Document: STE-3-68-32

Effects of fire practices on neotropical migrant, forest-obligate bird species in Holly Springs National Forest, MS USA.

AQUILANI, S.M.* and J.S.BREWER

University of Mississippi, Oxford, MS 38677 USA ¹

Abstract:
One wildlife concern with regard to the use of prescribed fires in pine-oak forests is that fires may adversely impact nesting habitat for forest songbirds. By focusing on a guild of ground- and shrub-nesting migrants, we investigated whether fires resulted in 1.) the rejection of altered habitat due to the absence of key nesting habitat components; or 2.) increased chick mortality due to increased brood predation and parasitism. Also, we examined potential differences in tree species composition and vegetation structure between sites with different fire histories. Fixed-radius point counts surveying the entire avian community and intensive nest searches for ground-/shrub-nesters were conducted in sites with different fire frequencies (unburned, 2 burns/past 20 years, and 4 burns/past 20 years). In addition, within each fire frequency site, 2-3 tree sampling plots and 10 vegetation structure sampling points were established. Relative abundance of ground-/shrub-nesting migrants (Kruskal-Wallis = 6.056; P = 0.10) and avian community composition (Multi-Response Permutation Procedure = -0.685; P = 0.226) did not differ between study sites. Although nesting success varied between study sites, nesting success was not lower in the 4burn (0.605, S.E.=0.007) and the 2burn (0.331, 0.011) sites compared to the 2 unburned sites (0.424, 0.017 and 0.343, 0.013). Cowbird parasitism was relatively absent in all sites. Tree species composition differed between sites (Monte Carlo p < 0.01), yet was largely correlated with longitude (r = -0.98) rather than fire frequency. Interestingly, Detrended Correspondence Analysis (DCA) revealed that avian community structure differed within sites. Samples sorted with respect to relative abundance of nesting-guilds. Axis 2 sorted with resepct to midcanopy-nesting migrants vs. canopy-nesting residents (eigenvalue for axis 2 was 0.33). Axis 3 sorted with respect to obligate brood parasites vs. ground-/shrub-nesting migrants (eigenvalue was 0.21). Our research suggests that fire regime may have little adverse impact on ground- and shrub-nesting Neotropical migrants in pine-oak forests of north Mississippi. However, our preliminary results indicate that fragmentation and other landscape factors may significantly affect avian nesting success and community composition.

Keywords: Neotropical migrants, prescribed fire, nesting success

This abstract is being presented at: 10:30 AM in session:
AVIAN ECOLOGY