The problem of biodiversity conservation. Decrease in biodiversity under the influence of anthropogenic activities

That spread and live in various natural areas Oh. Such biodiversity in different climatic conditions is not the same: some species adapt to the harsh conditions of the arctic and tundra, others learn to survive in deserts and semi-deserts, others love the warmth of tropical latitudes, the fourth inhabit forests, and the fifth spread over the wide expanses of the steppe. The state of the species, which is at the moment on Earth, was formed over 4 billion years. However, one is the decline in biodiversity. If it is not solved, then we will forever lose the world that we know now.

Reasons for the decline in biodiversity

There are many reasons for the decline in animal and plant species, and they all directly or indirectly come from people:

• expansion of the territories of settlements;
• regular emissions of harmful elements into the atmosphere;
• transformation of natural landscapes into agricultural objects;
• usage chemical substances in agriculture;
• pollution of water bodies and soil;
• road construction and the position of communications;
• requiring more food and territories for life;
• experiments on crossing plant and animal species;
• destruction of ecosystems;
• caused by people.

Of course, the list of reasons goes on. Whatever people do, they affect the reduction of the areas of flora and fauna. Accordingly, the life of animals changes, and some individuals who are unable to survive die prematurely, and the number of populations is significantly reduced, often leading to the complete extinction of the species. Roughly the same thing happens with plants.

The value of biodiversity

Biological diversity different forms life - animals, plants and microorganisms is valuable in that it has genetic and economic, scientific and cultural, social and recreational, and most importantly - ecological significance... After all, the diversity of animals and plants makes up the natural world that surrounds us everywhere, so it must be protected. People have already caused irreparable damage, which cannot be compensated in any way. For example, many species have been destroyed all over the planet:

Quagga

Sylphius

Solving the problem of biodiversity conservation

It takes a lot of effort to preserve biodiversity on earth. First of all, it is necessary that the governments of all countries pay special attention to this problem and protect natural objects from the encroachments of different people. Also, work on the preservation of the world of flora and fauna is carried out by various international organizations in particular, Greenpeace and the UN.

Among the main measures that are being taken, it should be mentioned that zoologists and other specialists are fighting for each individual of an endangered species, creating reserves and natural parks, where animals are under observation, create conditions for them to live and increase populations. Plants are also artificially bred in order to increase their ranges, to prevent valuable species from perishing.
In addition, it is necessary to carry out measures to preserve forests, protect water bodies, soil and atmosphere from pollution, apply in production and everyday life... Most of all, the preservation of nature on the planet depends on ourselves, that is, on each person, because only we make a choice: to kill an animal or keep it alive, to cut down a tree or not, to pick a flower or plant a new one. If each of us protects nature, then the problem of biodiversity will be overcome.

Global changes in biological diversity

The number of species of organisms inhabiting the Earth is very large, but estimates of this value differ greatly, varying from 5 to 80 million. However, more or less clear taxonomic affiliation has been established for 1.4 million species. Of this known number of species, approximately 750,000 are insects, 41,000 are vertebrates, and 250,000 are plants. The rest of the species are represented by a complex set of invertebrates, fungi, algae and other microorganisms.

The species “richness” of different climatic-geographical zones is very different, although there is a clear tendency to increase from the poles to the equator.

Biodiversity is the basis of life on Earth, one of the most important life resources. It is difficult to overestimate the importance of the total quantity of goods and services provided by biodiversity.

In this case, some species are vital. So people use about 7 thousand types of plants for food, but 90% of the world's food is created at the expense of only 20, and 3 types of them (wheat, corn, rice) cover more than half of all needs.

Evolutionary processes that took place in various geological periods, led to significant changes species composition inhabitants of the Earth.

According to experts, in the next 20 - 30 years, approximately 25% of the entire biodiversity of the Earth will be under a serious threat of extinction.

There are four main reasons for species loss:

Habitat loss, fragmentation and modification;

Overexploitation of resources;

Pollution the environment;

Displacement of natural species by introduced exotic species.

In all cases, these reasons are anthropogenic.

Biodiversity conservation measures. It can be considered that one of the principles of environmental morality is the following: each generation has the right to the same biodiversity as the previous one.

Four types of measures are being developed to conserve and sustainably use biodiversity.

1. Protection of a special habitat - the creation of national parks, biosphere reserves and other protected areas.

2. Protection of certain species or groups of organisms from overexploitation.

3. Conservation of species in the form of a gene pool in botanical gardens or in gene banks.

4. Reducing environmental pollution.

An important means of biodiversity conservation is the development of international national programs and conventions aimed at implementing these measures.

The Convention on Biological Diversity, adopted by 153 states, reflects the urgency of the situation and is the result of long-term efforts to reconcile the conflicting interests of various states.

Global environmental problems and priorities of the 21st century

June 1997 in New York at a special session The General Assembly The UN summed up the results of its work in the 5 years that have passed since the 2nd UN Conference on Environment and Development in Rio de Janeiro (COSR-2). It is noted that the concept sustainable development still has not received a clear and constructive definition.

The state of affairs on environmental issues is as follows:

Freshwater is a high priority issue. Globally, water resources are sufficient. The severity of the problem is associated with the low quality and shortage of water, primarily in developing countries Oh.

Issues that need to be addressed include: water supply problems in large cities, transboundary problems and ways to resolve possible conflicts.

Excessive exploitation of surface and groundwater sources is fraught with a drop in the level groundwater, destruction and salinization of coastal water sources.

Oceans and seas. The problem of the depletion of fish resources and the protection of the marine environment remains acute. It is necessary to analyze the economic aspects of marine fisheries, information on the state of the marine environment.

The priority problem is considered to be the problem of coastal regions of the World Ocean, which are exposed to intense anthropogenic impact, including pollution.

Agriculture and forestry. The main concern about food production is that, despite the increased use of fertilizers, the average global yield per hectare of arable land is declining. The uneven distribution of food resources remains.

Energy. The world's energy needs continue to grow. Average annual rate of energy development in 1970-1997 amounted to 2.3%. The contribution of developing countries increased over this period from 14% to 30%. The relative annual average global increase in energy consumption has decreased, as has energy consumption per unit of output. Taking into account the expected population growth by 2100 to 10 billion people, energy production should be increased at least 4 times, and in developing countries - 10 times.

