Smoke water and heat influence emergence of shortgrass prairie species

Exposure to smoke can influence the germination of seeds in many fire-prone ecosystems, but this effect is not well studied in grasslands. Smoke treatments such as smoke water could be useful as management and restoration tools if the response of target species in natural settings is well understood. We tested eight species native to the southern High Plains region in Texas, USA, that were already known to respond to smoke water in the laboratory, for their responses in a less controlled glasshouse environment. We exposed seeds to smoke water, heat, or a combination of the two, sowed them into greenhouse flats, and observed and recorded emergence. Emergence of nearly all species was influenced by smoke water, with most species experiencing either lower emergence or longer times for emergence when exposed to high-concentration smoke water. Smoke water exposure enhanced emergence of broom snakeweed (Gutierrezia sarothrae [DC.] A. Gray) seeds, with more than twice as many treated seeds emerging than untreated seeds (germination of control seeds = 26% ± 4.39% SE; germination of treated seeds = 69% ± 4.62% SE). Because many species displayed different results in the glasshouse as compared to the laboratory, smoke treatments should be tested in the field before being used on a larger scale. Doing so will allow a better understanding of how target species might respond to smoke treatments with more realistic soils, fluctuating temperatures, and other complications encountered in the field.