Nature Ritual, do levels only increase hp or also range?

I know the spirits gain more HP every level they have, but do they get increased range? For example, does a level 9 spirit have a bigger range than a level 3 spirit?

Thanks.

I beleive its only the hp.

Aw, that sucks. Does anyone know how much? The difference between level 8 and 9. Level 9 is usually attribute 13, is it worth it?

they last longer... (unless they get killed ofcourse)