What is Biodiversity?

Biodiversity, an ecological term, is a broad concept that describes the degree of diversity in nature. Different scholars have proposed various definitions.

Biodiversity (English: biological or biological dlersity) is a description

Usually includes three components of genetic diversity, species diversity and ecosystem diversity. ^[2]

Since the 20th century, with

Protection in place :

In order to protect biodiversity, a certain area of land or water body including the objects to be protected is divided for protection and management. For example, the establishment of nature reserves

Biological resources are also biodiversity. Some organisms have been used by people as resources, and there are many more organisms. People have not yet known that their value is a potential biological resource. The value of biodiversity is often not valued by people. When people use biological resources, they are directly consumed without going through market circulation, but only for their own use. Biodiversity has high development and utilization value.

Biodiversity is the basis for the survival and development of human society. Many aspects of our clothing, food, shelter, transportation and material cultural life are closely related to the maintenance of biological diversity.

First, biodiversity provides us with food, fiber, wood, medicinal materials and a variety of industrial raw materials. All our food comes from the natural world, maintaining biodiversity, and our food varieties will continue to be rich. The people's quality of life will continue to improve, and they will shift from a subsistence type to a well-off type.

Biodiversity is still being maintained

China is one of the most biodiverse countries on the planet. Occupies a very unique position in the world. In 1990, biodiversity experts ranked China's biodiversity No. 8 among the 12 richest countries in the world. Among the countries in the northern hemisphere, China is the country with the most biodiversity. The characteristics of China's biodiversity are as follows.

1. Species are highly abundant China has

In recent years, the extinction of species, the reduction of genetic diversity, and the large-scale destruction of ecosystems, especially tropical forests, have aroused great attention from the international community on biodiversity. The direct cause of biodiversity loss is habitat. Loss and fragmentation, invasion of alien species, transitional development of biological resources, environmental pollution, global climate change and industrialized agriculture and forestry, etc., but these are not the root of the problem. The root cause lies in the rapid increase in population and the consumption of natural resources High-speed, increasingly narrow trade spectrum of agriculture, forestry and fisheries, economic systems and policies fail to assess the value of the environment and its resources, imbalances in the distribution of benefits arising from the use and protection of biological resources, inadequate knowledge and its application And the unreasonableness of laws and institutions. In short, human activities are the root cause of biodiversity loss at an unprecedented rate. ^[5]

Reason 1

-The number of people has grown since the existence of humans. When productivity is lagging, the population is controlled by natural factors such as droughts, insects, fires, floods, earthquakes, etc. In addition, human-made disasters such as war and poverty also control the population. However, modern science and technology Progress has increased the number and life of people.

-After the Industrial Revolution in the 19th century, population growth has become the global mainstream, most notably in economic developing countries. The global population was only 1 billion in 1830, reached 2 billion in 1930, reached 6 billion in 2000, and now reaches 6.5 billion.

-China had a population of about 300 million in 1790, about 400 million in 1860, and 800 million in 1970. In 2000, it exceeded 1.3 billion.

-After the population increases, the area of arable land must be expanded to meet the needs of food. This poses the most direct threat to natural ecosystems and living species.

-Due to rapid population growth and policy errors such as the Great Leap Forward, China has formed a large number of degraded ecosystems. The area of soil and water loss in China is about 1.8 million square kilometers, accounting for 19% of the country's land area, of which about 80% is local soil and water loss in the Loess Plateau.

-The area of desert, Gobi and desertified land in the north is 1.49 million square kilometers, accounting for 16% of the country's land area. In 1987, 200,000 square kilometers of desertified land and 130,000 square kilometers of potential desertified land.

-59 million acres of farmland and 74 million acres of grassland are now threatened by desertification. The grassland retreat area is 1.3 billion mu, which is increased by 20 million mu each year. Every year, 2.3 billion mu of pesticides are used for prevention and control, and 25 million mu of farmland is polluted by poor-quality fertilizers.

The increase in human demand for food, the continuous change of land in the pursuit of increasing land production, reduces the land's productive capacity, the singular ecosystem, accelerates the spread of pests and diseases, reduces ecological stability, and increases agricultural risk.

Reason 2

-The most important reason for the decrease in biodiversity is that the ecosystem deviates from the natural state under natural or human disturbance, the habitat is broken, and the organisms lose their homes.

-Compared with natural systems, generally, the composition of degraded ecosystems changes, community or system structures change, biodiversity decreases, biological productivity decreases, soil and microenvironment deteriorate, and interrelationships change.

