What is a biological invasion?

"Biological invasion" refers to the phenomenon that certain organisms are naturally introduced from other places or artificially introduced and then become wild and cause certain harm to the local ecosystem. Alien organisms have many limiting factors in their places of origin that prevent the vicious expansion of their populations, among which predators and parasitic natural enemies play a critical role, as they can control their population density below a certain number. Therefore, those alien species usually do not cause great harm in their places of origin. But once they invade a new area and lose the control of their original natural enemies, their population density will rapidly increase and spread into disasters. In nature, there is a food chain in the ecological environment, and natural enemies restrict each other. Once a certain organism is artificially extinct or introduced, a series of unimaginable consequences will occur. Therefore, some foreign scholars list the secondary effects of blind introduction, habitat reduction and fragmentation, overhunting, and species extinction as the four major causes of species extinction, and vividly call them the "devil quartet."

Biological invasions are divided into two types: intentional and unintentional. With the introduction of species, these foreign immigrants may benefit mankind on the one hand, and may also have a certain impact on the local ecological environment and even economic development.

How to solve the problem of "biological invasion", an "illegal immigration" in the biological world, so that they do not cause harm to foreign lands? The experts' answer is: first, we must introduce species with caution and strengthen the management of introduced species; second, we must find out the types and harm status of existing harmful alien species in our country; third, we must strengthen the control of known major harmful alien species. Prevention and comprehensive management of species.

The International Union for Conservation of Nature pointed out in the "Preventing the Loss of Biodiversity Due to Biological Invasions" adopted in Switzerland in February 2000: "For thousands of years, oceans, mountains, rivers and deserts have been home to rare species. In recent hundreds of years, these barriers have become ineffective due to the impact of global changes, and invasive alien species have traveled across the ocean to reach new habitats and habitats, and have become invasive alien species. .

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