With the implementation of the Measures for the Management of Invasive Alien Species on August 1, the mainland's management and prevention and control of invasive alien species will be more stringent and perfect. From 2003 to 2016, the mainland has released four batches of the "List of Invasive Alien Species in China", recording a total of 71 species, including the red fire ant, apple beetle moth, etc., most of which are agriculture-related species, and the grassland night moth that invaded the mainland in 2019 has not yet been included in the list.
In this regard, in 2022, the mainland launched a census of invasive alien species, including surface surveys and key monitoring, led by the Ministry of Agriculture and Rural Affairs, with the coordinated participation of departments such as natural resources, customs, environmental protection, housing and forestry. Li Zhihong, a professor in the Department of Plant Biosecurity of the College of Plant Protection of China Agricultural University, believes that this census will have a more detailed and accurate grasp of the existing information on the types, distribution areas, and degrees of harm of invasive alien species on the mainland.
Meadow nocturnal moth. Photo by Yan Xiaorui
Among the species that are constantly in exchange, what is an invasive alien species?
Corn comes from the Americas, carrots are native to West Asia, watermelons are native to Africa... In human history, the exchange of species has a long history and has never been broken. But why have some species become a necessity in people's lives, and some have been named "invasion" and strictly controlled?
The Administrative Measures for Invasive Alien Species, which came into effect on 1 August, clearly define the distinction between alien species and invasive alien species. The Management Measures clearly point out that invasive alien species refer to alien species that have been introduced into colonization and pose a threat or hazard to ecosystems, habitats and species, affect the ecological environment of the mainland, and damage the sustainable development of agriculture, forestry, animal husbandry and fisheries and biodiversity. Li Zhihong, who participated in the formulation of management measures and the collection of opinions, told reporters, "That is to say, there are two basic criteria for judging invasive alien species, the first is alien, and the second is to cause harm." Species that are alien, that do not cause harm, or that have been integrated into the native ecosystem over a long period of time, we generally call them 'naturalized species'. ”
With the development of globalization, climate change and the evolution of pests, the flow of people and commodities has grown rapidly, there are more and more alien species, and the phenomenon of biological invasion has become more and more frequent, such as grassland night moth, desert locust, red fire ant, etc. The grassland moth is a major migratory agricultural pest warned by the Food and Agriculture Organization of the United Nations (FAO) globally, native to the Americas, where it broke out in Nigeria and other countries in Africa in 2016 and caused serious harm to maize, invaded Asian countries such as India in 2018, and invaded the Yunnan region of mainland China in January 2019; According to data released by the National Agricultural Technology Extension Service Center, the grassland moth has spread to 27 provinces in the mainland, posing a serious threat to the mainland corn industry. Red fire ants are also extremely harmful to invasive alien species, and the monitoring data released by the Ministry of Agriculture and Rural Affairs in 2022 shows that red fire ants have spread to 12 provinces (autonomous regions and cities) in the mainland, causing great harm to crops and the ecological environment, and threatening human health.
Species invade pathways, both man-made and natural
How exactly do invasive alien species invade? The Measures for the Management of Invasive Alien Species point out that the pathways of invasion are naturally and artificial. Nature, that is, through the migration of animals themselves into the mainland, such as the grassland night moth, there are also species that enter the mainland with the wind, birds and so on.