Increasing demand will have to be met through the use of non-renewable energy sources, which will lead to an increase in carbon dioxide emissions into the atmosphere.

Transport. Average global growth in road transport 1980-1993 reached 50%. The development of transportation is a prime example of how the advances in energy conservation through engine improvements are offset by the impact of increased transportation. By 2015, air transport pollution emissions into the atmosphere will triple.

Atmosphere. The main problem remains the reduction of greenhouse gas emissions, which is at the center of attention in the study of climate change. As you know, the concentration of carbon dioxide, methane and nitrous oxide has doubled in comparison with the pre-industrial period. If the current trend continues by 2010, the temperature on the planet will increase by 1-3 C, which will cause a rise in the level of the World Ocean (according to various estimates, from 0.3 to 1 m).

Waste. The growth of municipal waste continues.

Particular attention is drawn to the problem of hazardous waste. At the UN session, special attention was paid to radioactive waste - its safe storage and the responsibility of countries.

Land surface and stable Agriculture... Tasks in this area: to stop the process of degradation of soil fertility, to create conditions for sustainable agriculture. Food security depends on their solution, especially in the regions of Africa and Western Asia. To meet the challenges, developing countries need financial support.

Desertification and drought. The measures are determined by the Convention to Combat Desertification and the Session Documents (1997).

Biodiversity. The main goals are defined by the Convention on Diversity: conservation and equitable use of biodiversity.

Tourism. Environmental and legal measures and international assistance to developing countries in the development of the tourism industry and restrictions are important negative consequences the impact of tourism on the environment.

Natural disasters. The measures are stipulated by the documents of the World Conference on Natural Disasters (1994). Against the background of a trend towards an increase in the destructive consequences of natural disasters special attention demanded by developing countries without early warning capabilities.

Technogenic disasters. The main tasks are expansion international cooperation to eliminate the consequences.

Deforestation. KOSR-2 noted in special documents the need for global reforestation of the Earth.

During 1980-2000. there has been a significant decrease in forest area in developing countries. The most significant rainforest losses have been reported in Latin America and the Caribbean, Africa, Asia and the Pacific. In some regions, especially in Western Asia, deforestation has led to increased soil erosion, in Africa - to increased sensitivity to floods.

The structure of production and consumption. The goals of changes in this area are formulated in the document "Agenda 21". The main task is the creation of a stable structure of consumption - production.

In this photo we see many species of plants growing together in a meadow in the floodplain of the river. Budyumkan in the southeast of the Chita region. Why did nature need so many species in one meadow? About this and in question in this lecture.

Diversity of biotic cover, or biodiversity, is one of the factors for the optimal functioning of ecosystems and the biosphere as a whole. Biodiversity ensures the resilience of ecosystems to external stressors and maintains a mobile balance in them. Living from non-living things first of all differs by several orders of magnitude in great diversity and the ability not only to preserve this diversity, but also to significantly increase it as it evolves. In general, the evolution of life on Earth can be considered as the process of structuring the biosphere, the process of increasing the diversity of living organisms, forms and levels of their organization, the process of the emergence of mechanisms that ensure the stability of living systems and ecosystems in the constantly changing conditions of our planet. It is the ability of ecosystems to maintain balance, using for this hereditary information of living organisms, that makes the biosphere as a whole and local ecosystems material-energy systems in the full sense.

Russian geobotanist L.G. Ramensky in 1910 he formulated the principle of ecological individuality of species - a principle that is the key to understanding the role of biodiversity in the biosphere. We see that many species live together in each ecosystem at the same time, but what is the ecological meaning of this, we rarely think about it. Environmental individuality plant species that live in one plant community in one ecosystem, allows the community to quickly rebuild when changing external conditions... For example, in a dry summer in this ecosystem the main role in ensuring the biological cycle, individuals of species A, which are more adapted to life with a moisture deficit, play. In a wet year, individuals of species A are not at the optimum and cannot provide biological circulation under the changed conditions. In this year, individuals of species B begin to play the main role in ensuring the biological cycle in this ecosystem. The third year turned out to be cooler, in these conditions neither species A nor species B can ensure the full use of the ecological potential of this ecosystem. But the ecosystem is rapidly rebuilding, since it contains individuals of species B that do not need warm weather and photosynthesize well at low temperatures.

If we look at how things are in the real ecosystems of Primorsky Krai, we will see that in a coniferous-deciduous forest, for example, on a plot of 100 sq. meters grow individuals of 5-6 species of trees, 5-7 species of shrubs, 2-3 species of lianas, 20-30 species of herbaceous plants, 10-12 species of mosses and 15-20 species of lichens. All these species are ecologically individual, and in different seasons of the year, in different weather conditions, their photosynthetic activity varies greatly. These species complement each other, as it were, making the plant community as a whole ecologically more optimal.

By the number of species of a similar life form with similar requirements for external environment living in one local ecosystem, one can judge how stable the conditions in this ecosystem are. In stable conditions, such species, as a rule, will be less than in unstable conditions. If weather conditions have not changed for a number of years, then the need for a large number species disappears. In this case, the species is preserved, which in these stable conditions is the most optimal of all possible types of this flora. All the rest are gradually eliminated, unable to withstand competition with him.

In nature, we find a lot of factors or mechanisms that provide and maintain a high species diversity of local ecosystems. First of all, such factors include excessive reproduction and overproduction of seeds and fruits. In nature, seeds and fruits are produced hundreds and thousands of times more than is necessary to compensate for the natural loss due to premature death and dying from old age.

Thanks to adaptations to the spread of fruits and seeds over long distances, the rudiments of new plants fall not only on those areas that are favorable for their growth now, but also on those whose conditions are unfavorable for the growth and development of individuals of these species. Nevertheless, these seeds germinate here, exist for some time in a depressed state and die. This happens as long as the environmental conditions are stable. But if conditions change, then previously doomed to death seedlings of species unusual for this ecosystem begin to grow and develop here, going through the full cycle of their ontogenetic (individual) development. Ecologists say that in nature (read, in the biosphere) there is powerful pressure from the diversity of life to all local ecosystems.

