Fire regime

A fire regime is the pattern, frequency, and intensity of the bushfires and wildfires that prevail in an area.[1] It is an integral part of fire ecology, and renewal for certain types of ecosystems. If fires are too frequent, plants may be killed before they have matured, or before they have set sufficient seed to ensure population recovery. If fires are too infrequent, plants may mature, senesce, and die without ever releasing their seed.

Effects from altered fire regimes

Biotas that are able to survive and adapt to their particular fire regimes can receive significant benefits: the ability to regrow stronger, greater protection against fire and disease, or new space to grow in formerly occupied locations.[1] As fire regimes change the area both current and future species may begin to suffer.[1][2] Decreasing fire intervals negatively affect the ability of fire-killed species to recover to pre-disturbance levels, leading to longer recovery times. Some species, such as resprouters, are better able to withstand changing fire regimes through increased resistance and resilience. But, many fire-killed species may be unable to recover if shortened fire intervals persist over time.[2]

Australia

Bushfire is especially important in Australia, where much of the vegetation has evolved in the presence of regular fires caused by the Aboriginal practice of firestick farming. As a result of this, components of the vegetation are adapted to, and depend upon, a particular fire regime, and their survival is affected by disruption of that fire regime.

An example is found in the many Banksia species that are both fire-sensitive and serotinous; these species are killed by fire, but fire also triggers the release of seed, ensuring population recovery. Under an ideal fire regime, a plant that recruits following a bushfire will have sufficient time to mature and build an adequately large bank of seed, before the next fire kills it and triggers seed release.

United States

The California chaparral and woodlands ecoregion, covering a large portion of the U.S. state, is dependent on periodic natural wildfires for optimal health and renewal.[3] The increasing rural-urban fringe interface and wildfire suppression practices of the last century have resulted in an increased vulnerability to less frequent, more severe wildfires; fire suppression increased fuel in coniferous forests. [4] Chaparral fire suppression, unlike fire suppression in coniferous forests, has not affected the natural fire regime, according to a study conducted by the United States Geological Survey. Furthermore, prescribed burning in the shrubland area was also proven ineffective at reducing the risk of wildfires, which are normally driven by high winds and unaffected by modern fire suppression.[4]

See also

References

  1. 1 2 3 Stephen J. Pyne. "How Plants Use Fire (And Are Used By It)". NOVA online. Retrieved 2009-06-30.
  2. 1 2 Enright, Neal J.; Fontaine, Joseph B.; Lamont, Byron B.; Miller, Ben P.; Westcott, Vanessa C. (2014-11-01). "Resistance and resilience to changing climate and fire regime depend on plant functional traits". Journal of Ecology. 102 (6): 1572–1581. doi:10.1111/1365-2745.12306. ISSN 1365-2745.
  3. ↑ http://www.californiachaparral.com/fire/firenature.html Wildfire in the Chaparral . 9/29/2010
  4. 1 2 Keeley, Jon E.; Fotheringham, C. J.; Morais, Marco (1999-06-11). "Reexamining Fire Suppression Impacts on Brushland Fire Regimes". Science. 284 (5421): 1829–1832. doi:10.1126/science.284.5421.1829. ISSN 0036-8075. PMID 10364554.

External links


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