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Lecture 3: Protecting Biodiversity

1. What is biodiversity?

According to the United Nations

“Biological diversity refers to the diversity of living organisms from all sources, including terrestrial, marine and other aquatic ecosystems and the ecological complexes they constitute; this includes diversity within species, between species and ecosystems. ”

Due to the evolution of life, biological diversity on the earth has gradually formed. Biodiversity includes all plant, animal and microbial species on the earth and the genes they possess, as well as the ecosystems and ecological processes formed by the interactions between species and their habitats.

Biological diversity is an umbrella term and is generally considered to have three levels, namely genetic diversity, species diversity and ecosystem diversity.

Some scholars believe that there is a fourth level of biodiversity, namely landscape diversity.

Genetic diversity refers to the sum of genetic information carried by all living things on earth.

The richer the genetic variation of a species, the wider its adaptability to the environment. In other words, the genetic diversity within a population reflects the evolutionary potential of the species.

When studying genetic diversity, morphological polymorphism, chromosomal polymorphism, protein polymorphism and DNA polymorphism should be considered.

Species are the basic units of biological classification. Species are reproductive units, consisting of continuous and discontinuous populations; species are evolutionary units, the basic links in biological systems, and the basic units of classification. In taxonomy, morphological, geographical, and genetic characteristics must be considered simultaneously to determine a species.

As a species, it must meet the following conditions:

① Have relatively stable and consistent morphological characteristics to distinguish it from other species;

② Live in a certain space in the form of a population, occupy a certain geographical distribution area, and survive and reproduce in this area;

③Each species has a specific genetic gene pool, and those of the same species Different individuals can mate with each other and reproduce offspring, but there is reproductive isolation between individuals of different species, and they cannot mate or even if they cross, they will not produce offspring with the ability to reproduce.

Under normal circumstances, the origin of new species is a long process, which takes thousands of years, at least hundreds of years. The evolution process of new families and new genera is slower and may take hundreds of thousands or even millions of years. Even though new species are constantly being formed on the earth, the current extinction rate of species is about 1,000 times more than the formation rate of new species. This is very serious. situation.

Speciation is the process by which new species differentiate from old species, that is, the process by which another new species is produced from within one species. It includes three links: mutation provides raw materials for evolution; natural selection is the dominant factor in evolution; geographical isolation is a necessary condition for the formation of new species

When studying species diversity in a certain area, we must not only count its species Quantity is species richness, and more importantly, it is necessary to estimate the richness of higher-level taxonomic units above species, such as genera, families, orders, and phylums, which is the diversity of taxa.

Endemic species (endemism or endemic species) refers to "a species whose distribution is limited to a specific geographical area or continent due to historical, ecological or physiological factors, etc., and does not appear in other places." Koalas and red kangaroos are only found in Australia and have not been found anywhere else in the world, so both are endemic to Australia.

Why is the distribution area of ??endemic species so narrow?

① The origin time is relatively recent;

② The last remnant of the distribution area of ??ancient endemic species;

③ The habitat conditions are unique or there are geographical obstacles in the periphery

The pigeon tree, a rare tree species unique to China, is distributed in western Hubei, Sichuan, Guizhou and northern Yunnan. The silver fir, a relict tree species unique to China, is produced in Guangxi, Sichuan, Hunan and Guizhou. The ginkgo, a relict tree species unique to China, China’s unique relict tree species such as metasequoia

Grassland species diversity

Grassland plants are one of the ecosystem types with high species richness. It is a rich gene pool.

It is the origin of food crops

In the context of future global warming, water scarcity, environmental pollution, and the development of pests and diseases, it is necessary to discover drought-resistant genes, salt-tolerant genes, and resistance genes. It is possible to find genes for diseases and insect pests, genes for accumulation of heavy metal elements, etc. from grassland plants.

It is a natural medicinal botanical garden

Ecosystem diversity refers to the diversity of habitats, biomes and ecosystems within the biosphere, as well as the amazing differences in habitats and changes in ecological processes within the ecosystem. diversity.

Ecosystem refers to a unified whole composed of biological communities and inorganic environment

In 1935, British ecologist Sir Arthur George Tansley first proposed Propose the concept of ecosystem. An ecosystem is a ‘system’ as a whole.

