Ecological migration to Jilin

Lecture 3: Protecting Biological Diversity

1. What is biodiversity?

According to the United Nations

"Biodiversity refers to all kinds of organisms from all sources, including terrestrial, marine and other aquatic ecosystems and their ecological complexes; This includes diversity within species, between species and between ecosystems. "

Due to the evolution of life, the biodiversity on the earth has gradually formed. Biodiversity includes all plant, animal and microbial species and their genes, ecosystems formed by the interaction between species and their habitats and their ecological processes.

Biodiversity is a general term, which 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 adaptation range to the environment, which means that the genetic diversity within a population reflects the evolutionary potential of a species.

Morphological polymorphism, chromosome polymorphism, protein polymorphism and DNA polymorphism should be considered when studying genetic diversity.

Species are the basic unit of biological classification. Species are reproductive units, consisting of continuous and discontinuous populations; Species is the unit of evolution, the basic link of biological system line and the basic unit of classification. In taxonomy, morphological characteristics, geographical characteristics and genetic characteristics must be considered at the same time to determine a species.

As a species, the following conditions must be met at the same time:

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

② As a population, it lives in a certain space, occupies a certain geographical distribution area, and lives and breeds in this area;

(3) Each species has a specific genetic database, and different individuals of the same species can pair with each other to reproduce. Individuals of different species have reproductive isolation, and even if they cross, they cannot mate or produce different reproductive offspring.

In general, the origin of new species is a long process, which takes thousands of years, at least hundreds of years. The evolution of new families and genera is slower, which may take hundreds of thousands or even millions of years. Even though new species are constantly forming on the earth, the extinction rate of species today is about 65,438+0,000 times that of new species, which is a very serious situation.

Speciation is a process in which a new species differentiates from an old species, that is, one species produces a new species. It includes three links: mutation provides raw materials for evolution; Natural selection is the dominant factor of evolution; Geographical isolation is a necessary condition for the formation of new species.

When studying the species diversity in an area, we should not only calculate the number of species, that is, the species richness, but also estimate the richness of higher taxonomic units, such as genera, families, orders and phyla, that is, the diversity of taxonomic units.

Endemic or endemic species refers to "a species is confined to a specific geographical area or continent due to historical, ecological or physiological factors and does not appear elsewhere". Koalas and red kangaroo are unique to Australia, but not in other parts of the world.

Why is the epidemic area so narrow?

(1) The origin time is close;

(2) The last remnant of the distribution area of ancient species;

③ The habitat conditions are special or there are geographical obstacles around.

Davidia involucrata is a unique and precious tree species in China, which is distributed in western Hubei, Sichuan, Guizhou, northern Yunnan and China. It is produced in Ginkgo biloba, a unique residual tree species in Guangxi, Sichuan, Hunan, Guizhou and China, and Metasequoia glyptostroboides, a unique residual tree species in China.

Grassland species diversity

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

Is the origin of food crops.

Under the background of global warming, water shortage, environmental pollution and the development of pests and diseases in the future, it is possible to find drought-resistant genes, salt-tolerant genes, insect-resistant genes and genes that accumulate heavy metal elements from grassland plants.

It is a natural medicinal botanical garden.

Ecosystem diversity refers to the diversity of habitats, biological communities and ecosystems in the biosphere, as well as the amazing diversity of habitat differences and ecological process changes within the ecosystem.

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

1935, the British ecologist Sir Arthur George Tansley first put forward the concept of ecosystem. Ecosystem is a "systematic" whole. This system includes not only organic complex, but also the whole physical factor complex that constitutes the environment ... This system is the basic unit of nature on the earth's surface, and they have various sizes and types.

The composition of ecosystem is divided into two parts: inorganic environment and biological community, in which inorganic environment is the foundation of an ecosystem. Its conditions directly determine the complexity of the ecosystem and the richness of the biological community; The response of biological community to inorganic environment. Biological communities not only adapt to the environment in the ecosystem, but also change the appearance of the surrounding environment. All kinds of basic materials closely link the biological community with the inorganic environment, and the primary succession of the biological community can even turn a desolate bare land into an oasis with rich aquatic plants. The close relationship between the components of the ecosystem makes the ecosystem an organic whole with certain functions.

Terrestrial ecosystem, aquatic ecosystem and wetland ecosystem.

The structural characteristics and functional process of wetland ecosystem are transitional, and its role is also very important, which has attracted more attention in recent years.

Wetlands only occupy 6% of the earth's surface, but provide a living environment for 20% of the known species on the earth. It has irreplaceable ecological functions and enjoys the reputation of "kidney of the earth".

