Animals (including humans and various other beasts on land, but most noticeably aquatic and avian animals in the water and in the air) can and do travel long distances, bringing different microbiomes to different parts of the planet
Humans have dramatically accelerated the speed of this movement, first through ships, roads, and railways, and later through the development of aircraft
The rise of radio communications, the telegraph and the subsequent rise of the internet has then even more dramatically increased the speed with which information can move around the planet