95% of world consumption of protein derives from a few domesticated species, i.e. poultry, cattle and pigs.
Human food production therefore rests on the tips of pyramids of biodiversity, leaving the majority of species not utilised and not domesticated.
[2] Species naturally migrate and expand their ranges, utilising new habitats and resources, e.g. the cattle egret.
Arguably, that environment becomes more diverse, equally it has also "become more similar to the rest of the world",[6] though ecological interactions between the invaders and the natives are likely to be unique.
Indeed, many species are so well naturalised that they are considered native, yet they were originally introduced; with the best examples probably being the Roman and Norman introduction of the hare and the rabbit respectively to Britain.