How we cite our quotes: (Chapter.Paragraph)
Quote #7
A thought spread across [Kynes's] mind—clear, distinct: The real wealth of a planet is in its landscape, how we take part in that basic source of civilization—agriculture. (30.8)
Agriculture helped grow the first civilizations in the Fertile Crescent (source). It keeps our civilization going, and it looks like that won't change in the far-flung future. That is, until we develop those food replicators.
Quote #8
"To the working planetologist, his most important tool is human beings," [Kynes's] father said. "You must cultivate ecological literacy among the people. That's why I've created this entirely new form of ecological notion." (30.24)
Herbert goes totally meta here. Pardot creates a new ecological notion; Herbert writes a new type of ecology book.
Quote #9
It came to [Paul] that he was surrounded by a way of life that could only be understood by postulating an ecology of ideas and values. He felt that this Fremen world was fishing for him, trying to snare him in its ways. And he knew what lay in that snare—the wild jihad, the religious war he felt he should avoid at any cost. (36.116)
If Paul is ensnared in the Fremen religion, he'll become locked in the complete ecology of Arrakis, including the environment. It's just like the ecology of a dance club. You go to hang out with friends, but the next thing you know, you're twirling glow sticks to some trance on the dance floor. Only in this case, there's less trance and more jihad.