Comparative characteristics of natural ecosystems and agroecosystems. Climate change

Human economic activity led to the formation of artificial ecosystems with certain properties, which are called agrocenoses (agrobiogeocenoses or agroecosystems).

Agromozozos (Greek. Agros - the field) is a community of organisms living on the lands of agricultural use engaged in crops or plantings of cultivated plants. At the same time, their structure and function creates, supports and controls the person in his own interests. Examples of such ecosystems are fields, gardens, gardens, parks, artificial pastures, flower beds, etc. Communities of plants and animals, artificially created by a person in marine and freshwater reservoirs, can also be attributed to the category of agrocenoses.

Agricultural ecosystems occupy about 1/3 of the land area, while 10% are arable land, and the rest of the natural feed. In order to control the agrocenosis, a person spends anthropogenic energy for the treatment of soil, sowing high-yielding plant varieties, amelioration, fertilizer and chemical plant protection products, for heating of animal breeding rooms, etc. Control may be intense (high energy investment) and extensive (low energy investments). However, even with an intensive management strategy, the proportion of anthropogenic energy in the ecosystem energy budget is no more than 1%. Organisms living within the agrocenosis and non-human human business facilities are experiencing the constant impact of anthropogenic factors and are forced to adapt to them.

Between natural and artificial biogeocenoses, along with similarities, there are great differences that it is important to take into account in agricultural practice.

The differences of agrocenoses from biogeocenoses are (Table 1):

1. Small species diversity of living organisms

On the fields, one or more species (varieties) of plants typically cultivate, which leads to a significant depletion of the species composition of animals, mushrooms, bacteria. In addition, the biological monotony of the varieties of cultural plants occupying large areas (sometimes tens of thousands of hectares) is often the main cause of their mass destruction by specialized insects (for example, Colorado beetles) or damage to the pathogens of diseases (mutnyworthy, rust, head mushrooms, phytoofluoro, etc. ).

2. Short power chains

In Agromozoz, as in Biogeocenosis, there are producers (cultivated plants and weeds), consiefs (insects, voles, birds, mice, foxes, etc.), Roduznuts (mushrooms and bacteria). In this case, the mandatory link of food chains is a person, cultivating fields, gardens and harvest. But, due to a small number of species in agrodenozos, having a high number (cultural plants, weeds, pests, causative agents), power chains in it are short and simple.

3. incomplete cycle of substances

In natural biogeocenosis, primary plant products (harvest) are consumed in numerous nutrition (networks) of nutrition and again returns to the system of biological circulation in the form of carbon dioxide, water and mineral power elements. In agrocenosis, such a circulation of elements is sharply violated, since there is a significant part of them permanently withdrawn with harvest. Therefore, to reimburse their losses and, consequently, increasing the yield of cultivated plants must be constantly made into the soil fertilizer.

4. Energy source (anthropogenic energy)

For natural biogeocenosis, the sole source of energy is the sun. At the same time, agriculture, in addition to solar energy, receive anthropogenic additional energy, which has spent a person to produce fertilizers, chemicals against weeds, pests and diseases, irrigation or drainage of land, etc. Without such an additional energy costs, the long-term existence of agrocenoses is practically It is impossible.

5. Artificial selection

In natural ecosystems, there is a natural selection that rejects non-competitive views and forms of organisms and their communities in the ecosystem and thereby ensuring its basic property - stability.

A man directed primarily to the maximum increase in crop yields.

6. Instability

The smaller the number of compounds of agrocenosis of species, the less stable this ecosystem. The least stable monoculture (wheat, rice, cotton, etc.), requiring its existence of fertilizers and pesticides. Multi-shaped ecosystems, such as meadow, are most stable from agrocenoses. The instability of agrocenosis is also due to the fact that the protective mechanisms of producers - cultivated plants are weaker than that of wild species that have tools have been improved during the natural emergency for millions of years.

Table 1

Comparative characteristics of natural ecosystems and agrocenoses

7. Lack of full self-regulation

Agrosystems are not capable of self-regulation and self-recovery, susceptible to the threat of death with mass reproduction of pests or disease pathogens. Agromozoz is regulated by a person, and if it is not supported, it will quickly destroy and disappear. Cultural plants will not solve competition with wild species and will be ousted. At the site of the agrocenosis in the arid climate there will be a steppe, in a colder and wet - forest.

