We are fighting a tough battle with the "alien biological army"...

Fifty years ago, in 1972, the United Nations held the first Conference on the Human Environment, which brought the important connotation of "There is only one Earth" into people's vision. As early as 1970, before the conference, two young men, Gaylord Nelson and Dennis Hayes, began to campaign to protect the Earth and held the first "Earth Day" event in human history, which was April 22.

So what is Earth Day? It is very easy to understand. It is a holiday set up to protect the world's environment. Its main purpose is to raise people's awareness of existing environmental problems and mobilize them to protect our common home, the Earth.

Today, we would like to take this opportunity to discuss with you an issue that is often mentioned but easily overlooked when it comes to protecting the earth - species invasion.

01

Why are invasive species so difficult to eradicate?

Before we know about invasive species, some people may wonder, are invasive species really that scary? Maybe the situation is not as serious as we think?

However, according to statistics, more than 400 "comprehensive" invasive alien species have been found in my country. Among the 100 vicious invasive alien species in the world announced by the International Union for Conservation of Nature, more than half have invaded my country, among which 11 major invasive alien species cause economic losses of up to 57 billion yuan to my country each year.

Distribution of invasive alien species in various provinces across the country | Reference 1

The reason why invasive species are so difficult to deal with is that they have three magic weapons: first, they have strong ecological adaptability; second, they have strong reproductive capacity; and third, the ecosystems they invade usually have sufficient available resources and lack natural control mechanisms. Therefore, invasive species without natural enemies can quickly occupy the high ground and dominate the local environment after entering it.

02

10,086 variants of invasive species

Invasive species are very cunning, and sometimes, some easily ignored dangers quietly come without warning, such as the plant killer "Canada goldenrod" and the red fire ants that bite people. These two invaders must come every spring. If they are properly prevented and controlled, they can only go back home in disgrace, but if you take it lightly and fail to prevent them, it will be a disaster.

Let's talk about the "Canada goldenrod" first. It is very similar to the "Goldenrod" native to my country in appearance and name, but they are not the same species.

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In the 1930s, the Asteraceae plant "Canada Goldenrod", native to North America, was introduced to my country as an ornamental flower. It was initially cultivated in parks and botanical gardens, and later gradually spread to the wild.

It has a strong reproductive capacity, with a single plant being able to produce 20,000 seeds, and a survival rate of over 80%. If it reproduces through rhizomes, it only takes two years for a single plant to grow into a "big family" with more than 200 members. Moreover, it not only has a strong reproductive capacity, but also competes with native plants for light, water, and nutrients.

Canada goldenrod | Tuchong Creative

What’s even more frightening is that “Canada Goldenrod” secretes harmful substances during its growth process. Once these harmful substances enter the soil, they will have a lasting toxic effect on surrounding plants.

"Canada goldenrod" starts to sprout in March every year, enters the vegetative growth period from April to September, and the plant is usually more than 1 meter tall in early July, and blooms in mid-to-late October. Based on the principle of "early discovery and early suppression", people usually pull it out, burn it, or kill it with chemicals in April and May.

For ordinary people, it is our duty to know and discover it. Government landscaping departments, city hotlines, and even street community offices can receive reports about "Canada goldenrod".

Compared to the Canadian goldenrod, which likes to bully native plants, the red fire ants are more aggressive. Not only are other animals bullied by them, but humans are also their targets.

Note where the arrows point. The nodules of red fire ants are like two rosary beads | Ye Zhengrong

Red fire ants were originally distributed in the Paraná River Basin in South America. They invaded North America in the early 20th century and were later brought to Australia, New Zealand and other countries through international trade. They entered Taiwan Province of my country in 2003 and then spread rapidly in China through the Guangzhou port. As of April 2021, red fire ants have invaded 448 counties (cities, districts) in 12 provinces (autonomous regions, municipalities) in my country.

As a vicious invasive organism, the red fire ant, like the Canada goldenrod, has a strong reproductive capacity. The queen ant lays a limited number of eggs for the first time, about 30 to 40 eggs, all of which are worker ants. When these workers grow up, the queen ant's egg-laying capacity will soar to 1,500 to 5,000 eggs per day. The average lifespan of a queen ant is 6 to 8 years. In a mature red fire ant nest, there are about 200,000 to 400,000 red fire ants, which is almost the population of a county in my country.

