Wednesday, 19 November 2003: 9:00 AM
Spatial heterogeneity in fire temperature: causes and consequences for plant diversity
As part of our study of the factors controlling plant diversity in the Sierra Nevada mixed-conifer forest, we investigated how fine-scale variability in fire temperature influences post-fire distributions of herbs, shrubs, and tree seedlings. If species respond differentially to fire temperature, then a more heterogeneous burn should lead to a more diverse plant community after fire. We collected high-resolution (1 meter) floristic and environmental data along 256-meter transects in the Fire/Fire Surrogates plots at Sequoia National Park. In addition, we used temperature-sensitive paints to estimate maximum fire temperature at every meter on our transects. Using spatial statistical approaches designed to account for the fact that different environmental variables exert their influence on plants at different spatial scales, we show (1) remarkable fine-scale variability in fire temperature, some of which is predictable from pre-fire heterogeneity in fuels, light and soil moisture, and local topography; and (2) how post-fire species distributions reflect this heterogeneity in fire temperature. We discuss how heterogeneity can be incorporated into fire management plans to maintain understory plant diversity.