Maybe some friends in the north are interested? Sweeper? I don't know what it is, but many rivers in the south are flooded, which makes local friends very helpless. What does it say here? Scavenger? It is a gray-black fish with black and white patterns. Some friends who like aquarium will keep it as an ornamental fish to clean the aquarium.
Scavengers are not native creatures in China, but exotic species. They are native to South America, also known as sucker fish and trash fish. You can get a general idea of the habits of this fish from its name. Their lips are very developed, like suckers, feeding on all kinds of garbage at the bottom of the water. This is a good thing. It can help us clean the fish tank indoors and help us clean the garbage in the river in the wild.
But in addition to moss, garbage and algae, scavengers also like to eat fish eggs and fry. A scavenger can eat 5000 fish eggs a day. As the name implies, whatever can be eaten, whether it is dead fish or algae, comes, so basically other fish will suffer in the river with the scavenger.
Sweeper/sweeper
The influence of scavengers on rivers in China The reason why scavengers can flood in the south, but not common in the north, is mainly due to water quality problems. It is a kind of fish from South America, where the water quality is acidic, similar to that in the south of China, while the water quality in the north is alkaline.
When I saw the news that New Zealand crayfish surrounded the northern and southern islands, Danish oysters flooded, and there were so many salmon in Australia that we could only feed lobsters and other similar exotic species, I don't know if everyone thought: If only we could flood here.
However, when our country was flooded with alien species, even people in China felt at a loss, and they all ate food, which puzzled everyone. Why are all exotic species delicious, but it's our turn to have low value and poor taste, which makes people have no appetite at all? Scavenger? And then what?
Boiled sweeper
What kind of influence does the sweeper have on some rivers in southern China? First of all, we must understand the habits of street sweepers. Although the scavengers in childhood are ugly, the scavengers at this stage are very gentle and basically feed on moss and algae, which is considered as a harmless fish. But after growing up, the eating habits of scavengers have changed a lot. They become fond of eating meat, especially fish eggs, fry, small fish, and large adult fish with wounds and infections, which are the favorite of scavengers.
Because scavengers are nocturnal fish and are inactive during the day. Anyone who has raised them knows that scavengers are usually in the daytime? Rotten? At the bottom of the fish tank or on the tank wall, they become extremely active at night. Most rivers in southern China are dominated by crucian carp, grass carp, carp, wicker fish and other fish, which are basically fish that lie in the daytime and are inactive at night, just giving the street sweeper a chance to eat fish.
In South America, scavengers have natural enemies, such as American alligators and puffer fish, so they will not be overrun. After arriving in China, although herons will feed on some scavengers, most herons only live in wetlands with good ecology, so their inhibition on scavengers is limited, which leads to the rapid proliferation of scavengers. Scavengers will eat fish eggs and fry, and other fish in the river together can't reproduce basically, so once a large number of scavengers appear in a certain river section, it means that the ecology is destroyed and a large number of protozoa disappear.
The body surface is hard and has no nutritional value. China eating goods also expressed helplessness. In China, where per capita food property is good, it is hard to imagine that there is a kind of fish that can be flooded. People have been trying the street sweeper's cooking methods for a long time, but whether it is steaming, frying, frying or cooking, it is always impossible to get rid of the foul smell on it. In addition, for some people, it is ugly and even horrible. Therefore, street sweepers have never appeared on the dining tables of China people in large numbers, nor have they.
The sweeper's body is streamlined, with two teeth on the upper and lower lips, two dorsal fins, four rows of large scales and a hard shell, and there is little soft meat on his body.
If we take care of a scavenger, we will find that we can eat very little. In the end, I basically eat one fifth, and the rest are shells and bones. We should not imagine how much nutritional value this fish will have. Therefore, seeing the crowds sweeping the streets, the foodies said: Although they really want to help, there is nothing they can do.
What are the hazards of biological invasion? In the era of underdeveloped transportation and information, people don't even have the concept of biological invasion. However, in the era of rapid development, the phenomenon of biological invasion is well known, and some cases of biological invasion even deeply affect the lives of local people. For example, Alternanthera philoxeroides, a plant that makes farmers uncomfortable, cannot be cleaned up every year. As long as there is a little root left, the next year will be lush. So what harm will biological invasion bring?
Alternanthera philoxeroides
Biological invasion will accelerate the extinction of native species. When alien species invade a new area, due to low competition, the population will multiply rapidly and gradually develop into a local species. Dominant species? , seriously endangering local ecological security.