General the gene pool of the vegetation cover of the landscape area- its flora-local ecosystems of this area are used most fully precisely due to the pressure of biodiversity. At the same time, local ecosystems in terms of species become richer. During their formation and restructuring, the ecological selection of suitable components is carried out from more applicants, whose diazachat came to this habitat. Thus, the probability of the formation of an ecologically optimal plant community increases.

This graph (Willie, 1966) shows how the number of hares (curve 1) and the number of lynxes (curve 2) change synchronously in one of the ecosystems. As the number of the hare increases, the number of the lynx begins to grow with some delay. Having increased its numbers, the lynx has a depressing effect on the hare population. At the same time, the number of hares decreases, lynxes cannot provide themselves with food and leave this ecosystem, or die. Lynx press decreases and the number of hares increases. The fewer species of predators and species of herbivorous animals in the ecosystem, the more abrupt fluctuations in their numbers are, the more difficult it is for the ecosystem to maintain its balance. With a large number of prey and predator species (see the previous diagram), the fluctuations in abundance have a much smaller amplitude.

Thus, a factor in the stability of a local ecosystem is not only the diversity of species inhabiting this local ecosystem, but also the diversity of species in neighboring ecosystems, from which the introduction of diazachobs (seeds and spores) is possible. The foregoing applies not only to plants leading an attached lifestyle, but even more so to animals that can move from one local ecosystem to another. Many individuals of animals, not belonging specifically to any of the local ecosystems (biogeocenoses), nevertheless play an important ecological role and participate in ensuring the biological cycle in several ecosystems at once. Moreover, they can alienate biomass in one local ecosystem, and throw out excrement in another, stimulating the growth and development of plants in this second local ecosystem. Sometimes this transfer of matter and energy from one ecosystem to another can be extremely powerful. This stream links together completely different ecosystems.

For example, migratory fish, accumulating their biomass in the sea, go to spawn in the upper reaches of rivers and streams, where after spawning they die and become food for a large number species of animals (bears, wolves, many species of mustelids, many species of birds, not to mention hordes of invertebrates). These animals feed on fish and discard their feces in terrestrial ecosystems. Thus, matter from the sea migrates to land inland and here it is assimilated by plants and is included in new chains of the biological cycle.

Stop spawning in the rivers of the Far East salmon fish, and in 5-10 years you will see how much the abundance of most animal species will change. The number of animal species will change, and, as a result, reorganizations in the vegetation cover will begin. A decrease in the number of carnivorous animal species will lead to an increase in the herbivore population. Having quickly undermined their food base, herbivores will begin to die, and epizootics will spread among them. The number of herbivorous animals will decrease, and there will be no one to distribute the seeds of some species and eat the biomass of other plant species. In short, when red fish stops entering the rivers in the Far East, a series of restructuring will begin in all links of ecological systems, hundreds and even thousands of kilometers away from the sea.

And these graphs (G.F. Gauze, 1975) show how in one ecosystem the number of slipper ciliates (unicellular animal) (curve 1) and predatory ciliates feeding on ciliates with slippers (curve 2) changes. The two upper graphs - the ecosystem is closed and limited in space: a - the ciliate of the shoe has no shelter; b - the slipper ciliate has a refuge. Bottom plots (c) - the ecosystem is open, with the onset of favorable conditions both species can hide or go into another system. With the onset of favorable conditions, both species can return.

Unfortunately, ecologists are not yet able to model the behavior of real ecosystems under conditions of changes in certain environmental factors... And the point here is not only the extreme complexity of ecological systems and the lack of sufficient information about their composition. In ecology, there is no theory that would allow such a simulation. In this regard, with a powerful impact on ecosystems, great care is required and adherence to the rule: "Before influencing the ecosystem and bringing it out of balance, measure seven times" and ... do not cut it off - give up this impact. The twentieth century convinced us that protecting natural ecosystems by maintaining them in equilibrium is much more reasonable than reworking these ecosystems in an attempt to optimize them. It should be said that in order to maintain equilibrium in local ecosystems and for their biogeochemical optimization, it is not taxonomic diversity in itself, according to the principle “the more species, the better,” is important, but functional variety, or a variety of ecobiomorphs. A measure of the functional diversity of an ecosystem is the number of ecobiomorphs and synusias of plants, animals, fungi and microorganisms. Measure taxonomic diversity is the number of species, genera, families and other higher taxa.

The variety of species and the variety of life forms or ecobiomorphs are far from the same thing. I will demonstrate this with the following example. In a meadow, species, genera and families of plants can live 2-3 times more than in dark coniferous forest... However, in terms of ecobiomorphs and synusia, it turns out that the biodiversity of the dark coniferous forest as an ecosystem is much higher than the biodiversity of a meadow as an ecosystem. In the meadow, we have 2-3 classes of ecobiomorphs, and in the dark coniferous forest, 8-10 classes. There are many species in the meadow, but they all belong either to the class of ecobiomorphs, perennial mesophytic summer-green grasses, or to the class of annual grasses, or to the class of green mosses. In the forest, different classes of ecobiomorphs are: dark coniferous trees, deciduous trees, deciduous shrubs, deciduous shrubs, perennial mesophytic summer-green grasses, green mosses, epigeic lichens, epiphytic lichens.

The biodiversity of organisms in the biosphere is not limited to the diversity of taxa and the diversity of ecobiomorphs of living organisms. For example, we can find ourselves in an area that is entirely occupied by one local elementary ecosystem - a raised bog, or a damp alder forest at the mouth of a large river. In another area, on the same territory, we will meet at least 10-15 types of local elementary ecosystems. Ecosystems of coniferous-broad-leaved forests at the bottom of river valleys are regularly replaced here by ecosystems of cedar-oak mixed herb-shrub forests on the southern gentle slopes of mountains, larch-oak forb forests on the northern gentle slopes of mountains, spruce-fir forests in the upper part of the northern ecosystems of steep mountain slopes and steppe meadows and curtain vegetation on the steep southern slopes of the mountains. It's not hard to understand what is Intra-landscape diversity of ecosystems is determined not only by the diversity of their constituent species and ecobiomorphs, but also variety of ecological landscape background, associated primarily with a variety of landforms, a variety of soils and underlying rocks.

