Fig. 4
Effect of cold stress on microbial community assembly processes in the cecum of Hu and Hulunbuir sheep. A Categorization of deterministic and stochastic processes underlying cecal microbiota diversity using βNTI and RCBray metrics. Hete_S: heterogeneous selection, βNTI < − 2; Homo_S: homogeneous selection, βNTI > 2; D_limit: dispersal limitation, |βNTI|< 2 and RCBray > 0.95; Homo_D: homogenizing dispersal, |βNTI|< 2 and RCBray < − 0.95; Undominated: |βNTI|< 2 and |RCBray|< 0.95 along the sheep cecal microbiota. βNTI, β-nearest taxon index; RCBray, Bray–Curtis-based Raup–Crick Index. B Quantifying the stochasticity in ecological processes using phylogenetic normalized stochasticity ratio (pNST). C Fitting the neutral model to each group of cecal microbiota. R.2: goodness of fit for the overall neutral community model, Nm: product of metacommunity size (N) and migration rate (m) (Nm = N*m)