The vegetation of even a small plot of land is extremely diverse. And you can observe how much the forest plants differ from those that live in a meadow or lake. Representatives of the flora can be adjacent only to those species with which they are ready to coexist. That is, plant life is possible when a certain plant community has developed.
Basic concepts
To understand what a plant community is, it is necessary to recall the requirements of various plant species for the conditions of growth and development. Each of them needs a certain humidity, lighting, temperature. Based on this, in nature, individual plant species do not live in isolation from each other, but together, forming thickets called phytocenoses or plant communities.
So, the plant community is a collection of plants that have adapted to the same conditions of existence on an established plot of land and are connected by mutual influence on each other.
The more diverse is the species composition of the phytocenosis, the more fully is the living space and its resources used, the richer and more diverse are the relationships. For example, the forest provides both a table and shelter to many different animals, and they provide its stability by destroying pests, spreading seeds, and loosening the soil.
All types of plant communities that live in a particular area are called vegetation. Depending on the prevalence of certain types of phytocenoses, they are combined into large groups (types of vegetation). Each of the groups got its name, for example, meadow, forest, swamp, steppe, tundra and so on. All types of vegetation have their own characteristics, according to which they are easy to distinguish from each other.
Types of Plant Communities
As already mentioned, a phytocenosis is characterized by a certain type of soil, the level of illumination, humidity and other conditions for the existence of plants. This explains the diversity of plant communities and the specific composition of the flora for each of them.
When they say that a plant community is a forest, field, meadow, body of water, virgin steppe, etc., it is the conditions of existence of species that are implied.
Sometimes the name phytocenosis is given by the prevailing form in it. For example, spruce, pine, birch, oak forest or feather grass. Communities within the same type may vary in species composition, for example, sorrel forests or blueberries.
It is possible to classify and determine the types of plant communities, taking into account the human influence on the formation of phytocenoses. Based on this, natural and artificial plant communities are distinguished.
All representatives of the flora of forests, meadows, swamps, lakes, steppes, tundra constitute natural plant communities. A person did not have a direct impact on their formation.
Artificial phytocenoses created by man. They can be formed in the likeness of natural ones (for example, a forest, a pond, a meadow) or have no analogues in nature (field, square, park). Due to their small species diversity, such plant communities are weaker than natural ones and can exist only when a person cares for them.
Otherwise, there is a change of plant communities. Representatives of the field flora can be replaced by forest plants. A similar process is possible in natural communities. So, the lake, slowly overgrowing, turns into a swamp.
It must be remembered that different types of plant communities attract certain types of animals, bacteria and fungi. Together, they form a biocenosis.
Meadows and steppes
Grassy and small-shrub plants predominate in the steppe. Meadows are characterized by a wide variety of grasses, mainly perennial. Floodplain meadows located in floodplains have the richest composition of species. As well as upland meadows, located far from the rivers, in elevated places.
Forest
The multi-tiered plant community, the most complex in terms of species composition, is the forest. It includes woody, shrubby, and herbaceous plants. Forests are divided into deciduous and coniferous. Those, in turn, are divided into broad-leaved, small-leaved, dark coniferous and light coniferous. In addition, there are mixed forests where both coniferous and deciduous species of trees are represented.
Walking through the forest, we take over the ownership of a community. A good connoisseur of nature, an experienced picker of mushrooms and berries, will go for lingonberries to the thickets of coniferous forests, for a bunch of flowers - for clearings and clearings, and for wild strawberries - for sunny hillocks and edges. How do plants unlike each other get along? What makes their coexistence possible?
The plant community consists of many plant species adapted to the same natural environment, but using it in different ways. After all, the requirements for light, moisture, temperature conditions are not the same for them.
For example, how do forest plants use light? Light-loving oaks, ash, and linden trees carried their crowns to the highest tiers. In the second tier mountain ash, bird cherry, aspen feel comfortable. These trees are less demanding on light. Shrubs are located in the third tier. And the most shade-hardy, mosses and herbs, are located in the fourth.
The plant community forest has a unique constituent called forest litter. Sometimes scientists rank it in the fifth tier. Mushrooms are the main inhabitants of the litter. Together with the mushrooms, small forest inhabitants and bacteria adapted to the existence in it. Feeding on dead parts of plants, they turn them into humus, and humus into mineral salts, which are vital for new plants.
The layering also exists underground. The roots of the trees have gone deep. Shrubs rooted slightly above, grassy plants at the very surface. The tiered arrangement of the roots allows them to absorb nutrients from different layers of the soil.
Seasonal principle of existence
To get along with each other in the forest allows not only the tiered placement of aboveground and underground parts of plants, but also their development at different times.