It is based on species diversity. It includes millions of species of animals, plants, microorganisms living on our planet. However, biodiversity also encompasses the entire set of natural ecosystems that are composed of these species. Thus, biodiversity should be understood as the diversity of organisms and their natural combinations. On the basis of biodiversity, the structural and functional organization of the biosphere and its constituent ecosystems is created, which determines their stability and resistance to external influences.

Exists three main types of biodiversity:

• genetic, reflecting intraspecific diversity and due to the variability of individuals;
• specific, reflecting the diversity of living organisms (plants, animals, fungi and microorganisms);
• ecosystem diversity, encompassing the differences between ecosystem types, habitats and ecological processes. The diversity of ecosystems is noted not only in structural and functional components, but also in scale - from biocenosis to biosphere.

All types of biological diversity are interrelated: genetic diversity provides species diversity; the diversity of ecosystems and landscapes creates conditions for the formation of new species; an increase in species diversity increases the overall genetic potential of living organisms in the biosphere. Each species contributes to diversity, and from this point of view, there are no useless or harmful species.

Biodiversity convention

In accordance with the 1992 Convention on Biological Diversity, to which 181 states are parties as of August 14, 2001, their governments have committed to conserve biological diversity, use its components in a sustainable manner and share equally the benefits arising from the use of genetic resources. Despite this, the planet's biodiversity is being irreversibly lost at an alarming rate as a result of large-scale deforestation and deforestation activities; the predatory scale of harvesting plants; non-selective use of pesticides and other persistent pesticides; drainage and backfilling of swamps; destruction of coral reefs and mangroves; the use of predatory fishing methods; climate change; water pollution; transforming unspoiled natural areas into agricultural land and urban areas.

In the capital of Malaysia, Kuala Lumpur, in February 2004, under the auspices of the UN, the seventh conference of the Parties to the Convention on Biological Diversity was held. More than 2 thousand representatives from over 180 countries of the world took part in it. The conference discussed issues of protecting the environment and endangered species, explored the possibility of creating a special network that would help the population of developing countries to protect their heritage.

The Director General of the UN Environment Program K. Topfer said at the forum that after 2000 about 60 thousand people disappear from the planet every year. biological species and this number is growing steadily.

Biodiversity characterizes the process of real evolution, which takes place at many levels of the organization of living things. According to scientists, the total number of species of living beings is from 5 to 30 million. Of these, no more than 2.0 million are currently described. Thus, since the time of Linnaeus, who tried to create a classification of living organisms, the number of species of animals and plants known to science , increased from 11 thousand to 2 million.

Animals are one of the leading components of the Earth's ecological systems. Currently, science knows (described) a little more than 1 million animal species, which is approximately half of all existing on the planet. The main groups of organisms and their numbers (number of species, thousand) are presented as follows:

The biological diversity of species is maximal among insects and higher plants... According to experts, the total number of organisms of all life forms varies between 10 and 100 million. These millions of species of animals and plants support the conditions necessary for the continuation of life on Earth.

In 1982, the American researcher T. Erwin published an article that provoked heated controversy. He claimed that more than 30 million species of arthropods, mainly insects, can live in tropical forests. The basis for this bold conclusion was his estimate of the number of insect species specifically associated with only one tree species from the legume family (Luehea seemanni) in the Panama rainforest. Using an insecticide fumigation of tree crowns and collecting all the fallen arthropods on a plastic wrap stretched below, Erwin counted the total number of beetle species (he believed that many of them were unknown to science) and came to the conclusion that the tree serves as a food plant for only 136 of them. Taking a number of assumptions, he calculated that the number of species of all arthropods associated with one species of trees (including those living on earth) reaches 600. Since there are about 50 thousand tree species in the tropics, it is easy to calculate that there are 30 million of them. Thus, with the species already known to science (about 1 million), this amounted to 31 million! Some entomologists were very skeptical about Erwin's calculations: having accepted his logic, one would expect that most insects in the tropics should belong to new species, but in fact they are not so common.

Recently, this hypothesis was tested by the Czech scientist V. Novotny (Institute of Entomology of the Czech Academy of Sciences) together with colleagues from the USA, Panama, Sweden and the Czech Republic.

Surveying a section of low-lying tropical rainforest in New Guinea for several years, scientists collected insects from the leaves of 51 plant species, including 13 species from the genus Ficus and four from the genus Psychotria. In total, more than 50 thousand insects belonging to 935 species were collected, among which beetles, caterpillars of butterflies (lepidoptera) and orthoptera predominated. In addition, the researchers raised caterpillars on different plants, trying to bring them to the chrysalis.

Analysis of this extensive material showed that, per forage species, there are 7.9 species of beetles, 13.3 - butterflies and 2.9 - Orthoptera. Thus, the idea of ​​the extreme prevalence of stenophagy in the tropics turns out to be nothing more than a myth. Novotny and his colleagues also calculated how many insect species can be associated with food plants at the genus level, and then calculated the total number of arthropod species: there were about 4.9 million, and not 31 million, as Erwin assumed.

The importance of biodiversity conservation

Biological diversity is the main source of satisfaction for many and serves as the basis for its adaptation to changing environmental conditions. The practical value of biodiversity lies in the fact that it is, in fact, an inexhaustible source of biological resources. These are primarily food products, medicines, sources of raw materials for clothing, production building materials etc. Biodiversity is of great importance for the organization of human recreation.

We know very little about the beneficial properties of most organisms. In the asset of mankind, for example, there are only about 150 species of cultivated plants that are widely used, and out of 265 thousand species of all plant organisms, only 5 thousand have ever been cultivated by humans. To an even lesser extent, the diversity of microorganisms and fungi is taken into account.

Currently, there are about 65 thousand species of mushrooms. And how many of them does a person use?

