Table 4. Repeated-measures ANOVA for the effects of four years of water addition (+50% of the long-term average) on species richness in grassland, shrubland and mixed vegetation (sites) in central New Mexico, USA. Statistically significant post-hoc comparisons (P<0.10) for significant interactions with treatment effects are also presented; w=water addition, a= ambient precipitation plots.

Factor / DF / SS / F / P / R2 / P / Contrasts
Forbs / Year / 3,3 / 0.39 / 39.61 / <0.001 / 0.83 / <0.001
Site / 2,2 / 0.22 / 33.26 / <0.001
Treatment / 1,1 / 0.00 / 0.80 / 0.376
Year x Site / 6,6 / 0.10 / 5.09 / <0.001
Year x Treatment / 3,3 / 0.02 / 2.29 / 0.090
Site x Treatment / 2,2 / 0.03 / 5.11 / 0.010 / Shrubland w<a, Mixed w<a
Year x Site x Treatment / 6,6 / 0.02 / 1.18 / 0.331
Grasses / Year / 3,3 / 0.13 / 7.98 / <0.001 / 0.74 / <0.001
Site / 2,2 / 0.40 / 38.44 / <0.001
Treatment / 1,1 / 0.03 / 6.56 / 0.014 / w<a
Year x Site / 6,6 / 0.09 / 2.80 / 0.020
Year x Treatment / 3,3 / 0.01 / 0.94 / 0.428
Site x Treatment / 2,2 / 0.02 / 1.78 / 0.180
Year x Site x Treatment / 6,6 / 0.01 / 0.45 / 0.838
Shrubs / Year / 3,3 / 0.08 / 8.35 / <0.001 / 0.58 / 0.001
Site / 2,2 / 0.05 / 7.62 / 0.001
Treatment / 1,1 / 0.01 / 4.72 / 0.035 / w>a
Year x Site / 6,6 / 0.03 / 1.45 / 0.214
Year x Treatment / 3,3 / 0.01 / 1.12 / 0.351
Site x Treatment / 2,2 / 0.01 / 2.32 / 0.109
Year x Site x Treatment / 6,6 / 0.01 / 0.59 / 0.733
Proportion annual to perennials / Year / 3,3 / 0.08 / 20.71 / <0.001 / 0.86 / <0.001
Site / 2,2 / 0.00 / 1.34 / 0.271
Treatment / 1,1 / 0.00 / 1.87 / 0.178
Year x Site / 6,6 / 0.01 / 1.72 / 0.136
Year x Treatment / 3,3 / 0.01 / 2.33 / 0.087 / 2008 w<a
Site x Treatment / 2,2 / 0.00 / 0.08 / 0.927
Year x Site x Treatment / 6,6 / 0.01 / 1.44 / 0.218
Subdominants / Year / 3,3 / 0.19 / 25.64 / <0.001 / 0.81 / <0.001
Site / 2,2 / 0.12 / 24.31 / <0.001
Treatment / 1,1 / 0.00 / 0.06 / 0.809
Year x Site / 6,6 / 0.13 / 8.89 / <0.001
Year x Treatment / 3,3 / 0.03 / 3.67 / 0.018 / 2005 w>a, 2006 w<a
Site x Treatment / 2,2 / 0.03 / 5.50 / 0.007 / Shrubland w>a, Mixed w<a
Year x Site x Treatment / 6,6 / 0.02 / 1.09 / 0.382

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