This review compares the current state of ichthyofauna in the largest rivers of the northern coast of the Black Sea (Don, Kuban, Dnieper and Dniester rivers) with data published by B e r g (1948–1949). Changes in species composition are characterized by the disappearance or decline in anadromous and semi-anadromous fishes. The total number of native species that are extinct, protected, in declined or become rare has reached from 19 % in the Kuban to 36 % in the Dnieper River basins. Appreciable changes have occurred in the ratios between rheophilous and limnophilous fishes (the latter becoming predominant in many parts of the rivers). Euryhaline and even marine species have invaded most of river basins. And the number of introduced or established alien species varies from 9.7 % in the Dnieper to 16.8 % in the Kuban River basins. These changes, which have yielded quite altered ichthyofauna, must be taken into consideration in conservation endeavours.
Based on a combination of data from the Czech National Phytosociological Database and expert knowledge, a database of vascular plant species pools for 88 habitats, representative of the diversity of Czech vegetation, was compiled. This database contains 1820 native species, 249 archaeophytes and 278 neophytes, each assigned to one or more habitats. Besides the data on species occurrence in different habitats, the database contains information on a species’ ecological optimum in the habitat or its dominance. The largest pools of native species were found in rather rare habitats of dry and warm herbaceous or woody habitats at low altitudes, some of which contain > 530 species (maximum of 695 species for thermophilous forest fringes). These were followed by common habitats on mesic soils. The smallest pools of native species were in saline, aquatic and bog habitats ( 350 native species always contained > 5 archaeophytes and > 5 neophytes, and often many more. Two hundred and thirty two native species, 18 archaeophytes and 30 neophytes were identified as potential dominants in at least one habitat. However, potentially dominant species made up less than 3% of the species pool for 78 out of 88 habitats. Larger percentages (up to 14.6%) of potential dominants were included in habitats with small species pools and species-poor stands (e.g., aquatic, saline and mire habitats). The number of habitats in which a species occurred was used as a measure of its ecological range. Most ecological generalists were found among the native species, less among the archaeophytes and least among the neophytes. Out of the 36 species that occur as dominants in three or more habitats, 34 were native (many are grasses), onewas an archaeophyte (Cirsium arvense) and one was a neophyte (Impatiens parviflora).