Table 3.

Major topological properties of the observed picophytoplankton (pico) and micro- and nanophytoplankton (micro- and nano) co-occurrence networks in the headwater streams of Xijiang River for three altitudinal groups and their associated random networks.

Sample	Pico observed networks			Pico random networks			Micro- and nano observed networks			Micro- and nano random networks
	LA	MA	HA	LA	MA	HA	LA	MA	HA	LA	MA	HA
No. of ASVs	413	413	413	413	413	413	413	413	413	413	413	413
No. of nodes	92	64	50	92	64	50	196	113	112	196	113	112
No. of edges	479	252	300	479	252	300	803	344	663	803	344	663
Average number of neighbors	17.63	8.76	18.78	10.41	7.875	12.00	8.79	8.23	10.37	8.19	6.08	11.84
Network diameter	5	4	2	3	4	3	11	11	7	5	6	4
Network radius	3	2	1	3	3	2	6	6	4	3	4	3
Average path length	1.725	1.969	1.304	2.148	2.207	1.792	4.41	4.137	2.582	2.72	2.788	2.152
Clustering coefficient	0.719	0.606	0.843	0.104	0.132	0.239	0.528	0.548	0.728	0.041	0.033	0.109
Network density	0.477	0.351	0.696	0.114	0.125	0.245	0.078	0.161	0.221	0.042	0.054	0.107
Network heterogeneity	0.557	0.57	0.304	0.277	0.295	0.236	0.667	0.723	0.712	0.339	0.386	0.278
Network centralization	0.324	0.357	0.328	0.085	0.084	0.128	0.146	0.199	0.28	0.035	0.054	0.084
Connected components	9	7	6	1	1	1	8	10	6	1	1	1
Modularity	0.493	0.675	0.225				0.762	0.746	0.519

LA, low altitudes (altitudes <1,000 m); MA, intermediate altitudes (1,000 m < altitudes <2,000 m); HA, high altitudes (altitudes >2,000 m).