Thus, compared with natural biogeocenoses, agriculture have a limited species composition of plants and animals, are not capable of self-renewal and self-regulating, are affected by the threat of death as a result of mass reproduction of pests or causative agents of diseases and require the tireless activities of a person to maintain them. Their indisputable advantages compared to natural ecosystems lies in unlimited potential possibilities for increasing productivity. However, their implementation is possible only with constant, scientifically based soil care, ensuring plants by moisture and elements of mineral nutrition, plant protection against adverse abiotic and biotic factors.

The components of biogeocenosis and agrocenosis are the same components of the medium. In the other system, living organisms are combined with territorial and dietary ties. But in each case you can see your features.

Definition

Biogeocenosis - This is an independent ecosystem in which representatives of the living world are closely related to the inorganic components that make up their habitat. Examples: coniferous forest, flower meadow.

Agrocenosis - This is a system that appears when a person's intervention in the natural environment. Like biogeocenosis, it includes organic and inorganic parts. Examples: Prices, corn field.

Comparison

By comparing the systems under consideration, it should first of all pay attention to their species composition. For biogeocenosis in this respect, it is characterized by more variety. In agrocenosis, one or more crops chosen by man for growing (for example, planted on the potato section), and, accordingly, the number of species of animals and lower organisms (bacteria, mushrooms) is also limited.

In this regard, the power chain in artificially created systems is shorter and easier. However, in the territory where many plants of one species are located, all conditions are created for the vital activity of malicious organisms capable of coexisting precisely with such cultures. Without experiencing biological competition, they can multiply strongly and destroy crops or cause diseases in plants. As a result, the whole system often turns out to be threatened. Biogeocenosis in this respect is much resistant.

The difference between the biogeocenosis from the agrocenosis is also the way there is a circulation of substances in each case. In the natural natural community, it is closed. All plants produced (as well as their remains) are consumed by representatives of numerous food links and returns to the soil enriching it. At the same time, agrovenosis is created precisely in order to obtain a crop. Accordingly, on the moment of cleaning operations, accompanied by a significant deposancy of biomass, the cycle of substances in such a system is broken, therefore, in this case, it is called unlocked. Fertilizers make fertilizers to maintain balance.

It is also important that the structure of biogeocenosis is formed in the implementation of natural selection that eliminates the weak species of organisms. In agrocenosis, cultures are involved, carefully selected by a person, given the degree of their productivity. In other words, artificial selection is mostly operating in the formations of this type. At the same time, a person not only determines that it will grow on a land area, but also provides an admission to the agrocenosis of additional energy. For example, heated greenhouses produced, artificial lighting is created. Meanwhile, ecosystems existing without human intervention, they get energy mainly from the Sun.

What is the difference between biogeocenosis and agrocenosis? The fact that the latter brings a person a real benefit, because it serves as a source of necessary products. Biogeocenosis, in turn, is not always useful from a practical point of view. However, it is a steady self-regulating education. Agrocenosis is safely exists more or less long term only subject to control by people. To maintain such a system, the use of all sorts of agrotechnical techniques is required.

Table

Comparison of natural and simplified anthropogenic ecosystems (Miller, 1993)

The main goal of agriculturally generated is the rational use of those biological resourceswhich are directly involved in the sphere of human activity - sources of food, technological raw materials, drugs.

Agroecosystems are created by a person to obtain a high harvest - clean car products.

Summarizing everything already said about the agro-ecosystems we emphasize the following basic differences from natural (Table 2).

1. In agroecosystems sharply reduced a variety of species:

§ the decrease in the types of cultivated plants reduces the visible diversity of the animal population of biocenosis;

§ the species diversity of animals bred by man is negligible compared to natural;

§ cultural pastures (with herbs sowing) in the species variety are similar to agricultural fields.

2. Types of plants and animals cultivated by a person "evolve" due to artificial selection and non-competitive in the fight against wild species without human support.

3. Agroecosystems receive additional energy subsidized by a person except solar.

4. Clean products (crop) are removed from the ecosystem and does not enter the biocenosis power supply chain, and partially use it by pests, loss during cleaning, which can also get into natural trophic chains. In every way manifolded by a person.

5. Ecosystems of fields, gardens, pastures, vegetable gardens and other agriculturaloses are simplified systems supported by a person in the early stages of Suksessia, and they are equally unstable and unable to self-regulation, like natural pioneering communities, and therefore cannot exist without human support.

table 2

Comparative characteristics of natural ecosystems and agroecosystems.

Agricultural ecosystems (agroecosystems)

The main goal of agriculturally generated is the rational use of those biological resourceswhich are directly involved in the sphere of human activity - sources of food, technological raw materials, drugs. This also includes specifically cultivated species that are objects of agricultural production: fish farming, animal growing, special cultivation of forest crops, as well as species used for industrial technologies.

