Ecologies

Species naturally organize into associations that somewhat resist invasion. This is obviously because species that do not resist invasion do not stick around. An interesting system of ecologys for the game would be ones that are relatively stable until the player disturbs them.

An example of this is this fire based grassland.

The &s are highly flammable bushes

the ;s are dry grass and the ,s are young grass

Gs are grazers that survive on the grass. Not seen are predators that survive on the grazers

Ts are trees slowly invading the grassland.
Because of the presence of the highly flammable bushes, fire keeps the grassland free of trees. But when the bushes are removed grassland turns to forest. Introducing creatures that eat the bushes would create this forest, if not for the high population of predators (due to the grazers) and relative scarcity of bushes. So this system is both naturally stable and disturbable with work by the player.

Slightly different uses of a resource can allow the coexistence of similar organisms.

All four of these species grow inside of walls any only one can live in a wall at a time.

# lichen: spreads by placing seeds onto adjacent walkable tiles which can then spread into walls.

# moss: can only survive in a wall with a face flat to the air. Spreads to adjacent tiles.

$ slime: Wanders orthogonally within the walls until it touches air. When it touches are it spreads into tiles that do not.

# algae: Only spreads in tiles that do not touch air. Doesn't like touching more than two other algae at once.

Moss and algae always win when they fight a different organism for a tile which is how they survive in their more specialized niches. Lichen always loses and compensates by it's ability to spread across air gaps. As I said in my last post, the layout of walls effects the balance between these four organisms which then really changes the resulting ecologies of the species that eat them.