The deterioration of ecological environment intensifies and species are threatened. At present, the situation of natural ecological environment in China is grim, the forest coverage rate is low (China forest coverage rate 16.5%, the world average level is 26.6%), the grassland is overloaded and overgrazing, the quality is reduced, and the degradation and desertification are intensified; The natural ecological environment in areas rich in biodiversity at the source of major rivers such as the Yangtze River and the Yellow River is deteriorating. Rivers in the northern region are cut off and lakes are dried up; The water bodies of major rivers and lakes in China are polluted. Due to the degradation and destruction of the ecological environment of wild species, coupled with overfishing and hunting in some areas, the number of wild animals and plants has been decreasing. Among the 640 endangered species listed in the Convention on International Trade in Endangered Wild Fauna and Flora, there are 156 species in China, accounting for14 of the total.
Alien invasive species are seriously harmful. According to preliminary investigation by experts, about half of the worst alien invasive species in the world 100 have invaded China. There is an important principle in ecological science, that is, the more species, the more complex the biological system and the more stable its system structure. Numerous biological species and their mutual restriction and balance are of great significance to the stability and sustainable utilization of the whole ecosystem. Therefore, we should pay special attention to the research on the protection and sustainable utilization of biodiversity.
Biodiversity refers to the existence of many biological types on the earth, which are interdependent and mutually restrictive, keeping the natural ecology and food chain in dynamic balance and stability, and all kinds of organisms can survive and develop in an ever-changing environment. Biodiversity is the basis for the long-term existence, reproduction and prosperity of all kinds of creatures on the earth and the source of social wealth.
Biodiversity includes genetic diversity, species diversity and ecosystem diversity. Protecting biodiversity means protecting the ecosystem and natural environment, maintaining and restoring the viable groups of various species in the natural environment and protecting various genetic resources. However, due to the expansion of human biological activities and over-exploitation of nature, many species have become extinct or are in danger of extinction.
According to statistics, in the last year of 2000, there were 106 species of mammals and 127 species of birds extinct on the earth. There are 406 species of endangered mammals, 593 species of birds, 209 species of reptiles, 242 species of fish, and countless other lower animals. Giant panda, Siberian tiger and Asian black bear in China. Indonesia's Maruk white parrot, Asian orangutan, African black rhinoceros, North American stone turtle and North American hawksbill are all on the verge of extinction. From 1950 to 1992, the number of elephants in Ivory Coast in Africa dropped sharply from 654.38+10,000 to 1500. If poaching is not banned, African elephants will be extinct at the beginning of the next century.
According to incomplete statistics, the illegal trade volume of wild animals currently reaches $5 billion to $9 billion per year, which is the second largest economic crime after drug trafficking. The survival of marine life is also seriously threatened, with millions of dolphins and turtles dying every year. According to the report of the International Whaling Commission, there are only 400 blue whales, the largest animal on earth, which are on the verge of extinction. Many fish are on the verge of extinction because of drift-net fishing. With the deforestation and the destruction of ecological environment, many rare wild animals have been devastated. For example, the tropical rain forest located at the equator of the earth is a natural animal and plant park, a treasure house of life on earth, and a "lung of the earth". However, at present, the global tropical rain forest is decreasing at a rate of 20 hectares per minute. At this rate, within 100 years, the global tropical rain forest will disappear, and a large number of rare creatures will become extinct with the disappearance of the tropical rain forest. According to statistics, at present, two species are extinct every hour in the world. At this rate, the existing 1/5 species will be extinct by the end of this century, and the protection of biodiversity will be severely challenged.
The most important thing to protect biodiversity is to take action, which requires extensive cooperation and positive actions of all parties, formulate necessary laws and regulations, technically combat and control activities that cause great losses to biodiversity, and effectively protect and save endangered species, seriously damaged ecosystems and genetic resources. Another important measure to protect biodiversity is ex situ conservation, such as the establishment of genetic resource germplasm bank, plant gene bank, wildlife park, botanical garden, aquarium and so on.
China is the origin center of many kinds of organisms, and its species resources are very rich. In order to protect biodiversity, active measures have been taken to protect rare animals and fish such as giant pandas, golden monkeys and baiji. A national germplasm bank has been established, and more than 300,000 germplasm resources have been preserved. Only 60,000 rice varieties have been preserved, accounting for more than 40% of the world total.
2. Main causes of biodiversity loss
The loss of biodiversity occurs both naturally and naturally, but at present, human activities (especially in the last two centuries) are undoubtedly the main reason for the loss of biodiversity. In addition, the imperfection of the system, especially the legal system, is another major reason for the loss.
2. 1 natural causes
One is the biological characteristics of the species itself. One is that the formation and extinction of species is a natural process. Fossil records show that the average life span of most species is100 ~1000000 years. Secondly, the adaptability, variability and adaptability of species to the environment are poor, and it is difficult to adapt when the environment changes greatly, so it is in danger of extinction. For example, the endangered reasons of giant pandas are not only climate change and human activities, but also related to their own physical characteristics such as narrow eating habits and low reproductive capacity. Second, sudden environmental changes (natural disasters), such as earthquakes, floods, fires, blizzards, droughts and other natural disasters.