Natural vegetation is the main base for obtaining medicines, with the help of which mankind got rid of many diseases. So, for example, if the cinchona tree (Chinchona), which gives quinine, was not found in the selva on the eastern slopes of the Andes, the inhabitants of the tropics, subtropics and many inhabitants of the temperate zones would be doomed to suffer from malaria. The appearance of synthetic analogues of this drug became possible only thanks to detailed study original. Mexican yam, belonging to the genus Dioscorea, is a source of diosgenin, which is used in the production of cortisone and hydrocortisone.

Trying to change natural conditions, man came into conflict with the forces of natural self-regulation. One of the results of this conflict was the decline in the biological diversity of natural ecosystems. Currently, the number of species on Earth is rapidly decreasing. Up to 10 animal species disappear daily and 1 plant species disappears weekly. The death of one plant species leads to the destruction of about 30 species of small animals (primarily insects and roundworms- nematodes) associated with it during feeding. In the next 20-30 years, humanity may lose about 1 million species. This will be a serious blow to the integrity and stability of our natural environment.

Biodiversity reduction occupies a special place among the main environmental problems of our time. There is a massive destruction of natural ecosystems and the disappearance of many species of living organisms. Natural ecosystems have been completely altered or destroyed on a fifth of the land. Since 1600, 484 animal species and 654 plant species have disappeared.

The species are unevenly distributed over the planet's surface. Variety of species in natural environments habitat maximum in tropical zone and decreases with increasing latitude. The richest in species diversity ecosystems - rainforests, which occupy about 7% of the planet's surface and contain more than 90% of all species. Coral reefs and Mediterranean ecosystems are also species rich.

Biodiversity provides genetic resources for agriculture, forms the biological basis for global food security and is a prerequisite for the existence of humankind. A number of crop-related wild plants are of great importance to the economy at the national and global levels. For example, Ethiopian Californian barley varieties provide protection against disease-causing viruses, in monetary terms, amounting to $ 160 million. USA per year. Genetic resistance to diseases achieved with wild wheat varieties in Turkey is estimated at $ 50 million.

There are many reasons for the need to preserve biodiversity: the need for biological resources to meet the needs of humanity (food, materials, medicines, etc.), ethical and aesthetic aspects, etc. However, the main reason is that biodiversity plays a leading role in ensuring the sustainability of ecosystems and the biosphere as a whole (absorption of pollution, stabilization of the climate, provision of habitable conditions). Biodiversity performs a regulatory function in the implementation of all biogeochemical, climatic and other processes on Earth. Each species, no matter how insignificant it may seem, makes a certain contribution to ensuring the sustainability of not only its local ecosystem, but also the biosphere as a whole.

As the anthropogenic impact on nature increases, leading to the depletion of biological diversity, the study of the organization of specific communities and ecosystems, as well as analysis of changes in their diversity, becomes an urgent need. In 1992, the United Nations Conference on Environment and Development was held in Rio de Janeiro (Brazil). At it, representatives of most of the states of the world signed the Convention on Biological Diversity.

In the Convention, “biological diversity” refers to the variability of living organisms from all sources, including terrestrial, marine and other aquatic ecosystems and ecological complexes of which they are a part; it includes diversity within a species, between species and diversity of ecosystems.

The objective of the Convention on Biological Diversity was formulated as follows: “the conservation of biological diversity, the sustainable use of its components and the equitable distribution of income from the use of genetic resources”.

In addition to the Convention, a Program of Action for the 21st century was adopted. It recommends directing the activities of mankind, first of all, towards identifying the state of biodiversity and potential threats to it in each of the countries that recognize the values ​​proclaimed at this conference.

Today it is obvious that the preservation of the diversity of living organisms and biological systems on Earth is a necessary condition for human survival and sustainable development of civilization.

The normal state and functioning of the biosphere, and, consequently, the stability of the natural environment are impossible without ensuring favorable environment habitat for all biotic communities in all their diversity. The loss of biodiversity threatens not only human well-being, but also his very existence.

The rate of decline in biodiversity, both in our country and throughout the world, has sharply increased over the past 30-40 years. A decline in biodiversity is noted at all levels - genetic, species and ecosystem, which is already leading to irreversible changes in the natural environment. The most significant extinction of plant and animal species in the last 65 million years is taking place at a rate five thousand times higher than the natural course of evolution on Earth.

Anthropogenic impacts on the main components of biotic communities will be considered in the following order: vegetable world (forests and other communities), animal world.

Of primary importance in nature and in human life are forests... Russia is rich in forest. More than 1.2 billion hectares, or 75% of the land area is occupied by forests. No country in the world has large timber reserves. The total area of ​​forests in Russia today constitutes a significant part of all forests on the Earth. These are the most powerful lungs of the remaining planets.

The distribution of forests in our country is uneven; the largest part of the entire forested area is located in Western and Eastern Siberia and the Far East. The main areas of Scots pine, spruce, larch, fir, Siberian cedar and aspen are concentrated here. The main forest resources are concentrated in Eastern Siberia (45% of the forests of the entire country) and stretch from the Yenisei almost to the Sea of ​​Okhotsk. This richest forest land is represented by such valuable tree species, like Siberian and Daurian larch, Scots pine, Siberian cedar, etc.

Forests are important component the natural environment. As an ecological system, the forest performs various functions and at the same time is irreplaceable natural resource(fig. 67). Numerous studies both in our country and abroad have confirmed the exceptional importance of forests in maintaining ecological balance in the natural environment. According to experts, the importance of the environmental protection function of the forest, that is, the preservation of the gene pool of flora and fauna, is an order of magnitude higher than theirs. economic significance as a source of raw materials and products.

The impact of forests on the natural environment is extremely diverse. It manifests itself, in particular, in the fact that forests:

They are the main supplier of oxygen to the planet;

Directly affect the water regime both in the occupied and adjacent territories and regulate the water balance;

Reduce the negative impact of droughts and dry winds, restrain the movement of moving sand;

By softening the climate, they contribute to an increase in crop yields;

Absorb and transform part of atmospheric chemical pollution;

Protect soils from water and wind erosion, mudflows, landslides, coastal destruction and other adverse geological processes;

They create normal sanitary and hygienic conditions, have a beneficial effect on the human psyche, and are of great recreational value.

