Table 2 Linear mixed-effects regression model results from testing for differences between treatment and referent quadrats in vegetation cover, percent nonnative vegetation cover, and soil strength for horse trails at Coyote Canyon, Anza-Borrego Desert State Park, California, USA; Spring 2003.
Covariate | Coefficient (95% CI) | Back-Transformed coefficient | P-value |
|---|---|---|---|
Percent Total Vegetative Cover a | |||
Intercept | 1.14 (1.08, 1.20) | 29.03 (26.21, 31.93) | <0.01 |
Soil strength | 0.03 (0.01, 0.05) | 0.022 (0.002, 0.06) | <0.01 |
Dripline | 0.003 (0.0004, 0.005) | 0.002 (3.9 × 10-6, 0.0006) | 0.02 |
Quadratb | --- | --- | <0.01b |
   Quadrat 1 (trail) | -0.55 (-0.61, -0.49) | -7.35 (9.08, 5.77) | <0.01 |
   Quadrat 2 (0 m) | -0.03 (-0.09, 0.03) | -0.02 (0.22, 0.02) | 0.32 |
   Quadrat 3 (0.4 m) | -0.09 (-0.15, -0.03) | -0.19 (0.53, 0.02) | <0.01 |
   Quadrat 4 (1.4 m) | -0.09 (-0.27, 0.10) | -0.19 (1.85, 0.24) | 0.35 |
   Quadrat 5 (Referent) | --- | -- | --- |
Random effects | 0.12 (0.09, 0.15) | 0.12 (0.21, 0.59) | <0.01 |
Percent nonnative cover a | |||
Intercept | 0.38 (0.30, 0.47) | 3.60 (2.23, 5.31) | <0.01 |
Soil strength | 0.15 (0.08, 0.21) | 0.53 (0.16, 1.13) | <0.01 |
Soil strength2 | -0.03 (-0.04, 0.21) | -0.02 (0.04, 1.13) | 0.01 |
Dripline | 0.003 (0.0002, 0.005) | 0.0002 (1.0 × 10-6, 0.0006) | 0.03 |
Quadratb | --- | --- | <0.01b |
   Quadrat 1 (trail) | -0.17 (-0.23, -0.11) | -0.72 (1.32, 0.30) | <0.01 |
   Quadrat 2 (0 m) | -0.02 (-0.07, 0.04) | -0.01 (0.14, 0.03) | 0.51 |
   Quadrat 3 (0.4 m) | -0.04 (-0.09, 0.02) | -0.03 (0.20, 0.01) | 0.20 |
   Quadrat 4 (1.4 m) | -0.09 (-0.23, 0.06) | -0.19 (1.35, 0.09) | 0.25 |
   Quadrat 5 (Referent) | --- | -- | --- |
Random effects | 0.18 (0.15, 0.22) | 0.79 (0.53, 1.16) | <0.01 |
Soil strength | |||
Intercept | 2.44 (2.148, 2.727) | 88.19 (77.37, 95.82) | <0.01 |
Rain | -0.73 (-0.95, -0.51) | 12.74 (6.36, 20.92) | <0.01 |
Trail Area | -2.1 × 10-5 (-3.2 × 10-5, -0.0010) | -1.0 × 10-5 (3.0 × 10-10, 3.0 × 10-9) | <0.01 |
Dripline | -0.0045 (-0.0081, -0.0010) | -0.0005 (3.0 × 10-5, 0.002) | 0.01 |
Horse sign (present) | -0.15 (-0.29, -0.01) | -0.56 (0.002, 0.02) | 0.04 |
Horse sign (Referent) | --- | --- | --- |
Quadratb | --- | --- | <0.01b |
   Quadrat 1 (trail) | 0.48 (0.27, 0.68) | 0.24 (1.81, 11.12) | <0.01 |
   Quadrat 2 (0 m) | -0.15 (-0.28, -0.01) | -0.56 (0.002, 1.95) | 0.03 |
   Quadrat 3 (0.4 m) | -0.15 (-0.28, -0.02) | -0.56 (0.01, 1.95) | 0.02 |
   Quadrat 4 (1.4 m) | NA | NA | NA |
   Quadrat 5 (Referent) | --- | --- | --- |
Random effects | 0.48 (0.45, 0.64) | 0.48 (0.45, 0.64) | <0.01 |