Skip to main content
. 2002 Aug 12;99(17):11235–11240. doi: 10.1073/pnas.172700199

Table 3.

Results of logistic regression of Wood Thrush occurrence on environmental variables

Variable Est. param. Wald χ2 Pr. >χ2 Std. est. Odds ratio
Intercept 2.82 0.63 0.429
FC1 0.38 1.80 0.180 0.21 1.46
FC2 −0.47 10.03 0.002 −0.17 0.63
FC3 0.26 6.54 0.011 0.14 1.30
FC4 2.47 6.53 0.011 1.26 56.18
FC5 0.94 15.37 0.000 0.52 2.55
FC6 4.03 6.73 0.010 1.90 2.56
PC1 −6.12 5.01 0.025 −2.31 0.002
PC2 −0.11 0.15 0.696 −0.05 0.90
pH −0.82 1.59 0.206 −0.28 0.44
Trend 0.02 0.10 0.749 0.05 1.02
FC4 × pH −0.42 5.76 0.016 −1.19 0.66
FC6 × pH −0.67 6.46 0.011 −1.73 0.514
PC1 × pH 1.27 6.61 0.010 2.65 3.560
FC1 × PC1 −0.73 4.93 0.026 −0.47 0.483
FC5 × PC1 −0.76 15.54 0.000 −0.49 0.468
FC6 × PC1 0.72 5.13 0.024 0.37 2.064
Trend × FC1 −0.15 6.84 0.009 −0.39 0.863
Trend × FC6 0.22 9.83 0.002 0.54 1.242
Trend × PC2 0.12 4.90 0.027 0.24 1.128

Est. param., estimated parameter; Std. est., standardized estimate; pH, pH of the top 5 cm of soil; Trend, natural log of estimated abundance of Wood Thrush at any site; AIC intercept only, 841.792; AIC intercept and covariates, 761.130. FC1 reflects landscape-level forest fragmentation; FC2, coniferous dominance; FC3, patch size and distance-from-edge; FC4, deciduous shrubs; FC5, sapling layer; FC6, decreases with increasing altitude and decreasing canopy height (22). PC1 represents acid ion deposition; PC2, calcium and ammonium deposition (see Tables 1 and 2).

HHS Vulnerability Disclosure