This system includes not only organic complexes, but also the entire complex of physical factors that form the environment... Such systems are the basic units of nature on the surface of the earth, and they come in various sizes and types

Ecosystem composition It is divided into two parts: "inorganic environment" and "biological community". Among them, the inorganic environment is the basis of an ecosystem. The quality of its conditions directly determines the complexity of the ecosystem and the richness of the biological communities in it; the biological communities react on the inorganic environment, and the biological communities in the ecosystem are both adapting to the environment and changing the appearance of the surrounding environment. Various foundations Materials closely connect biological communities with the inorganic environment, and the primary succession of biological communities can even turn a desolate bare land into an oasis with rich water and grass. The close connection between the various components of the ecosystem makes the ecosystem an organic whole with certain functions.

Terrestrial ecosystem, water ecosystem, wetland ecosystem

The structural characteristics and functional processes of the wetland ecosystem are transitional, and its role is also very important. Recently, it has attracted more attention. Pay more attention.

Wetlands cover only 6% of the earth’s surface, but provide a living environment for 20% of the known species on the earth. They have irreplaceable ecological functions and are known as the “kidneys of the earth”

< p> In the past 2000 years, 106 species of mammals and 127 species of birds have become extinct on the earth; 406 species of mammals, 593 species of birds, 209 species of reptiles, and 242 species of fish are on the verge of extinction. There are countless other lower animals.

The reasons for the destruction of biological diversity

Massive deforestation

Lecture 5 Soil erosion and desertification

In a broad sense, soil erosion and desertification Soil erosion in the narrow sense

In the broad sense: "Surface soil, parent material, and rocks are affected by external forces such as water, wind, gravity, and freezing and thawing, causing them to suffer various damage and movement, accumulation processes, and the loss of water itself. Phenomenon.

Narrow sense: specifically refers to the phenomenon of water erosion.

According to the "power" of water and soil erosion, water and soil erosion can be divided into

hydraulic erosion and

Gravity erosion and

Wind erosion are the most widely distributed. In mountainous areas, hilly areas and all sloping ground, hydraulic erosion will occur during heavy rains. Erosion.

The characteristic is that the water on the ground washes away the soil.

Gravity erosion mainly occurs in gullies and steep slopes in mountainous and hilly areas, and on both sides of steep slopes and ditch walls. , part of the lower part was emptied by the water flow. Due to the gravity of the soil and its soil-forming parent material, it could not remain in its original position and scattered

or collapsed in pieces.

Wind erosion is mainly distributed in deserts, sandy lands and hilly sand-covered areas in northwest, north and northeast my country, followed by sandy lands on the southeast coast, and thirdly in the "yellow flood areas" in Henan, Anhui and Jiangsu provinces (historically due to Formed by the diversion of sediment from the Yellow River)

The characteristic is that the sand particles are lifted up by the wind and float to other places with the wind.

Soil erosion in my country. Three major characteristics:

1. Large area and wide distribution. Soil erosion occurs not only in rural areas, but also in urban and industrial and mining areas, in almost every river basin and every province. /p>

2. The intensity is high and the proportion of serious erosion areas is much higher than the allowable soil loss. Compared with countries with serious soil erosion such as India, Japan, the United States, and Australia, China's water and soil erosion is more severe. Serious.

3. The causes are complex and the regional differences are obvious: the black soil area in the northeast, the rocky mountainous area in the north, the loess plateau area, the upper reaches of the Yangtze River and the river areas in the southwest, the agricultural and pastoral areas in the north, and the karst rocky desertification area in the southwest. The natural and economic and social development conditions of various regions such as the Red Soil Region in the South and the South are quite different, and the main causes of water and soil erosion, the harm caused, and the focus of treatment are different.

3. The hazards of water and soil erosion—take the Yellow River. For example: 1. Raise the river bed 2. Affect the effective use of water resources 3. Restrict economic and social development 4. Deteriorate the ecological environment

4. Causes of soil erosion

There are natural factors and human factors

Natural factors -

Topography. The steeper the ground slope, the faster the surface runoff flows, and the stronger the erosion and erosion force on the soil. The greater the surface runoff, the stronger the scouring force.