In recent 2000, 106 species of mammals and 127 species of birds were extinct on the earth. Endangered mammals? There are 406 kinds of things, 593 kinds of birds, 209 kinds of reptiles, 242 kinds of fish and countless other lower animals.

Reasons for the destruction of biodiversity

Large-scale deforestation

Lecture 5 Soil Erosion and Desertification

Soil erosion in a broad sense and soil erosion in a narrow sense

Broadly speaking: "Surface soil, parent materials and rocks are subjected to external forces such as water power, wind power, gravity, freezing and thawing, which make them suffer from various kinds of destruction, movement, accumulation and loss of water itself.

Narrow sense: especially the phenomenon of hydraulic erosion.

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

Hydraulic erosion,

Gravity erosion and

Three types of wind erosion.

Hydraulic erosion is the most widely distributed. In mountainous areas, hilly areas and all slopes, hydraulic erosion will occur during heavy rain.

It is characterized in that groundwater is used as the power to wash away soil.

Gravity erosion mainly occurs in ravines and steep slopes in mountainous and hilly areas, steep slopes and ditch walls on both sides of ditches, and some lower parts are hollowed out by water flow. Because of the gravity of soil and its parent material, it can't remain in its original position and disperse.

Collapse to the ground or break into pieces.

Wind erosion is mainly distributed in the desert, sandy land and hilly sand-covered areas in the northwest, north China and northeast China, followed by the sandy land in the southeast coast, and then the "Yellow River floodplain" in Henan, Anhui and Jiangsu (the sediment brought out by the breach of the Yellow River in history).

Its characteristic is that sand is lifted by the wind, leaves its original position, and floats to another place with the wind to land.

Three characteristics of soil erosion in China;

First, it has a large area and a wide distribution range. Soil erosion not only occurs widely in rural areas, but also in towns and industrial and mining areas, almost in every river basin and province.

Second, the intensity is high and the proportion of severely eroded area is high. The erosion intensity is much higher than the allowable soil loss. Compared with Indian, Japanese, American, Australian and other countries with serious soil erosion, the soil erosion in China is more serious.

Third, the causes are complex and the regional differences are obvious. The natural, economic and social development of black soil area in Northeast China, rocky mountain area in North China, loess plateau area, upper reaches and rivers of Yangtze River in Southwest China, farming-pastoral ecotone in North China, karst rocky desertification area in Southwest China and red soil area in South China are quite different, and the main causes, hazards and control priorities of soil erosion are also different.

3. The harm of soil erosion-taking the Yellow River as an example 1. Raise the riverbed 2. Affect the effective use of water resources. Restrict economic and social development. Deteriorate the ecological environment.

4. Causes of soil erosion

There are natural factors and human factors.

Natural factors—

Terrain. The steeper the slope of the ground, the faster the surface runoff speed and the stronger the erosivity to the soil. The greater the slope, the more surface runoff collected and the stronger the scouring force.

Rainfall The rainfall that causes soil erosion is usually rainstorm. Only when the rainfall intensity exceeds the soil infiltration intensity will surface runoff be generated and the surface will be eroded.

Vegetation. Forest and grass vegetation with a certain canopy density can protect the soil from erosion. The higher the canopy density, the stronger the soil and water conservation capacity.

Human factors. The unreasonable use of land by human beings has destroyed the ground vegetation and stable terrain, resulting in serious soil erosion.

Destruction of vegetation

Unreasonable farming system

open out/up a mine

5. Comprehensive control of soil erosion-comprehensive control of small watersheds

Closing hillsides in the upper reaches to facilitate afforestation. Closing hillsides to facilitate afforestation is a way to restore forest vegetation in mountainous areas with suitable natural conditions by using the regenerative capacity of forests and regularly closing hillsides to facilitate afforestation, and prohibiting man-made destructive activities such as reclamation, grazing and firewood cutting.

Steep slope farming should be gradually changed to terraced fields.

Overall promotion. Combination of biological measures and engineering measures

Returning farmland to forest and grassland, enclosure, grazing prohibition, etc. To promote ecological and natural restoration, restore vegetation cover and accelerate the process of soil erosion control.

High standard farmland construction and modern farmland construction. Improve the existing farmland water conservancy, farmland shelterbelt and agricultural mechanization system, realize dry energy irrigation and waterlogging drainage, and increase the ability to resist natural disasters.

