图3. 不同气候带、固氮功能、生活型分类下, 入侵区域和无入侵区域土壤的总氮(A)、铵态氮(B)、硝态氮(C)、无机氮含量(D)和入侵区域相对于无入侵区域土壤总氮(E)、铵态氮(F)、硝态氮(G)、无机氮(H)含量的相对变化(平均值+标准误差)。温带、亚热带、热带分别缩写为WD、YRD、RD; 固氮、非固氮分别缩写为F、NF; 一年生草本、多年生草本、常绿灌木、落叶灌木、常绿乔木、落叶乔木、多年生草质藤本、落叶木质藤本、常绿木质藤本分别缩写为AH、PH、ES、DS、ET、DT、PV、DV、EV。N.A.表示没有数据; 图E-H中不同小写字母表示差异显著性(p < 0.05); *表示入侵区域相对于无入侵区域土壤氮含量变化显著(p < 0.05)。

Fig. 3. Soil total N (A) , NH₄⁺-N (B) , NO₃^--N (C) , inorganic N (D) contents in invaded and uninvaded areas and relative variation (RV) values of soil total N (E) , NH₄⁺-N (F) , NO₃^--N (G), inorganic N (H) contents in invaded areas compared to uninvaded areas among different climate zones, invasive plants with different N₂-fixing functions and life forms (mean + SE). WD, YRD, and RD represent temperate, subtropical, and tropical zones, respectively; F and NF represent invasive plants with N₂-fixing and non-N₂-fixing functions, respectively; and AH, PH, ES, DS, ET, DT, PV, DV, and EV represent annual herb, perennial herb, evergreen shrub, deciduous shrub, evergreen tree, deciduous tree, perennial vine, deciduous vine, and evergreen vine, respectively. N.A. denotes data not available, and different letters in panels E-H indicate significant differences (p < 0.05) while * indicates significant variation of soil N contents in invaded areas compared to uninvaded areas (p < 0.05).