Outside of using the claim block, you can just kill them all.
Biome spawns have a set rate for zeds and animals. Once they are cleared, no more will spawn until the timer resets.
Same applies to fully cleared POI's. (MUST be FULLY cleared.)
The default delay for re-spawning after clearing is 5 game days.
Random wandering hordes, screamer hordes, and bloodmoon spawns all ignore the above mentioned respawn delays.
Also note that it is possible for zeds and animals to wander across biome borders.