Landscape heterogeneity following large fires: insights from Yellowstone National Park, USA

Abstract

We characterised the remarkable heterogeneity following the large, severe fires of 1988 in Yellowstone National Park (YNP), in the northern Rocky Mountains, Wyoming, USA, by focussing on spatial variation in post-fire structure, composition and ecosystem function at broad, meso, and fine scales. Ecological heterogeneity at multiple scales may enhance resilience to large, severe disturbances by providing structural, biological and functional redundancy. Post-fire heterogeneity in stand age, coarse wood abundance, microbial and understorey communities reflected interactions between existing pre-fire patterns and fire severity at different scales, suggesting that environmental context plays an important role in successional responses to large fires. In response to these post-fire patterns, heterogeneity in carbon (C) and nitrogen (N) storage, N mineralisation, decomposition, and productivity was also evident at multiple scales and may confer resiliency to large fires. For example, at broad scales, C storage in YNP appears resistant to changes in age-class structure associated with large stand-replacing fires. In summary, the YNP landscape is recovering rapidly from the 1988 fires through natural mechanisms, owing to the abundance and spatial heterogeneity of post-fire residuals, but other systems with fewer biotic legacies may be less resilient to such large, severe fires.