minimal area

The smallest area that contains the species representative of a particular plant community. When the number of species recorded in increasingly larger sample units is plotted graphically (to give a species–area curve) the minimal area is the point at which the curve becomes horizontal. In practice, the curve rarely becomes truly horizontal because of natural heterogeneity, and some subjective assessment of the minimal area is made from the curve. Alternatively, the ‘minimum quadrat number’ may be defined as the ‘equivalence point’ (i.e. the point at which the number of species and the number of quadrats are equal).