2.2 Human causes
Because human beings do not know enough about the importance of biodiversity to human beings, and at the same time pay too much attention to economic development, but have a weak awareness of biodiversity protection, which leads to habitat destruction from time to time; Over-exploitation of biological resources, some even predatory exploitation; Serious environmental pollution; Insufficient attention to alien species invasion and imperfect system are the main reasons for the decrease of biodiversity.
2.2. 1 Habitat loss, fragmentation and degradation
Habitat destruction and fragmentation have become the main reasons for the decrease in the number and distribution of some mammals in China, and they are on the verge of extinction. Logging and land occupation are the two main causes of habitat destruction in China. The sharp decline of natural forests directly threatens the survival of species ranging from mosses and lichens to higher species. In addition, logging is also a major cause of forest fires. In the past 25 years, China has lost 8.6 million hectares of forest due to forest fires. The occupation of forests, wetlands and grasslands by agriculture and buildings is another reason for habitat destruction. It is estimated that 1/3 of farmland in China used to be virgin forest, and this problem is particularly serious in tropical areas of China. In the past half century, about half of the coastal wetlands have changed, and the wetlands around plateau lakes have also suffered serious losses. In addition, the lake area in China decreased from 1980/10.
Habitat fragmentation refers to the process that a large and continuous habitat is divided into two or more small pieces and gradually decreases. Various human activities may lead to habitat fragmentation. Such as railways, highways, ditches, telephone networks, farmland and other partitions that may restrict the free activities of living things, as well as artificial facilities such as roads built in nature reserves. Especially due to the establishment of these artificial facilities, the activities of animals are restricted, which affects their foraging, migration and reproduction, and the spread of pollen and seeds of plants will also be affected. As a result, the number of animal and plant populations decreased, resulting in local extinction. At the same time, due to the fragmentation of habitats, changes in sunlight, temperature, humidity and wind will also lead to some species being endangered or even extinct. In addition, habitat fragmentation contributes to the invasion of alien species, which in turn threatens the survival of local species.
Habitat degradation refers to the loss of the original function of habitat. For example, due to economic development, overgrazing and other reasons, grassland is seriously degraded, resulting in the decline of grassland biological and physiological functions, thus posing a threat to its survival.
Grassland degradation.
Predatory overexploitation
Many biological resources have direct economic value to human beings. With the increase of population and the establishment and development of global commercialization system, the demand of human beings rises rapidly, which leads to the over-exploitation of these resources and the decline of biodiversity.
However, when there is a great demand for a certain wildlife resource in the commercial market, it usually leads to the over-exploitation of the species. A typical example is the relationship between the hunting activities of marine whales by human beings and the growth and decline of whale population. There are many medicinal plants in China, among which poaching and smuggling of wild animals pose the most serious threat to biodiversity.
2.2.3 Environmental pollution
water pollution
Water pollution can have sub-lethal or lethal effects on aquatic organisms (especially fish) at any stage of their life cycle, affecting their predation, foraging and reproduction. Among them, the impact of sublethal water pollution on water biodiversity is more prominent, universal and lasting. In this environment, biological reproductive capacity declines, growth slows down or dies of diseases related to environmental stress. However, eutrophication will significantly reduce the biodiversity of water bodies, such as Dianchi Lake in Kunming.
Soil pollution in 2.2.3.2
Soil pollution usually degrades local vegetation, even becomes barren land, and at the same time, soil animals will become scarce or even extinct, and their biodiversity is obviously lower than that of unpolluted areas. For example, there are few trees growing in mining areas, tailings accumulation areas, mining wasteland and landfill wasteland.
Air pollution in 2.2.3.3
All kinds of toxic and harmful substances discharged into the atmosphere by human beings will cause different degrees of losses to organisms and harm to ecosystems. Sulfur dioxide, ammonia and ozone that enter the air through various channels can directly kill organisms. Toxic metals in the waste gas from smelters will directly poison plants. However, the destruction and reduction of biodiversity by greenhouse gases such as ozone hole, acid rain and carbon dioxide have attracted more and more attention of the international community, especially the impact of acid rain caused by global warming and greenhouse effect on biodiversity.
2.2.4 Invasion of alien species
The invasion of alien species poses a great threat to biodiversity. There are three ways of invasion: one is to introduce or improve urban parks for the purpose of greening, beautifying and viewing because of agricultural, forestry, animal husbandry and fishery production, such as water hyacinth and genetically modified organisms flooding in Dianchi Lake; Second, species introduced with trade, transportation, tourism and other activities, that is, new species brought about by the pressure of ships on water and soil; Third, it is introduced by its own spreading ability or with the help of natural forces, that is, natural invasion, such as Eupatorium adenophorum and Eupatorium odoratum in the southwest. About 35% ~46% of the global endangered species and plants list is caused by partial or total invasion of alien species. In 2002, piranha from the Amazon River in South America, also known as piranha, caused an uproar in China. Once it flows into a certain water area, it may kill a large number of other fish, bring crisis to ecological balance and biodiversity, and cause incalculable losses.
Policy:
Study and formulate biodiversity protection programs.
Supervision of alien invasive species
Laws and regulations on biological resources.
Organize the national key investigation of biological species resources.
To organize the formulation of plans for the protection and utilization of biological species resources.
Provide policy guidance and investment guarantee for the protection and sustainable utilization of species resources.
Formulate the national patent protection strategy for biological species resources.