Scavengers are a typical example. After entering the rivers in the south of China, because the local reach is suitable for them to grow, the scavengers soon showed strong reproductive ability and eventually became the local reach? The strongest fish? . Under the influence of the scavenger, the local fish eventually disappeared because they could not reproduce.
In reality, there are many examples of the accelerated extinction of native species by exotic species, such as the Australian marsupial wolf, which was in the limelight on the Australian continent in the early days. After the extinction of marsupials, they became the only large carnivore in Australia, but this situation was broken by the subsequent arrival of human beings. People will try their best to kill marsupials and bring powerful? Little buddy dog.
About 5000 years ago, dogs came to Australia with humans. Later, some dogs got out of people's control and returned to the wild. With the increasing number of wild dogs, they gathered together to form a huge dog group, which directly competed with the marsupial wolf and eventually accelerated the extinction of the marsupial wolf.
Tasmanian wolf
Biological invasion will destroy the ecological balance and even rebuild the ecosystem. For animal invasion, the biggest harm may be to accelerate the disappearance of native species, while for plant invasion, the most serious harm may be to destroy the ecology. The invasion of exotic plants will affect the stability of plant soil, water and other nutrients, and even affect the structure of biological communities, thus breaking the ecological balance, and what is more serious is to rebuild the local ecosystem and make it single and fragile.
For example, friends in Leizhou Peninsula may be impressed by Mikania micrantha. As an exotic species, it absorbs a lot of water in the soil, which makes the land dry and other local plants wither.
Mikania micrantha
Sometimes biological invasion not only destroys ecology directly, but also indirectly. For example, the dingo mentioned above has become a wild animal in Australia since its development.
Wild dogs in Australia will prey on a large number of domestic animals, which will have an impact on local agriculture and animal husbandry. In order to protect the developed sheep industry in the southeast, Australians who like to build fences have built a wild dog fence of more than 5,000 kilometers to stop wild dogs. Later, it was found that the side without wild dogs was lush with vegetation, and the side with wild dogs was covered with yellow sand, so the land desertification was serious.
After investigation and study, it is found that wild dogs in Australia will inhibit the population development of foxes and wild cats. On the side with wild dogs, the number of foxes and wild cats is relatively small, while wild dogs like to prey on some large animals, such as kangaroos and wombats, but they despise small animals, such as mice and rabbits. Gradually, rabbits and mice increased. They kept eating grass and roots of plants, and finally the land became bare. On the side without wild dogs, there are more foxes and wild cats, so herbivores such as rabbits and mice are limited, and their ability to destroy grasslands is limited.
How to prevent biological invasion? The harm of biological invasion is now widely understood, so how to prevent it? Bian Que has a famous saying, which roughly means that the eldest brother has the best medical skills and can cure diseases that have not happened, followed by the second brother, who can cure diseases that have just happened, and his own medical skills are the worst, and he can only cure diseases that have happened. From this allusion, many wise sayings can be derived. There are three stages to prevent biological invasion, namely, imminent transmission, early development and flooding. Then there are three corresponding prevention methods, namely, cutting off the invasion channels, early treatment, and late comprehensive treatment.
Australian wild dog
There are basically three channels for biological invasion, namely:
Natural invasion, such as wind, river and birds. Such biological invasion is relatively secret, and it is often very serious when people find it;
Unintentional introduction generally refers to foreign objects that humans inadvertently bring in, such as plant seeds and insects brought by airplanes. This kind of invasion is similar to natural invasion, and it is often more serious when it is discovered;
Deliberately introduced, easy to understand. Generally speaking, people know that it is an alien species, but it must be introduced for some reasons. For example, for the need of agricultural development, China introduced kiwifruit.
At present, the most effective means of prevention and control is to improve the evaluation mechanism. When we need to introduce a species, we need to make a comprehensive evaluation of the species. After controllable and uncontrollable, what are the coping styles that people can finally control completely? This should be shown on the evaluation form.
Australian wildcat
The prophase and metaphase of biological invasion are relatively easy to control in reality, especially when the tracking and monitoring process is perfect, it can often be suppressed and stopped in time. For example, if Australia can find out early that wild cats will bring disasters to local small animals, and strictly control the import of pet cats and the handling of stray cats in time, there will be no subsequent flooding of wild cats.