FIELD: ecology.
SUBSTANCE: method includes statement of the presence of plant species in ecotopes of plant communities in different areas of anthropogenic transformation, establishment of scores of their occurrence and projective coverage, and calculation of the ecotopic confinement index (S), expressed as the ratio of the product of occurrence scores and the square root of the sum of projective coverages of a particular species in an array of geobotanical descriptions to the total number of descriptions, using the formula: 
where S is the ecotopic confinement index; B - occurrence in the interval of values of the projective coverage (P) according to the 5-point quadratically-transformed scale of percent coverage in the range 0-100%: 0-4% - 1 point, 4-16% - 2 points, 16-36% - 3 points, 36-64% - 4 points, 64-100% - 5 points; P is the sum of the projective coverages of a particular species in an array of geobotanical descriptions; N is the number of geobotanical descriptions of communities, with the highest absolute value of the ecotopic confinement index indicating high information content (activity) of the species, and the smallest - information content (activity).
EFFECT: application of the ecotopic confinement index leads to simplification of the method, increase of accuracy, reliability, significance of quantitative characteristics of species that show anthropogenic transformation of the environment, reduction of labour costs, application of species features available for mathematical processing.
2 tbl,1 ex
