Interrelation between frequency dominance and dry-weight percentages of species in grassland vegetation.

Abstract

In botanical grassland research in the Netherlands, dry weight analysis and the combined 25 cm² frequency and order method have mainly been applied. Since the botanical composition of many fields had been analysed by both methods, it was possible to study the interrelation between the percentages of frequency, dominance and dry weight. The results showed that the relation between dominance and percentage dry weight depended on the plant-size/ quadrat-size ratio. As this quotient becomes greater, the relation progressively approaches the 45 degrees line. In the analysis of tropical grasslands it is possible to obtain sufficiently reliable information about the quantitative ratios of the various grass species fairly rapidly by determining the dominance percentage. The relation between frequency percentage (F%) and dominance percentage (D%) is also determined by plant-size ratio and can be expressed by the general equation: D% = -m Iog₁₀ (100-F%) + 2 m. The coefficient m is a reliable standard of the dominance tendency of the grassland species.-A.G.G.H. (Abstract retrieved from CAB Abstracts by CABI’s permission)