The decline in biodiversity on earth is an example. Causes of biodiversity decline Biodiversity decline. Reduction of biodiversity

Reduction of biodiversity. Reasons for the decline and extinction of species. The value of biodiversity for ecosystems and the biosphere as a whole.

Biodiversity- short for "biological diversity" - means the diversity of living organisms in all its manifestations: from genes to the biosphere. The issues of study, use and conservation of biodiversity began to receive much attention after the signing by many states of the Convention on Biological Diversity (UN Conference on Environment and Development, Rio de Janeiro, 1992).

There are three main types of biodiversity:

- genetic diversity, reflecting intraspecific diversity and due to the variability of individuals;
- species diversity, reflecting the diversity of living organisms (plants, animals, fungi and microorganisms). Currently, about 1.7 million species have been described, although their total number, according to some estimates, is up to 50 million;
- diversity of ecosystems covers differences between ecosystem types, habitat diversity and ecological processes. They note the diversity of ecosystems not only in terms of structural and functional components, but also in terms of scale - from microbiogeocenosis to the biosphere;

An increase in species diversity increases the overall genetic potential of the living organisms of the Biosphere. Each species contributes to diversity - from this point of view, there are no useless and harmful species.

The distribution of species over the surface of the planet is uneven. Species diversity in natural habitats is highest in the tropical zone and decreases with increasing latitude. The richest ecosystems in species diversity are tropical rainforests, which cover about 7% of the planet's surface and contain more than 90% of all species.

In the geological history of the Earth in the biosphere, the emergence and disappearance of species has constantly occurred - all species have a finite time of existence. The extinction was compensated by the emergence of new species, and as a result, the total number of species in the biosphere increased. The extinction of species is a natural process of evolution that occurs without human intervention.

Currently under the influence anthropogenic factors there is a reduction in biological diversity due to the elimination (extinction, destruction) of species. In the last century, under the influence of human activity, the rate of extinction of species has exceeded the natural rate by many times (according to some estimates, 40,000 times). There is an irreversible and uncompensated destruction of the unique gene pool of the planet.

Elimination of species as a result of human activity can occur in two directions - direct extermination (hunting, fishing) and indirect (habitat destruction, disruption of trophic interactions). Overfishing is the most obvious direct cause of the direct decline of species, but it has a much lesser impact on extinction than indirect causes of habitat change (eg, chemical pollution of a river or deforestation).

To account for species that are on the verge of extinction, many countries create Red Books - lists of rare and endangered species of living organisms. In order to preserve and maintain biological diversity, specially protected natural areas are created - protected areas (reserves, National parks etc.), genetic databanks. The preservation of an individual species is possible only if its habitat with the entire complex of species included in it, as well as climatic, geophysical and other conditions, is protected. A special role is played by the conservation of environment-forming species (edificatory species), which form the internal environment of the ecosystem. The creation of protected areas is aimed at protecting not only individual species, but also entire complexes and landscapes.

Reserves also serve to assess and monitor the state of biodiversity. There is no unified system for monitoring the state of biodiversity in Russia today. The most complete and permanent control over changes in biodiversity components is carried out in reserves. Every year, reserves prepare reports on the state of ecosystems ("Chronicles of Nature") - summaries of data on the state of protected areas, protected populations of plants and animals. Some reserves have been keeping "Chronicles of Nature" for more than 50 years, which include continuous series of data on the number of animals, biological diversity, ecosystem dynamics, as well as data on climate observations.

Part of the reserves of Russia (18) is part of the international network of biosphere reserves, specially created to monitor the state of biodiversity, climatic, biogeochemical and other processes on the scale of the Biosphere.

There are many reasons for the need to preserve biodiversity: the need for biological resources to meet the needs of mankind (food, materials, medicines, etc.), ethical and aesthetic aspects (life is valuable in itself), etc. but main reason biodiversity conservation lies in the fact that it plays a leading role in ensuring the sustainability of ecosystems and the biosphere as a whole (absorption of pollution, climate stabilization, provision of conditions suitable for life). Biodiversity performs a regulatory function (see the concept of biotic regulation, Gorshkov V.G.) in the implementation of all biogeochemical, climatic and other processes on Earth. Each species, no matter how insignificant it may seem, contributes to ensuring the sustainability of not only the "native" local ecosystem, but the Biosphere as a whole.

