Microbial Communities in Fire-Affected Soils

Of all the ways in which human activities can affect soil environments, fires are perhaps the most dramatic. Whether set deliberately or accidentally, the worldwide impact that such fires have is extensive, including the loss of human and animal lives as well as economic and ecological damage (UNECE et al. 2000; UNECE and FAO 2001; Davidenko and Eritsov 2003; Kudoh 2005; FAO 2005). The United Nations Food and Agricultural Organization (2005) estimated that 350 million hectares burn annually, and that approximately 90% of those fires are of human origin. The frequency and severity of surface fires have also increased in many parts of the world due to changes in climate and land management practices (Houghton et al. 1992; Renkin and Despain 1992; Glantz 1996; Neary et al. 1999; Westerling et al. 2006). Large fires tend to draw media attention, particularly when they impinge on densely inhabited or well-known wildlife areas. Their rapid spread, extreme temperatures, and the barren landscapes they leave behind can alter the surrounding ecosystem for years, decades, or even permanently. It is no surprise, therefore, that a premium has historically been placed on extinguishing fires as they happen, rather than on studying their ecological significance. Only recently have scientists begun to understand the critical roles that some fires play in sustaining natural environments, and on the parts that soil micro-organisms play in that process.