The vegetation of the tundra and forest-tundra, its forms, methods of plant propagation, and adaptability to survival largely depend on the features that characterize these zones.
Geographical position
The location of the tundra zone falls on the subarctic belt of the Earth. On the continent of Eurasia, it stretches along the entire coast of the seas of the Arctic Ocean for tens of thousands of kilometers. The northern coast of mainland North America is also occupied by the tundra. The length of the zone from north to south is on average about 500 kilometers. In addition, the tundra occupies some islands near Antarctica. In the mountains, where altitudinal zonation is expressed, mountain tundra are formed. Considering all the territories where the zone is located, its total area on the planet is calculated. It is about 3 million km2.
Lesotundra is a zone where tundra vegetation and taiga vegetation are located in small areas. The forest-tundra stretches from west to east south of the tundra on the continents of Eurasia and North America. The length of the strip from north to south ranges from 30 to 400 kilometers. On its southern borders, the forest-tundra passes into the forest zone.
Climatic conditions affecting plant growth
The climate of the tundra and forest-tundra zones is very severe. The duration of winter is from 6 to 8 months a year. Throughout this time, a constant snow cover is maintained, the air temperature sometimes drops to 50 degrees below zero. The polar night lasts about two months. Strong cold winds and snowstorms almost never subside.
Summer in the tundra is short and cool. Chance of freezing and precipitation in the form of snow. Despite the polar day, the surface of the earth does not receive much heat, since the sun does not rise high above the horizon and sends scattered rays to the earth. To survive in such conditions, the tundra vegetation must adapt.
The influence of permafrost on the species composition of vegetation
In the warm season in the tundra zone, the soil thaws only to a depth of not more than 50 centimeters. Next is a layer of permafrost. This factor is one of the decisive factors in the settlement of plants in the tundra zone. The same factor affects their species diversity.
Permafrost has a significant impact on the terrain. Freezing and thawing of rocks leads to their deformation. As a result of the heaving process, surface forms such as tubercles appear. Their height is not more than two meters above sea level, but the appearance of such forms also affects the vegetation of the tundra, its distribution over a certain territory.
The effect of soil on the species diversity of vegetation
In the tundra and forest-tundra zones, high bogging of soils is noted. It is especially noticeable during the melting snow. Water cannot penetrate deep due to the presence of permafrost. Its evaporation is also not of great intensity due to the low air temperature. For these reasons, meltwater and precipitation accumulate on the surface, forming large and small swamps.
High bogging, the presence of permafrost, the prevalence of low temperatures impede the flow of chemical and biological processes in the soil. It contains little humus, iron oxide accumulates. Tundra-gley soils are suitable for the growth of only certain types of plants. But the vegetation of the tundra also adapts to such living conditions. A person who visited these parts during the flowering period of the plants will have indelible impressions for many years - the flowering tundra is so beautiful and attractive!
In the forest-tundra, the natural fertile layer of the earth is also thin. The soil is poor in nutrients, it is characterized by high acidity. When cultivating land, a large amount of mineral and organic fertilizers is applied to the soil. In the treated areas of the forest-tundra, more diverse types of grassy vegetation, trees and shrubs are found.
Types
The vegetation of the tundra and forest-tundra largely depends on the type of natural zones. Their landscapes seem monotonous only at first glance.
Kochkarnaya and tuberous tundra occupy the largest territories. Among the bogs, the plant turf forms mounds and hummocks, on which many plant species take root. A special type of tundra is polygonal. Here you can observe the relief forms in the form of large polygons, which are broken by hollows and frost cracks.
There are other approaches to the classification of such a natural zone as the tundra. What vegetation prevails in a certain territory, such will be the type of tundra. For example, moss-lichen tundra consists of areas covered by different types of mosses and lichens. There are also shrub tundra, where thickets of polar willow, cedar dwarf pine, bushy alder are common.
Plants
As mentioned earlier, the vegetation of the tundra and forest-tundra had to adapt to the harsh climatic conditions of the Earth’s subarctic belt. Otherwise, her life and development would be impossible here.
The fitness of tundra and forest-tundra plants is expressed as follows. Most fauna species are perennials. Annual plants with a short summer would not be able to complete their life cycle. Only a small fraction of the plants reproduce by seed. The main way to prolong life is vegetative.
The stunted plants of the tundra allow them to stay during strong winds. The creeping nature of the shoots and their ability to intertwine among themselves, contributing to this, form the likeness of a soft pillow. In winter, all parts of the plants are under snow. This saves them from severe frosts. Most plants of the tundra and forest-tundra have a wax coating on the leaves, which contributes to the moderate evaporation of moisture from their surface.
The vegetation of the tundra, photographs of individual species of which are presented in the article, is represented by perennial frost-resistant herbs: sedge, prevailing in lowlands and swamps, buttercup, cotton grass, dandelion, poppy seeds. Dwarf birch, polar willow, bushy alder grow from trees. These tree species in the forest-tundra can already reach a height of three or more meters. Among shrubs, blueberries, cloudberries, blueberries, and lingonberries are widespread. On the hills, mosses and lichens take root, many of which are the main type of food for animals living in these places.
Lesotundra and taiga
The vegetation of the tundra and taiga is very different from each other. Lesotundra is a transition zone between them. On the territory of the forest-tundra, among the forestless space, you can find islands of thickets of spruce, birch, larch and other tree species.
The forest-tundra zone is unique, since tundra vegetation and taiga vegetation are found on its territory, which becomes more noticeable with the advance to the south. Forest areas, consisting of individual species of trees and shrubs, create the most favorable conditions for the growth of grassy vegetation. Thanks to trees and shrubs, the wind speed decreases, more snow is delayed, which covers the plants, saving them from freezing.
The study of vegetation subarctic belt
The vegetation cover of the tundra and forest-tundra has not yet been fully studied. A systematic scientific description of the species growing here began only in the middle of the last century.
To continue this work, special expeditions are being created today. During them, scientists also try to establish how the animals living in these zones influence the vegetation of the tundra and forest-tundra. They want answers to questions about whether the species diversity of plants in areas protected from the presence of certain animal species is changing, how much time is required for the complete restoration of the destroyed vegetation cover. So far, scientists have not found answers to all questions regarding the natural balance in the zone of the subarctic belt of the planet.