-Daily (1995) ranked human activities that cause ecosystem degradation and biodiversity reduction: overexploitation (including direct damage and environmental pollution) accounts for 35%, deforestation accounts for 30%, agricultural activities account for 28%, and excessive Harvesting fuelwood accounts for 6%, and the bio industry accounts for 1%. The first three human activities accounted for 93%, and the most intuitive result of these damages was the fragmentation of species habitats and the islandization of habitats.

-The degree of biodiversity reduction depends on the degree of disturbance of the structure or process of the ecosystem, for example, human interference with the process of plant resource acquisition (such as excessive irrigation affects the water cycle of plants, and excessive fertilization affects the biogeochemical cycle) The direct effects on producers or consumers (such as felling or hunting) have greater negative effects.

-In general, disturbances are eliminated before the components of the ecosystem have been completely destroyed. The degradation of the ecosystem will stop and resume (for example, the restoration of a small amount of deforestation), and biodiversity may increase; Disturbances are eliminated after destruction, and ecosystem degradation is difficult to stop and may increase (for example, forest land restoration after burning mountainous areas).

Reason 3

-With the development of human beings, environmental pollution has also increased. Environmental pollution will affect the structure, function and dynamics of all levels of the ecosystem, and then lead to ecosystem degradation. The impact of environmental pollution on biodiversity currently has two basic views: one is that biodiversity will be lost because organisms may have significant limitations in adapting to sudden pollution, and the other is that pollution will change the original organism Evolution and adaptation model, biodiversity may develop under pollution-led conditions, thus deviating from its natural or conventional orbit. Environmental pollution will cause biodiversity to be reduced at three levels: genetics, populations and ecosystems.

-Impact at the genetic level. Although pollution can lead to adaptation of the organism's resistance, it ultimately leads to a reduction in genetic diversity. This is because under contaminated conditions, the sensitive individuals of the population disappear, and the genetic variation of these individuals has disappeared, leading to a reduction in the level of genetic diversity of the entire population; pollution caused by the reduction of the population size, due to random genetic The increase of drift may reduce the level of genetic diversity of the population; pollution causes the population to decrease, so that the genetic threshold of the population is reached, and even when the population finally returns to the original population size, the source of genetic variation is greatly reduced .

-Impact at the population level. Species exist in the form of a population. Studies have shown that when a population exists as a composite population, the subpopulation disappears due to pollution in one place, and it is obviously no longer suitable for another subpopulation due to the pollution of the habitat. Invasion and settlement. In addition, due to the different resistance of species populations to pollution, some populations will disappear and some populations will survive, but the end result is that the local species richness will decrease.

-Impacts at the ecosystem level. Pollution affects the structure, function and dynamics of ecosystems. Severe pollution may be convergent, that is, different types of ecosystems eventually become dead zones that are largely free of organisms. General pollution will change the structure of the ecosystem, leading to changes in function. It is worth pointing out that the pollution of heavy metals or organic matter in the ecosystem through the food chain will have an amplification effect, which will eventually affect human health.

Reason 4

-The invasion of alien species is literally understood to increase the biodiversity of a region. In fact, the harmless creatures in history have also expanded their distribution through human efforts. Some domesticated crops or animals have become Friends of humans, such as potatoes, tomatoes, sesame, pumpkin, sweet potatoes, celery, etc. in our food; acacia, sycamore, torch tree in trees; alfalfa in animal feed; red trout, bay scallops in animals, The benefits of these species entering other countries are greater than harm.

-However, in terms of ecological balance and biodiversity, biological invasion is a process that disrupts ecological balance after all, because the ecological balance and biodiversity in any area is the result of billions of years of evolution. If you disrupt it, you will lose control and cause harm.

-When people first introduced species, they only entered a component of the ecosystem of the place of origin. There was no way to introduce some natural enemies in the food web or the species it controlled. In this way, poor control would be unavoidable, and A direct consequence of the disaster is the damage to the local ecological diversity, and even the disaster.

Reason 5

Urbanization can shape the environment, but its approach depends so much on the region and way of urban development. Dozens in an attempt to outline urbanization in the future

City Expansion Map ^[6]

In the study of how global biodiversity and the carbon cycle will be affected during the year, scientists made detailed forecasts of how cities might grow. ^[6]

Urban growth is growing rapidly, especially in developing countries. The United Nations (UN) predicts that in the next 40 years, cities will absorb all of the world's growing population-approximately 2.3 billion people. Considering the predictions of the research team that urban areas around the world will double by 2030, Seto believes that the smart decisions made today will still have a huge impact. She hopes that conservation groups can start thinking about "urbanized hotspots" and help shape the next generation of urban infrastructure responsible for biodiversity. ^[6]