Regional differences in the occurrence of understorey species reflect nitrogen deposition in Swedish forests.
Possible links between the occurrence of Vaccinium myrtillus, V. vitis-idaea and Deschampsia flexuosa and rates of nitrogen deposition were investigated in 557 coniferous forest stands. In areas with high N-deposition, V. myrtillus was less frequent, less abundant and more susceptible to the leaf pathogen Valdensia heterodoxa than in areas with lower levels of N-deposition. The occurrence of V. vitis-idaea was also strongly negatively correlated with increasing N-deposition, but no such trend was found for D. flexuosa. In regions with high N-deposition, V. myrtillus was more common in stands dominated by Scots pine than in stands dominated by Norway spruce. This was not the case in regions with lower levels of N-deposition. The patterns observed accord with results from N-addition experiments that demonstrate significant effects on vegetation, caused by N-deposition. The data suggest that even low rates of N-deposition may decrease the abundance of the most dominant species in coniferous forest ground flora.
Strengbom
Joachim
J
Department of Ecology and Environmental Science, Umeå University, Sweden. Joachim.Strengbom@eg.umu.se
Walheim
Mats
M
Näsholm
Torgny
T
Ericson
Lars
L
D017753:Ecosystem; D009584:Nitrogen / Q000032:analysis*; D006109:Poaceae; D011157:Population Dynamics; D013548:Sweden; D064028:Tracheophyta; D014197:Trees; D029796:Vaccinium
D009584:Nitrogen