Australia was once an isolated continent, once considered a large island, due to Australia's lack of strong external competition, indigenous organisms are mostly marsupials, which are obviously different from other continents, retaining more ancient characteristics, and at the same time, this also makes them not enough to cope with the invasion of foreign species. In Australia's history, there are three major invasive species that can be called nightmares, and the invasion of each species has almost caused the extinction of a large number of native animals in Australia.
The first, the first ancient African brown immigrants 40,000 to 50,000 years ago
About 40,000 to 50,000 years ago, due to changes in the geological environment, the sea level between Australia and Asia dropped by more than ten meters, resulting in the emergence of many islands, and ancient African brown people along the coastline, riding a simple raft island after island to the Australian mainland.
In Australia at that time, native predators were gathered, followed by the top predator ancient monitor lizard, the sub-top predator thyrosman, followed by the thylacine. These three predators were the most common predators in Australia at that time, among which the ancient monitor lizard and the pocket lion posed a great threat to the african ancients who first arrived, and the first humans were ambushed and tracked and hunted by the ancient monitor lizards after their arrival, and they were forced to move to the open land and barren hillsides on the coast to survive, and every time they went to the bushes and grasslands to hunt, they could suffer losses.
As human beings gradually gained a foothold, in a lightning flash thunder, lightning caused a grassland fire, humans found and mastered the tool of fire, from this form reversed, the ancients used fire attack step by step to burn the jungle where the ancient monitor lizard hid, many ancient monitor lizards and pocket lions were extinguished by fire, and some other lucky escapes, due to the loss of shelter in the woodland in the habitat, unable to hide and ambush prey, and eventually died of hunger.
With the expansion of human territory, the living area of ancient monitor lizards and thylacines gradually shrank and eventually became extinct, and the thylacine survived because it was not too aggressive to humans, becoming a predator at the top of Australia's food chain. The immigrant African Brown people became indigenous people.
Second, five or six thousand years ago, our South China fishermen arrived in Australia, and finally lost to the indigenous and retreated, leaving the Chinese pastoral dog to become a top beast and evolved into a Australian wild dog.
However, the status of the thylacine did not last long, five or six thousand years ago, human navigation technology has made great progress, the east Asian region of fisheries developed, fishermen go farther and farther, and even began to use the boat as their home, the whole family and the family's livestock live on the boat.
With the development of shipping, the fishermen explored a wider area, they found one island after another, and used it as a foothold, and eventually reached Australia, however, due to the local indigenous language barrier and long-term isolation, the conflict between tribes continued to drive them away as invaders, and due to the small number, the South Chinese immigrants eventually retreated, and in a hurry abandoned the pastoral dogs that came with the boats, and these domestic dogs fled into the wilderness.
However, domestic dogs due to complex feeding habits, not picky eaters, plant rhizomes, fish, local small animals can become their food, so survived and began to breed, due to long-term rewilding, their offspring in pure wild environment began to return to the nature of their ancestors South China gray wolf, they became wild and extremely united, in the competition with the native beast thylacine to gain the upper hand, and then gradually expanded the territory, with the increase of the territory of wild dogs, thylacines gradually became extinct in Australia and New Guinea, Only survived on the isolated island of Tasnia.
The Chinese Pastoral Dog eventually evolved into the top predator Of the Soil Australian Dingo.
The third, the European hare that arrived with European colonists two hundred years ago
Australian herbivores are mostly marsupials, originally there were no rabbits, two hundred years ago, Europeans opened the door to Australia with a strong boat cannon, and occupied the whole of Australia, establishing large farms and farms in Australia.
With the continuous influx of Europeans, the farmers who were not willing to be lonely planned to engage in some entertainment, hunting was very popular, however, the native herbivores moved slowly, hunting was not fun, so a farmer remembered the rabbits in his hometown, he entrusted people to send a batch of rabbits from Europe, perhaps the commissioned person was worried that the rabbit was not flexible enough, affecting the pleasure of hunting, so there were five hares with the rabbits.
However, what I did not expect was that due to a fire, the farmer's captive rabbits all slipped away, the rabbits were like fish into the sea, the birds were no longer bound, in the words of uncle Huang, "I am like a fish, no longer bound", they have no natural enemies on the grassland, coupled with the fertile grassland, very suitable for rabbit life, they breed very fast, in less than fifty years actually spread rapidly to the whole of Australia, the maximum number reached more than ten billion.
As the number of rabbits soared, the Australian grasslands were overwhelmed, and the rabbits ate the grass on the ground and then burrowed and ate the grass roots, and many grasslands became deserts. The farmer's pasture was not spared, ten rabbits can eat a sheep's pasture, especially in the pasture there are too many rabbit holes, horses, cattle and other livestock often lose their front hooves, the breeding industry has suffered great losses, so the local people began to kill rabbits.
Initially they introduced the rabbit's natural enemy, the fox, but contrary to their wishes, the fox found a better native animal to prey on, turned a blind eye to the rabbit, and reduced the number of native animals, indirectly helping the rabbit to reduce competitors.
Subsequently, the whole people began to be mobilized to join the rabbit hunting activities, however, Australia is too big, many places are inaccessible, there is no condition to hunt. Coupled with the fact that Australians don't like to eat rabbits, they treat eating rabbit meat as much as we hate dogs.
So they came up with a gradual fence wall, thousands of kilometers of fence wall was built, the rabbits were trapped in a fixed area, however, there was no impermeable wall, let alone a fence, this useless work was quickly proved to be a decoration, the number of rabbits was still increasing, and the Australians realized that if they did not control the rabbits, Australia would become a desert.
So, the local indigenous scientists developed a virus for rabbits, through mosquitoes to spread to rabbits, soon the virus spread, the effect is very good, the mortality rate of 99.9%, less than a year, 90% of rabbits died, however, the virus is not omnipotent, we are familiar with a term called herd immunity, natural selection, the survival of rabbit mortality declined, and did not begin to re-expand.
Today, the number of rabbits has returned to about 600 million, although it is not enough to pose a threat, but it is time to cause a new round of vigilance.
The invasion of these three species has completely changed the biological structure of Australia, and it can be called a nightmare-level invasive animal for Australia.