<h1 class="pgc-h-arrow-right" data-track="1" > preface</h1>
Species invasion is a clichéd topic, and it's not far away. With the in-depth development of globalization, the exchanges and ties between countries in the world have become more and more inseparable, and the earth has been reduced to a "global village", and almost no modern country can be separated from the international community today.
It is precisely because of this that some creatures are also carrying "hitchhikers" and crossing the ocean to a new foothold. Due to the geographical and natural environment of different countries, the arrival of new species often becomes an "uninvited guest" and disrupts the local ecological balance.
The flooded Australian hare, the American carp wreaking havoc, the destructive American "super boar"... Species invasions do plague many countries around the world, and China is naturally not spared.
Australian hares are infested
Invasive alien species in the country are also a headache: the Fushou snail, the American white moth, the African giant snail... According to a communiqué issued by the Ministry of Ecology and Environment in August 2020, as many as 660 invasive alien species have been found in the territory!
Plants that can't move or speak seem milder than the infamous pests, but the reality is not so simple, and an invasive plant called water hyacinth once flooded waters across the country, causing terrible "green pollution".
The water hyacinth left the deepest impression on the Chinese people, that is, the "lake disappearance technique", because they really multiply too fast, as long as a water hyacinth appears in a piece of water, then soon, it will be occupied by densely grown water hyacinth communities, and eventually become a green "field", the entire river, lake as if disappeared.
The "Lake Disappearing Technique" of Water Hyacinth
However, in recent years, the water hyacinth we see in rivers and lakes seems to have become less, and the water hyacinth that once grew and flooded in our country seems to have disappeared. Today, we will explore in detail the evolution of water hyacinth from flooding to rare in China.
<h1 class="pgc-h-arrow-right" data-track="10" > history of water hyacinth invasion</h1>
As the name suggests, water hyacinth grows in water and is a large, free-floating aquatic plant. There is a part between its roots and leaves that is swollen like a gourd, hence the easy-to-understand name. In fact, its scientific name is very literary, called hyacinth or hyacinth blue, native to South America.
The water hyacinth is about 0.5 meters tall and can grow to nearly 1 meter in Southeast Asia. Its leaves are thick and round, about 10 to 20 cm in diameter, and glow with emerald green color. The stems rise above the water, and the green leaves are usually slightly curved, wavy on the sides, with fine veins and brilliant purple or pink flowers at the tip.
Water hyacinth
With about 8 to 15 flowers and six petals, it is because of this beautiful purple flower that water hyacinth has become a popular ornamental plant in the pond, and now it has spread to more than 50 countries on five continents.
With its good appearance and strong ornamental value, water hyacinth was introduced to China in the early 20th century. When it first arrived, this plant was planted in the garden of Empress Dowager Cixi and was loved by the royal family and nobles.
By the 1940s and 1950s, water hyacinth was vigorously promoted in southern China, and its reproductive ability was extremely strong, and it no longer existed only as an ornamental plant. The pH of water hyacinth is highly alkaline (> 9), so it is also used as an organic fertilizer and to purify water quality. They remove heavy metals from sewage and sludge tanks and purify water sources.
Water hyacinth purifies water sources
From 1950 to around 1970, water hyacinth was widely used as animal feed. At that time, the rural economy was in a depressed period, and in order to understand the food and clothing problems of animals, the huge number of weed-like water hyacinth became the first choice for raising poultry. It was not until the late 1980s that the use of water hyacinth declined significantly, as a mere test plant for feeding ducks and as a purifying sewage.
However, this seemingly harmless green plant has gradually brewed an "ecological disaster", and when people react, they have almost spread across a large number of waters across the country. Since the mid-20th century, after artificial transplanting and large-scale breeding, water hyacinth has been widely distributed in almost all provinces in China.
Water hyacinth flooding
<h1 class="pgc-h-arrow-right" data-track="19" > culprit of "green pollution"</h1>
The growth of water hyacinth is closely related to local environmental conditions, the northern latitude of northern China is high, and the rivers generally have a freezing period, which makes it difficult for water hyacinth to survive the cold winter in its natural state.
They prefer high temperature and humidity, so the most serious "green pollution" is the many provinces and cities in central, eastern and southern China. At the beginning of 2000, the Pearl River system has been completely occupied by the dense figure of water hyacinth, and in the distance, it is already a turquoise "field".
Turquoise "fields"
The transmission routes of water hyacinths fall into two broad categories: their charming purple flowers make them a favorite of visitors to ornamental ponds and botanical gardens, and human transmission is an important route that causes water hyacinths to flood.
In addition, discarded plant rhizomes are discarded into streams, rivers and dams, and with water sources, the tenacious water hyacinth can soon "regain life", which becomes another major way of transmission.
It took only a few decades for the hyacinth to be introduced to flooded. The root cause is probably related to the growth characteristics of the water hyacinth itself and the unique natural environment in China.
First of all, the water hyacinth has an unusually high reproductive rate, at first, a piece of water may only have 10 water hyacinths, but in just 8 months, they can grow crazy to 600,000 plants!
Water hyacinths reproduce extremely quickly
In addition, water hyacinth is also recognized as one of the fastest growing plants in the world, their breeding method is mainly asexual reproduction, as long as the temperature is suitable (25 ~ 35 ° C), rich in organic matter, and the flow rate is slow (preferably static water), the time for water hyacinth to reproduce offspring alone only takes 5 days.
They are also able to reproduce sexually, producing up to 300 seeds in one inflorescence. The time of seed ripening is also very short, and when it is launched, it grows into a new plant. In this way, in about 12 days for a cycle, the number of water hyacinths can easily double!
