Определение опорных единиц для характеристики флоры

Abstract

The minimum area of the elementary flora is a certain trial area, which can characterize flora in the main features. The minimum area has two most important and related characteristics: the number of species and the area. At the same time, the list characterizing the flora is, in fact, the number of species encountered. The area acts as a value that fixes the sufficiency of building up this list. According to the «number of species-area» curve, an area estimate was obtained on four trial areas (Samara Zavolzhie, forest-steppe zone), which, depending on the anthropogenic transformation of the territory and the level of preservation of natural vegetation, can vary significantly and amounts to 400–1 000 km2. It is shown that the minimum area is the floristic sample, which includes at least 700 species. Such a sample should be considered as a reference unit for assessing the floristic structure of the territory, including for assessing the homogeneity of the flora composition. A comparison of the eight floral samples according to the difference indicator was made. Significant differences between physical and geographical areas are due primarily to the environmental conditions of flora formation.