only marginally significantp = 0.082
A significant negative relationship between δ 13 C and N mass was found for most of the functional groups studied, although the relationship was not significant for annual herbaceous ( r = -0.234, p = 0.251) or evergreen woody plants ( r = -0.003, p = 0.989), and it was only marginally significant for ferns ( r = -0.521, p = 0.082)( Table 1 , Fig 3B–3I ).