Effects of Large-Scale Fire on Plant Regneration on Subalpine Plateaus in Yellowstone National Park

Abstract

The scale of the 1988 fires in Yellowstone National Park (YNP) raised numerous questions for the management of natural areas subject to large but infrequent natural disturbances. The central question that we have addressed in our postfire studies is whether the effects of large-scale fires, such as those in 1988, differ qualitatively as well as quantitatively from effects of smaller fires. The answer to this question has important implications for our understanding of the evolution of natural systems and for management of future disturbances in places like YNP (Christensen et al. 1989). We approached this question on Yellowstone's extensive subalpine plateaus by comparing patterns of plant regeneration in large vs. small fire-generated patches after the 1988 fires. This research complements our work in northern YNP that focused on the landscape-level interactions among ungulates, vegetation, and fire, and was published in the UW-NPS Report for 1992 (Turner et al. 1992). Recent research into the mechanisms of plant succession following fire or other disturbances has demonstrated that species responses may vary with different kinds and severities of disturbance and with the larger spatial and temporal context of the disturbance. For example, Rowe (1983) describes several species of ·boreal plants that resprout from surviving belowground structures after low-severity fires and dominate early successional stages; these same species are killed by severe fires and replaced by other species having greater dispersal abilities (also see Miller 1982, Malanson 1984, and Halpern 1989). The scale and heterogeneity of the 1988 yellowstone fires provide an exceptional opportunity to evaluate the relative importance of the size and spatial patterning of fire-created patches for reestabishment of plant species representing different modes of reproduction.