Li Zhihong, Director of the Key Laboratory of Monitoring and Prevention of Plant Quarantine Pests of the Ministry of Agriculture and Rural Affairs, Professor and Doctoral Supervisor of the Department of Plant Biosecurity, College of Plant Protection, China Agricultural University, Scientist of the National Modern Agricultural Industry Technology System for the Prevention and Control of Invasive Alien Species of Corn, And Famous Teacher of Beijing Colleges and Universities. Courtesy of respondents
What is human-induced transmission? Li Zhihong explained that there are many ways of artificial transmission, including introduction and trade. "Introduction is a common way to obtain better germplasm resources. In the past, when introducing alien species, there was no risk analysis and no consideration of the potential harm it might cause, which caused biological invasion problems. For example, virillinum, listed among the first invasive alien species in the mainland, but at the beginning, it was introduced as an ornamental plant and entered China in the early 20th century, a hundred years ago. Another example is the hyacinth, also known as water hyacinth, which was originally introduced as a raw material for animal feed, and later replaced by better raw materials, but it has become an 'ecological killer' in nature. ”
More often, species invasion only originated from an unintentional purchase, such as Brazilian turtles, alligator eels, etc., which were purchased as pets by people, and then released into nature, causing disasters in the natural world, "When we Chinese going abroad, we see local delicious fruits and beautiful plants, and we are willing to bring back some fruits and seeds." This may seem normal, but in fact, these fruits and seeds may themselves cause invasion, or the pathogens and pests carried on the fruits and seeds may also cause invasion. Li Zhihong said, "Of course, the cute pet insects and mollusks brought back from abroad may also cause great harm, such as the African snails carried by African students in Recent Years by Guangzhou Customs." The African snail is very large and has a beautiful shell and wants to keep it as a pet. But in fact, it is a creature on the list of the first invasive alien species on the mainland, and it is also a quarantine pest in the mainland. ”
African snail. Photo by Liao Zuxing
Trade is also one of the main ways to cause species invasion, such as imported grain, fruits and vegetables, seeds and seedlings and other propagating materials, logs, etc., may be adulterated with pathogens, pests, weeds and so on. Although the mainland has strict customs quarantine measures, it is still impossible to completely eliminate them in the face of huge quantities.
Among the many alien species, why are some of the hazards so great
Defining invasive alien species, causing harm is one of the important criteria. Of the many alien species, only a few cause significant harm. More may disappear in natural evolution or merge into the local biosphere.
Species capable of causing invasion often have capabilities that other species do not have. Li Zhihong introduced that the characteristics of the species itself, its ability to adapt to the environment, and the constraints of natural enemies all affect the occurrence of invasion phenomena.
In terms of self-ability, the ability to reproduce is one of the most typical abilities. The meadow moth produces a generation every month, and each female can produce 1,000-2,000 eggs, which grow rapidly and multiply and expand geometrically. In fact, many invasive alien species are super reproducible, "false sorghum, perennial herbaceous plants, propagated by seeds and underground stems, 1 plant can produce 10,000-20,000 seeds, 1 growing season can produce 5,000 nodes, each node can germinate and grow plants; A small orange fruit fly, the most timely conditions, breeds 1 generation in 20 days, and can breed more than 20 billion offspring in 60 days..." Li Zhihong said.
Fake sorghum. Photo by Li Zhihong
From a familiar environment to an unfamiliar place, if you want to survive, you must be super adaptable. Some alien species cannot adapt to the new environment and will gradually die out, at least it is difficult to spread naturally, while some are more adapted to the new environment, "such as the orange small fruit fly, which is a strongly resistant invasive alien species." It is native to India, from India to Southeast Asia and then to the mainland. It is extremely adaptable, originally a tropical subtropical insect, after invading the southern part of the mainland, gradually adapted to the temperature and humidity environment and spread north, in China's wintering line, has reached the Southern Henan Nanyang region. At the same time, the orange small fruit fly also has a high resistance to drugs, and it is very difficult to prevent and control in the field. Li Zhihong said.
The invasive alien species Purple Stem Zelan is a typical survival force in nature, "Purple Stem Zeeland will release special chemicals to affect the survival of other surrounding plants, this phenomenon is called the allelopathic effect; Eventually, where there is a purple-stemmed zeeland, there are fewer and fewer species, and biodiversity is severely affected. Li Zhihong introduced.
The lack of natural enemies is also one of the reasons why species are able to invade. In nature, each region has its own unique ecosystem, the food chain is complete, and it is difficult to have a biologically dominant phenomenon. Once a certain organism leaves the original ecosystem and enters a new ecosystem, the original food and natural enemies may disappear, thus becoming "lawless". For example, ragweed, in its place of origin, there are insects that can eat it. But after arriving on the mainland, due to the lack of natural enemies, once they adapt to the environment, they will multiply rapidly.
Invasion is highly harmful, and agriculture may be the most harmful
In 2003, 2010, 2014 and 2016, the mainland released the List of Invasive Alien Species in China in four batches, with a total of 71 species. There are 71 invasive alien species, including agriculture, forestry, fisheries, animal husbandry, wildlife, etc., but most of them are agriculture-related species.