Rice. 67. The value of the forest in nature and human life

At the same time, forests are a source of timber and many other types of valuable raw materials. More than 30 thousand products and products are produced from wood, and its consumption does not decrease, but, on the contrary, increases.

Let us emphasize once again that the significance of the forest is infinite. The famous Russian writer L.M. Leonov called him a Friend with a capital letter. Forests are important and most effective remedy maintaining the natural state of the biosphere and an irreplaceable factor of cultural and social significance. The positive ecological role of forests is reflected in the motto of the International Forestry Congress (India): "Forest is water, water is harvest, harvest is life."

According to their importance, location and functions performed, all forests are divided into three groups:

first group - forests performing protective ecological functions (water protection, field protection, sanitary and hygienic, recreational). These forests are strictly protected, especially forest parks, urban forests, especially valuable forests, national natural parks. In the forests of this group, only maintenance felling and sanitary felling of trees are allowed;

second group- forests of protective and limited operational value. They are widespread in areas with a high population density and a developed network of transport routes. The raw material resources of the forests of this group are insufficient, therefore, in order to preserve their protective and operational functions, a strict forest management regime is required;

third group - production forests. They are widespread in multi-forested areas and are the main supplier of timber. Wood harvesting should be carried out without changing natural biotopes and disrupting the natural ecological balance.

The belonging of a forest to a particular group determines the regime of forest use, which should be carried out on a strictly scientific basis in compliance with the basic principles of maximum conservation of natural ecosystems and rational use forest resources.

When characterizing the current state of the vegetation cover and, first of all, forest ecosystems, the term degradation is increasingly used. Forests were the first to experience other components of the natural environment. bad influence human activities. Forest degradation is one of the manifestations of the global changes taking place on Earth, which began with the advent of agriculture and livestock raising.

The impact of man on forests and in general on the entire plant world can be direct and indirect. TO direct impacts include : 1) clear cutting of forests; 2) forest fires and burning of vegetation; 3) destruction of forests and vegetation during the creation of economic infrastructure (flooding during the creation of reservoirs, destruction near quarries, industrial complexes); 4) the growing pressure of tourism.

Indirect impact - This is a change in living conditions as a result of anthropogenic pollution of air, water, the use of pesticides and mineral fertilizers. Penetration into plant communities alien plant species (introduced species).

The UNEP State of the Environment 2000 report emphasizes that “deforestation is probably the most serious ecological problem, facing humanity ... "The destruction (destruction) of forests in the list of human atrocities against the natural environment, according to A. Gore (1993), is in the first place. For several centuries, a significant part of all woodlands on the planet. At the present stage of development of productive forces, forest ecosystems become even more vulnerable, lose their protective functions, their potential environment-resistant capabilities are significantly weakened.

In the XVII century. on the Russian Plain, the area of ​​forests reached 5 million km 2, by 1970 there were no more than 1.5 million km 2 of them. Today, about 2 million hectares of forest are cut down in Russia annually. At the same time, the scale of reforestation through planting and planting forests is constantly decreasing. For the natural regeneration of the forest after clear felling, many tens of years are required, and to reach the climax phase, i.e. high degree closure of the nutrient cycle, and even more so - for the first hundreds of years (Danilov-Danilyan et al., 1994).

A similar condition associated with deforestation is observed in other countries of the world. According to FAO (UN Agriculture Program), drylands alone are deforested on 4 million hectares per year, of which 2.7 million hectares are in Africa. The forest is cut here mainly for firewood, as the demand for fuel wood is constantly growing. Suffice it to say that 82% of all energy used in eight Sahelian countries (Africa) comes from wood.

Evergreen humid (rain) tropical forests, ancient climax ecosystems, are in an even more dangerous position. This invaluable repository of genetic diversity is disappearing from the face of the Earth at about 17 million hectares per year. Scientists believe that at this rate, tropical rainforests, especially in the low-lying plains, will completely disappear in a few decades. According to 1992 data, 56% of forests have been destroyed in East and West Africa, and in some areas up to 70%; v South America(mainly in the Amazon basin) - 37%, in Southeast Asia - 44% of the original area. They are burned out in order to clear the land for pastures, they are intensively cut down as a source of wood fuel, they are uprooted if the farming system is not properly maintained, flooded during the construction of hydroelectric power plants, etc.

Pernicious influence impact on forest ecosystems Forest fires . They arise in the overwhelming majority of cases through the fault of people, as a result of careless handling of fire. In tropical rainforest zones, fires are formed as a result of deliberate burning of forests for grazing and other agricultural purposes. They deliberately burned forests during military operations, for example, during the war in Vietnam, Laos, Kampuchea (1961 - 1975).

Previously, forest fires in Russia occurred in every dry year. Huge tracts of forest (about 15 million hectares) burned, for example, in Eastern Siberia in 1915. Later, due to the development of new technical means of extinguishing fires and the improvement of methods for their detection, the area of ​​forest fires decreased. However, even today forest fires pose a serious threat to the forest fund not only in Russia, but also in all countries of the world. According to N.F. Reimers (1990), the largest forest fires in last years registered in 1972 (European part of Russia) and in 1979 and 1987. ( Eastern Siberia). Significant forest fires were observed in the 90s. in Yakutia and Magadan region, in the central and northwestern part European Russia... In 1997 alone, more than 31 thousand fires were registered, covering more than 726 thousand hectares of forest area.

Earlier, a very negative impact of atmospheric pollution and, first of all, sulfur dioxide on the state of forest ecosystems has been considered. In recent years, a significant factor in forest degradation has become Nuclear pollution... According to scientists, the total area of ​​forests affected by the accident at the Chernobyl nuclear power plant in the Chelyabinsk region and in the zone of influence of nuclear tests at the Semipalatinsk test site amounted to more than 3.5 million hectares.

In addition to forests, the increased negative impact of human activity is also manifested in relation to the rest of the plant cenosis (vascular plants, fungi, algae, lichens, bryophytes, etc.). Most often, the negative impact of humans on plant communities is manifested during mowing, picking medicinal plants and berries, grazing livestock and other types of direct use. Lots of different types plants die when exposed to pollutants, as well as in the process of land reclamation, construction and agricultural activities.

