Botany - B.Ye. Yakubenko 2017

Part Three. Plant Kingdom (Planthae)
Chapter XI. Fundamentals of Phytogeography
11.2. Geographical Distribution of Species on Earth and in Ukraine

There are over 350,000 known plant species on Earth. Their distribution is uneven: they are abundant in the tropics and subtropics, less numerous in temperate zones, and very sparse in arid and arctic regions. Southeast Asia, particularly Indonesia (45,000 species), and South America, notably Brazil (40,000 species), are renowned for their rich flora. Characteristic Features of this region include mangroves, the rainforests of the Amazon basin, numerous epiphytes of the bromeliad family, and about 4,500 orchid species. The tropical flora of the Malay Peninsula (20,000 species), Borneo (11,000), Cuba (5,785), and the Hawaiian Islands (1,729) is less diverse. Beyond the tropics, species richness declines due to less favorable climatic and moisture regimes. For instance, the flora includes 8,000 species in the Mediterranean, 7,000 in Mexico, 6,000 in California, 6,000 in the Caucasus, 4,500 in France, 3,500 in Romania, 2,667 in Germany, 2,300 in Poland, 2,100 in Norway, 1,762 in Moldova, 1,460 in Belarus, and 1,439 in Lithuania. The flora is sparse in the deserts of the Sahara (1,200) and Gobi (1,004), as well as in the polar regions (Greenland — 404, the Svalbard archipelago — 130, and the Tibesti mountain region in the Sahara — 350 species).

The flora of Ukraine is unevenly distributed across its regions. Optimal climatic conditions, the proximity of the Black and Azov Seas, and the mountainous and steppe landscapes of the Crimean Peninsula have fostered its rich floristic diversity. Currently, the flora of Crimea comprises 2,400 species, 52% of which are of Mediterranean origin. The distinctiveness of Crimean flora is defined by its endemic species, numbering over 240, which is more than in the rest of Ukraine combined.

The flora of the Ukrainian Carpathians is rich and diverse, having evolved since the Alpine Orogeny under METABOLISM/18.html">The Influence of Atlantic and Baltic climatic factors, species migration from adjacent territories, and, in modern times, human economic activity. It comprises over 2,100 species, of which 833 are alpine.

The flora of the lowland steppes is diverse, though 80% of these areas are now plowed and cultivated. Original natural vegetation survives only in nature reserves and on lands unsuitable for agriculture (gullies, slopes, rock outcrops). It encompasses over 2,000 species. In the Kherson region, subject to significant technogenic pressure, 1,500 native species have survived out of a once exceptionally rich flora. A key feature of the steppe flora is the high concentration of turf-forming species, particularly fescue and feather grass (Ukrainian, narrow-leaved, and Lessing's feather grass), as well as an Abundance of ephemerals and ephemeroids. The steppe flora features numerous rare and endemic species, with 77 found in the Southern Left-Bank region.

The flora of the Forest-Steppe zone is relatively rich and diverse: on the Left-Bank, it includes 1,600 species, two of which are endemic; on the Right-Bank, 1,700 species grow; and on the Kyiv Plateau, there are 1,222 species, 20 of which are endemics. A characteristic feature of the forest flora in the Forest-Steppe is the presence of early-spring nemoral species, while the steppe patches feature turf-forming xerophytes.

The flora of Polissia counts 2,000 species, of which 1,403 belong to the native flora. A notable feature is the presence of A large number of helophytes (320 species). The boreal character of the flora is defined by meadow and wetland species. Among them, Asteraceae (134), Poaceae (114), and Cyperaceae (95) are dominant. Almost all species belonging to these families are represented in Ukraine.