What are the hazards of biological invasion?

1, Eichhornia crassipes often blocks waterways and affects traffic due to excessive reproduction. It affects shipping and excretion and becomes the number one enemy of agriculture, water conservancy and environmental protection. It restricts the flow of water, reduces the dissolved oxygen in water, inhibits the growth of plankton and destroys the ecological environment of rivers. Provide breeding grounds for pathogens such as schistosomiasis, encephalitis and influenza, breed mosquitoes and flies, and provide opportunities for mosquito larvae to breathe and reproduce.

2. Ampullaria canaliculata has strong adaptability to the environment and rapid reproduction, so it spreads rapidly in rivers, lakes and fields; It has a large appetite and many kinds of food, which can destroy the growth of food crops, vegetables and aquatic crops.

3. The super fecundity of Spartina alterniflora in tidal flat wetland habitat threatens the native species of coastal wetlands around the world, so many countries are implementing large-scale control plans as invasive plants.

4. Mikania micrantha is one of the most dangerous and harmful plants in the world. It crawls around trees and shrubs in proper places and presses heavily on the top of the crown, which hinders the photosynthesis of attached plants and then leads to the death of attached plants.

5. Alternanthera philoxeroides will block the waterway and affect the water traffic; Squeeze out other plants and prefer Alternanthera philoxeroides to make the community species single; Covering the water surface, affecting the growth and fishing of fish; Harm farmland crops, damage the yield; The flooding of ditches in the field affects the irrigation and drainage of farmland; Invade wetlands and lawns and destroy landscapes; Breeding mosquitoes and flies, endangering human health.

Extended data:

Biological invasion channel

1, natural invasion

This invasion is not man-made, but the invasion of alien species caused by biological hazards caused by natural migration of plant seeds or animal larvae, eggs or microorganisms through wind, water or insects and birds.

Such as Eupatorium adenophorum, Mikania micrantha, Liriomyza sativae, etc., all invaded China by natural factors.

2. Unintentional introduction

Although this way of introduction is artificial, there is no subjective intention to introduce it, but with the import and export trade, ships or inbound tourism are inadvertently introduced.

For example, "Bursaphelenchus xylophilus" was brought in by China traders with wooden packing boxes when importing equipment. Millions of tons of ballast water discharged by ships sailing in world waters has also become the main channel for unintentional introduction of aquatic organisms. In addition, fruits, vegetables, meat and even the soles of passengers carried by inbound tourists may become channels for unintentional invasion by foreign creatures.

3. Intentional introduction

This is the most important channel for alien invasion. In order to develop agriculture, forestry and fishery, countries all over the world often introduce excellent animal and plant varieties consciously. For example, in the early 20th century, New Zealand introduced kiwifruit from China, and the United States introduced soybeans from China. However, due to the lack of a comprehensive risk assessment system, countries around the world have introduced a large number of pests, such as Spartina, Alternanthera philoxeroides, Ampullaria gigas and so on, while introducing excellent varieties. Because these invasive species have changed the living environment and food chain of species, they are flooded without the restriction of natural enemies.

References:

Baidu encyclopedia-biological invasion