Comment by karmakurtisaani

> Yes, some parts are inherently O(n²) (mate finding, crowd density, predator/prey proximity, pathogen spread). Ecology needs pairwise relationships.

You might be able to do a bit better for some of these, check this out https://en.wikipedia.org/wiki/N-body_simulation

Essentially the idea in some optimizations is to divide the space into cells, and so you can discard relations with elements in far away cells.