Table 1. Results of GLMM testing of the influence of honey bee abundance on wild bee richness and abundance.
Data were pooled across plots at each site and sampling period (N = 8 plots per site, 15 sites, 5 sampling periods). Covariates included, floral richness, floral density, greenspace type (park, community garden, cemetery), sampling period, and the proportion of herbaceous vegetation and impervious surface within a 500 m buffer around each site. Floral richness and density were measured locally at each site, and herbaceous vegetation was the amount of green vegetation of >3 m in height within the buffer zone, and was used as a proxy for floral resource availability within the foraging range of wild bees. Predictors for each model were scaled and centered on zero. β is the coefficients for each predictor, CI is the 95% confidence intervals and p is the significance. Significant predictors for either bee richness or abundance are in bold.
| Wild bee richness | Wild bee abundance | Small bee richness | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Predictors | β | CI | p | β | CI | p | β | CI | p |
| (Intercept) | 2.46 | 0.98–3.94 | <0.001 | 1.76 | −1.53–5.06 | 0.293 | 2.71 | 1.06–4.35 | 0.001 |
| Honey bee abundance | −0.18 | −0.36–0.01 | 0.043 | −0.07 | −0.18–0.05 | 0.246 | −0.20 | −0.41—0.00 | 0.046 |
| Floral richness | 0.40 | 0.07–0.73 | 0.018 | 0.48 | 0.22–0.75 | <0.001 | 0.01 | −0.37–0.38 | 0.964 |
| Floral density | 0.38 | 0.06–0.70 | 0.021 | 0.58 | 0.41–0.75 | <0.001 | 0.12 | −0.24–0.48 | 0.506 |
| Herbaceous veg. (%) | 0.29 | −0.25–0.84 | 0.291 | −0.05 | −1.45–1.36 | 0.947 | −0.14 | −0.74–0.46 | 0.649 |
| Impervious surface (%) | −0.24 | −1.04–0.55 | 0.546 | 0.34 | −1.78–2.45 | 0.756 | −0.77 | −1.65–0.12 | 0.089 |
| Greenspace type (garden) | −0.29 | −0.65–0.07 | 0.118 | 0.87 | 0.21–1.53 | 0.010 | 0.30 | −0.11–0.71 | 0.158 |
| Greenspace type (park) | −0.80 | −1.18–0.43 | 0.968 | <0.001 | 0.19–2.08 | 0.019 | −0.48 | −0.93–0.04 | 0.032 |
| Sampling period (2) | −0.08 | −0.54–0.68 | 0.838 | −0.19 | −0.47–0.09 | 0.181 | 0.35 | −0.47–1.17 | 0.408 |
| Sampling period (3) | 0.08 | −0.68–0.84 | 0.845 | 0.34 | 0.06–0.62 | 0.015 | 0.02 | −0.81–0.84 | 0.971 |
| Sampling period (4) | 0.20 | −0.56–0.96 | 0.604 | −0.17 | −0.45–0.11 | 0.238 | −0.52 | −1.36–0.32 | 0.221 |
| Sampling period (5) | −0.09 | −0.86–0.68 | 0.824 | −0.16 | −0.45–0.13 | 0.273 | −0.50 | −1.35–0.34 | 0.244 |