Restoring savanna using fire: Impact on the breeding bird community

Restoration of many terrestrial plant communities involves the reintroducti on of fire. However, there have been few studies of the effects of fire on the avifauna during the restoration process. To study the effects of oak sa vanna restoration on avian communities, breeding birds were censused and th e vegetation structure documented in seven experimental burn units (8-18 ha ) that had experienced different frequencies of controlled burns during the past 31 years (0-26 burns). Data were analyzed with both direct and indire ct gradient analyses using multivariate techniques. The results showed that , as savanna restoration proceeded, there was a general decline in predomin antly insectivorous species, particularly those that feed in the upper cano py region (leaves and air space), and a general increase in omnivorous spec ies, particularly those that feed on the ground and in the lower canopy. In sectivorous bark gleaners (woodpeckers) also increased during restoration a nd were correlated with the increase in standing dead trees resulting from the fires. Overall, savanna restoration resulted in increases in the abunda nce of many open country bird species, including many species that have bee n declining in central and eastern North America, including red-headed wood pecker, Baltimore oriole, eastern kingbird, vesper sparrow, field sparrow, lark sparrow, brown thrasher, American goldfinch, and brown-headed cowbird. The shifts in species and guilds were correlated with changes in burn freq uency and the macro vegetation structure-tree and shrub density, leaf area index, and relative proportion of standing dead trees. The findings show th at savanna restoration can increase bird diversity and provide important ha bitat for uncommon or declining bird species. These birds are most likely a ttracted to one or more of the distinctive habitat features of the restored savanna environments, including scattered mature trees, standing dead tree s and snags, and presence of both shrubby and grassland vegetation. The fin dings also suggest that restoration ecologists and wildlife biologists will need to work together to achieve desired goals, since different types of s avanna restoration efforts may produce different effects on the breeding bi rd community.