Summary of optimal models for vegetation responses in relation to N deposition and climate variables.

(+/−) = direction of response; x = interaction; P values = * <0.05, **<0.001, ***<0.001; gdd = growing degree days; ht = Calluna canopy height.(±) 代表反应方向；x 代表交互作用；P值标注标准如下：* 表示P<0.05，**表示P<0.001，***表示P<0.001；gdd 为生长度日（growing degree days）；ht 为帚石楠（Calluna）冠层高度。