Fig 1.
Soil property responses to different plant community composition along a grazing gradient. (a) pH value, (b) electrical conductivity, (c) soil water content, (d) the C/N ratio, (e) soil organic carbon, (f) total nitrogen, (g) total phosphorus and (h) the N/P ratio.
Values represent the means ± SE. Significant differences between different plant community composition levels within a grazing intensity are indicated by lowercase letters (a-c); significant differences between different grazing intensities within a plant community composition level are indicated by capital letters (A-C; P ≤ 0.05). Vertical bars ± 1 SE.
Table 1.
Two-way analysis of variance of the effects of grazing and plant community composition on soil pH, electrical conductivity (EC), soil water (SW), soil organic carbon (SOC), total N (TN), total P (TP), C/N and N/P ratios.
Fig 2.
PCR-DGGE analysis of soil bacterial 16S rDNA (a) and dendrogram constructed using the soil bacterial community fingerprints (b) along the grazing gradient with different plant community compositions. M: marker, L. chinensis: 1–3, Grass: 4–6, Legume: 7–9, L. chinensis & Forb: 10–12, Forb: 13–15. Control: 1, 4, 7, 10, 13; light grazing: 2, 5, 8, 11, 14; and heavy grazing: 3, 6, 9, 12, 15.
Difference between the profiles are indicated by the similarity percentage. The dendrogram of the cluster analysis was based on the Dice coefficient and UPGMA clustering algorithm.
Fig 3.
Effects of grazing on bacterial diversity. (a) Shannon-Wiener index, (b) richness, and (c) Pielou evenness index.
Error bars denote the SE. Significant differences between different plant community composition levels within a grazing intensity are indicated by lowercase letters (a-c); significant differences between different grazing intensities within a plant community composition level are indicated by capital letters (A-C; P ≤ 0.05). Vertical bars ± 1 SE.
Table 2.
Two-way analysis of variance of the effects of grazing intensity (G) and plant community composition (P) on the Shannon-Wiener index, richness and Pielou evenness index of the soil bacterial community.
Fig 4.
NMDS ordination of the DGGE profiles of 16S rRNA gene fragments with superimposed vectors derived from soil chemistry data.
Circles refer to the control, triangles refer to light grazing and squares refer to heavy grazing. The statistical differences between soil bacterial fingerprints were measured using ANOSIM (analysis of similarity).