Table 1. Network stucture of microbial communities.

The d′ statistic is a measure of specialization by habitat ranging from 0 (not specialized) to 1 (completely specialized). H2 is an index of specialization across all taxa within the network and is measured on the same scale. Both networks were significantly more specialized than randomized null simulations would predict. Plant parts are ordered by nestedness structure, with the most species-rich communities on the top. Turnover and nestedness proportions describe community dissimilarity among plant parts explained by that process.

Sample	d′	P
Rhizosphere	0.47	0.001
Soil	0.55	0.001
Leaf	0.29	0.001
Axil	0.31	0.001
Stem	0.34	0.001
Flower	0.25	0.001
Fruit	0.30	0.001
Nestedness Temp.	28.21	0.001
NODF	0.24	0.001
H2	0.64	0.001
Turnover	0.84
Nestedness	0.09