Table 1.

Results of Adonis¹ multivariate PERMANOVA analysis of β-diversity showing influence of main effects and interactions

Model effects/interactions	β-diversity metric
	Weighted UniFrac		Unweighted UniFrac		Bray–Curtis Dissimilarity		Jaccard index
	R2	P-value	R2	P-value	R2	P-value	R2	P-value
Day2	0.013	0.133	0.013	0.039	0.014	0.014	0.015	0.011
Transition3	0.032	0.001	0.052	0.001	0.037	0.001	0.042	0.001
Grazing system4	0.161	0.001	0.097	0.001	0.110	0.001	0.081	0.001
Horse	0.242	0.001	0.310	0.001	0.336	0.001	0.286	0.001
Day*transition	0.039	0.001	0.017	0.003	0.023	0.001	0.019	0.002
Day*grazing system	0.011	0.159	0.010	0.092	0.012	0.032	0.012	0.044
Day*horse	0.062	0.123	0.051	0.161	0.050	0.098	0.061	0.015
Transition*grazing system	0.024	0.011	0.023	0.003	0.024	0.001	0.025	0.001
Transition*horse	0.073	0.021	0.111	0.001	0.086	0.001	0.109	0.001
Day*transition*grazing system	0.035	0.002	0.012	0.040	0.018	0.003	0.015	0.004
Day*transition*horse	0.062	0.109	0.581	0.035	0.059	0.007	0.066	0.004

¹Analyses were conducted in Qiime2 (v.2020.8) (Boylen et al., 2019)

²Samples were collected on day 0, 2, 4, 6 of each transition

³Samples were collected for transitions from cool-season to warm-season pasture grass and from warm- to cool-season grass

⁴Horses were managed in two integrated systems, one of which contained Quick-N-Big crabgrass as the warm-season forage and the other contained Wrangler bermudagrass