Variation of LDMC and SLA Relationship Between Growth Forms in Natural Grasslands

In agro-ecological studies, there is a growing interest in measuring both leaf dry matter content (LDMC) and specific leaf area (SLA). This interest lies on the fact that leaf traits are linked to gradients of environmental factors and ecosystem functions. Working with three contrasting wild species, Garnier et al. (2001) proposed a model linking these two traits. The model shows a relatively simple non linear and negative correlation between LDMC and SLA. Nevertheless, none of the species used to build the model were grasses (GRA) or forb rosettes (ROS = i.e. dicotyledonous with large entire leaves and absence of stem at the vegetative stage); the species which make the largest contribution to the standing biomass of most natural grasslands. Furthermore, due to the divergent range of LDMC (and not SLA) values between these growth forms, Cruz et al. (2002) proposed that grass records alone could be used as an indicator of fertility gradients. The aim of this paper was to analyse discrepancies in the LDMC - SLA correlation with respect to model predictions in order to consider them in any development of LDMC-based tools for the management of natural vegetation