Understanding Experimental warming and grazing SPD 2 ◆-W-NW·-G-NG 1 -lojd 0 3ou3laJJ!( -2 3 2006 2007 2008 Experimental warming caused decrease in species richness- 3 - 2 - 1 0 1 2 2006 2007 2008 Difference in mean number of species plot-1 W-NW G-NG * Experimental warming and grazing SPD Experimental warming caused decrease in species richness Understanding