Environmentalists are sounding the alarm about the catastrophic reduction in biodiversity on our planet associated with activities modern man, who for the most part, living in the city, practically does not encounter nature, has no idea about its diversity and can only see it on TV. This gives him a sense of non-involvement of biodiversity in everyday life, but this is not so.

What is biodiversity?

The term biodiversity is commonly understood by scientists as the diversity of life on Earth - plants, animals, insects, fungi, bacteria and the ecosystems they form. In this concept, there is also a relationship that is present between them. Biodiversity can flow:

at the level of genes, determines the variability of individuals of a certain species;
at the species level, reflects the diversity of species (plants, animals, fungi, microorganisms);
diversity, this includes differences between them and different ecological processes).

It should be borne in mind that all the above types of diversity are interconnected. Many ecosystems and different landscapes create conditions for the emergence of new species, genetic diversity makes it possible to change within one species. The reduction of biodiversity indicates certain violations of these processes.

Currently, environmentalists are sounding the alarm due to the fact that human beings are violating living conditions, ecological processes, a person is creating new types of plants and animals at the gene level. How this will affect future life on Earth is unknown. After all, everything in nature is interconnected. This is the so-called "butterfly effect". The science fiction writer Ray Bradbury told the world about him in his story "Thunder Came" back in the middle of the last century.

Impossibility of life without biodiversity

The most valuable and important thing that exists on earth is biological diversity. Whether we know about it or not, but our whole life depends on the biological wealth of the earth, since animals and vegetation give it to us. Thanks to plants, we get enough oxygen, and materials based on them give us not only food, but also wood, paper, fabrics.

In our technogenic age, a huge amount of energy is needed, obtained by burning fuel, which is produced from oil formed as a result of the decomposition of the remains of many organisms and plants. Human life without biological diversity is impossible.

Coming to the store, we buy food packaged in bags, thinking little about where it comes from. The life of the majority of the population takes place in an artificial environment, which is made up of asphalt, concrete, metal and artificial materials, but this does not mean that the consequences of biodiversity reduction will bypass mankind.

Life on Earth and its diversity

The history of planet Earth suggests that at various times it was inhabited by many living organisms, most of which, as a result of evolution, died out and gave way to new species. Conditions and reasons contributed to this, but even during periods of natural stagnation there was no reduction in biodiversity, diversity increased.

Nature is arranged in such a way that everything in it is in interaction. No species of living organisms can live and develop in a closed environment. This was shown by numerous experiments on the creation of isolated biosystems that suffered a complete collapse.

Modern scientists have described and studied 1.4 million species of living organisms, but according to calculations, there are from 5 to 30 million species on Earth that live and develop depending on conditions. This happens naturally. Living organisms populated the entire planet. They live in water, air, and land. They can be found in the desert and in the Northern and Southern belts. Nature provides everything necessary to continue life on Earth.

With the help of living organisms, the nitrogen and carbon cycle takes place, which, in turn, supports the renewal and processing of natural resources. The environment favorable for life, which the Earth's atmosphere creates, is also regulated by living organisms.

What contributes to the reduction of biodiversity?

First of all, the reduction of forest areas. As mentioned above, plants play a very important role in the life of the planet. important role. The taiga and the jungle are called the lungs of the planet, thanks to them it receives a sufficient amount of oxygen. In addition, more than half of the species of living organisms exist in the jungle, which occupies only 6% of the earth's surface. They are called the genetic fund accumulated over 100 million years of evolution on Earth. Its loss will be irreplaceable and can lead the planet to a complete ecological catastrophe.

The reasons for the reduction of biodiversity are the activities of a person who transforms the planet in order to meet their own, not always reasonably increased, needs. Uncontrolled cutting of taiga and jungle leads to the disappearance of many species of life, even unexplored and not described by man, to disruption of ecosystems and water balance.

