The effect of fire interval on post-fire understorey communities in Yellowstone National Park

Abstract

Abstract Questions: How does the time interval between subsequent stand-replacing fire events affect post-fire understorey cover and composition following the recent event? How important is fire interval relative to broad- or local-scale environmental variability in structuring post-fire understorey communities? Location: Subalpine plateaus of Yellowstone National Park (USA) that burned in 1988. Methods: In 2000, we sampled understorey cover and Pinus contorta density in pairs of 12-yr old stands at 25 locations. In each pair, the previous fire interval was either short (7–100 yr) or long (100–395 yr). We analysed variation in understorey species richness, total cover, and cover of functional groups both between site pairs (using paired t-tests) and across sites that experienced the short fire intervals (using regression and ordination). We regressed three principal components to assess the relative importance of disturbance and broad or local environmental variability on post-fire understorey cover and r...