QUANTITATIVE CRITERIA FOR IDENTIFYING SPECIES OF PLANTS AND ANIMALS REQUIRING SPECIAL PROTECTION
A critical examination of the categories and criteria of the IUCN Red List, using mathematical and statistical methods of analysis suggests that the criteria for A ("downsizing"), and B ("the restriction of the range") are not suitable for addressing the issue of whether the species should be included in the Red books and Red lists, and the question as to which category should be classified as appearance. The following four criteria for attributing taxa to "endangered state" and therefore special protection, three of which are modifications of the relevant IUCN criteria: 1) On the direct basis of observations established that the total number of species is less than 10 000 individuals ( modification C.1); 2) found that the number of individuals capable of reproduction is less than 1000 (modification D1) on the basis of direct observation; 3) On the basis of direct observations established that the data area is not more than 5 localities (location, population) (modification of D2); 4) it found that the area of habitat is not more than 100 localities (location, population), provided that direct observations proved the disappearance of some localities (location, population) is not offset by the discovery of the new on the basis of direct observation. The presence of a type of at least one of these four features already allows to consider it "endangered state."