Rainfall that produces water and soil erosion is generally a heavy rainstorm with greater intensity. Surface (super-infiltration) runoff will occur only when the rainfall intensity exceeds the soil infiltration intensity. , causing erosion and erosion of the ground surface.

Vegetation. Forest and grass vegetation that reaches a certain canopy density can protect the soil from erosion. The higher the canopy closure, the stronger it is at retaining water and soil.

Human factors. Human beings' unreasonable use of land has destroyed ground vegetation and stable terrain, causing serious soil erosion.

Destruction of vegetation

Unreasonable farming system

Mining

5. Comprehensive management of water and soil erosion--Comprehensive management of small watersheds< /p>

The upper reaches are closed for afforestation. Mountain closure for afforestation is a method of afforestation that utilizes the renewal ability of forests to restore forest vegetation by regularly closing mountains in mountainous areas with suitable natural conditions and prohibiting man-made destructive activities such as reclamation, grazing, and firewood cutting.

Cultivation on steep slopes should be gradually changed to terraced fields

Comprehensive improvement. Combining biological measures with engineering measures

Converting farmland to forests and grazing, returning farmland to forests, and prohibiting grazing, etc., promote natural ecological restoration, restore vegetation coverage, and speed up the process of water and soil erosion control.

Construct high-standard farmland and construct high-standard modern farmland. Improve the existing farmland water conservancy, farmland shelterbelt and agricultural mechanization systems to achieve irrigation in droughts and drainage in floods, and increase the ability to resist natural disasters

Water-saving planting methods such as terraced fields and strip field planting, horizontal ditch planting, partition planting Slope horizontal ditch planting, Shen field planting, pit field planting, hole field planting, ridge and furrow planting, etc. These planting methods generally increase the soil moisture content by 1% to 8%. Compared with slope fields, the soil moisture content of terraced fields is increased by 2%. The yield of terraced fields with better fertilization is 50% higher than that of sloped fields. The yield increase rate of dam fields is 1 to 2 times that of slope fields, and can even reach 3 times.

Adopt drought-resistant varieties

Promote irrigation-saving technology. Micro-drip irrigation and micro-sprinkler irrigation can be used to promote water cellar technology. As a new technology to control water and soil erosion, water cellars have the function of storing rainwater and blocking sand and mud. Water cellars built near the highway also have the function of protecting the highway and the farm roads and terraces on both sides. Water cellars built in the courtyard are used to store water and soil. Rainwater can not only supplement the lack of drinking water for humans and animals, but also develop plastic greenhouses and solar greenhouses to grow vegetables

Adjust the agricultural structure in accordance with market rules and develop sheep farming, which is 10 times more efficient than growing grains. Develop green food. Develop courtyard economy and ridge economy to increase income and create wealth for society.

In 1991, the State Council of China promulgated the Soil and Water Conservation Law, which was my country’s first professional technical regulation on water conservation and put an end to the long-term lack of legal support for my country’s water conservation workers

6. What is desertification

Desertification in a narrow sense (i.e. desertification)

refers to the occurrence of desertification in areas that were not deserts due to excessive human economic activities in fragile ecosystems. Environmental change processes similar to desert landscapes.

In the United Nations Convention to Combat Desertification in Countries Experiencing Serious Drought and/or Desertification, Particularly in Africa, adopted in 1994,

Desertification refers to climate change and Land degradation in arid, semi-arid and dry subhumid areas caused by various factors including human activities

7. Desertification Overview According to the United Nations, the current global 1/5 of the population and 1/3 of the land are affected by desertification.

At the World Conference on Environment and Development in June 1992, the prevention and control of desertification was listed as an area of ??priority development and action by the international community.

In December 1994, the United Nations General Assembly passed a resolution to designate June 17 every year as the "Global Day to Combat Desertification and Drought" from 1995 to publicize it to the public.

Our country is one of the parties to the Convention.

Overview of Desertification in my country

China is one of the countries in the world with a large desertification area, wide distribution, complex types, and serious hazards. The potential area of ??land desertification in China is 331.7 million hectares. Accounting for 34.6% of the total land area.