The dirt around the red fire ant nest, look carefully at the lower right corner | Ye Zhengrong

In addition to their amazing reproductive capacity, they are also highly aggressive and toxic. A bite from them can cause the wound to become red, itchy, and fester, taking at least half a month to heal, or cause shock or even death.

Red fire ants are so dangerous, so when should we "strike first"? The answer is: spring. At this time, they have not yet formed a strong population, which is a good time to "raid the house".

If you find them on the roadside or in the fields, be careful. Do not step on the ant nest, and do not touch it with your hands to avoid being bitten by red fire ants. You should report it to the relevant agricultural and forestry departments in a timely manner and ask professionals to come and kill them.

If you are bitten, don't panic. Wash the wound with soapy water to neutralize the toxins. Then apply ice to reduce the spread of toxins in the blood and lymph. Do not scratch to prevent infection. If you experience allergic symptoms such as chest tightness, abdominal pain, difficulty breathing, cold sweats on the limbs, etc., go to the hospital for treatment immediately.

03

How to eradicate invasive species?

After reading the previous introduction, you may have a big question: since invasive alien species are so difficult to deal with, can we use our expertise to solve them by eating?

This idea is good, but also very "naive".

For example, there is the water hyacinth (commonly known as "water hyacinth") that has plagued our country for many years. It is wet garbage that even pigs dislike. There is also the golden apple snail, which, although it looks very similar to the field snail, should never be eaten easily because it contains a large number of parasites in its body.

There are very few invasive species that can be truly eliminated by "eating" them, and the vast majority of invasive species are inedible. So, what is the way to prevent and control biological invasions?

First, we need to mobilize all citizens to detect and report invasive species early, and nip them in the bud.

Sina Hot List

Secondly, preventing and controlling biological invasions is not the exclusive responsibility of the customs and gardening departments. We ordinary people also have the obligation and responsibility to stop biological invasions. For example, when traveling abroad, we should not bring local animals and plants back home, and take practical actions to protect local organisms; we should not buy foreign organisms out of curiosity, and cooperate with customs inspections.

Guangming Daily

Of course, the country is also actively working to control the spread of existing invasive organisms and conducting research on biological, chemical, physical and mechanical control technologies.

Among these control methods, biological control, especially the method of cultivating natural enemies of harmful invasive organisms, is the most effective. For example, weevils or borers are used to control water hyacinth, red ladybugs are used to control citrus cottony scale, and Zhou's white moth wasps are used to control American white moths. At the same time, relevant departments are also actively strengthening international cooperation to jointly resist the invasion of alien species and improve the level of biological protection and biological quarantine.

Today is the 53rd World Earth Day. We hope that through this article everyone can further realize the damage that invasive species cause to our environment. The beautiful rivers and mountains of our motherland need us to protect together!

Author: Song Qinping

Produced by | Science Popularization China

Producer | China Science Expo

References:

1. Yang Jian, Li Chuanren. The Convention on Biological Diversity and the Control of Invasive Species in my country[J]. Journal of Yangtze University (Social Science Edition), 2021(2013-2):54-56.

2. Lei Juncheng, Xu Haigen. Prediction of the potential distribution area of ​​Solidago canadensis in China based on MaxEnt[J]. Journal of Ecology and Rural Environment, 2010, 26(002):137-141.

3. [In-depth] Dangerous red fire ants have no natural enemies] https://baijiahao.baidu.com/s?id=1699518258535963314&wfr=spider&for=pc

4. "There are as many as 6,000 parasites in the golden apple snail, which can be fatal in severe cases" https://www.sohu.com/a/395000536_120437964

5. Li Kuntao. Current status and prevention strategies of biological invasion in my country[J]. Biology Teaching, 2007, 32(2):8-9.

6. Liu Wei, Yang Zhen, Yan Juan. Harms and control measures of biological invasion[J]. Journal of Anhui Agricultural Sciences, v.43;No.495(26):104-107.

7. Qin Zhiya, Tao Jingyi, Hu Chen, Ruan Aidong. Distribution, impact and control measures of water hyacinth in my country's waters[J]. Journal of Anhui Agricultural Sciences, 2016, 44(28):81-84.

8. Hao Changhua. Control effect of Zhou's gypsylla on the American white moth in forests[J]. Liaoning Forestry Science and Technology, 2019(1):29-31.

9. Earth Day[EB/OL]//Baidu Encyclopedia.

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