Excessive atmospheric nitrogen deposition is known to alter nutrient cycles and species composition in temperate forest ecosystems. Foliar N concentrations reflect the nutrient status of plants and can be used to assess the impact of atmospheric N deposition on ecosystems. Our objective was to test whether the foliar N content reflects increasing N deposition in the understory vegetation of temperate forests on acidic soil. Therefore, we analyzed the foliar N content of seven plant taxa representing different functional groups of the understory vegetation and correlated them to modeled deposition datasets. Linear mixed models revealed no relationship of N deposition with foliar N concentrations across all species examined but decreasing foliar concentrations with increasing soil C/N ratio. Nevertheless, we found positive correlations of foliar N concentrations with increasing deposition in conifer saplings (Picea abies and Abies alba), the dwarf shrub Vaccinium myrtillus and the graminoid Luzula luzuloides. Such an increase was, however, not found in saplings of broad-leaved trees (Fagus sylvatica and Quercus petraea/robur) and the moss Polytrichum formosum. This suggests marked species-specific differences in nitrogen uptake and allocation. Foliar N concentrations were more strongly correlated to NO_y than NH_x and to wet than dry deposition. Since foliar N concentrations were correlated to deposition while the species’ cover was not, they may provide a valuable indicator of N deposition.

众所周知，过量的大气氮沉积会改变温带森林生态系统中的养分循环和物种组成。叶面氮的含量反映了植物的营养状况，可用于评估大气中氮沉积对生态系统的影响。我们的目标是检验叶面氮含量是否反映了酸性土壤上温带森林林下植被中氮的增加。因此，我们分析了代表底层植被不同功能组的七种植物类群的叶面氮含量，并将其与模拟沉积数据集相关联。线性混合模型显示，在所有检查的物种中，氮沉降与叶面氮浓度没有关系，但随着土壤C / N比的增加，叶面浓度降低。不过，云杉和银冷杉），矮灌木越桔和禾草Luzula luzuloides。然而，这种增加在阔叶树的树苗（青豆（Fagus sylvatica）和栎栎（Quercus petraea / robur））和苔藓多枝for中没有发现。这表明氮的吸收和分配存在明显的物种特异性差异。叶面氮的浓度与NO _y的相关性比NH _x与湿润的关系强于干沉降。由于叶的氮浓度与沉积物相关，而物种的覆盖率却不相关，因此它们可以提供有价值的氮沉积指标。