By 2004, the total area of ??desertified land in the country was 263.6 million hectares, accounting for 27.46% of the land area and 79.47% of the total area where desertification may occur, higher than the world average of 69%

China’s desertified land is mainly distributed in 18 provinces and autonomous regions including Beijing, Tianjin, Hebei, Shanxi, Inner Mongolia, Liaoning, Jilin, Shandong, Henan, Hainan, Sichuan, Yunnan, Tibet, Shaanxi, Gansu, Qinghai, Ningxia, and Xinjiang There are 498 counties in China

There are 4 types of desertified land in my country: wind erosion desertification, water erosion desertification, freeze-thaw desertification, and soil salinization

The area of ??wind erosion desertification land is 183.9 million hectares. Accounting for 19.16% and 69.77% of the land area and desertified land area respectively, they are mainly distributed in 13 provinces in northwest, north and northeastern regions, forming a line starting from the Tarim Basin in the west to the western Songnen Plain in the east, with an east-to-west length of about 4,500 kilometers. The wind-sand belt is about 600 kilometers wide from north to south

The land area of ??water-eroded desertification is 25.93 million hectares, mainly distributed in the Loess Plateau area in the middle and upper reaches of the Yellow River

The area of ??freeze-thaw desertification land is 36.36 million hectares, mainly Distributed in the alpine zone of the Qinghai-Tibet Plateau

Saline land is 17.37 million hectares, relatively concentrated and contiguously distributed in the oases around the Tarim Basin and the piedmont alluvial plains at the northern foot of the Tianshan Mountains, as well as the Hetao Plain and the North China Plain .

8. Measures to prevent and control desertification in my country

Protect existing vegetation, vigorously afforestation and grass planting; rationally utilize water resources to ensure ecological water use; implement ecological migration to control the population in desertified areas; Strengthen publicity and education to raise public awareness of desertification prevention; transform livestock production and management methods to reduce pressure on grasslands; adjust the energy structure to reduce pressure on vegetation; adjust industrial structure and implement protective development; optimize land use patterns and promote sustainable socio-economic and ecological environment Sustainable development; implement nine specific measures including national ecological governance.

Carry out ecological migration to control the population in desertified areas

Ecological migration refers to migration carried out to protect the special ecology of a certain area or to restore the ecology of a certain area< /p>

9. National Key Desertification Prevention and Control Project

Beijing-Tianjin Sandstorm Source Control Project

The construction scope includes 75 areas in the five provinces of Beijing, Tianjin, Hebei, Shanxi, and Inner Mongolia County, the total area of ??the project area is approximately 46 million hectares, including 10.2 million hectares of wind-eroded desertified land.

The "Three Norths" protective forest system construction project

The project construction scope covers 590 counties in 13 provinces in northwest, northeast and north China. Build a number of relatively complete regional protective forest systems to initially curb the trend of ecological deterioration in the Three North Regions

Returning farmland to forest project

The project to return farmland to forest covers wind-eroded and desertified areas in northwest and North China; There are four types of areas: water erosion and wind erosion areas in the Northeast; water and soil erosion areas on the Loess Plateau; and river source areas on the Qinghai-Tibet Plateau, including 14 provinces including Qinghai and Xinjiang.

National Desertification Prevention and Control Comprehensive Demonstration Zone Project

Test and demonstrate three construction types: technical model type, policy mechanism type and industrial development type.

The natural grassland restoration project in the western region

Includes degraded grasslands, desert grasslands and grasslands in 96 counties in Inner Mongolia, Xinjiang, Qinghai, Sichuan, Yunnan, Gansu and Ningxia provinces River source grasslands in the eastern Qinghai-Tibet Plateau

What is the Western Development Initiative?

"Western Development" is a concept that promotes comprehensive economic development in a broad sense.

"Great Development" not only means a substantial increase in economic indicators, but also includes a series of complete contents such as the improvement of the ecological environment and the improvement of people's spiritual and cultural living standards. This is what "Great Development" means. "The meaning of "big" in ". Since when?

What is the guiding ideology of the Western Development?

