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Supporting Information 801
802
Additional supporting information may be found in the online version of this article.
803
Appendix S1. Plant-pollinator networks.
804
Table S1.1. Flowering plant species present in the study plots.
805
Table S1.2. Pollinator species observed visiting flowering plants 806
Appendix S2. Rarefaction curves.
807 808
34 Figure legends
809 810
Figure 1. Non-native Hedysarum (left) and detail of an inflorescence being visited by 811
a honeybee (right). Photographs by A. Montero-Castaño.
812 813
Figure 2. Effect of Hedysarum on the pollination patterns of resident plants. Mean ± 814
95%CI (a) visits (standardised per flower and hour and log-transformed), (b) 815
normalised degree, (c) niche overlap and (d) proportion of honeybee visits to 816
Hedysarum and resident papilionate and non-papilionate species in invaded and 817
removal plots. Upper case symbols represent the significance levels for differences 818
between invaded and removal plots according to the post hoc multilevel comparisons 819
conducted for the models: ** p < 0.01, n.s = no significant.
820 821
Figure 3. Effect of Hedysarum on the foraging behaviour of pollinators. Mean ± 822
95%CI (a) visits (standardised per flower and hour and log-transformed), (b) 823
normalised degree, (b) and (c) niche overlap of the honeybee, bees and non-bees in 824
invaded and removal plots. Upper case symbols represent the significance levels for 825
differences between invaded and removal plots; in the case of bees and non-bees 826
functional groups, according to the post hoc multilevel comparisons conducted for 827
the models: ˙ p-value = 0.05, ** p < 0.01, *** p < 0.001, n.s = no significant.
828 829
Figure 4. Relationship between interaction rewiring and changes in the foraging 830
behavior of the honeybee. (a) Positive relationship between these two variables and 831
(b) its bipartite network representation. Changes in the foraging behaviour of the 832
honeybee are defined as the difference in the proportion of visits to a given plant 833
species that the honeybee achieved in invaded and removal paired networks.
834
35 Shared species of the three pairs of networks studied are pooled and represented 835
together. In (b) the size of the circles representing plant species indicates differences 836
in the proportion of honeybee visits between invaded and removal plots. Grey lines 837
represent rewired interactions (whether exclusive of invaded or removal plots) and 838
black lines represent non-rewired interactions (i.e. those observed in both invaded 839
and removal plots).
840
36 Tables
841 842
Table 1. Response variables estimated for both plant (p) and animal pollinator (a) species.
843
Parameter Symbol Definition
Visits Vp Number of visits a plant species receives Va Number of visits a pollinator species makes
Normalised degree Dp Proportion of the total number of pollinator species a particular plant species is visited by Da Proportion of the total number of plant species a particular pollinator species visits
Niche overlap NOp Proportion of the total number of plant species a particular plant species shares pollinators with
NOa Proportion of the total number of pollinator species a particular pollinator species shares visited plants with Interaction rewiring Proportion of the interactions involving plant species shared between paired invaded and removal plots
that are exclusive to invaded or to removal plots
37 Table 2. Likelihood Ratio Tests (LRT) of the effects of treatment and flower morphology and their interaction on visitation rates, normalised degree and niche overlap for resident plant and pollinator communities. Significance levels:
˙ p-value ≈ 0.05, * < 0.05, ** < 0.01, *** < 0.001.
Resident
community N Response variable Explicative variable p-value
Plants 54 Visits (Vp) Treatment 0.732
Flower morphology < 0.001 ***
Treatment*Flower morphology 0.854
54 Normalised degree (Dp) Treatment 0.892
Flower morphology < 0.001 ***
Treatment*Flower morphology 0.973
54 Niche overlap (NOp) Treatment 0.187
Flower morphology < 0.001 ***
Treatment*Flower morphology 0.562 54 Proportion honeybee visits Treatment < 0.001 ***
Flower morphology 0.845
Treatment*Flower morphology 0.403
Pollinators 178 Visits (Va) Treatment 0.005 **
Functional group 0.988
Treatment*Functional group 0.405
191 Normalised degree (Da) Treatment 0.828
Functional group 0.140
Treatment*Functional group 0.929 191 Niche overlap (NOa) Treatment < 0.001 ***
Functional group < 0.001 ***
Treatment*Functional group 0.002 **