Everything that forms the world around us - natural communities, characteristic for certain conditions - is an integrated system. Elements of this structure directly or indirectly interact with each other. What are the natural areas and communities? How do they differ from each other? How do the natural communities of organisms interact? More about this later in the article.
Biogeocenosis
This definition was first introduced by Vladimir Sukachev, a Russian scientist, geobotanist. The concept of biogeocenosis (bios - "life", "earth" - ge, koinos - "general") is considered to be a system of a level higher than the biostructure "organism". This is due primarily to the fact that the interaction within is not between organs. Within the framework of biogeocenosis, relationships occur between different types of living organisms. Together they perform specific functions, ensure the holistic existence of biogeocenosis.
Ecosystem
Different types of plants do not spread evenly over the surface of the planet, but in accordance with local conditions. As a result, they form natural "groupings." The interaction of living organisms, conditions of the abiotic zone ensures the unity of the components of the community. This integrity is also called an ecosystem (ecological system). This concept, along with the definition of "biogeocenosis", acts as a description of the natural community. But at the same time, these definitions are different characteristics of the system. Thus, the concept of "ecosystem" is usually used in cases where the relationships of elements within the natural community are considered. "Biogeocenosis" is usually used to characterize a specific, defined natural system that occupies a given territory, and its interaction with other "groups". Examples of natural communities are: field, continent, river and others.
Animals and plants
Considering examples of natural communities, one cannot but take into account the influence that animals have in these structures. It is often believed that wild animals can freely choose their habitat, live as and where they want. But actually it is not. If we consider examples of natural communities, the composition of animal groups under certain conditions, then we can see not a random, but a very specific set of species characteristic of a particular system. As a result, the concrete relationships between plants and animals are clearly visible. In turn, representatives of flora and fauna interact with microorganisms, which are also located within the boundaries of one natural range. The natural communities of the seas and oceans differ in species diversity, in the conditions in which their participants exist, from other ecosystems. But, despite this, the general principles of interaction are preserved regardless of the circumstances.
general information
Any natural community is a complex of different organisms. Under the same conditions, animals, plants, microorganisms are present. All of them influence each other and are adapted to certain conditions of existence in a particular territory. Inside this "ecosystem" a cycle of various substances is formed and maintained. The scale of the ecological system may vary. Large ones include the natural communities of the seas and oceans. At the same time, smaller ecosystems are included in larger ones. So, the natural community of the swamp can be part of the taiga ecosystem. In addition to natural systems, there are artificial ones. They are created by man. Such examples of natural communities are ponds, aquariums, zoos and others.
Nutritional interconnection within the ecosystem
Regardless of what kind of natural community is considered (swamp, mainland, pond and others), various interactions are carried out inside it. The main relationship is nutritional interaction. The main, initial link contributing to the formation of energy reserves, which includes any natural community (seas, taiga, etc.), are plants. Only they, using the energy of the sun, are able to form organic compounds from mineral substances, carbon dioxide present in water or in soil . Plants are food for herbivorous vertebrates and invertebrates. They, in turn, feed on predators - carnivorous individuals. So there are food connections. The food chain looks, in general, as follows: plant-animals (herbivorous) -predators. In some cases, this chain may be complicated by the addition of intermediates. For example, the first predators can be food for the second, those, in turn, for the third and so on. Thus, the natural community may include caterpillars eating plants. These creatures, in turn, are food for any predatory insects eaten by carnivorous birds, which are prey for birds of prey. Considering various examples of natural communities, one can see that in any ecosystem there are creatures whose food is waste: dead plants or their parts (leaves, branches), the corpses of dead animals or their excrement. These include, in particular, earthworms, grave beetles and others. However, the main role in the decomposition of organic substances belongs to bacteria and molds. It is thanks to them that there is a change in organic substances to mineral compounds, which subsequently can again be used by plants. So the cycle of substances.
Microclimate
Considering any natural community (ocean, mainland), you can see, in addition to food, other connections. So, plants form a certain climate, microclimate. Various factors of inanimate environment - humidity, temperature, air movement, illumination and others - under the vegetation cover will have significant differences from the general ones in the same area. So, the natural community of the rainforest is characterized by high humidity during the day. It is cooler and shady during the day, and at night, on the contrary, it is much warmer than in the open. Or in a meadow, for example, the humidity and temperature of the surface of the earth will differ from those observed on a bare surface. Among other things, the vegetation cover prevents erosion - erosion and spraying of the soil. The microclimate affects the livelihoods and species composition of animals that inhabit this area. Individuals choose places for their habitats in which not only there is the necessary food, but also in general climate, temperature, humidity and other conditions will be optimal.
The impact of animal activities on the state of the ecosystem
First of all, many flowering plant varieties are pollinated by insects, and in some cases by their specific species and, if they are absent, then plants cannot multiply. The distribution of seeds in some representatives of the flora is also carried out by animals. In addition, the activity of certain species of living creatures has a significant impact on the preservation of certain conditions in the ecosystem. So, for example, earthworms, leading a digging lifestyle, contribute to loosening the soil, as a result of which air, water penetrate deeper and easier, and also the decomposition of various organic residues occurs faster.
