What are the hazards of biological invasion?

1, economic loss. In China, from south to north and from east to west, the troubles brought by these alien invaders can be seen almost everywhere. China is one of the countries suffering the most from the invasion of alien species. From 200/KLOC-0 to 2003, the former State Environmental Protection Administration organized a national survey of alien invasive species. According to the survey, there are 283 alien invasive species in China, which cause economic and environmental losses of about 654.38+02 billion yuan every year, but now the loss has reached 200 billion yuan. According to the report of the International Union for Conservation of Natural Resources (IUCN), the global economic losses caused by the invasion of alien species exceed 400 billion dollars every year. Worryingly, 46.3% of these alien invasive species have invaded nature reserves. Director Jesson Wang of the Biosafety Management Office of the Department of Natural Ecology Protection of the Ministry of Environmental Protection said recently. Environmental experts believe that in recent years, the phenomenon of alien biological invasion in China is increasing day by day, which brings more and more serious biological safety problems, and it is urgent to effectively prevent alien species from invading.

2. Species extinction. After alien pests invade new suitable growth areas, their populations will multiply rapidly and gradually develop into new local "dominant species", which will seriously damage the local ecological security. Specifically, the negative consequences mainly include the following points: First, the invasion of alien species will seriously destroy the biodiversity of organisms and accelerate species extinction. Biodiversity is a complex system with different levels, including all plants, animals, microbial species and their genetic information, organisms and living environment. Although the biodiversity of a country or region is endowed by nature, any country must invest a lot of manpower and material resources to try its best to maintain its biodiversity. However, the invasion of alien species is the number one enemy threatening biodiversity. After the introduction of invasive species into different places, due to the lack of natural enemies and other restrictive factors that can limit their reproduction, the consequences are rapid diffusion, massive expansion, formation of dominant species, and competition with local species for limited food and space resources, which directly leads to the degradation or even extinction of local species.

3. Destroy the ecology. The invasion of alien species will affect the water and other nutrients in plant soil, as well as the structural stability and genetic diversity of biological communities, thus destroying the local ecological balance. For example, Mikania micrantha, an exotic species introduced from Australia and invaded many forest farms in Hainan Island and Leizhou Peninsula, is extremely dry because it can absorb a lot of soil moisture, which is very unfavorable to soil and water conservation. In addition, Mikania micrantha can secrete chemicals to inhibit the growth of other plants, which once seriously affected the production and development of the whole forest farm.

4. Threatening health. For example, dutch elm disease, which originated in East Asia, invaded Europe twice at 19 10 and 1970, causing elm death in most European countries. Another example is ragweed introduced to China 40 years ago. Pollen fever caused by its pollen will do great harm to human health. When pollen drifts from July to September every year, people who are allergic to the body will have symptoms such as asthma, sneezing and runny nose, and even die of other complications.