Fire return interval and season of fire alter bud banks

Authors: RUSSELL, MORGAN - Texas A&M University; Vermeire, Lance; GANGULI, AMY - New Mexico State University; Hendrickson, John

Submitted to: Rangeland Ecology and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/5/2018
Publication Date: 1/25/2019
Citation: Russell, M.L., Vermeire, L.T., Ganguli, A.C., Hendrickson, J.R. 2019. Fire return interval and season of fire alter bud banks. Rangeland Ecology and Management. 72(3):542-550. https://doi.org/10.1016/j.rama.2018.12.003.
DOI: https://doi.org/10.1016/j.rama.2018.12.003

Interpretive Summary: Despite the importance of vegetative reproduction in annual tiller replacement, little is known about the patterns and timing of tiller recruitment from the bud bank, especially regarding fire return intervals, seasons of fire, and drought. This study examined aboveground plant density, seasonal patterns of tiller production, and belowground bud bank dynamics for blue grama, western wheatgrass and needleandthread following summer, fall, and spring prescribed fires and 2-yr, 3-yr, and 6-yr fire return intervals. Fire treatments were started in 2006 and buds were assessed July 2011 through July 2013. Density and number of reproductive blue grama tillers increased in 2013 following drought during 2012, unlike needleandthread, which decreased reproductive tiller production. Irrespective of fire treatments, blue grama produced the most buds (8-10 buds · tiller-1) and needleandthread produced the least (2-3 buds · tiller-1), with western wheatgrass producing an intermediate amount (6-8 buds · tiller-1). Immediate blue grama and western wheatgrass bud mortality did not occur for any season or fire return interval treatments. However, needleandthread bud mortality increased immediately following summer and fall prescribed fires. Three-year fire return intervals increased active buds throughout the 2013 winter and growing season for blue grama and western wheatgrass relative to control plots and 2 and 6-yr fire return intervals. Fire stimulated bud activity of blue grama and western wheatgrass relative to non-burned plots. The above and belowground response of needleandthread indicated meristem limitations following fire treatments, illustrating greater vulnerability to fire for that species than blue grama and western wheatgrass.

Technical Abstract: Despite the importance of vegetative reproduction in annual tiller replacement, little is known about the patterns and timing of tiller recruitment from the bud bank, especially regarding fire return intervals, seasons of fire, and drought. This study examined aboveground plant density, temporal patterns of tiller production, and belowground bud bank dynamics for Bouteloua gracilis (Willd ex. Kunth) Lag. ex Griffiths), Pascopyrum smithii (Rydb.) A. Löve, and Hesperostipa comata (Trin. & Rupr.) Barkworth following summer, fall, and spring prescribed fires and 2-yr, 3-yr, and 6-yr fire return intervals, and their interactions. Fire treatments were initiated in 2006 and buds were assessed July 2011 through July 2013. Density and number of reproductive B. gracilis tillers increased in 2013 following drought during 2012, unlike H. comata, which decreased reproductive tiller production. Irrespective of fire treatments, B. gracilis produced the most buds (8-10 buds · tiller-1) and H. comata produced the least (2-3 buds · tiller-1), with P. smithii producing an intermediate amount (6-8 buds · tiller-1). Immediate B. gracilis and P. smithii bud mortality did not occur for all season and fire return interval treatments. However, H. comata bud mortality increased immediately following summer and fall prescribed fires. Three-year fire return intervals increased active buds throughout the 2013 winter and growing season for B. gracilis and P. smithii relative to control plots and 2 and 6-yr fire return intervals. Fire stimulated bud activity of B. gracilis and P. smithii relative to non-burned plots. The above and belowground response of H. comata indicated meristem limitations following fire treatments, illustrating greater vulnerability to fire for that species than B. gracilis and P. smithii.