The development of the western region must be based on infrastructure construction, ecological and environmental protection as the fundamental, economic structural adjustment and the development of characteristic industries as the key, relying on scientific and technological progress and cultivating talents as the guarantee, and reform and opening up as the driving force. , with the starting point of prospering the economy and making people of all ethnic groups uniformly prosperous

China's western region includes 12 provinces and municipalities. Including Chongqing, Sichuan, Guizhou, Yunnan, Tibet Autonomous Region, Shaanxi, Gansu, Qinghai, Ningxia Hui Autonomous Region, Xinjiang Uygur Autonomous Region, Inner Mongolia Autonomous Region, Guangxi Zhuang Autonomous Region

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Administrative areas, etc.

2. Why should we implement western development

1. The western region is rich in resources, has great market potential, and has an important strategic location.

2. However, due to natural, historical, social and other reasons, the economic development of the western region is relatively backward. The per capita GDP is only equivalent to two-thirds of the national average and less than the average of the eastern region. 40%

3. There is an urgent need to speed up the pace of reform, opening up and modernization. 4. The vast majority of China's poor people live in the west.

5. The development of the western region is a major strategic deployment related to the overall economic and social development of the country, national unity and border stability.

Geomorphy:

The surface form formed by the interaction of endogenous forces (such as crustal movements, volcanoes and earthquakes) and exogenous forces (such as flowing water, glaciers, etc.)

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Topography:

The undulations of the ground. Topography also refers to the undulations of the ground. It is different from terrain in that terrain generally refers to a smaller range, while terrain refers to a larger range.

1. Monsoon climate

The phenomenon of opposite wind directions prevailing in winter and summer in a large area. The phenomenon near the ground is not obvious above 2000 meters

Seasonal distribution of precipitation

1. Spring and autumn rainy areas in South China

2. Spring and summer rainy areas in the hills of Jiangnan

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3. Summer rainy area in the north

4. Less rainy area in the northwest inland basin; average monthly <2mm

5. Annual rainfall in the northwest mountainous area, not much rain, Evenly distributed.

6. Summer and autumn rainy areas in the Yunnan-Guizhou Plateau

7. Winter rainy areas in northeastern Taiwan

History and future trends of climate change in China

1. China’s climate change is quite consistent with global change, but there are also obvious differences.

2. Against the background of global warming, China's annual average surface temperature has increased significantly in the past 100 years, and the temperature increase rate is slightly higher than the global average for the same period.

3. The change trend of precipitation in the past 100 years and the past 50 years is not obvious, but there has been a slight increasing trend since 1956.

4. The frequency and intensity of major extreme weather and climate events in China have also changed significantly in the past 50 years.

5. China’s annual CO2 emissions are increasing, and the sum of positive radiative forcing of greenhouse gases is the main cause of climate warming.

6. In the next 20 to 100 years, China's surface temperature will increase significantly, and precipitation will also show an increasing trend.

Due to the combined influence of human activities and natural changes, the global climate is undergoing a significant change characterized by warming.

The global average temperature increased by 0.4 to 0.8°C from 1860 to 2000, and the 1990s were the warmest decade of the 20th century.

3) China’s soil types and characteristics

1. To the west of the three-level terrace.

It is the first and second level ladder

2. Landform characteristics: many mountains; many plateaus; many basins; many deserts; few plains

3. Vegetation characteristics: many grasslands; many deserts; Few forests

4. Climate characteristics: less precipitation, more evaporation, and more dry areas

5. Natural disasters: large areas of water and soil erosion; many sand and dust storms; serious land degradation and desertification

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6. Natural resources: Tibet and southwest regions are rich in water resources; rich underground resources; natural features are well preserved; natural landscapes are unique

What is the development of the western region?

1. Promote ecological construction and environmental protection to achieve ecological improvement and increase farmers' income;

2. Accelerate the construction of key infrastructure projects and lay the foundation for accelerated development in the western region;

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3. Strengthen the construction of agricultural and rural infrastructure and improve farmers’ production and living conditions;

4. Adjust the industrial structure and develop distinctive and advantageous industries;

5. Strengthen Science, technology, education, health, culture and other social undertakings to promote the coordinated development of economy and society;

6. Strengthen the construction of talent teams in the western region and provide strong talent guarantee for the development of the western region