Large-scale anthropogenic impact on forest communities leads to severe environmental consequences both at the ecosystem-biosphere and at the population-species levels.

In deforested areas, deep ravines, destructive landslides and mudflows occur, photosynthesizing phytomass, which performs important ecological functions, is destroyed, the gas composition of the atmosphere is deteriorating, and the hydrological regime is changing. water bodies, many plant and animal species are disappearing.

The reduction of large forests, especially humid tropical ones - these peculiar moisture evaporators, according to many researchers, adversely affect not only the regional, but also the biosphere level. The destruction of trees and shrubs and grass cover on pastures in arid regions leads to their desertification.

Another negative environmental impact of deforestation is albedo change the earth's surface . Albedo is a quantity that characterizes the ability of a surface to reflect rays falling on it. The integral albedo of tree crowns is 10 - 15%, grass 20 - 25, fresh snow - up to 90%. The albedo of the earth's surface is one of important factors determining the climate both in the world as a whole and in its individual regions. It has been established that serious changes in the planet's climate can be caused by a change in the albedo of the Earth's surface by only a few percent. At present, with the help of satellite images, a large-scale change in the albedo (as well as the heat balance) of the entire surface of the Earth has been detected. Scientists believe that this is caused, first of all, by the destruction of forest vegetation and the development of anthropogenic desertification on a large part of our planet.

The above-mentioned forest fires cause enormous harm to the state of natural forest ecosystems, for a long time, if not forever, slowing down the process of reforestation in burnt areas. Forest fires worsen the composition of the forest, reduce the growth of trees, disrupt the connection of roots with the soil, intensify windbreaks, destroy the food base of wild animals, nesting places for birds. In a strong flame, the soil is burned to such an extent that moisture exchange and the ability to retain nutrients... The area burnt to the ground is often quickly populated by various insects, which is not always safe for people due to possible outbreaks of infectious diseases.

In addition to the direct human impacts on biotic communities described above, indirect ones are also important, for example, their pollution with industrial emissions.

Various toxicants , and, first of all, sulfur dioxide, nitrogen and carbon oxides, ozone, heavy metals, have a very negative effect on conifers and broadleaf trees as well as shrubs, field crops and grasses, mosses and lichens, fruit and vegetable crops and flowers. In gaseous form or in the form of acid precipitation, they negatively affect the important assimilation functions of plants, the respiratory organs of animals, sharply disrupt metabolism and lead to various diseases. So, for example, under the influence of ozone (0 3) in plants, not only the activity of the transport system decreases, but also the content of chlorophyll. There is a high correlation between leaf damage and the amount of adsorbed sulfur dioxide (SO 2). High doses of SO 2 or prolonged exposure to low concentrations of it lead to a strong inhibition of photosynthesis and a decrease in respiration. Thus, from the above examples it follows that toxicants such as sulfur dioxide, ozone, etc., can significantly disrupt various biochemical and physiological processes and the structural organization of plant cells and lead to their death.

Extremely negatively affect the life of plants car exhaust fumes , containing 60% of all harmful substances in the city air and among them such toxic ones as carbon oxides, aldehydes, undecomposed fuel hydrocarbons, lead compounds. For example, under their influence in oak, linden, elm, the size of chloroplasts decreases, the number and size of leaves decreases, their lifespan decreases, the size and density of stomata decreases, and the total chlorophyll content decreases one and a half to two times (Yablokov and Ostroumov, 1985).

At the population-species level, the negative impact of humans on biotic communities is manifested in the loss of biological diversity, in the decline in the number and extinction of certain species. According to botanists, the impoverishment of flora is observed in all plant zones and on all continents, except for Antarctica. Moreover, the most vulnerable is the flora of the islands.

Destruction of natural natural communities has already caused the disappearance of a number of plants. In the not too distant future, many of the plant species that are now dwindling in numbers will also be threatened with extinction. In total, 25-30 thousand plant species, or 10% of the world's flora, need protection all over the world. The share of extinct species in all countries is more than 0.5% of the total number of flora species in the world, and in regions such as the Hawaiian Islands, more than 11%.

Currently in Russia more than a thousand species are on the verge of extinction and need urgent protection. From the flora of Russia, Chekanovsky's forget-me-not flower, Baksan wolfberry, arrowhead stroganovia and many other plant species have disappeared forever.

A decrease in the number of species of vascular plants, and in some cases their disappearance, leads to a change in the species composition of ecosystems. According to experts, this leads to the rupture of evolutionary food webs and to destabilization ecological system, which is manifested in its destruction and impoverishment. Recall that the reduction of areas covered with green vegetation, or its thinning is extremely undesirable for two reasons: firstly, the global carbon cycle in the biosphere is disrupted and, secondly, the intensity of absorption of solar energy by the biosphere during photosynthesis decreases.

Animal world - it is a collection of all species and individuals of wild animals (mammals, birds, reptiles, amphibians, fish, as well as insects, molluscs and other invertebrates) that inhabit a certain territory or environment and are in a state of natural freedom.

According to Federal law"On the animal world" (1995), the basic concepts associated with the protection and use of the animal world, are formulated as follows:

Object of the animal world - organisms of animal origin or their population;

Biological diversity of the animal world - the diversity of objects of the animal world within the same species, between species and in ecosystems;

Steady state of the animal world - the existence of objects of the animal world for an indefinitely long time;

Sustainable use of objects of the animal world is the use of objects of the animal world, which does not lead in the long term to depletion of the biological diversity of the animal world and in which the ability of the animal world to reproduce and sustainably exist is preserved.

The fauna is an integral element of the natural environment and biological diversity of the Earth, a renewable natural resource, an important regulating and stabilizing component of the biosphere (Fig. 68).

The main ecological function of animals is participation in biotic circulation and energy. The stability of the ecosystem is provided primarily by animals, as the most mobile element.