Agroecosystems are created by a person to obtain a high harvest - clean car products. Summarizing all the above-mentioned Agroecosystems, we emphasize the following major differences from natural (Table 10.2):

1. They are sharply reduced by a variety of species: a decrease in the types of cultivated plants reduces the species diversity of the animal population of biocenosis; The species diversity of animals bred by man is negligible compared to natural; Cultural pastures (with grazing herbs) in species variety are similar to agricultural fields.

2. Types of plants and animals cultivated by a person "evolve" due to artificial selection and non-competitive in the fight against wild species without human support.

3. Agroecosystems receive additional energy subsidized by a person except solar.

4. Clean products (crop) are removed from the ecosystem and does not enter the biocenosis power supply chain, and partially use it by pests, losses for cleaning, which can also get into natural trophic chains, every way man.

5. Ecosystems of fields, gardens, pastures, vegetable gardens and other agriculturaloses are simplified systems supported by a person in the early stages of Suksessia, and they are equally unstable and unable to self-regulation, like natural pioneering communities, and therefore cannot exist without human support.

Table 10.2.

In agrocenosis, it is much more often an excessive increase in individual species, named by C. Elton "Environmental explosion". From the history, such, for example, "Environmental Explosions" are known: In the past century, the fungus, phytophulat destroyed potatoes in France and caused his hunger, and the Colorado Caucasus spread to America to the Atlantic Ocean and at the beginning of XX . entered into Western Europe, in the 40s. - to the European part of Russia. In a difficult post-war time, this beetle literally "cleared" our fields, as we were not ready for its invasion.

In order not to occur such phenomena, artificial regulation of the number of pests with the rapid suppression of those that are just trying to exit from under control. At the same time, the opinion of a person does not coincide with the "opinion" of nature about the excess number of one or another pest. Thus, from the standpoint of natural selection, the stabilization of the number of apple-leaving fruzens at some level does not harm the existence of an apple tree as a species, but a person needs much more high-quality fruits for nutrition. Therefore, in agricultural practice, it uses such means to suppress the number of pests and in such quantities that they affect many times stronger than natural abiotic and biotic regulators.

Simplification of the natural environment of a person, with environmental positions, is very dangerous. Therefore, it is impossible to turn the entire landscape into an agricultural, it is necessary to maintain and multiply its diversity, leaving untouched protected areas that could be a source of species for the communities restored in the SUCSISSION RUNES.

In agrocenosis, it is much more often an excessive increase in individual species, named by C. Elton "Environmental explosion". From the history, such, for example, "Environmental Explosions" are known: In the past century, the fungus, phytophulat destroyed potatoes in France and caused his hunger, and the Colorado Caucasus spread to America to the Atlantic Ocean and at the beginning of XX . entered into Western Europe, in the 40s. - to the European part of Russia. In a difficult post-war time, this beetle literally "cleared" our fields, as we were not ready for its invasion.

In order not to occur such phenomena, artificial regulation of the number of pests with the rapid suppression of those that are just trying to exit from under control. At the same time, the opinion of a person does not coincide with the "opinion" of nature about the excess number of one or another pest. Thus, from the standpoint of natural selection, the stabilization of the number of apple-leaving fruzens at some level does not harm the existence of an apple tree as a species, but a person needs much more high-quality fruits for nutrition. Therefore, in agricultural practice, it uses such means to suppress the number of pests and in such quantities that they affect many times stronger than natural abiotic and biotic regulators.

Simplification of the natural environment of a person, with environmental positions, is very dangerous. Therefore, it is impossible to turn the entire landscape into an agricultural, it is necessary to maintain and multiply its diversity, leaving untouched protected areas that could be a source of species for the communities restored in the SUCSISSION RUNES.

Industrial-city ecosystems

About urbanization processes

Urbanization- This is the growth and development of cities, an increase in the share of the urban population in the country at the expense of the countryside, the process of increasing the role of cities in the development of society. The increase in population and its density is a characteristic feature of cities. Historically, the very first city with a million population was Rome at the time of Julia Caesar (44-10 years before. Er). The biggest city in the world in our time is Mexico City - 14 million people according to 1990, in 2000. It was expected to 31 million to 2000. The turn of 16 million people should have achieved and even exceed its cities such as Bombay, Cairo, Jakarta and Karachi, the turn of 20 million and above - Sao Paulo, Calcutta, Seoul. Moscow population by the end in 2002 is more than 10 million people

The total area of \u200b\u200bthe urbanized territories of the Earth in 1980 amounted to 4.69 million km 2, and by 2007 it will reach 19 million km 2 - 12.8% of the entire and more than 20% of the life-annual land area. By 2030, almost the entire population of the world will live in urban-type settlements (Reimers, 1990).

