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. 2015 Jun 7;282(1808):20150002. doi: 10.1098/rspb.2015.0002

Figure 2.

Figure 2.

Predictions of the final model for weed species richness (α-field diversity), biodiversity partitioning (α, β, γ) of species richness for the common and less frequent species, and observed mean species richness of less frequent species in field margins (α-field diversity), depending on the % of OF in the landscape. (a) Model predictions for the response of species richness (α-field diversity) to the proportion of OF in the landscape (model M4.b) in both organic and conventional fields, and both in field margins and field cores. The model shows an increase of species richness both in OF and conventional fields, and both in field cores and margins with the % of OF in the landscape but this response is stronger for field margins. (b) Additive partitioning approach of biodiversity (more common species). The figure shows the mean α, β and γ diversity for organic and conventional fields (core and margin) with the same number of fields per category (74 fields). One thousand repetitions were done by bootstrapping and we calculated the mean and the 95% CI for species richness by class on these repetitions. This figure shows that if γ-diversity for abundant species seems equal between field cores and margins and OF and conventional fields, we observe that α-diversity of conventional field cores appears lower. (c) Additive partitioning approach of biodiversity (less frequent species). One thousand repetitions were done by bootstrapping and we calculated the mean and the 95% CI for species richness by class on these repetitions (74 fields). We observe that the diversity of rare species is mostly explained by β-field diversity, and that diversity (both α and β) appears lower in field core than in field margin and in conventional than in OF fields. (d) Mean diversity of the field margins for less frequent species depending on the percentage of OF in the landscape. The species richness of each class was calculated on the same number of fields (12 fields). One thousand repetitions were done by bootstraping, and we calculated the mean and the 95% confidence interval for species richness by class on these repetitions. We observe that diversity increase with the percentage of OF in the landscape, both for OF and conventional fields.