It is necessary to realize that the animal world is not only an important component of the natural ecological system and at the same time a most valuable biological resource. It is also very important that all species of animals form the genetic fund of the planet, they are all needed and useful. There are no stepchildren in nature, just as there are no absolutely useful and absolutely harmful animals. It all depends on their number, living conditions and a number of other factors. One of the varieties of 100 thousand species of various flies - the housefly, is a carrier of a number of infectious diseases. At the same time, flies feed a huge number of animals ( small birds, toads, spiders, lizards, etc.). Only a few species (mites, pests, etc.) are subject to strict control.

Despite the enormous value of the animal world, man, having mastered fire and weapons, still in early periods his history rocked to exterminate animals (the so-called "Pleistocene overhunting", and now, armed with modern technology, has developed a "rapid attack" on the entire natural biota. different reasons was happening constant change its inhabitants. However, now the rate of extinction of species has increased dramatically, and more and more new species, which were quite viable before, are being drawn into the orbit of the disappearing ones. Prominent Russian environmental scientists A. V. Yablokov and S. A. Ostroumov (1983) emphasize that in the last century, the rate of spontaneous emergence of species is tens (if not hundreds) times lower than the rate of extinction of species. We are witnessing the simplification of both individual ecosystems and the biosphere as a whole.

Rice. 68. The value of the animal world in nature and human life

There is no answer yet to main question: what is the possible limit of this simplification, which should inevitably be followed by the destruction of the "life support systems" of the biosphere.

The main causes of biodiversity loss, population decline and extinction of animals are as follows:

Violation of the habitat;

Over-catching, fishing in prohibited areas;

Introduction (acclimatization) of alien species;

Direct destruction for the purpose of product protection;

Accidental (unintentional) destruction;

Contamination of the environment.

Habitat disruption due to deforestation, plowing of steppes and fallow lands, drainage of bogs, regulation of runoff, creation of reservoirs and other anthropogenic influences, it radically changes the breeding conditions of wild animals, their migration paths, which has a very negative effect on their numbers and survival.

For example, in the 60s - 70s. At the cost of great efforts, the Kalmyk saiga population was restored. Its population exceeded 700 thousand. At present, the saiga in the Kalmyk steppes has become much smaller, and its reproductive potential has been lost. The reasons are various: intensive overgrazing livestock, excessive enthusiasm for wire fences, the development of a network of irrigation canals that cut the natural migration routes of animals, as a result of which thousands of saigas drowned in canals on their way.

Something similar happened in the area of ​​Norilsk (Getov et al., 1986). The laying of the gas pipeline without taking into account the migration of deer in the tundra led to the fact that the animals began to stray into huge herds in front of the pipe, and nothing could force them to turn off the age-old path. As a result, many thousands of animals died.

Under mining I mean both direct pursuit and violation of the structure of the population (hunting), and any other, the removal of animals and plants from the natural environment for various purposes.

V Russian Federation there is a decrease in the number of hunting species animals, which is primarily due to the current socio-economic situation and their increased illegal production. Excessive prey serves the main reason reduction and number of large mammals (elephants, rhinos, etc.) in Africa and Asia. The high cost of ivory on the world market leads to the annual death of about 60 thousand elephants in these countries.

However, small animals are being destroyed on an unimaginable scale. According to the calculations of A.V. Yablokov and S.A. Volume international trade wild birds exceed seven million, most of which die either on the road or shortly after arrival.

The negative impact of such a factor of population decline as excessive harvesting is also manifested in relation to other representatives of the animal world. For example, the stocks of the East Baltic cod are currently at such a low level, which has not been noted in the entire history of the study of this species in the Baltic. By 1993, the total catches of cod had decreased by 16 times compared to 1984, despite the increasing fishing efforts (State Report ..., 1995).

Stocks of sturgeon in the Caspian and Azov Seas have been undermined to such an extent that, apparently, it will be necessary to impose a ban on their commercial fishing. The main reason for this is poaching, which has become everywhere on a scale comparable to fishing. The ban on fishing for capelin in the Barents Sea is expected to continue, as there is no hope of restoring a population undermined by predatory consumption. Since 1994, the fishing in the Don of the Azov-Kuban herring has been prohibited due to the low population size.

The third most important reason for the decline in the number and extinction of animal species is introduction (acclimatization) of alien species. The literature describes numerous cases of extinction of native (indigenous) species due to the influence of imported animal or plant species on them.

There are even more examples when local species are on the verge of extinction due to the invasion of "aliens". Examples of the negative influence of the American mink on the local species - the European mink, the Canadian beaver on the European mink, the muskrat on the desman, etc. are widely known in our country.

Many scientists believe that it is only in depleted anthropogenic ecosystems that it is possible to introduce new species to balance the ecological system. So, for example, according to A.G. Bannikov, the introduction of herbivorous fish - silver carp, grass carp - into artificial canals, where they will prevent their overgrowth, is quite permissible. In general, the experience of the production and acclimatization stations of Glavrybvod and some other organizations allows us to look more optimistically at the prospects for the acclimatization of fish and aquatic invertebrates, of course, with sufficient ecological justification. It is worth noting that a number of acclimatization works by Russian scientists were highly appreciated at the world level. This, for example, is the transoceanic transplantation of the Kamchatka crab into the Barents Sea, unprecedented in the history of acclimatization, where its self-reproducing population has now formed. Pilengas in the Sea of ​​Azov and pink salmon in the European North were also successfully acclimatized.

Other reasons for the decline in the number and disappearance of animals - their direct destruction to protect agricultural products and commercial objects (death of birds of prey, ground squirrels, pinnipeds, coyotes, etc.); accidental (unintentional) destruction(on highways, during military operations, when mowing grass, on power lines, when regulating water flow, etc.); pollution(pesticides, oil and oil products, atmospheric pollutants, lead and other toxicants).

Here are just two examples related to the decline in animal species due to unintentional human exposure. As a result of the construction of hydraulic dams in the Volga River, the spawning grounds for salmon (whitefish) and anadromous herring have been completely eliminated, and the area of ​​distribution of sturgeon fish has decreased to 400 hectares, which is 12% of the previous spawning fund in the Volga-Akhtuba floodplain.

Reduction of the mechanical energy of the system under the influence of friction forces