Table 1.
Effects of farming system on number of species (species density), diversity (dominance) and abundance.
| species density | dominance | abundance | |||||||
|---|---|---|---|---|---|---|---|---|---|
| p* | D** | R (CI)a | p* | D** | R (CI)a | p* | D** | R (CI)a | |
| plants (crop margin)b | <0.001 | 0.42 | 1.51 (1.37–1.67) | n.a. | n.a. | n.a. | n.a. | n.a. | n.a. |
| plants (field boundary)b | <0.001 | 0.16 | 1.17 (1.07–1.27) | 0.525 | −0.03 | 0.97 (0.87–1.07) | 0.249 | 0.04 | 1.04 (0.97–1.23) |
| plants (within-crop)b | <0.001 | 0.62 | 1.85 (1.68–2.05) | <0.001 | −0.44 | 0.64 (0.56–0.74) | <0.001 | 0.74 | 2.09 (1.74–2.53) |
| spiders (boundary pre-harvest) | 0.544 | 0.03 | 1.03 (0.92–1.17) | 0.618 | −0.01 | 0.99 (0.95–1.03) | 0.322 | 0.10 | 1.10 (0.92–1.32) |
| spiders (boundary post-harvest) | 0.171 | 0.10 | 1.11 (0.92–1.34) | 0.465 | 0.03 | 1.03 (0.96–1.12) | 0.011 | 0.20 | 1.22 (1.05–1.42) |
| spiders (crop pre-harvest) | 0.003 | 0.16 | 1.17 (1.06–1.30) | 0.099 | −0.04 | 0.96 (0.93–1.00) | 0.013 | 0.22 | 1.25 (1.05–1.48) |
| spiders (crop post-harvest) | 0.175 | 0.12 | 1.17 (0.92–1.46) | 0.088 | −0.07 | 0.93 (0.86–1.01) | 0.690 | 0.05 | 1.06 (0.83–1.36) |
| carabids (boundary pre-harvest) | 0.212 | −0.09 | 0.91 (0.79–1.06) | 0.092 | 0.05 | 1.05 (0.99–1.12) | 0.876 | 0.04 | 1.04 (0.78–1.37) |
| carabids (boundary post-harvest) | 0.046 | −0.01 | 0.83 (0.66–1.03) | 0.782 | −0.01 | 0.99 (0.93–1.05) | 0.119 | −0.12 | 0.83 (0.69–1.06) |
| carabids (crop pre-harvest) | 0.158 | 0.09 | 1.09 (0.99–1.20) | 0.484 | 0.02 | 1.02 (0.96–1.09) | 0.044 | 0.26 | 1.30 (1.02–1.66) |
| carabids (crop post-harvest) | 0.345 | 0.09 | 0.92 (0.77–1.09) | 0.575 | 0.02 | 1.02 (0.95–1.11) | 0.590 | 0.16 | 0.87 (0.64–1.21) |
| birds (winter 2000/01) | 0.162 | 0.08 | 1.05 (0.98–1.12) | 0.651 | −0.01 | 1.03 (0.89–1.16) | <0.001 | 0.27 | 1.39 (1.16–1.62) |
| birds (winter 2002/03) | 0.142 | 0.07 | 1.03 (0.99–1.06) | 0.663 | −0.03 | 0.98 (0.89–1.07) | 0.005 | 0.41 | 1.26 (1.08–1.44) |
| bats | 0.013 | 0.29 | 1.33 (1.08–1.65) | 0.006 | −0.17 | 0.84 (0.73–0.97) | 0.026 | 0.31 | 1.35 (1.06–1.75) |
Dominance is measured as the Berger–Parker dominance index (May 1975). *Significance of system effect (shown in bold) was based on z-tests (birds) or GLM models taking account of year (all other taxa). **Mean difference between organic (O) and non-organic (N) log-scale attribute (positive values indicate O>N).
a
Sample mean ratio of the O/N attribute with 95% confidence intervals in parentheses (values greater than 1 indicate O>N).
b
Excluding cropped plants.