The first, before the leaves bloom, wind-pollinated bloom. While the tall trees have not yet blossomed, the wind will freely carry pollen.
The snow also did not come down, and below on the warm forest litter insects have already awakened. Now, when the bare branches of the forest let a lot of sunlight pass down, insect-pollinated primroses are also blooming.
Shrubs were green, and the primroses managed to bloom, accumulate nutrients in the rhizomes. Their life fades away until next spring. And their place is occupied by other herbs. While there is a lot of light in the forest, the grass cover becomes thicker, more diverse, the process of photosynthesis is actively ongoing.
Under a blossoming green tent, when it gets warmer and the wind subsides, insect-pollinated undergrowth plants bloom. In this way, the conditions necessary for the life of all its representatives are created in the forest.
Spruce
Spruce forests usually grow on heavy loamy soils. Fir needles, falling, decompose slowly. Accumulating over the years, it forms a litter that affects moisture, soil temperature and some of its other characteristics. In the spruce forest there is little light, humidity is increased. Even on a hot summer day it is cool here. Grass cover is not rich in species. Under the thick fir trees, shade-loving sour acid, various types of mosses, blueberries, and lingonberries grow.
Pine trees
Forests, where the main representative is pine, are called pine trees. They prefer light sandy soils. There is enough sunlight in them, but due to a lack of nutrients, the variety of plants is small. The soil here is covered with mosses and lichens. Among them grow bone, blueberries, lingonberries, some types of ferns.
Deciduous forests
The plant community of deciduous forests is usually associated with soils rich in minerals. The species composition is diverse. From the trees you can find oak, linden, elm, maple. Of the shrubs most often comes across hazel, forest honeysuckle and euonymus. The grassy cover is rich in species: hoof, raven eye, horn, several varieties of bell, anemone and many others.
Swamp
This community of plants is represented by unique species that can exist in conditions of excessive soil moisture and lack of oxygen in it. In Russia, swamps are most widespread in the north of the forest zone and in the forest-tundra.
They are divided into lowlands, which, in turn, are sedge and moss, and upland. Each of them has a characteristic composition of plant forms.
Lake
Lake plants are different, but live in the same natural environment. Only use it in different ways.
Near the shore, where there is a shallow reed, cattail, reeds. Their stems and leaves are placed above the water. They get carbon dioxide from the air and a lot of light. Here also the egg capsules grow. Their stems are rooted at the bottom, and long stalks carry leaves to the light.
But there are plants that do not rise to the surface. They take nutrients directly from the water and are content with diffused light. The deeper the less. The plant composition also changes: there are few higher plants, mainly microscopic algae live.
In nature, every plant community is associated with a community of animals inhabiting the same site. Here and coastal thickets sheltered many inhabitants of the lake, as in shallow water there is enough light, heat, food resources.
The life of a reservoir would be impossible without the activities of its inhabitants. They cleanse the lake, participate in the cycle of substances, in a word, by their vital activity they maintain a constant living environment. They are connected by this environment among themselves. The existing community creates the conditions necessary for the life of all its representatives.
Tundra
In special conditions are plant communities of the tundra. There is little heat, frequent strong winds, permafrost.
In harsh conditions, tall trees do not grow, but this does not mean that they are not in the tundra, they are just very small, stunted. Only here you can see birch trees that are higher than birch. Or a tree along with berry bush cloudberries.
Polar trees grow very slowly. Annual rings are distinguishable only with a magnifier, their width is calculated in hundredths of a millimeter.
Tundra plants adapt differently. Many are characterized by pillow growth. This shape helps withstand hurricane winds. Inside the pillow, heat is better retained. Mosses and lichens, flowering shrubs, grasses grow in the tundra.
Human influence on plant communities
The formation of a certain plant community takes more than one millennium. And, having developed, it can persist for a long time until its interconnections are violated.
Failure in the life of even a small part of the forest cannot pass without a trace. For example, a corner by a forest river was a favorite destination for tourist camps. From many campfires, grass cover and young forest growth died. The shrub that protected the slope from landslides was cut down. Having lost green protection, the river began to dry up.
Changes in the life of the plant community have led to undesirable changes in the natural environment.
Residents of the tundra are well aware of the laws of nature of their land. So, for example, driving herds of deer from place to place, they retain vegetation. Indeed, the reindeer pasture eaten by deer is restored in 15–20 years. The layer of soil thawing in summer is very small, below is permafrost, and the vegetation is thin.
The nature of the tundra is unusually vulnerable. And each abrasion applied here to the vegetative cover heals for a long time.
Any activity of people on earth cannot but affect the life of plants. And if a person knows what a plant community is, by what laws it develops, then it will act carefully and reasonably.