Responses of understory plant diversity to nitrogen (N) additions were investigated in reforested forests of contrasting disturbance regimes in southern China from 2003 to 2008: disturbed forest (withharvesting of understory vegetation and litter) and rehabilitated forest (without harvesting). Experimental additions of N were administered as the following treatments: Control, 50 kg N ha1yr1, and 100kg N ha1yr1. Nitrogen additions did not signiﬁcantly affect understory plant richness, density,and cover in the disturbed forest. Similarly, no signiﬁcant response was found for canopy closure in thisforest. In the rehabilitated forest, species richness and density showed no signiﬁcant response to Nadditions; however, understory cover decreased signiﬁcantly in the N-treated plots, largely a functionof a signiﬁcant increase in canopy closure. Our results suggest that responses of plant diversity to N deposition may vary with different land-use history, and rehabilitated forests may be more sensitive to N deposition.
Lu X, J Mo, FS Gilliam, G Yu, W Zhang, Y Fang, and J Huang. 2011. Effects of experimental nitrogen additions on plant diversity in tropical forests of contrasting disturbance regimes in Southern China. Environmental Pollution 159:2228-2235.