Water-saving planting methods, such as terrace, strip planting, horizontal ditch planting, horizontal ditch planting with separated slopes, deep field planting, pit field planting, underground hole field planting, valley planting, etc. Generally, the soil water content is increased by 65438 0% ~ 8%. Compared with sloping farmland, the soil water content of terraced fields increased by 2%, the yield of terraced fields with better fertilization increased by 50%, and the yield increase rate of dam land was 1~2 times or even 3 times.

Adopt drought-resistant varieties

Popularize water-saving irrigation technology. Micro-drip irrigation and micro-sprinkler irrigation can be used.

Popularize water cellar technology. As a new technology to control soil erosion, water cellar has the functions of storing rainwater, blocking sand and mud, and the water cellar built near the highway also has the function of protecting the highway and agricultural roads and terraces on both sides. Using the water cellar built in the hospital to store rainwater can not only supplement the shortage of drinking water for people and animals, but also develop plastic greenhouse to grow vegetables.

Adjusting agricultural structure and developing sheep industry according to market rules is 10 times the benefit of growing grain. Develop green food. Develop courtyard economy and ridge economy, increase income and create wealth for society.

199 1 year, the State Council City, China promulgated the Law on Soil and Water Conservation, which is the first professional technical regulation on soil and water conservation in China, ending the long-term lack of legal support for soil and water conservation workers in China.

6. What is desertification

Desertification in a narrow sense (desertification)

Refers to the fragile ecosystem, due to excessive human economic activities, so that the original non-desert areas have a similar desert landscape environmental change process.

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

Desertification refers to land degradation in arid, semi-arid and dry sub-humid areas caused by various factors including climate change and human activities.

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

1At the World Conference on Environment and Development in June, 1992, combating desertification was listed as a priority development and action area of the international community.

19941In February 1994, the United Nations General Assembly passed a resolution to designate June 17 every year as "Global Day to Combat Desertification and Drought" from 1995, so as to publicize it to the masses.

China is a party to this convention.

General situation of desertification in China

China is one of the countries with large desertification area, wide distribution, complex types and serious harm in the world. The potential area of land desertification in China is 3310.7 million hectares, accounting for 34.6% of the total land area.

By 2004, the total area of desertified land in China was 263.6 million hectares, accounting for 27.46% of the national territory and 79.47% of the total area where desertification is likely to occur, which is higher than the world average of 69%.

Desertification land in China is mainly distributed in 498 counties in 18 provinces, including Beijing, Tianjin, Hebei, Shanxi, Inner Mongolia, Liaoning, Jilin, Shandong, Henan, Hainan, Sichuan, Yunnan, Tibet, Shaanxi, Gansu, Qinghai, Ningxia and Xinjiang.

There are four types of desertification land in China: wind erosion desertification, water erosion desertification, freeze-thaw desertification and soil salinization.

Wind erosion and desertification land area is 654.38+839 billion hectares, accounting for 19. 16% and 69.77% of the national land area and desertification land area respectively. It is mainly distributed in northwest, north China and northeast provinces 13, forming a river with a length of about 4500 kilometers from Tarim Basin in the west to Songnen Plain in the east.

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

The frozen-thawed desertification land covers an area of 36.36 million hectares, mainly distributed in the alpine region of the Qinghai-Tibet Plateau.

Salinized land17.37 million hectares, distributed in oasis around Tarim basin, alluvial plain in front of the northern foot of Tianshan Mountain, Hetao Plain and North China Plain.

8. Measures to Combat Desertification in China

Protect existing vegetation and vigorously plant trees and grass; Rational use of water resources to ensure ecological water use; Implementing ecological migration to control the population in desertification areas; Strengthen publicity and education to raise public awareness of combating desertification; Change the production and management mode of animal husbandry and reduce the pressure on grassland; Adjust the energy structure and reduce the pressure on vegetation; Adjust the industrial structure and implement protective development; Optimize the land use pattern and promote the sustainable development of social economy and ecological environment; Implement nine specific measures such as national ecological management.

Implementing ecological migration to control population in desertification areas

Ecological migration refers to migration in order to protect the special ecology or restore the ecology of a certain area.

9. National key projects to prevent and control desertification

Beijing-Tianjin sandstorm source control project

The construction scope includes 75 counties in Beijing, Tianjin, Hebei, Shanxi and Inner Mongolia. The total area of the project area is about 46 million hectares, including 6.5438+0.02 million hectares of wind erosion and desertification land.

"Three North" Shelterbelt System Construction Project

The construction scope of the project includes 590 counties in northwest, northeast and north China 13 provinces. Build a number of relatively complete regional shelterbelt systems to initially curb the trend of ecological deterioration in the three northern regions.

