Regolith Biome

The Regolith Biome is the part of the map associated with regolith deposits, and it is notable mainly for the material found there. In practice, the biome matters less as terrain and more as a source of regolith, since regolith itself is treated as a Filtration Medium. That makes it especially valuable in setups that need to conserve water, because it can replace more expensive filtration materials when water starts to run low.

The biome also has an indirect ranching use. Shove Voles can be effectively run as starvation ranches, turning them into nearly free meat: their upkeep costs next to no material, and the main requirement is Duplicant labor to keep them groomed. This only works when they are not allowed to eat the full amount they are capable of consuming; if they are fed normally, they become completely unsustainable.

In short, the Regolith Biome is useful for two reasons: it provides regolith for filtration, and it supports low-input Shove Vole ranching for meat production. For colonies that are trying to stretch resources, both of these uses make the biome worth exploiting whenever it is accessible.