The grassland moth is an important invasive alien species that has harmed corn production on the mainland in recent years, but because it was first discovered on the mainland in 2019, the invasion is late and has not yet been included in the list. Wang Zhenying, a researcher at the Institute of Plant Protection of the Chinese Academy of Agricultural Sciences, introduced that the grassland moth that invaded the mainland mainly harmed 19 crops and 5 kinds of weeds such as corn, sorghum, sugarcane, millet and wheat. Experimental data from Yunnan show that when there are 173 larvae in 100 plants, it can cause a loss of 53% of maize yield, and when the larval density is high, it may cause a harvest failure.
Another devastating quarantine pest, the potato beetle, is also an invasive alien species that threatens food security, of which the potato beetle is native to the Americas and has been introduced to Europe and Central Asia in the past hundred years. It has a certain ability to fly, can fly by itself and travel with the air current to new places. In 1991, the potato beetle invaded the Xinjiang region of the mainland, and its harm was extremely serious, from larvae to adults will eat the stems and leaves of potatoes, resulting in reduced or even extinction of production. Therefore, the mainland has adopted strict quarantine prevention and control measures for it, and has been controlled in the Xinjiang region for nearly three decades; However, in recent years, the insect has been found in the area near the border between Heilongjiang and Russia.
Pear fire blight. Photo by Li Zhihong
Vegetables and fruits are also the main targets of invasive alien species, Li Zhihong introduced, "such as pear fire plague, once found on pear and other fruit trees, it is devastating; First discovered in the United States, it has invaded the Xinjiang region of mainland China in recent years, posing a major threat to pear tree cultivation. Another example is the apple beetle moth, which has invaded Xinjiang, Gansu, Ningxia, Inner Mongolia, Heilongjiang, Jilin, Liaoning, Tianjin, Beijing and other regions, seriously endangering apple and other hosts. There are also orange small fruit flies, the host range is very wide, the harm is extremely large, serious may lead to fruit and vegetable harvest failure, or more than 80% of the yield reduction. ”
Orange small fruit fly. Zhao Tan photo
At the same time, some invasive alien species can directly harm humans and animals. Another example is poisonous wheat, as the name suggests, is a poisonous wheat-like plant that can produce narcotic toxins that harm humans and animals. Another example is false sorghum, where young shoots contain cyanide and livestock are susceptible to poisoning after eating. There is also ragweed, an invasive alien species that has invaded the Beijing area, and its pollen is easy to cause allergies and difficult to cure.
Red fire ants are also typical invasive alien species that are aggressive to humans, and can directly bite humans, causing serious death. Huang Qiuying, a professor of agricultural insect and pest control at Huazhong Agricultural University, introduced, "The adaptability of red fire ants is extremely strong, and their invaded areas may continue to expand to the northern region, eradicating red fire ant nests, usually using bait traps." Some places have also enabled drones to fully cooperate with spraying, the reason for the use of drones, one can effectively avoid the occurrence of staff being bitten by red fire ants, and the other can also cover areas that are difficult for many people to reach. ”
Prevent and control invasive species, and build a three-layer control system
For invasive alien species, the mainland has a complete set of prevention and control systems, taking the agricultural field as an example, from prevention to control, there are corresponding measures and systems. Although the grassland moth, which has caused great harm abroad, has invaded and settled in the mainland, its degree of harm is much lower than that of foreign countries, and there is no phenomenon of large-scale crop extinction.
The reporter learned that before the grassland moth entered the mainland, the plant protection department has begun to conduct continuous monitoring, and conducted risk assessment, and formulated a series of relevant prevention and control methods, which is the main reason for controlling the harm of the grassland moth within a certain range. Wang Zhenying introduced, "For invasive insects, the mainland has a three-layer prevention and control system. First, conduct risk assessments and provide early warnings of potential, likely, and new intrusions. Second, for cross-border pests, such as grassland night moth, African locust, tomato leafminer moth, etc., develop rapid detection technology, establish regional monitoring networks, establish resistance zones, and hunt them in various ways. Third, it has entered and occurred in large areas, such as potato beetles and apple beetle moths, to control the occurrence trend and block the spread. ”
Quarantine is also one of the main preventive measures, including sanitary quarantine, animal quarantine and phytosanitary. Li Zhihong introduced that the quarantine system has a history of nearly 700 years, and in the past ten years, the mainland's phytosanitary technology has developed rapidly, and innovative achievements have been made in risk assessment, testing and identification, quarantine treatment, epidemic monitoring and other aspects, providing technical support for the implementation of quarantine measures.