The population density in cities, especially large, ranges from several thousand to several tens of thousands of people per 1 km 2, and in Hong Kong - 1500 thousand per 1 km 2. As is known, the person does not apply the effect of factors depending on the density of the population, overwhelming animal reproduction: the intensity of population growth is not automatically reduced. But objectively high density leads to deterioration of health, to the emergence of specific diseases associated, for example, with pollution of the medium, makes an environment of epidemiologically dangerous in the event of a free or involuntary violation of sanitary standards, etc.

Particularly intensively proceed urbanization processesin developing countries, the above indicators of the growth in the number of cities in the coming years are evidenced by eloquently.

The person himself creates these complex urban systems, pursuing a good goal - to improve living conditions, and not only simply "Feeding" from limiting factors, but also creating a new artificial environment that increases the comfort of life. However, this leads to a man with a natural environment and disruption of natural ecosystems.

Urban systems

Urban system (urbosystem) -"Unstable natural and anthropogenic system, consisting of architectural and construction facilities and sharply disturbed natural ecosystems" (Reimers, 1990).

As the city is developing, its functional zones are increasingly differentiated - it is an industrial, residential, forest park. Industrial zones - these are the territories of concentration of industrial facilities of various industries (metallurgical, chemical, engineering, electronic, etc.) - they are the main sources of environmental pollution.

Residential zones -this is the territory of the concentration of residential buildings, administrative buildings, cultural facilities, enlightenment etc.

Lesoparkovaya- This is a green area around the city, an indulged by man, i.e., adapted for mass recreation, sports, entertainment. Its sections are possible and inside the cities, but usually here city parks- Wood plantings in the city, occupying enough extensive territories and also serving citizens to relax. Unlike natural forests and even forest parks, city parks and their smaller plantings in the city (squares, boulevards) are not self-sustaining and self-regulatory systems.

Forestry area, city parks and other areas of the territory, allocated and specially adapted for recreation people, are called recreational zones (territories, sites, etc.).

The deepening of the urbanization processes leads to the complication of the infrastructure of the city. Significant place begins to occupy transportand transport facilities(Automobile roads, gas stations, garages, service stations, railways with its complex infrastructure, inincluding underground - metropolitan; Airfields with a service complex and others). Transport systems cross all the functional areas of the city and influence the entire urban environment (urbosred).

Wednesdaythese conditions are a combination of abiotic and social media, together and directly affect people and their farm. At the same time, according to N. F. Reymmers (1990), it can be divided into natural environmentand man converted natural environment(anthropogenic landscapes up to the artificial environment of people - buildings, asphalt roads, artificial lighting, etc., i.e. artificial environment).In general, the urban and settlements of urban type are part of technospherei.e. biospheres, fundamentally transformed by a person in technical and man-made objects.

In addition to the terrestrial part of the landscape, his lithogenic basis, that is, the surface part of the lithosphere, which is accepted by the geological medium (E. M. Sergeev, 1979 is also included in the orbit. Geological Wednesday -these are rocky rocks, groundwater, which has the impact of human economic activity (Fig. 10.2).

In urban areas, in urboosososystems, a group of systems can be distinguished, reflecting the complexity of the interaction of buildings and structures with the environment, which called natural and technical systems(Trofimov, Epishin, 1985) (Fig. 10.2). They are closely connected with anthropogenic landscapes, with their geological structure and relief.

Thus, urbosystems are the focus of the population, residential and industrial buildings and structures. The existence of urbosystems depends on the energy of combustible fossil and atomic raw materials, artificially regulated and supported by a person.

Wednesday Urbosystems, both its geographical and geological part, is most strongly changed and in essence it became artificial there are problems of disposal and reuterization of natural resources involved in the turnover, pollution and cleaning of the environment, there is an all large isolation of economic and production cycles from natural metabolism (biogeochemical revolutions) and energy flow in natural ecosystems. And finally, it is here that the highest population density and artificial environment that threaten not only man healthbut also the survival of all mankind. Man's health is the quality indicator of this environment.

Control questions

1. What is the basis of Y. Oduma based on the allocation of four fundamental types of ecosystems? List these types.

2. What is characteristic of the first and second type of ecosystems (natural)?

3. What is the difference between the third type of ecosystems (agroecosystems) from natural ecosystems similar to them?

4. What is the features of the energetics of the odd-type ecosystem (industrial-urban)?

5. What is urbanization and urban systems?

6. What is understood as a natural and technical system and an artificial environment?