Botany - B.E. Yakubenko 2017

Part Three. Plant Kingdom (Planthae)
Chapter XI. Fundamentals of Phytogeography
11.3. Ranges, Their Types and Formation Pathways

Under optimal conditions, certain species span vast continental expanses or ocean waters, while others are narrowly localized to specific regions such as islands, mountainous areas, river valleys, or saline soils. The geographic territory inhabited by a particular species is called its range (or distribution area). Ranges are distinguished for genera, species, subspecies, or plant communities.

Class="center">Types of Distribution Ranges

Ranges vary greatly in their taxonomic affiliation, spatial expression, and configuration. Several MAIN TYPES OF distribution ranges are recognized.

Continuous ranges are those where a species occupies an unbroken, contiguous territory, which is why they are also referred to as closed ranges. In Ukraine, species with continuous ranges include the Crimean pine, Crimean beech, Ukrainian feather grass, and Carpathian rhododendron.

Disjunct, or discontinuous, ranges are those whose parts are separated and located very far apart from one another, or occupy land areas on different continents or distinct islands. The distance between them is great enough to preclude the dispersal of seeds or diaspores from one element of the range to another.

If small insular patches exist at the periphery of a range and a partial exchange of plant propagules occurs between them, such a range is termed fragmented or dissected. A similar range is characteristic of the curved sedge, which grows on isolated highest peaks in Ukraine—Hoverla, Petros, and Pip Ivan.

Cosmopolitan ranges are those whose species are widespread across all or most continents. The plants forming them are called cosmopolites. These include marine and continental cosmopolites (Algae, mosses, ferns, common reed, cattail, Water spangles) as well as anthropogenic ones (stinging nettle, lamb's quarters, common sow thistle, common chickweed, Canadian fleabane).

Endemic ranges are those whose species cover a limited area of the globe and are not found anywhere else. They can be general, when spanning an entire continental territory (e.g., eucalyptus), or narrowly localized, growing, for instance, exclusively within the Carpathian mountain system (e.g., Carpathian rhododendron).

Paleoendemics are species that were very widespread in the distant past and subsequently reduced their distribution range under the Influence of Environmental changes (e.g., Campanula lozensis in the Alps, saxifrage in the Tatras).

Neoendemics are species that emerged in the relatively recent past and diverged from their ancestral forms by a series of traits. Therefore, they are also referred to as microendemics. They are young and evolutionarily progressive.

Relict ranges are those whose species were formerly widespread and later died out across a significant portion of their territory. Researchers distinguish climatic relicts, formed under METABOLISM/18.html">The Influence of long-term climate shifts (e.g., Tmesipteris, Psilotum, Sequoia, Nypa, Agathis); topographic relicts, determined by ancient landscape types of the modern territory (e.g., Widdringtonia juniperioides in South Africa); and edaphic relicts, conditioned by changes taking place in the soils.

Ranges of cultivated plants. Influenced by agrotechnical measures in cultivation, many species have altered their natural ranges. One of the centers of the natural range of maize was the highlands of South America, but As a result of selective breeding and the Introduction of new varieties into agricultural production, its range now spans vast areas across many continents and islands. Tomatoes and potatoes have also significantly expanded their ranges thanks to human economic activity.