As opposed to prevention, it is control. In fact, with the exception of species with limited distribution, most invasive species cannot be completely eradicated, and invasions are constantly emerging. From the American white moth that was introduced to the mainland in the late 1970s, to the American spotted fly introduced in the 1990s, to the grassland night moth that invaded in 2019...
The war against invasive alien species is a long and protracted war. The main goal of plant protection workers is to control the hazards within an acceptable range through prevention and control. Lu Yanhui, director of the Institute of Plant Protection of the Chinese Academy of Agricultural Sciences, introduced that over the past few decades, the plant protection methods in mainland China have undergone changes in agricultural control, chemical control and comprehensive control. Agricultural control mainly relies on ways such as improving the farmland environment to reduce or avoid the occurrence and development of harmful organisms, and chemical control is mainly the use of chemical pesticides. In the 1970s, the mainland determined the policy of plant protection work, that is, prevention first and comprehensive treatment. Comprehensive management, also known as integrated control, is the coordinated use of a variety of technologies, including agricultural control, biological control, chemical control and so on. After entering the new century, the concept of green development and sustainable development has gradually become popular, and plant protection technology has once again been developed and entered a new stage of green prevention and control.
Data from the National Agricultural Technology Center show that through the implementation of effective pest control, in the three major staple grains, more than 200 billion catties of grain losses are recovered every year through effective prevention and control. But there are still 50 billion to 60 billion catties of food losses, many of which are due to invasive alien species.
After the implementation of the management measures, more departmental linkage is needed
With the implementation of the Measures for the Management of Invasive Alien Species, the management and prevention and control of invasive alien species on the mainland will be more rigorous and perfect.
In 2022, the mainland launched the census of invasive alien species, the census work is a surface survey and key monitoring, and how many invasive alien species are available nationwide, which is the primary issue that needs to be clarified in the face survey; Priority monitoring is a survey of 164 key invasive alien species. Led by the Ministry of Agriculture and Rural Affairs, the Departments of Natural Resources, Customs, Environmental Protection, Housing and Construction, Forestry and Grassland and other departments are involved in coordination. Li Zhihong believes that this census will have a more detailed and accurate grasp of the existing information on the types, distribution areas, and degrees of harm of invasive alien species on the mainland.
In January 2022, the Ministry of Agriculture and Rural Affairs added a new ministerial key laboratory, namely the Key Laboratory of Phytosanitary Pest Monitoring and Prevention of the Ministry of Agriculture and Rural Affairs, led by China Agricultural University, the Institute of Plant Protection of the Chinese Academy of Agricultural Sciences and Nanjing Agricultural University. The purpose of the construction of the key laboratory is to further strengthen and promote the prevention and control of phytosanitary pests and invasive alien species.
"In the future, there are two aspects of linkage work that need to be strengthened." Li Zhihong said, "First, the linkage of more departments, although the impact of invasive species on agriculture is the largest, in fact, they are also affecting forestry, fisheries, animal husbandry and ecological environment, so multi-sectoral linkage is needed; There is also customs, which, at ports, play an extremely important role in preventing quarantine animal diseases and plant pests and invasive alien species from entering the continent. In addition to further strengthening the biosecurity education of undergraduate and graduate students in universities and scientific research departments, it is very important for primary and secondary school students and the public to know more about the basic knowledge of invasive alien species and prevention and control. In recent years, many people have bought introduced pets and then released them, causing species to invade. Therefore, the prevention and control of invasive alien species is not only the work of the competent authorities, but also the common responsibility of all people. Mainland China's Biosecurity Law clearly stipulates that those who introduce, release or discard alien species without authorization shall bear legal responsibility, and those who cause serious consequences may also bear criminal liability. Therefore, it is very necessary for more people to understand the relevant knowledge to prevent and control species invasion. Among them, Beijing's education and scientific research forces are very strong, in this regard, we can give more play to the role of universities and scientific research institutes, strengthen the publicity of science popularization, and play a leading role. ”
Beijing News reporter Zhou Huaizong
Edited by Zhang Shujing Proofreader Lucy