Change of ecosystems as a result of species changes
Such processes can occur under the influence of abiotic, biotic factors, as well as as a result of human activity. The change of natural communities due to the influence of the life activity of different organisms lasts hundreds, thousands of years. The main role in all these processes belongs to plants. There are various examples of natural communities that have changed under the influence of external factors. The rate of change in this case depends on different circumstances. You can consider the ecosystem of the "lake". The natural community — in this case, the body of water — is gradually beginning to shrink and grind. Over time, silt appears at the bottom. Its layer begins to grow: the remains of coastal and aquatic animals and plants accumulate, washed away from the slopes of the soil particles. As the pond becomes shallow, reeds and reeds begin to grow along the banks, and then sedge. So the lake - a natural community of one type - is changing and becoming a qualitatively different ecosystem. The accumulation of organic residues is happening faster, forming peat deposits. Some species of plants and animals are replaced by others that are more adapted to life in new conditions. As a result, a new natural community is formed - the swamp. However, it should be said that changes in the ecosystem continue further. As a result, fairly unpretentious trees and shrubs may appear. And gradually, a forest will already appear on the site of the reservoir.
Ecosystem Change Due to Human Activities
Above were given examples of natural communities that have changed under natural conditions due to species substitution. It should be noted that the emergence of new plants, animals, microorganisms, fungi and the formation of new conditions is a rather long process, and can last for tens, hundreds, or even thousands of years. But the change of ecosystems under the influence of human activity is much faster. In some cases, even several years may be enough for another ecosystem to appear instead of one. So, if in the same lake - a natural community with a certain species composition of plants and living creatures - they begin to discharge sewage, household waste, fertilizers from the fields, the oxygen present in the water begins to be spent on oxidation. As a result, the species that inhabit this ecosystem begin to receive less oxygen and other nutrient compounds. This provokes the death of many plants and living creatures. As a result, species diversity is significantly reduced. Some plants begin to replace others, water begins to “bloom”. Commercial fish are replaced by “low value” species, many insects, mollusks, and microorganisms disappear. As a result, the once rich ecosystem turns into a decaying pond.
Ecological system restoration
If a person’s influence at a certain stage ceases (when the condition is still not completely neglected), then within the natural community the process of self-healing begins. And in it the main role is again given to plants. So, for example, on pastures at the end of grazing, tall grasses begin to appear. In the lake, the natural process of cleansing from the spread of unicellular algae, blue-green, starts, as a result of which crustaceans, mollusks and fish begin to appear again. If the trophic and species structure is too simplified and the process of self-healing is simply impossible, a person again has to intervene in the ecosystem. But in this case, his activity is not aimed at destruction. So, for example, grasses begin to be planted on pastures, trees are planted in the forest. Ponds are cleaned, then young fish are launched into them. Thus, we can conclude that the restoration of the natural community is possible only with partial violations. In this regard, human activity should not exceed the threshold after which self-regulation processes are impossible.
The influence of abiotic factors
The development and change of natural communities occur also under the influence of a sharp change in climatic conditions, fluctuations in solar activity, volcanic eruptions, mountain-building processes. These and other factors of inanimate nature are called abiotic. They provoke disturbances in the stability of the living environment of living organisms. It should be said that ecosystems have unlimited ability to restore. And if the external influence is above a certain limit, then the natural community will undergo destruction. The area where the changes will occur will act as a source of environmental imbalance. And even if ecosystem restoration is possible, it can cost much more than modern conservation measures.
Factors contributing to the ability of ecosystem self-regulation
Independent restoration of natural communities becomes possible due to the natural diversity of living beings, which, as a result of prolonged joint evolution, have adapted to each other. In the event of a decrease in the abundance of any species, the ecological niche that it vacates takes a similar appearance for some time, preventing the development of any destabilizing processes. But another situation occurs if some link has completely dropped out of the chain. In this case, the “mutual safety net” of the species may not work, part of the resources ceases to be used - an environmental imbalance arises. In the process of subsequent depletion of the existing species composition, conditions are formed for excessive accumulation of organic compounds, the settlement of alien species, a sharp increase in the number of insects and other things. As a rule, rare species begin to disappear first. Their scarcity is determined by their exactingness to environmental conditions and sensitivity to changes. In a stable natural community, such categories should be present among other groups of organisms. Their presence in the chain is an indicator of the conservation of natural biodiversity as a whole, the ecological usefulness of the entire system.
Substance cycle
This process is provided by species that occupy different trophic levels:
- Organic producers of inorganic substances are producers. First of all, these are green plants.
- Consuming phytomass consumer goods of the 1st order. These include invertebrate and vertebrate herbivores.
- Consumers of the 1st order, consumers of the 2nd and highest orders. These include, in particular, predatory fish, spiders, insects, reptiles, amphibians, insectivores, mammals, carnivores.
- The decaying dead organic elements are reducers. They mainly include soil organisms.
Studies of full-fledged natural communities show that rare species are present at every trophic level. The highest indicator of ecosystem stability is the presence of viable populations of higher-order consumers. These species are located at the very top of the trophic structure, and their condition largely depends on the state of the entire system as a whole. One of the most important characteristics for a species is the size of the territory, which is minimally necessary for the existence and development of a viable population.