Until the early Middle Ages, the islands were completely virgin, but with the arrival of the first settlers, foreign species were introduced to these areas. These were not only crops and trees but also farm animals such as pigs and even pests - rats, which have become perfectly at home on the islands, destroying their original fauna and flora. It is not known exactly how many endemic species became extinct before Europeans arrived on the islands, but their arrival only accelerated the process. With the advent of modern agricultural technologies, more and more forest areas were cleared, monoculture crops were introduced and more and more foreign fauna and flora were introduced. Of the endemics that have survived to this day, most are at risk of extinction.