What are the current invasive alien species in China?

Praying mantis, carp and hairy crabs have successfully invaded foreign countries. Hairy crabs invaded the Thames River Basin, carp invaded the United States, and praying mantis invaded North America. <>

1. Hairy crabs invaded the UK.

The Thames River is a very important river in the United Kingdom, and it has witnessed the rise and development of the United Kingdom, while China's hairy crabs have invaded the Thames. Hairy crab is a river crab species in the north and south of the Pearl River in China, the output of the Yangtze River system is very large, and it is also a very famous agricultural and sideline product in China, every autumn there are many people will buy hairy crabs, and then go home to cook, after all, hairy crabs are very delicious. But the British were not particularly fond of eating hairy crabs at that time, so when the hairy crabs invaded the Thames, the British were very troubled.

When the British first found that hairy crabs invaded their own country, the first way they thought of was to export these hairy crabs to the people of our country at a low price, but it was easy to catch freshwater eels when fishing for hairy crabs, and freshwater eels are fish that are about to become extinct in the United Kingdom, so the idea of exporting them to our country at a low price has not been implemented, and the problem of hairy crabs has not been solved. <>

2. Carp invaded the United States.

Carp prefer to eat aquatic plants, and algae invaded the United States in 1960, when the Americans used fences to fence carp, although some carp managed to escape, but a small number of carp were left in the United States, and the carp's reproductive ability is very strong, so soon carp in the United States to breed. Because there are more freshwater rivers in the interior of the United States, the carp is raised very fat, not only large, but also a lot of quantity, and even endangers the native fish of the United States, and now it is approaching the Five Lakes area, seriously damaging the local ecosystem, it is recommended that Americans eat more carp. <>

Finally, the size of the praying mantis is also very large among insects, and the great mantis invaded North America, and the North American people will place containers in the yard to provide water and food for hummingbirds, and the great praying mantis can eat these hummingbirds very easily, so the great mantis also reproduces very quickly in North America.

Carp, hairy crabs, crayfish, bullfrogs, snails and other species have invaded foreign countries and have affected the ecological environment abroad.

For example, there are hairy crabs, carp, white-tailed pheasants, black fish, and silver carp. All of these species have invaded foreign countries, leaving people abroad at a loss.

Hairy crabs, which are a delicacy in China, carp, are nutritious foods, and black fish, which are used as a recreational activity in the United States to shoot bows and arrows, and these species have invaded foreign countries.

There are hairy crabs, carp, black fish, cuttlefish, bighead carp, snails and so on.

1. Eupatorium purpurea.

Native to Central America, it was discovered in southern Yunnan in 1935 and may have been introduced via Burma. It is distributed in Yunnan, Guangxi, Guizhou, Sichuan (southwest), Taiwan, and the upper limit of vertical distribution is 2500 meters. Globally invasive species.

2. Mikania.

Mikania, perennial grassy or woody vine, slender stem, creeping or climbing, multi-branched, the leaves in the middle of the stem are triangular ovate to ovate, the base is heart-shaped, the apex is acute, the edge is serrate, the head inflorescence is numerous, often arranged in a compound inflorescence at the end of the branch, containing 4 small flowers, all are sturdy amphoteric flowers, 4 total bracts, the base of the narrow oval total bract has a line-like oval small bract, and the flowers are fragrant.

It is a globally invasive species found in Hong Kong, Macao and the Pearl River Delta region of Guangdong.

3. Hollow lotus seed grass.

Hollow lotus seed grass, perennial herb. Rhizome propagation. 3 April, rhizome budding is unearthed; The stolons are well developed, rooting at the nodes, and the segments of the stem can also germinate into plants.

The leaves are opposite, with short stalks, and the leaves are oblong-elliptic to obovate-lanceolate. The capitate inflorescence is solitary in the leaf axils, composed of 10 20 sessile white florets, with a peduncle in total; The bracts and bracts are dry membranous, persistent.

4. Ragweed. ragweed, an annual grass, 20 250 cm high. Stems erect, ridged, multi-branched, lower leaves opposite, upper leaves alternate, leaves triangular, 1 3 pinnate deeply lobed. The inflorescence is unisexual, monoecious; About 50 60 are arranged in racemes at the ends of the branches, the corolla pale yellow, the bracts obovate, inverted conical, capsular, without corolla and crown hairs, the columella 2, filamentous, protruding from the bracts.

