Season of fire manipulates bud bank dynamics in northern mixed-grass prairie

Abstract

In perennial grassland dominated systems, belowground bud banks regulate plant community dynamics. Plant community responses to disturbance are largely driven by the ability to generate future aboveground growth originating from belowground axillary buds. This study examined bud bank dynamics for Bouteloua gracilis, Hesperostipa comata, and Pascopyrum smithii following fire in northwestern mixed-grass prairie in eastern Montana, USA. Belowground axillary buds were counted and classified for three growing seasons to determine immediate and short-term effects of summer, fall, and spring prescribed burns on patterns of bud bank activity, dormancy, and mortality. Prescribed burns did not result in immediate mortality of B. gracilis, H. comata, or P. smithii buds. Surprisingly, spring prescribed burns immediately increased the number of active B. gracilis buds. Summer fire, however, reduced B. gracilis active bud numbers. Fall burns immediately activated P. smithii buds, whereas fire did not influence any immediate bud dynamics for H. comata. Reduced bud numbers of H. comata may limit the ability to respond to fire. Season of fire directly manipulated bud activity, dormancy, and mortality for these species throughout the growing and dormant seasons following fire. Using season of fire to manipulate bud bank dynamics illustrates potential to improve post-fire management strategies based on known bud development trajectories and bud dynamics following fire.

Effects of drought and fire on resprouting capacity of 52 temperate Australian perennial native grasses

“…Tiller density (i.e. packing) had a positive effect on the capacity of grasses to regenerate after fire, reflecting an expectation that the density of axillary buds, and the capacity to maintain those bud reserves undamaged from fire, are higher in grass species that evolved with frequent fires (Russell et al ., ). Typically, such plants have traits that make them ignite easily and burn quickly (Pausas et al ., ).…”

“…nonstressed plants) appear more vulnerable to fire than droughted grasses, perhaps because root carbohydrate stores are lower and meristems are actively growing at the time of burning. These findings contrast with observations of reduced tiller regeneration in burned, drought‐affected prairie (Engle & Bultsma, ; Russell et al ., ). The season of burn affects fire intensity (Govender et al ., ) and has been shown to impact bud bank dynamics (Russell et al ., ), with implications for the abundance of species when fire occurs in the growing season vs dormant season (Forrestel et al ., ).…”

“…Drought is common in Australia, a product of El Niño–Southern Oscillation cycles that cause large interannual variation in precipitation (Vines et al ., ) and significantly affects net primary productivity in grasslands (Morgan et al ., ). It is also known to compromise post‐fire regeneration of grasses (Carter et al ., ; Russell et al ., ) by reducing the metabolic functions and recovery rates of C 4 grasses (Knapp, ), a photosynthetic pathway that is generally assumed to be resilient to arid conditions (Ripley et al ., ; Taylor et al ., ). While the drought responses of Australian native grass species have been reported (e.g.…”

Annual burning of semi‐natural grasslands for conservation: winners and losers among plant species

“…Hence, although part of the response in the present study is attributable to the lack of biomass removal during the growth season, there are species that clearly suffer from a spring burn. Whether this is due to the location of overwintering buds (Clarke et al 2013, Russell et al 2015 or the phenology of growth (Henderson 1990a(Henderson , 1990b remains to be evaluated. At the same time, there are also species that clearly benefited from repeated spring burns more than they would if left to free development.…”

Seasonality of prescribed fire weather windows and predicted fire behavior in the northern Great Plains, USA

“…Prescribed fire use is subject to management decisions based on fuel and weather conditions at the time of ignition, and it is important to determine when it is most appropriate to burn to meet conservation objectives. In the northern Great Plains of North America, burning in different seasons does little to affect grassland productivity and composition (Clarke et al 1943, Biondini et al 1989, Engle and Bidwell 2001, Vermeire et al 2011, Russell et al 2015. However, it remains unclear to what extent the opportunity to conduct prescribed fire exists in any season, and to what extent this opportunity is affected by regional climate change (Huffman 2014, Chiodi et al 2018.…”