As an alien species, water hyacinth has no natural enemies in China, and they also have strong environmental adaptability, and soon they are safely stationed on this new water and soil, growing and multiplying unscrupulously. The water hyacinths that rage in rivers, lakes and ponds have a nickname of "water devils", and their harms are definitely not as simple as affecting the beauty, pollution and occupying waters.
Known as the "Water Devil"
<h1 class="pgc-h-arrow-right" data-track="29" > china's strict prevention and control measures</h1>
Flooded hyacinths can infest and block waterways, restricting boat passage, swimming and fishing. In addition, the water hyacinth floats extremely densely on the surface of the water, preventing sunlight and oxygen from reaching the water, resulting in a worrying living condition for underwater plants. Their sheltering and plundering of native aquatic plants and living space greatly reduces biodiversity in aquatic ecosystems.
Water hyacinth also competes with other aquatic species for light, nutrients and oxygen, reducing dissolved oxygen levels in plants, obscuring valuable light, and greatly affecting local ecosystems and flora and fauna communities. Native fish populations in low-oxygen waters are also damaged, with significantly reduced spawning and consequent degradation of important waterfowl habitats.
In rural areas, thick water hyacinths also cover rice paddies, block irrigation channels and affect food harvests. During floods, they also float with washed-away buildings, promoting mosquito breeding and thus transmitting a large number of diseases.
Affect the ecosphere
Human activities have further contributed to the damage to the ecological environment caused by the breeding of water hyacinths, and wetland ecosystems involving irrigation canals, hydropower projects and artificial lakes are particularly vulnerable to water hyacinth invasion. This weed blocks waterways, causing hydropower stations to stop working in severe cases, affecting the quality of life of residents in surrounding towns, creating a vicious circle.
Human water use is also negatively affected by the ravages of water hyacinths, which grow in drainage canals to reduce flow, causing flooding and damage to canal embankment structures. In irrigation channels, they can obstruct water flow and block pump inlets for irrigation. Restrictions on water use reduce the commercial value of real estate and tourism, resulting in significant economic losses.
In order to control the water hyacinth and slow down this menacing "green pollution", China spends about 100 million yuan every year to manually remove it, but this method is obviously time-consuming, laborious and expensive, and ultimately does not achieve the imaginary governance effect.
Manual salvage is time-consuming and laborious
In order to effectively control the ecological problem of water hyacinth flooding, China has traced back to the roots and adopted a series of strict governance measures. First of all, the water hyacinth also has requirements for the choice of water quality, that is, it is rich in organic matter, such as nitrogen, phosphorus, potassium, etc., which become excellent nutrients for the growth of water hyacinth.
Therefore, from the perspective of water system management, China will invest funds in environmental protection, especially for those water systems and water bodies that are seriously polluted, so as to inhibit the growth of water hyacinth at the root. In addition, the state has also arranged a large number of manpower and machinery to carry out orderly salvage of water hyacinths in sub-districts and sub-districts.
The vitality of the water hyacinth is extremely tenacious, so the salvaged plants must not be discarded at will, and crushed and destroyed by professional means and machinery to prevent the re-spread of this invasive species.
Water hyacinth is treated harmlessly
In addition, with the development of technology, the scientific research team in our country has realized the skill of "turning waste into treasure" of waste water hyacinth, and use them to produce biogas and combustible gas methane, becoming an environmentally friendly green fuel.
In the years of fighting wits and courage with water hyacinths, China has accumulated a lot of effective practical experience in removing water hyacinths. For example, water hyacinths reproduce faster, and they do not have the ability to cross the barrier of the fence, and placing a fence change in the water hyacinth community effectively prevents them from expanding further.
After several years of efforts to control "green pollution", prevent water hyacinth flooding and combine pollution control and pollution prevention in the water system, our country has achieved gratifying results.
Nowadays, many domestic water systems have a new look, no longer "dirty, smelly, rotten", but replaced by pure water quality and good ecology.
The water environment has improved
The root cause of the growth of the water hyacinth has been severely inhibited, and with the manual salvage and containment, a water system in the south that was once plagued by water hyacinth has been improved. Under the implementation of these comprehensive measures, it is now very difficult for us to see the figure of water hyacinth in our lives, and they seem to have faded out of the vision of the Chinese people.
<h1 class="pgc-h-arrow-right" data-track="45" > disappear? Eradicating species invasions is difficult</h1>
However, does not seeing mean disappearing? In fact, the situation is not as optimistic as we think, the domestic water hyacinth is not really "extinct", they seem to have been removed from most of China's waters, but China's water system is too complex and wide, some places still exist in the watersheds of the water hyacinth figure, but it has rarely been noticed.
The tenacious vitality of water hyacinth shows that they may come back at any time, and it takes great efforts to treat and restore the aquatic environment, which requires the love and maintenance of every Chinese citizen, so as to avoid the flooding of water hyacinth again and spend a lot of money to treat and restore the environment.
Respect the fruits of labor
The losses and harm caused by alien invasions are themselves irreversible, and it is difficult to completely eradicate them. Theoretically, the main reason why a new species can thrive unscrupulously in the local area is due to the lack of natural enemies of the species, and the natural environment is highly up to standard with the breeding needs of the species.
Even with this in mind, we cannot introduce natural enemies of the species at will, because this is likely to lead to a new round of species invasion. In summary, the introduction of new species is a matter that needs to be treated with caution, and relevant experts need to evaluate and judge in combination with the status of species and the current status of the ecological environment.
Invasive species in China
<h1 class="pgc-h-arrow-right" data-track="51" > conclusion</h1>
Although the water hyacinth that invaded China has been effectively treated by domestic scientists, it is too late to really wait until the invasive species affect the environment and economy, so the most important thing is to understand and remember its seriousness, strictly abide by customs regulations, and be vigilant against species invasion.
Strict customs inspection