Table 1 Statistical models for the effects of landscape composition and potential interactions with predator releases on lepidopteran larval abundance, plant damage, crop biomass, predation rates, and natural enemy abundance. Statistical models were used to estimate mean and 95% CI of effect sizes for overall effects of augmentative predator releases (Fig. 2) and the interactions with landscape composition (Figs 3–5). Dashed lines represent interaction terms not included in the final models because they were not significant (P > 0.05). Boldface text indicates significant relationships (P < 0.05).
From: Effectiveness of augmentative biological control depends on landscape context
Response variables and predictors | d.f. | F | P-value |
|---|---|---|---|
Lepidoptera abundance | |||
Cropland (1000 m) | 1, 11.887 | 4.885 | 0.047 |
Treatment (control and predator releases) | 1, 40.407 | 5.200 | 0.028 |
Interaction (cropland × treatment) | 1, 40.918 | 4.797 | 0.034 |
Plant damage | |||
Cropland (2000 m) | 1, 11.335 | 7.656 | 0.018 |
Treatment (control and predator releases) | 1, 43.651 | 19.520 | <0.001 |
Interaction (cropland × treatment) | 1, 43.617 | 23.079 | <0.001 |
Crop biomass | |||
Cropland (2000 m) | 1, 12.707 | 0.584 | 0.459 |
Treatment (control and predator releases) | 1, 43.513 | 10.107 | 0.003 |
Interaction (cropland × treatment) | 1, 43.049 | 10.976 | 0.002 |
Predation on sentinel larvae | |||
Semi-natural areas (2000 m) | 1, 30.273 | 1.820 | 0.187 |
Treatment (control and predator releases) | 1, 32.988 | 4.355 | 0.045 |
Interaction (semi-natural × treatment) | ----- | ----- | ----- |
Predation on sentinel eggs | |||
Semi-natural areas (2000 m) | 1, 11.505 | 0.128 | 0.727 |
Treatment (control and predator releases) | 1, 26.408 | 5.229 | 0.030 |
Interaction (semi-natural × treatment) | 1, 25.844 | 4.618 | 0.041 |
Ground-dwelling predators | |||
Cropland (2000 m) | 1, 11.301 | 6.753 | 0.024 |
Treatment (control and predator releases) | 1, 31.629 | 0.001 | 0.973 |
Interaction (cropland × treatment) | ----- | ----- | ----- |
Parasitoids | |||
Semi-natural areas (1000 m) | 1, 33.140 | 2.447 | 0.127 |
Treatment (control and predator releases) | 1, 28.234 | 4.880 | 0.035 |
Interaction (semi-natural × treatment) | 1, 27.759 | 6.105 | 0.020 |
Foliar-foraging predators | z-value 2 | P-value 2 | |
Semi-natural areas (500 m) | −0.791 | 0.429 | |
Treatment (control and predator releases) | −5.121 | <0.001 | |
Interaction (semi-natural × treatment) | 4.815 | <0.001 | |
