An index of divergence from species to life-form diversity based on the notion of intrinsic diversity ordering

In this paper, we propose a measure of divergence from species tolife-form diversity based on the notion of intrinsic diversity ordering. First,species and life-form relative abundances within the analyzed community aredetermined. Next, community intrinsic diversity profile is computed both fromspecies and life-form relative abundances. Finally, the speed of decrease fromspecies to life-form diversity is obtained by comparing the area under thespecies diversity profile with the area under the corresponding life-formdiversity profile. Since life-forms classify plants into ecologically relevantgroups irrespective of their systematics, the proposed measure might be usefulto quantify the ecological similarity of different communities without loosinginformation on traditional taxonomic diversity figures. As an application fordemonstration, a small data set from a garigue community on ultramafic soils ofTuscany (central Italy) is used.