume 20, Issue 4 (2021): 589–601

Abstract
Bothriochloa ischaemum (Old World Bluestem) is a problematic invasive grass throughout the southern United States. We measured the long-term effects (12 years) of a single growing-season fire (September 2006) in a grassland dominated by Old World Bluestem. Prescribed fire drastically reduced Old World Bluestem cover (prefire: 76 ± 4% [mean ± standard error], 2007: 8 ± 2%) and cover remained low (21 ± 6%) in 2018 with no additional management. Surprisingly, Old World Bluestem cover in unburned plots decreased 12% during the same time. After the burn, native graminoid cover peaked after 3 years (29 ± 7%) but decreased to 18 ± 5% by 2018, and native annual forb cover, almost absent before the fire, increased dramatically to 39 ± 7% in 2007, then quickly decreased to pre-burn levels. Native perennial forb cover more than doubled in 2007 and continued to increase to 58 ± 5% in 2018. A single growing-season fire greatly reduced the cover of Old World Bluestem, likely due to high fuel loads, low rainfall, and phenological timing; the fire also allowed perennial forbs to establish. Restoring dominance of native grasses after removal of this invasive species will require additional active restoration such as seeding or planting.

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