When was a Canadian yellow flower introduced into China? What's the harm? Expert answers

Recently, a plant called "a yellow flower of Canada" was "encircled and suppressed" by Xi'an, Luoyang and other places in Shaanxi Province. It is reported that Canada's yellow flower has a strong reproductive ability. It has a bad reputation of "killing hundreds of flowers where this flower blooms", and has been included in the list of alien invasive species in China.

When was a Canadian yellow flower introduced into China? What should be done after discovery? In this regard, the Beijing News reporter interviewed Zhao Shiwei, chief engineer of Beijing Academy of landscape Sciences, and Wu Yongbin, senior experimenter of the school of forestry and landscape architecture of South China Agricultural University. Attention 1: when was the Canadian yellow flower introduced into China? What do you look like?

According to the bulletin on the state of China's ecological environment in 2019 issued by the Ministry of ecological environment, more than 660 alien invasive species have been found in China, and 71 species have caused or potential threat to the natural ecosystem and have been listed in the list of alien invasive species in China. A Canadian yellow flower has been included in the list of alien invasive species in China (the second batch)

Wu Yongbin said that alien invasive plants refer to species that are introduced through intentional or unintentional activities due to human or natural factors and later exceed their natural distribution. Most of the plants intentionally introduced have certain utilization value. For example, Solidago canadensis was first introduced into China as an ornamental plant. According to records, a Canadian yellow flower originated in North America and was introduced into Shanghai, Nanjing and other places as an ornamental plant in 1935.

According to Zhao Shiwei, a Canadian yellow flower, also known as "yellow warbler", is bright in color. It is a string of yellow flowers, which are often used as matching flowers to set off the main flowers in flower shops. Concern 2: what is the harm of a yellow flower in Canada?

Zhao Shiwei said that the imported species themselves are not terrible. Sweet potatoes and corn are all imported species, but some plants leave their original habitat and go to new places. Due to the lack of local natural enemies or the conditions limiting their growth, they have "grown wildly" and occupy a dominant position in the new environment, which means that they are particularly aggressive, They are called alien invasive species.

"The successful invasion of alien plants can be divided into four stages: introduction, settlement, domestication and diffusion." Wu Yongbin said that shortly after the introduction, due to the large number of seeds and strong reproductive ability of a Canadian yellow flower, and its underground stem of "endless wild fire and spring breeze". With the dispersal of seeds, they escaped to the wild and began to spread rapidly in the 1980s, becoming malignant weeds. It will destroy the ecological balance of the invasive area, occupy the growth space of native plants, and seriously threaten the biodiversity of the invasive area.

Zhao Shiwei recalled that about 20 years ago, a Canadian yellow flower spread seriously in Shanghai and Jiangsu. "The high temperature and humid air in the South also provided good conditions for the rapid growth of a Canadian yellow flower. At that time, from Shanghai to Nanjing, you saw a Canadian yellow flower on both sides of the road. They could grow more than one meter high, competing with the surrounding plants for sunlight, space and water, seriously encroaching on the territory of other local plants. Attention 3: the proliferation of a Canadian yellow flower How strong is fertility?

Solidago canadensis is a perennial perennial herb of Compositae, with annual aboveground stems and perennial rhizomes growing horizontally underground. Wu Yongbin said that the reason why a Canadian yellow flower is difficult to eliminate is that it has both sexual reproduction and asexual reproduction. Sexual reproduction means that its flowering and fruiting rate is very high. About 20000 seeds can be produced per Canadian yellow flower, and the seeds are small, which can be spread far away with the help of wind.

On the other hand, its rhizome is very developed. After the stem on the ground dries up, it can sprout new plants from the root the next year. Therefore, in addition to the seeds planted last year, its underground roots can also be superimposed to form a piece. Focus 4: where is a Canadian yellow flower found?

Canadian yellow flower comes from North America. According to the principle of plant adaptability to climate, similar climatic conditions are conducive to the reproduction and diffusion of invasive plants. At present, the distribution of Solidago canadensis is the most concentrated in the middle and lower reaches of the Yangtze River in China. It has formed certain harm in East China, Southeast and central China, including Zhejiang, Shanghai, Henan, Anhui, Hubei, Hunan and Jiangxi.

Is there a Canadian yellow flower in Beijing? Zhao Shiwei said that the two teachers had seen a Canadian yellow flower in Orson park before. However, in the past, it has been considered that its winter ability in the north is relatively poor, so its reproductive ability is not strong and its transmission is slow.

Recently, a yellow flower in Canada is in full bloom. Its traces have been found in Xi'an, Wuhan, Chengdu and other places, including Xinxiang in Henan Province for the first time. Villagers in Suohe Town, Caidian District, Wuhan said that a Canadian yellow flower competing for fertilizer with crops has reduced the yield of farmland. Recently, eight departments including Wuhan Agricultural and rural Bureau jointly held a work conference on the prevention and control of "a yellow flower in Canada", which required to complete the prevention and control tasks on the ground of farmland, roads and scenic spots in the city before November 20. Focus 5: what should the public do if they find it? How to clean up a Canadian yellow flower?

Wu Yongbin said that the public should treat alien invasive species such as a yellow flower in Canada rationally. There is no need to panic excessively, let alone demonize. We should know how to identify some common plants, and the government can also publicize more scientific knowledge of alien invasive organisms.

He said that for these invasive organisms with strong reproduction and transmission ability, we should adhere to the "second early": early detection and early elimination. The reason why invasive organisms erupt and have an impact on the local environment is often because they miss the best time to eliminate them.

For example, a Canadian yellow flower must be uprooted at the beginning of its discovery. After it spreads into pieces, it is more difficult to eliminate it. "It is also very important to remove them before the fruit matures, which can prevent the spread of seeds. Because the seeds of Solidago canadensis are very small, each plant can produce about 20000 seeds. According to the germination rate of 80%, it is 16000 seeds." Attention 6: what alien species have invaded China in recent years?

Wu Yongbin said that the damage caused by alien invasive organisms to garden plants in South China is very serious. For example, the larvae of purple grey butterfly endangering cycads, Erythrina Jifeng endangering Erythrina, coconut heart leaf beetle endangering palm family, and red fire ants endangering farmland or lawn will have a great impact on everyone's life and health. Zhao Shiwei said that now everyone has a stronger and stronger awareness of environmental protection, and has gradually realized that the plants deliberately introduced into China in the past may bring harm. For example, he said, in the past, some coastal beaches had poor environment and there were no plants on saline alkali land. Some people specially introduced flood and salt tolerant rice grass from abroad. As a result, rice grass once grew wildly and grew full on the beach, affecting the original plants, and then gradually carried out the removal plan.

The invasion of alien species is a problem facing the world. For example, water hyacinth has caused River blockage and destruction of aquatic ecosystem all over the world. Zhao Shiwei mentioned that Chinese plants also have examples of rapid growth after going abroad. For example, kudzu vine with three leaves has a beautiful appearance and has been introduced abroad for vertical greening. Kudzu vine also grows rapidly, but in China, people often dig kudzu vine roots to make kudzu powder for consumption, but foreign countries do not pay attention to eating kudzu vine roots. Kudzu vine will quickly climb onto trees to shield the sun, resulting in the death of other trees.

Zhao Shiwei said that at present, the use of natural enemies such as insects and fungi is one of the methods to control alien invasive species.