There are no examples of flood pulse theory influencing ecosystem formation 10

At the beginning of the 20th century, there were about 4,000 wild deer in the Kaibab Forest in the Rocky Mountains of the western United States, and they were accompanied by packs of wolves, threatening the survival of the deer. For the sake of the tranquility of these deer, in 1906, the United States decided to carry out a wolf eradication operation, and by 1930 more than 6,000 wolves had been shot. The wolf is nowhere to be seen in the Kaiba Burlin district.

So the deer began to give birth there without any worries and "unplanned", and soon the number of deer grew to more than 100,000. Thriving deer eat all edible plants, eat up weeds, destroy forests, and reduce the number of other animals that feed on plants, leaving the herd suffering from hunger and disease. By 1942, the number of deer in the Kaibab Forest had dropped to 8,000, and the majority of them were sick and weak, and the once-thriving deer family was in sharp decline.

This backfires because the wolf has been exterminated. On the one hand, wolves prey on some deer, so that the total number of deer is controlled, so that they do not reproduce to the extent that they degrade vegetation; On the other hand, most of the deer preyed on by wolves are old, weak, sick and disabled, which helps the survival of the fittest and the succession of deer herds. On the other hand, the deer is often in a state of escape under the chase of wolves, which promotes the robust development of the deer. Since the wolf disappeared, the deer had no natural predators, the "lazy man" was weak, and the deer herd degenerated.

In order to save the evil consequences of wolf extermination, the United States formulated a plan to "lure wolves into the house" in the 70s of the last century. However, this plan was opposed by some people and was not implemented in time. With the increase in people's awareness of the environment, the "Bringing Wolves into the House" program was finally implemented in 1995.

The first wild wolves were released from Canada into the Rocky Mountains, and the forest was full of life.

Don't know if any of this will be useful to you?

I think that's what I used to learn about the story of the deer and the wolf.

(1) Global warming.

The temperature of the earth is quietly rising, and it has reached the point where it is noticed. Its harm should not be ignored. It causes the melting of glaciers at the poles, brings frequent storms, leads to the reduction of biological species, and even raises sea levels and floods coastal areas, which can be seen when you consider that half of the world's population lives within 50 kilometers of the coast.

The cause of changes in the earth's temperature is human activities. In the process of human use of fossil fuel coal, in some industrial production processes, in the fermentation process of organic waste, carbon dioxide, methane, nitrogen oxides and other gases are continuously released. These gases have the effect of preventing the heat from the earth's surface from dissipating, and their existence is like forming a huge greenhouse on the earth's surface, so these gases are collectively called greenhouse gases.

At present, the control of greenhouse gas emissions has become one of the world's hot spots.

ii) Ozone layer depletion.

The ozone layer is located in the stratosphere of the atmosphere within an area of 10 to 50 kilometers above the ground, and the ozone layer absorbs most of the sun's ultraviolet rays and blocks ultraviolet radiation to the ground, so it has a protective effect on life on Earth.

Since the middle of the 20th century, it has been found that ozone concentrations in the Arctic Circle have decreased significantly, and holes in the ozone layer have appeared in the Antarctic Circle. The serious consequences of ozone layer depletion are also not negligible: it will increase the incidence of cancer and cataract in humans, damage the human immune system, and it will also seriously damage marine and terrestrial ecosystems and hinder the normal growth of plants.

The culprit of the destruction of the ozone layer turned out to be humans. In recent decades, HCFCs and halons have been widely used as refrigerants, deodorants, sprays, etc., and these chemicals will react with ozone to decompose ozone into oxygen after being released into the atmosphere and diffusing into the ozone layer.

iii) Reduction of biodiversity.

With the progress of science and technology and the development of industrial construction, the destruction of animals and plants by human beings is increasing day by day. Statistics show that 4,000,600 species are currently disappearing from the planet every year, and many more are under threat. 1996 World Association for the Protection of Flora and Fauna.

Soil destruction Arable land is now decreasing in fertility in 110 countries. In Africa, Asia and Latin America, soil erosion is severe due to the loss of forest cover, overexploitation of cultivated land and overgrazing of pastures.

Air pollution. The problem of air pollution is also the problem of acid rain. Previously, the problem of acid rain had only concerned the older industrialized countries of Europe and North America. But now, parts of Asia and Latin America, where the economy is booming, are also being hit by acid rain.

Air pollution also disrupts the functioning of ecosystems, accelerates the damage to homes, and leads to climate variability.

Fresh water is threatened.

In developing countries, 80% of 90% of diseases and more than 1 3 deaths are related to bacterial infections or chemically contaminated water. Today, 10,000 men, women and children die every day from water-borne diseases.

climate change and energy waste.

The greenhouse effect is a serious threat to humanity as a whole. According to a representative group of 2,500 experts, sea levels will rise, and rising temperatures will have serious impacts on agriculture and ecosystems.

Reduced forest area.

Over the past few hundred years, temperate countries have lost most of their forests. In recent decades, the decline in forest area in tropical countries has also been severe. At the current rate of forest loss, in 40 years' time, forests will be inaccessible in some Southeast Asian countries.

Reduction in biological variety.

Due to urbanization, agricultural development, deforestation and environmental pollution, the natural areas where organisms exist are becoming smaller and smaller, which has led to the extinction of thousands of species.

Chemical contamination. Millions of compounds from industry are found in the air, soil, water, plants, animals, and the human body. Even the ice caps, which are the last large natural ecosystems on Earth, are polluted.

Chaotic urbanization.

The deterioration of the population and the deterioration of agricultural land and poverty have prompted millions of peasants in the Third World to leave the countryside and gather in the slums of the big cities. With the advent of the new century, living conditions in some large cities will deteriorate further.

Overexploitation of the oceans and pollution of coastal strips.

As a result of overfishing, the ocean's fishery resources are dwindling at a frightening rate. As a result, many poor people who depend on seafood protein for their livelihoods are at risk of hunger.

The polar ozone layer hole.

Every spring, an ozone layer hole is formed over the Earth's two polar regions, with the loss of the ozone layer in the Arctic by 20 30 and the ozone layer in the Antarctic by more than 50.