Montane valley grasslands are highly resistant to summer wildfire

Abstract

AbstractAimsUnderstanding the ecological role of fire in shaping plant communities in fire‐prone ecosystems is needed for ecosystem restoration, preservation and management. We investigated the effects of wildfire on plant community structure and the biotic and abiotic factors that are most influential in stabilizing and/or driving change before and after burning in high‐elevation montane grasslands dominated by C3 species receiving a mean annual precipitation of 545 mm.LocationValles Caldera National Preserve, Jemez Mountains, New Mexico, USA.MethodsLong‐term data (10 year pre‐fire; 5 year post‐fire) on plant community composition of nine burned and seven unburned grassland sites were used to determine the response of montane grasslands to a summer wildfire. We used multivariate and univariate analyses to determine changes in plant community composition and structure, pre‐ and post‐wildfire on burned and unburned grasslands.ResultsThe montane grassland community consisted of 155 plant taxa, including 44 perennial grasses, one annual grass, 92 perennial forbs and nine annual forbs. We found that these fire‐adapted plant communities were highly resilient to fire; fire had no significant effects on composition or structure beyond the normal range of inter‐annual variability. Instead, seasonal precipitation had the largest influence on plant community dynamics over time, with lower average plant canopy height and diversity during drought periods.ConclusionOur results show that fire has very limited effects on the composition and structure of these C3‐dominated montane grasslands. Our results support efforts by land managers to reintroduce fire on these historically burned landscapes.