Action: Use prescribed burning on shrublands
- One controlled study from the USA, of eight captured, found that overall bird densities were similar between burned and unburned areas, whilst a replicated and controlled study found that species numbers and bird densities did not vary between areas burned in summer and those burned in winter.
- Three studies found that some species were more abundant on areas that were burned, compared to those managed differently, or not at all. Four studies found that the densities of individual species were similar or lower on burned areas compared to control areas or those under different management.
- A before-and-after study found that sage sparrows chose different nest sites before burning compared to after. A controlled study found no differences in greater sage grouse movement between burned and unburned areas.
Fire can play an important part in shrublands by maintaining the balance between woody and herbaceous vegetation types. If the natural systems have been modified so that fire does not occur as regularly as it used to, for example to reduce risks to homes and property, then prescribed burning may be necessary to maintain the natural dynamics of the habitat.
Supporting evidence from individual studies
A before-and-after study in shrubland in 1962-1963 in Wisconsin, USA (Anderson 1969), found that the number of male prairie chickens Tympanuchus cupido displaying at a site increased from seven to 13 following prescribed burning. However, the authors note that the number at other sites without burning also increased over the period, (by a single male each time).
A controlled study in 1980 in Utah, USA (Castrale 1982), found that response of breeding songbirds in sagebrush habitat chained or burned 3-4 years earlier varied between species. Total bird densities and diversity were similar between a chained site (i.e. vegetation knocked down by dragging a large chain), burned sites and sites without any intervention for 17 years. However, a burned site had 50-86% fewer Brewer's sparrow Spizella breweri (a sagebrush specialist) territories than chained or untreated sites. Horned lark Eremophila alpestris densities were 200-250% higher on the burned site compared to the untreated one. Vesper sparrow Pooecetes gramineus and western meadowlark Sturnella neglecta densities appeared unaffected by sagebrush control.
A before-and-after study in Artemisia spp. sagebrush habitat around the Idaho National Engineering Laboratory, Idaho, USA (Winter & Best 1985), found that in 1982 all 34 sage sparrow Amphispiza belli nests found were within sagebrush plants. In 1983, after a prescribed burn created a mosaic of burned and unburned patches, 23 of 29 nests (79%) were within sagebrush but six were in atypical locations: five on the ground under small plants and one within a grass clump.
A replicated and controlled study in shrub dominated by saw-palmetto Serenoa repens (a type of palm) in 1988-1989 in Myakka River State Park, Florida, USA (Fitzgerald & Tanner 1992), found that the total number of birds and the number of species found did not vary between two sites burned in winter (January 1988) and two burned in summer (June 1988) (1.7 species and 2.4 individuals/winter burned site vs. 1.5 and 1.9 for summer burned). There were no differences between winter-burned and control (unburned) sites, but summer-burned sites had significantly fewer species and individuals (2.0 species and 2.7 individuals/unburned site).
A controlled before-and-after study in May-August 1989 in Wyoming big sagebrush Artemisia tridentata wyomingensis and threetip sagebrush A. tripartita scrub in Big Desert, Idaho, USA (Fischer et al. 1996), found that relative abundances of greater sage grouse Centrocercus urophasianus were similar between a burned and unburned area before and after burning. Abundances of Hymenoptera species (an important part in grouse diets) were significantly lower in the burned area two and three years after burning.
A controlled study in 1987-1992 in the Big Desert sagebrush ecosystem (dominated by Wyoming big sagebrush) of southeast Idaho, USA (Fischer et al. 1997), found that there were no differences in timing, distance or direction of movement of 81 greater sage grouse between burned and unburned areas. A 5,800 ha area of sagebrush was burned in late summer 1989, removing vegetation from approximately 57% of the area.
A replicated, controlled study in montane shrubland in Rocky Mountain National Park, Colorado, USA, (Jehle et al. 2006) found that green-tailed towhee Pipilo chlorurus occurrence and nesting density was significantly lower for 3-5 years after burning in four areas of subject to prescribed burning (0.05-0.30 birds/ha) compared with three unburned sites (0.60-1.95 birds/ha). Two sites, Deer Ridge Low (55 ha) and Deer Ridge High (80 ha), were burned in 1998 and 1999 respectively, with towhee density estimated in June 2002-2003. Of 179 nests found, only 14 (8%) were at burned sites, and were within remnant patches of live shrubs (in areas where burn severity had been lower).
A controlled study in 1999-2001 on Nantucket Island, Massachusetts, USA (Zuckerberg & Vickery 2006), found that eastern towhee Pipilo erythrophthalmus and common yellowthroat Geothlypis trichas were significantly more abundant in burned areas of shrubland than in mown areas. Towhees (but not yellowthroats) were also more common in burned areas than controls (towhees: 1.4 birds/ha for burned areas vs. 1.1 for control areas; yellowthroats: 0.4 for both control and burned areas). Song sparrows Melospiza melodia were not significantly more abundant on burned areas than on control or mown areas (0.3 birds/ha for mown areas vs. 0.4 for controls and burned areas).
- Anderson R.K. (1969) Prairie chicken responses to changing booming-ground cover type and height. The Journal of Wildlife Management, 33, 636-643
- Castrale J.S. (1982) Effects of two sagebrush control methods on nongame birds. The Journal of Wildlife Management, 46, 945-952
- Winter B.M. & Best L.B. (1985) Effect of prescribed burning on placement of sage sparrow nests. The Condor, 87, 294-295
- Fitzgerald S.M. & Tanner G.W. (1992) Avian community response to fire and mechanical shrub control in south Florida. Journal of Range Management, 45, 396-400
- Fischer R.A., Reese K.P. & Connelly J.W. (1996) An investigation on fire effects within xeric sage grouse brood habitat. Journal of Range Management, 49, 194-198
- Fischer R.A., Wakkinen W.L., Reese K.P. & Connelly J.W. (1997) Effects of prescribed fire on movements of female sage grouse from breeding to summer ranges. The Wilson Bulletin, 109, 82-91
- Jehle G., Savidge J.A. & Kotliar N.B. (2006) Green-tailed towhee response to prescribed fire in montane shrubland. The Condor, 108, 634-646
- Zuckerberg B. & Vickery P.D. (2006) Effects of mowing and burning on shrubland and grassland birds on Nantucket Island, Massachusetts. Wilson Journal of Ornithology, 118, 353-363