This is facilitated by deforestation and burning of forests, harvesting different kind plants and fisheries carried out at predatory levels, the use of pesticides, the draining of swamps, the death of coral reefs and the cutting down of mangroves, an increase in the number of agricultural land and the area of \u200b\u200bsettlements.

It is clear that the development of technology, technical progress cannot be stopped. But steps need to be taken to address environmental issues reduction in biodiversity.

International Convention on Biological Diversity

For this purpose, the "Convention on Biological Diversity" was adopted, which was signed by 181 countries, whose governments assumed obligations to preserve it in their countries, pledged to act jointly with other states and share the benefits of using genetic resources.

But this has not prevented the reduction of biodiversity on the planet. The ecological situation on Earth is becoming more threatening than ever. But there is hope that the common sense that God has given to man will prevail.

Evolution is the engine of life

The engine of life forward is evolution, as a result of which some species die out and new ones appear. All modern living beings have replaced the extinct ones, and, as scientists have calculated, out of the whole variety of species that existed on Earth, their current number is only 1% of their total number.

The extinction of species is a natural moment of evolution, but the current rate of biodiversity reduction on the planet is rampant, there is a violation of natural self-regulation and this has become one of the most important environmental problems of mankind.

The role of the species in the biosphere

The knowledge of mankind about the role played by representatives of one species or another in the biosphere is negligible. But scientists know for certain that each species has a certain meaning in nature. The disappearance of one species and the inability to replace it with a new one can lead to a chain reaction that will lead to the extinction of man.

Necessary actions

First of all, humanity should try to save the rainforests. Thus, leaving the opportunity to save some species of living beings and plants from extinction. The preservation of the jungle will lead to climate stabilization.

The jungle is a direct source of the richest genetic material, a treasury of various types of living beings. In addition, it is a source of plants, on the basis of which a person creates unique medicines. By moistening the atmosphere, tropical forests prevent global climate change.

Global environmental issues

Global environmental problems of our time

Anthropogenic climate change

Annual increase in atmospheric content:

– combustion of fossil fuels;

– Anthropogenic disturbances in the living conditions of microbial communities in the soils of Siberia and North America.

Consequences:

– the process of desertification is accelerating (in the world annually 6 million hectares);

– climate change in Siberia and Scandinavia;

- the rise in sea level is accelerating (due to melting polar ice). Over the past century, the ocean level has risen by 10-12 cm, and by the middle of the XXI century. a rise of 150 cm is predicted.

Thinning of the ozone layer in the stratosphere

Antarctica - 2/3 of the southern mainland ozone "hole":

–1% O3 leads to an increase in the incidence of skin cancer by 5–7%, which is 6–9 thousand people in the European territory of the country.

Causes: freon emissions ( special group chlorofluorocarbons), space launches, supersonic flights at high altitudes.

Consequence: an increase in the frequency of cancer, the death of forests and even the death of all terrestrial life on earth.

pollution environment

– uncontrolled increase in the number of various pollutants ( Agriculture, industry, transport, domestic pollution);

– extensive use of water resources;

- water management construction without taking into account the impact on nature (for example, the problem of the Aral Sea).

Environmental impacts of energy production

acid rain

- reduce the content of nutrients in the leaves (coniferous) and increase the removal of minerals from the soil

- reduce yield

- destroy natural vegetation (forests of Belarus and Ukraine)

- destroy life in freshwater bodies at pH 5 or lower (in the US, more than 80% of lakes are lifeless)

- convert insoluble compounds in the soil into soluble ones; as a result of soil acidification with compounds of Al, Co and other metals, they accumulate in plants and in the waters of reservoirs in large quantities

Reduction of biodiversity

Biodiversity (biological diversity) is the diversity of life in all its manifestations. Biodiversity is also understood as diversity at three levels of organization: genetic diversity (the diversity of genes and their variants - alleles), species diversity (the diversity of species in ecosystems) and, finally, ecosystem diversity, that is, the diversity of the ecosystems themselves.