Returning farmland to forest project

The project of returning farmland to forest is a wind erosion and desertification area in northwest and north China; Northeast water erosion and wind erosion area; Soil erosion area of loess plateau; There are four types of regions in the source area of Qinghai-Tibet Plateau, including Qinghai, Xinjiang and other 14 provinces.

National comprehensive demonstration zone project for sand prevention and control

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

Returning grazing to grassland project of natural grassland in western China

Including degraded grassland, desert grassland and river source grassland in 96 counties of Inner Mongolia, Xinjiang, Qinghai, Sichuan, Yunnan, Gansu and Ningxia.

What is the western development?

"Western Development" is a broad concept to promote all-round economic development.

"Great development" not only means the substantial increase of economic indicators, but also includes a series of complete contents such as the improvement of ecological environment and the improvement of people's spiritual and cultural living standards. This is the meaning of "big" in "great development". When did it start?

What is the guiding ideology of western development?

The development of the western region should be based on infrastructure construction, ecological environment protection, economic restructuring and the development of characteristic industries, scientific and technological progress and personnel training, reform and opening up as the driving force, and economic prosperity and prosperity of people of all ethnic groups.

The western part of China includes 12 provinces and cities. Include Chongqing, Sichuan, Guizhou, Yunnan, Xizang Autonomous Region, Shaanxi, Gansu, Qinghai, Ningxia Hui Autonomous Region and Xinjiang Uygur Autonomous Region.

Inner Mongolia Wuer Autonomous Region

Guangxi Zhuang Autonomous Region

Manage a region, etc.

2. Why should we carry out the western development?

1. The western region is rich in resources, with huge market potential and important strategic position.

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

It is urgent to speed up the pace of reform, opening up and modernization. Most poor people in China live in the west.

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

Geomorphy (geomorphy):

Surface morphology formed by the interaction of internal forces (such as crustal movement, volcanoes and earthquakes) and external forces (such as flowing glaciers).

Terrain:

The undulating state of the ground. Terrain also refers to the ups and downs of the ground. Unlike topography, it generally refers to a smaller and larger range of terrain.

1. Monsoon climate

In winter and summer, the phenomenon of opposite wind directions prevails in a large area. The near-surface phenomenon above 2000 meters is not obvious.

Seasonal distribution of precipitation

1. South China Spring and Autumn Rain Area

2. Rainy areas in spring and summer in hilly areas of the south of the Yangtze River

3. Summer rain area in the north

4. Less rain area in northwest inland basin; Average monthly

5. In the annual rain area in the northwest mountainous area, there is not much rain and it is evenly distributed.

6. Summer and autumn rain areas in Yunnan-Guizhou Plateau

7. Winter Rain Area in Northeast Taiwan Province Province

The History and Future Trend of Climate Change in China

1. Climate change in China is quite consistent with global change, but there are also obvious differences.

2. Under the background of global warming, in recent 100a, the annual average surface temperature in China has obviously increased, and the warming range is slightly higher than the global average level in the same period.

3. The change trend of precipitation in recent 100a and 50 years is not obvious, but it increases slightly from 1956.

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

5. The annual CO2 emission in China is increasing, and the sum of greenhouse gas positive radiation forcing is the main reason for climate warming.

6. In the next 20 ~ 100a, the surface temperature in China will increase obviously, and the precipitation will also increase.

Due to the joint influence of human activities and natural changes, the global climate is undergoing major changes characterized by warming. 1860 ~ 2000, the global average temperature rose by 0.4 ~ 0.8℃, and the 1990s was the warmest decade of the 20th century.

3) Soil types and characteristics in China.

1. The terrain is to the west of the three steps. It's only a step or two away.

2. Landform features: mountainous; Many plateaus; Many basins; There are many deserts; simple

3. Vegetation characteristics: there are many grasslands; There are many deserts; Forest reduction

4. Climatic characteristics: less precipitation, more evaporation and more arid areas.

5. Natural disasters: extensive soil erosion; There are many sandstorms; Land degradation and desertification are serious.

6. Natural resources: Tibet and Southwest China are rich in water resources; Abundant underground resources; The natural features are well preserved; Natural landscape has its own characteristics.

What is the western development for?

1. Promote ecological construction and environmental protection, realize ecological improvement and increase farmers' income;

2. Accelerate the construction of key infrastructure to lay a foundation for the accelerated development of the western region;

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

4. Adjust the industrial structure and develop industries with distinctive advantages;

5. Strengthen social undertakings such as science and technology, education, health and culture, and promote coordinated economic and social development;

6. Strengthen the construction of talent team in the western region to provide a strong talent guarantee for the development of the western region.