Is Permaculture about cycles?

I’ve been thinking about a lot of things recently and have been reading about Permaculture and I’m trying to answer some questions.

It seems to me that Permaculture is about creating, fostering and protecting beneficial cycles (aka growth) while disrupting or damaging detrimental cycles (flora and fauna with undesirable effects, invasive species etc).

How do you identify which cycle is which?

How do you reinforce the cycles that you want while stopping or slowing the detrimental ones?

How do you protect the cycles you want from negative outside influences while making the ones you don’t want more vulnerable to those influences.