After alien pests invade a new area suitable for growth, their population will rapidly multiply and gradually develop into a new “predominant species” in the local area, which will seriously damage the local ecological security. Specifically, the consequences are mainly caused by the following:
(1) Lead to loss of ecosystem diversity, species diversity, and loss of biological genetic resources. In particular, alien weeds in the invasive land often lead to a single diversity of flora and damage to cultivated land. The spread of ragweed, Eupatorium adenophorum, airplane grass, water hyacinth, and rice grass that invaded China has reached an uncontrollable situation.
Biodiversity is a complex system of all levels, including all plants, animals, microbial species and their genetic information, and organisms and living environments.
Although the biodiversity of a country or region is endowed by nature, no country is investing a lot of manpower and material resources to protect its biodiversity. Invasion of alien species is the number one enemy threatening biodiversity. After the invasive species are introduced into different places, due to the lack of natural enemies and other constraints that can restrict their reproduction, the consequences are rapid spread, massive expansion, and advantages. Populations and limited competition for food resources and space resources with local species directly lead to the degradation of local species and even extinction.
(2) The invasion of alien species will seriously damage the ecological balance. Invasion of alien species can affect the soil moisture and other nutrients, as well as the structural stability and genetic diversity of the plant community, thereby destroying the local ecological balance. For example, the alien species Mikania micrantha, which was invaded from Australia and invaded many forest farms in Hainan Island and Leizhou Peninsula, is very unfavorable to soil and water conservation because it can absorb soil moisture in a large amount and cause the soil to be extremely dry. In addition, Mikania micrantha can also secrete chemicals to inhibit the growth of other plants, which once seriously affected the production and development of the entire forest farm. It also poses a direct threat to the survival of other organisms and even to human health because of the pathogenic microorganisms it may carry.
(3) Serious economic losses leading to the production of agriculture, forestry, animal husbandry and fishery. For example, Liriomyza sativae, potato beetle, pine wood nematode, wetland pine whitefly, American white moth, etc., in recent years, the area of such serious damage in China is more than 3 million hm2 per year.
The invasion of alien species will also cause huge economic losses to the affected countries. For any country, it is quite difficult to completely eradicate alien species that have been successfully invaded. In fact, the cost of governance to control its spread is quite expensive.
According to a study submitted to the United Nations by the United States, India, and South Africa, the economic losses caused by the invasion of alien species in these three countries are 150 billion, 130 billion, and more than 80 billion US dollars respectively.
(4) Threatening human health. Pollen produced by common ragweed and ragweed can cause human pollen allergy and lead to hay fever.
Water gourds in the pond
Water gourd, known as the phoenix eye lotus (ic/i/iorniacrawi/) es), rain long flower section. Aquatic upright or floating herbs. Leaf erect, egg-shaped or round, smooth, leaf handle long or short, the middle of the following puffed as large as a ball, the base has a sliver-shaped sliver, a single stem, the middle also has a sliver-shaped sliver, spiked flower sequence blue-purple.
The case of the loss caused by water hyacinth to the pond is one of the classic cases of invasive species hazard. In the 1980s, Kunming built an ideal water tourism route for the Great View River, a mountain of the West Mountain, where visitors can take a boat trip to Yuchi and Xishan. But in the early 1990s, the water hyacinths in the Daguan River and the Ponds went mad and covering the entire river surface and part of the water surface of the pond, resulting in the cancellation of this tourist route, the construction of supporting tourism facilities on both sides of the Daguan River had to be abandoned or converted to other uses, the Daguan River has also been converted into underground river. These are only direct economic losses, but the ecological losses caused by water hyacinths are difficult to measure.
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