The reasons for the extinction of species and the fact that they become rare are divided into two main groups:

1. Direct pursuit hunting, etc.

2. Disappearance or change, degradation of the habitat.

the main factors threatening vertebrate animals:

67% - destruction or degradation of habitat;

37% - overexploitation;

19% - the influence of introduced species, i.e. species that have been intentionally or accidentally moved outside the range;

4% - loss, reduction or deterioration of the food base;

3% - destruction in order to protect agricultural plants, domestic animals, fishery objects;

2% - random loot.

(Numbers are the number of species (in%) threatened with extinction (the sum exceeds 100% due to the fact that a number of species are threatened by more than one factor)

NUMBER OF ANIMAL SPECIES THAT ARE DANGEROUS

International Red Book:

236 species of mammals;

287 bird species;

119 species of reptiles;

36 species of amphibians.

demographic problem

The global demographic problem has two parts:

1. rapid and poorly controlled population growth in developing countries (the so-called countries of the “South region”),

2. aging of the population of developed countries and many states with economies in transition (the so-called countries of the "Northern region").

Never in the history of mankind have the growth rates of world population been as high as in the second half of the 20th and early 21st centuries. During the period from 1960 to 1999, the world's population doubled (from 3 billion to 6 billion people), and in 2007 it amounted to 6.6 billion people. Although the average annual growth rate of the world population has decreased from 2.2% in the early 60s. to 1.5% in the early 2000s, the absolute annual increase increased from 53 million to 80 million people.

Demographic transition from traditional (high birth rate - high death rate - low natural increase) to modern type population reproduction (low birth rate - low mortality - low natural population growth) ended in developed countries in the first third of the 20th century, and in most countries with economies in transition - in the middle of the last century. At the same time, in the 1950s-1960s, a demographic transition began in a number of countries and regions of the rest of the world, which begins to end only in Latin America, East and Southeast Asia and continues in many countries of Asia, Africa, the Near and Middle East.

The rapid rate of population growth compared to the rate of socio-economic development in these regions leads to an aggravation of the problems of employment, poverty, the food situation, the land issue, to a low level of education, and a deterioration in the health of the population. The authorities of these countries see a solution (or do not pay attention to these problems) to their demographic problem in accelerating economic growth and at the same time reducing the birth rate (an example would be China - a successful solution to the problem).

The main factor influencing the birth rate on present stage- cultural and civilizational.

In Europe, Japan and a number of CIS countries since the last quarter of the 20th century. going on demographic crisis, which manifests itself in slow growth and even natural decline and aging of the population, stabilization or reduction of its able-bodied part. Demographic aging (an increase in the proportion of the population over the age of 60 over 12% of the total population, over 65 over 7%) is a natural process based on advances in medicine, improved quality of life and other factors that prolong the life of a significant part of the population. population.

As for such an aspect of the demographic problem in these countries as the reduction of the economically active population, the authorities of many of these countries see its solution, primarily in the influx of immigrants from other countries.

Ecologists are sounding the alarm about the catastrophic reduction of biodiversity on our planet, associated with the activities of modern man, who, for the most part, living in the city, practically does not encounter nature, has no idea about its diversity and can only see it on TV. This gives him a sense of non-involvement of biodiversity in everyday life, but this is not so.

What is biodiversity?

at the level of genes, determines the variability of individuals of a certain species;
at the species level, reflects the diversity of species (plants, animals, fungi, microorganisms);
diversity of ecological systems (ecosystems), this includes differences between them and different conditions (habitat, ecological processes).

Impossibility of life without biodiversity

Life on Earth and its diversity

What contributes to the reduction of biodiversity?

First of all, the reduction of forest areas. As mentioned above, plants play a very important role in the life of the planet. The taiga and the jungle are called the lungs of the planet, thanks to them it receives a sufficient amount of oxygen. In addition, more than half of the species of living organisms exist in the jungle, which occupies only 6% of the earth's surface. They are called the genetic fund accumulated over 100 million years of evolution on Earth. Its loss will be irreplaceable and can lead the planet to a complete ecological catastrophe.

This is facilitated by deforestation and burning, the harvesting of various types of plants and fishing carried out in predatory sizes, the use of pesticides, the drainage of swamps, the death of coral reefs and the cutting down of mangroves, an increase in the number of agricultural lands and the area of \u200b\u200bsettlements.

