Comparison by vegetation zone
The overall network pattern of each vegetation type along the gradient is summarized in Fig 3, illustrating the differences in numbers of OTUs linked to each plant species along the gradient from the semi-arid desert steppe, through alpine meadow to alpine steppe. For the plant-fungi networks, there was a mean of 36, 145 and 179 edges to fungi per plant species in desert steppe, alpine meadow and alpine steppe, including 0%, 15.17% and 25.14% of negative edges, respectively. There were more plant species in networks of both the alpine steppe (Fig 4c, 28 plant species) and alpine meadow (Fig 4b, 21 plant species), with each plant species associated with a greater diversity of fungi than in the semi-arid desert steppe (Fig 4a, 8 plant species).
There were fewer plant species in desert steppe (Fig 4d, 13 plants) and alpine steppe (Fig 4f, 6 plants) than meadow steppe (Fig 4e, 21 plants), while 306, 98 and 15 edges in desert steppe, alpine meadow and alpine steppe, including 0%, 19.39% and 33.3% of negative edges in the plant-microbial networks, respectively. The relatively few species of plants in desert steppe were thus associated with the widest range of bacteria.