- Title:
-
Effects of Repeated Low-intensity Fire on Bird Abundance in a Mixed Eucalypt Foothill Forest in South-eastern Australia
- Date:
- December 2003
- Organisations
- DSE
- Authors:
- Richard H. Loyn, Ross B. Cunningham and Christine Donnelly
- Location:
- Victoria, Australia
Overview
Bird communities were assessed in 1992–94 in the Wombat State Forest on 25 areas that had been subject to one of five experimental low-intensity burning treatments (frequent or infrequent burning in spring or autumn, or no burning—control), as part of a multidisciplinary study established in 1984. The 1992–94 assessments were made at least a year after the most recent burn. The frequently burnt areas had all been burned at least twice since experiments began in 1985 and the infrequently burnt areas just once, six to eight years previously. Data on bird abundance and species per count were analysed with respect to burning treatment by analysis of variance. Time, habitat data and pre-treatment data were also considered in supplementary analyses.Insectivorous birds that forage from open ground increased in abundance on burnt areas compared with controls, especially on areas burned frequently in autumn. Nectarivores showed complex patterns, apparently responding to fire positively or negatively at different times. Other changes were subtle, but birds that feed in shrub layers tended to be less common on burnt areas than controls, especially on areas burned frequently in spring. Overall, burning season had no significant effect on any group except as an interaction with frequency. Frequent burns served to maintain early successional stages that benefited some species and may have disfavoured others.
Habitat variables added little to this picture, except that hollow-nesting birds responded strongly and positively to hollow density indices for each area. Inclusion of pre-treatment data as covariates did not improve the models produced, though the data were helpful in describing qualitative changes and stability in bird communities.
Fuel reduction burning in patches of less than 40 ha appears to have minor effects on bird communities in this forest (compared with not burning), and may benefit some species that forage from open ground. Autumn burns are marginally preferable to spring burns. Greater effects would be expected in forests with different shrub structures. Effects of broadscale burning would depend on the mosaic of burnt and unburnt areas produced. Long-term vegetation changes should be avoided. All effects should be evaluated with regard to effects of wildfire and any influence of fuel reduction burning on wildlife behaviour.
