Fire and Riparian Zones

Gregory et al. (1991) defines riparian areas or zones as “three-dimensional zones of direct physical and biotic interactions between terrestrial and aquatic ecosystems.” In the Southeast, riparian buffer strips can be effective at reducing sediment and nutrient inputs to aquatic systems (Lowrance 1985, Dillaha et al. 1989, Daniels and Gilliam 1996). Furthermore, intact riparian zones are integral to aquatic habitats by reducing stream temperature and as a source for leaf detritus and coarse woody debris (allochthonous inputs), both of which are important as food and structure to aquatic organisms. Riparian zones provide a number of other benefits to stream ecosystems.

Uncontrolled fire within riparian areas can be detrimental to water quality under conditions where all vegetation is consumed. In such cases:

• the risk of soil erosion is increased,
• lower nutrient uptake by plants may occur,
• increases in runoff may be observed, and
• high stream temperatures may result.

Conversely, a properly executed prescribed fire can increase nutrient uptake and create more surface roughness by establishing dense vegetation. High surface roughness can reduce overland flow velocities, in turn reducing the risk of soil erosion.

An example of a native fire-dependent riparian species in the South is giant cane (Arundinaria gigantea). Giant cane is a grass species that requires fire for vigorous growth (Platt and Brantley 1997) and has shown its importance as an effective riparian species in its ability to attenuate nutrients and sediment from overland flow, soil water, and groundwater (Schoonover et al. 2001, 2002).

See also: Fire Effects on Watershed Hydrology.