Table 3.

Main and interactive effects of invasion, clipping, and N fertilization on (A) the 10 most abundant phyla and (B) nitrifying taxa. Effect sizes are presented for the relative changes in (A) and (B) by treatment.

	Invasion		Clipping		N fertilization		Clipping x N Fert
	Average % effect	P-value	Average % effect	P-value	Average % Effect	P-value	P-value
(A) DOMINANT PHYLA
Proteobacteria	+7.07	0.29	−8.14	0.07	+0.37	0.39	0.33
Actinobacteria	−10.67	0.36	+25.62	0.53	+25.51	0.93	0.01
Bacteriodetes	+9.31	0.70	−3.19	0.75	−10.67	0.59	0.14
Acidobacteria	+5.74	0.39	+7.17	0.36	−11.6	0.17	0.32
Gemmatimonadetes	+18.56	0.13	+4.33	0.64	−3.46	0.41	0.83
Verrucomicrobia	−5.93	0.35	+7.94	0.09	−0.65	0.73	0.35
Firmicutes	−1.37	0.25	−15.69	0.92	+14.13	0.13	0.17
Planctomyetes	+1.87	0.76	+8.74	0.99	+5.19	0.36	0.05
Chloroflexi	−2.77	0.59	+28.58	0.98	+25.96	0.97	0.00*
Crenarchaeota	−13.34	0.11	+112.84	0.42	+78.45	0.52	0.00*
(B) NITRIFIERS
Nitrospirae	+32.09	0.37	−2.68	0.98	+4.54	0.17	0.53
Nitrososphaeraceaea	−13.34	0.11	+112.8	0.29	+78.45	0.69	0.00*
Nitrosomonadaceaea	−45.54	0.05	−27.35	0.09	+122.92	0.84	0.97

Main effects of invasion were determined by comparing native and invaded treatments using a One-Way ANOVA. Main and interactive effects of clipping and N fertilization were determined using a Two-Way ANOVA. Significant (P < 0.05) and nearly significant (P < 0.1) values are highlighted in bold. When sequential bonferroni corrected, only P-values with ^* were still significant. Main (single) factor effect sizes were calculated as = (treatment – control/control)^*100, where the control for invasion was the native plant community and the control for clipping and N fertilization was the invaded plant community.