Invasion pathways of alien species:

1. Natural invasion.

This kind of invasion is not caused by human causes, but is caused by biological hazards caused by natural migration of plant seeds or animal larvae, eggs or microorganisms through wind vectors, water flows or by insects and birds. For example, ragweed gradually spread from North Korea to China due to the destruction of the surrounding vegetation caused by the construction of railways and highways.

2. Intentional introduction.

Intentional human introductions that purposefully transfer a species beyond its natural range and dispersal potential (such introductions may be authorized or unauthorized). These invasive species are thriving in the absence of natural predators due to the alteration of the species' living environment and food chain.

3. Unintentional introduction.

Unintentional introduction is when a species spreads beyond its natural range through humans or human teleportation systems, resulting in unintentional introductions.

Although this method of introduction is artificial, it has no subjective intention to introduce it. For example, the red fire ants invaded the southern United States in the early 20th century due to negligence in epidemic prevention and control, and eventually caused very important problems and economic losses in the United States in agriculture and environmental health.

Alien species invasion is a global problem, through natural invasion, artificial introduction, etc., after the settlement of the invasion site, these alien species will cause serious damage to the local biodiversity, ecological environment, so that the economy suffers a heavy blow.

Invasive alien species in China include: African giant snail, Fushou snail, bullfrog, red fire ant, crayfish, Brazilian tortoise, etc.

The List of Invasive Alien Species in China is a list of invasive species that are more harmful in China published by the People's Republic of China. It was released in 4 batches in 2003, 2010, 2014 and 2016, with a total of 71 species.

As of August 2020, the Ministry of Ecology and Environment recently released the 2019 Communiqué on the State of China's Ecology and Environment, showing that more than 660 invasive alien species have been found across the country. It is most severe in the south-west and coastal areas, but there is still a lack of an early warning mechanism. The invasion routes are mainly man-made; Sticking to the tourist's body and bringing it in; Spread naturally.

There are two main ways for invasive alien species to enter China:One is unintentional and the other is intentional.

Unintentional introductionGenerally, it is unintentionally entered into China with the international **, such as poplar mosaic virus introduced with seedlings and cuttings, Amaranth longifolia brought in by accident with imported grains and oils, goods or luggage, and Eupatorium purpurea that entered China from Southeast Asia through natural diffusion;

Intentional introduction, including the introduction of amaranth, amaranth and chrysanthemum as vegetables, the introduction of goldenrod and Brazilian turtle as ornamental species, the introduction of goldenrod as a medicinal plant, the introduction of snails and bullfrogs as breeding species, the introduction of carpet grass as turfgrass or pasture grass, and the introduction of rice grass to improve the environment - at first used for windbreak berms, but due to the extremely fast diffusion rate and strong fecundity, the result is a large-scale, singular, high-density invasion of China's coastal areas. Some of the invasions caused by alien aquaculture species are formed by escaping from the breeding area to natural habitats and failing to take protective measures, and some are caused by human abandonment.

China is an area that is vulnerable to the invasion of alien species

According to the introduction pathways of invasive alien species and the characteristics of invasive species and ecosystems, it can be predicted that alien species are prone to invasion in China.

Near important ports and ports, on both sides of railways and highways. Alien species introduced by international freight often land near ports and ports first, establish small populations under suitable environmental conditions, and then begin to spread. The ballast water discharge of ships and the marine species that live on the camp also often settle in the harbor; Alien species carried by trains and automobiles are easy to settle and spread on both sides of railways and highways.

Forests and pastures with serious human disturbance. Alien species can be directly brought in by human activities. Forests, grasslands and other ecosystems are originally stable, but serious human disturbances such as indiscriminate logging and overgrazing have degraded ecosystems and reduced their diversity, creating good conditions for the invasion of alien species.

The above content refers to Encyclopedia - Invasive Alien Species.

