We had lots of leverage over nature in the middle ages. By that point Britain had little woodland left, and what remained was often managed. People were digging ditches and creating hedgerow as a boundary.

Larger mammals like bear, lynx, and wolf were extinct or on their way out. Large birds of prey were aggressively persecuted. There was even land reclamation as far back as Roman times.

Humans have been dominant over wildlife in Britain for a long time. There are probably American zip codes areas that have more untouched landscape than the whole of britain.