It is clear that the development of technology, technical progress cannot be stopped. But it is necessary to take measures to solve the environmental problems of biodiversity reduction.

International Convention on Biological Diversity

Evolution is the engine of life

The role of the species in the biosphere

Necessary actions

Currently, biodiversity refers to all types of plants, animals, microorganisms, as well as the ecosystems and ecological processes of which they are part.

Quantitative assessments of biodiversity are based on the use of various indicators: from a simple number of species in a community to calculations of various dependencies and indices based on mathematical and statistical approaches. In this case, the time factor is necessarily taken into account, since biodiversity can only be assessed at a certain point in time. Diversity indicators have gained great popularity, which reflect not only the total number of species, but also the characteristics of the composition of biocenoses.

There are three levels of biodiversity: genetic, species and ecosystem. Genetic diversity is the total amount of genetic information contained in the genes of organisms that inhabit the Earth. Species diversity is the variety of species of living organisms that live on Earth. Ecosystem diversity refers to the different habitats, biotic communities, and ecological processes in the biosphere, and the vast diversity of habitats and processes within an ecosystem.

The indicator of biodiversity at the global level is considered to be the ratio of areas of territories of natural complexes, to varying degrees subject to anthropogenic impact and protected by the state.

Biodiversity is the basis of life on Earth, one of the most important life resources, it is considered the main factor determining the stability of biogeochemical cycles of matter and energy in the biosphere. Causal relationships between many species play a large role in the cycle of matter and energy flows in ecosystem components that are directly related to humans. So, for example, animals - filter feeders and detritophages, not used by humans for food, make a significant contribution to the cycle of biogenic elements (in particular, phosphorus). Thus, even species of organisms that are not included in the human food chain can be useful to him, although they benefit indirectly.

Many species have played a major role in shaping the Earth's climate and continue to be a powerful climate stabilizing factor.

The evolutionary processes that took place in different geological periods led to significant changes in the species composition of the inhabitants of the Earth. About 65 million years ago, at the end of the Cretaceous period, many species disappeared, especially birds and mammals, dinosaurs completely died out. Later, biological resources were lost faster, and, unlike the great extinction of the Cretaceous period, most likely caused by natural phenomena, the loss of species is now due to human activities. According to experts, in the next 20 hours 30 years, approximately 25% of all species on Earth will be under serious threat of extinction.

The threat to biodiversity is constantly growing. According to forecasts, between 1990 and 2020, between 5 and 15% of species may disappear. The most important causes of species loss are:

Habitat loss, fragmentation and modification;

Overexploitation of resources:

Environmental pollution;

Displacement of natural species by introduced exotic species.

The loss of species diversity as a life resource can lead to serious global consequences, as it threatens the well-being of man and even his very existence on Earth. Ecosystem resilience can be compromised when biodiversity declines; species that are not currently dominant can become dominant when environmental conditions change. It is not yet possible to predict how the loss of biodiversity will affect the functioning of the ecosystem, but experts suggest that such losses are unlikely to be favorable.

Active measures are being taken to conserve biodiversity. The Convention on Biodiversity was adopted in 1992 at KOSR-2. Russia ratified the Convention in 1995; adopted a number of laws related to the conservation of biodiversity. Russia is a party to the CITES convention (1976) as the legal successor of the USSR.

The following measures are being developed for the conservation of biodiversity and its sustainable use:

1) protection of a special habitat - the creation of national parks, biosphere reserves and other protected areas;

2) protection of individual species or groups of organisms from overexploitation;

3) preservation of species in the form of a gene pool in botanical gardens or banks;

4) reducing the level of environmental pollution.

The implementation of the planned measures is carried out through the development of international and national programs aimed at implementing these measures (for example, the DIVERS1TAS program). A Pan-European Strategy on Biological and Landscape Diversity (1995) has been developed. An information database BioNET is being created (in Great Britain), where data on all species of plants and animals known on Earth are concentrated; the world's first data bank on endangered animals and plants was created (in Germany).