At present, 544 species of invasive alien species have been confirmed in China, of which more than 100 species have occurred in a large area and caused serious harm. Examples can be found in animals (mammals, birds, amphibians, reptiles, fish, insects, crustaceans, molluscs, etc.), plants (trees, shrubs, herbs) and microorganisms (bacteria, viruses). Among the 100 most threatened alien species in the world published by the IUCN, more than 50 species have invaded China.

In the past 10 years, China has discovered the invasion of dangerous and explosive species such as western flower thrips, Q-type whitefly, and clover spotted diver fly, with an average increase of 1 to 2 species per year. In addition, the frequency of interceptions of potentially invasive species in China has increased dramatically.

Fushou snail Fushou snail, also known as large bottle snail, is native to the Amazon River basin in South America. In the 70s and 80s of the 20th century, it was introduced into Taiwan, Guangdong and other places, and the initial value was very high and quite popular, but its flesh was soft and lacked the crispiness of the local snails, which led to a great decline in sales, and people were forced to abandon them, so the Fushou snails became wild animals in rivers, ditches and ponds. Due to the miscellaneous, strong fecundity and fast development rate of the snail, it soon became a harmful animal in Fujian, Guangdong, Guangxi, Zhejiang, Shanghai and other places, and the snail often gnawed on the leaves and stems of aquatic plants, seriously affecting the growth of plants.

In Luzhai County, Guangxi, the occurrence density of Fushou snail in paddy fields was as high as m2, and the damage rate of rice was generally 7% 15%, and the highest was 64%. Fushou snail harms lotus root, young snail gnaws on the lotus leaf floating on the water surface from the bottom of the leaf, causing the leaf to become perforated or missing, and the leaf is eaten in severe cases, and it is difficult to pull out of the water surface; Fushou snails also harm other aquatic plants such as daffodils. In addition, the snail is also an intermediate host of a zoonotic parasitic disease, which is very likely to cause health problems to the surrounding residents. At present, the control of Fushou snail is mainly chemical control, supplemented by artificial control, and biological control has not been carried out.

Brazilian tortoises are also called red-eared turtles and red-eared painted turtles. The Brazilian tortoise is not native to Brazil, but to the Mississippi River and the Rio Grande River basin in North America. It is used by many families as pets for breeding or ornamental pets, but there are still restaurants that use it as a food animal.

Today, however, it has been listed by the International Union for Conservation of Nature as one of the world's 100 most dangerous invasive species, making it a global "wanted man". Brazilian tortoises are highly fertile and have a high survival rate. Its "marriage" with native turtles has led to genetic contamination of native freshwater turtles, which has seriously affected the living environment of native turtles.

Not only that, but it is also the main culprit in the spread of Salmonella, which has been shown to be transmitted to and among homeothermic animals, including humans. In recent years, due to factors such as pet abandonment, religious release, and breeding escape, Brazilian tortoises are widespread in the wild in China and are spreading rapidly. There are populations living in the wild in the Xiangjiang River in Hunan, the Pearl River in Guangdong, the Suzhou Creek in Shanghai, the West Lake in Zhejiang, the Qiantang River and the Jiangsu section of the Yangtze River.

At present, Chinese law has banned the import of Brazilian tortoises, but the embarrassing thing is that there are no laws and regulations in China to restrict the sale of Brazilian tortoises, so it is difficult to really make Brazilian tortoises disappear from the market.

Alien species invasion is a global problem, through natural invasion, artificial introduction, etc., after the settlement of the invasion site, these alien species will cause serious damage to the local biodiversity, ecological environment, so that the economy suffers a heavy blow.

Alien species that have invaded China include water hyacinth, American white moth, etc.

Source: Ecosystems are formed through long-term evolution, and the species in the system have gone through hundreds of thousands of years of competition, exclusion, adaptation, and mutual benefit, and have formed the close relationship that is now interdependent and mutually restrictive.

When an alien species is introduced, it may be excluded from the system because it cannot adapt to the new environment; It is also possible that because there are no competing or constraining organisms in the new environment, the introduced species may become a real invader, upsetting the balance, changing or destroying the local ecological environment, and seriously damaging biodiversity.

As of June 5, 2020, more than 660 invasive alien species have been discovered in China. Among them, 71 species have caused or have potential threats to natural ecosystems and have been included in the List of Invasive Alien Species in China.