Species diversity of plants

The concept of species diversity includes two components: species richness and evenness. Species richness is the number of species per unit area (geobotanical description). Evenness is the abundance distribution of species in a community. There is a positive correlation between these indices; however, high species richness is not necessarily accompanied by high-degree evenness. It is impossible to compare the species diversity of communities formed by plants of different sizes (tropical rainforest and meadow steppe). High species diversity is inherent in plant communities with moderate productivity and a moderate degree of disturbance and is not related to their stability.