Ecological Archives E083-012-A2

Paul B. Drewa, William J. Platt, and E. Barry Moser. 2002. Fire effects on resprouting of shrubs in headwaters of southeastern longleaf pine savannas. Ecology 83:755–767.

Appendix B. Mixed linear model ANCOVA of shrub stem densities (all species combined).

Source of Variation NDF DDF Type III F P
Covariate 1 237 439.29 <0.001
Geographic Region 1 10 17.12 0.002
Fire Season 1 10 16.67 0.002
Geographic Region x Fire Season 1 10 2.57 0.140
Plot (Geographic Region x Fire Season) 10      
Habitat 1 10 0.53 0.483
Geographic Region x Habitat 1 10 5.22 0.046
Habitat x Fire Season 1 10 5.97 0.035
Geographic Region x Habitat x Fire Season 1 10 0.03 0.877
Habitat x Plot (Geographic Region x Fire Season) 10      
Time 2 37 2.36 0.109
Geographic Region x Time 2 37 2.93 0.066
Fire Season x Time 2 37 2.61 0.087
Geographic Region x Fire Season x Time 2 37 1.89 0.165
Habitat x Time 2 37 0.38 0.688
Geographic Region x Habitat x Time 2 37 1.05 0.361
Habitat x Fire Season x Time 2 37 11.38 <0.001
Geographic Region x Habitat x Fire Season x Time 2 37 1.68 0.200
Time x Habitat x Plot (Geographic Region x Fire Season) 37      
Residual 237      

   Notes: Type III F statistics and P values are based on likelihood estimations rather than sums of squares. Densities (n + 1) were natural log-transformed before analysis. The covariate represents pre-treatment shrub densities in quadrats at the onset of the study. NDF: numerator degrees of freedom; DDF: denominator degrees of freedom. Geographic region: LA and FL; Fire Season: growing and dormant season fires; Habitat: upslope savannas and downslope seepages; Time: censuses conducted after fires in each plot; Plot: replicated areas within each region containing upslope savannas and downslope seepages and that were burned as units.



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