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Fire and birds in the southwestern United States

Posted date: July 26, 2006
Publication Year: 
2005
Authors: Bock, Carl E.; Block, William M.
Publication Series: 
Miscellaneous Publication
Source: In: Saab, V.; Powell, H., eds. Fire and avian ecology in North America. Studies in avian biology no. 30. Camarillo, Calif.: Cooper Ornithological Society: 14-32

Abstract

Fire is an important ecological force in many southwestern ecosystems, but frequencies, sizes, and intensities of fire have been altered historically by grazing, logging, exotic vegetation, and suppression. Prescribed burning should be applied widely, but under experimental conditions that facilitate studying its impacts on birds and other components of biodiversity. Exceptions are Sonoran, Mojave, and Chihuahuan desert scrub, and riparian woodlands, where the increased fuel loads caused by invasions of exotic grasses and trees have increased the frequency and intensity of wildfires that now are generally destructive to native vegetation. Fire once played a critical role in maintaining a balance between herbaceous and woody vegetation in desert grasslands, and in providing a short-term stimulus to forb and seed production. A 3–5 yr fire-return interval likely will sustain most desert grassland birds, but large areas should remain unburned to serve species dependent upon woody vegetation. Understory fire once maintained relatively open oak savanna, pinyon-juniper, pine-oak, ponderosa pine (Pinus ponderosa), and low elevation mixed-conifer forests and their bird assemblages, but current fuel conditions are more likely to result in stand-replacement fires outside the range of natural variation. Prescribed burning, thinning, and grazing management will be needed to return fire to its prehistoric role in these habitats. Fire also should be applied in high elevation mixed-conifer forests, especially to increase aspen stands that are important for many birds, but this will be an especially difficult challenge in an ecosystem where stand-replacement fires are natural events. Overall, surprisingly little is known about avian responses to southwestern fires, except as can be inferred from fire effects on vegetation. We call for cooperation between managers and researchers to replicate burns in appropriate habitats that will permit rigorous study of community and population-demographic responses of breeding, migrating, and wintering birds. This research is critical and urgent, given the present threat to many southwestern ecosystems from destructive wildfires, and the need to develop fire management strategies that not only reduce risk but also sustain bird populations and other components of southwestern biological diversity.

Citation

Bock, Carl E.; Block, William M. 2005. Fire and birds in the southwestern United States. In: Saab, V.; Powell, H., eds. Fire and avian ecology in North America. Studies in avian biology no. 30. Camarillo, Calif.: Cooper Ornithological Society: 14-32