Here's a bunch of quotations that I've collected. They focus on water, rivers, fish, nature and sustainability. I've likely shared some of them here before:
From Mighty River by Richard Bocking
"A thing is right when it tends to preserve the integrity, stability, and beauty of the biotic community. It is wrong when it tends otherwise." -- Aldo Leopold
"We are a restless, dissatisfied novice species, clamoring for rulership of a planet toward which we display not even a rudimentary form of allegiance." -- Robert Harrington
"It seems clear beyond the possibility of argument that any given generation of men can have only a lease, not ownership, of the earth; and one essential term of the lease is that the earth be handed on to the next generation with unimpaired potentialities." -- Roderick Haig-Brown
"This curious world that we inhabit is more wonderful than convenient; more beautiful than it is useful; it is more to be admired and enjoyed than to be used." -- Henry David Thoreau
"It is the salmon that expresses the force of our land. Without the salmon, the land and the rivers would only survive as a corpse survives the death of the nervous system and the departure of the spirit." -- Alan Haig-Brown
"The world was not created for people only, but for purposes that transcend the human race with its limited foresight and imagination; therefore it behooves all conscious inhabitants of this superb planet to nurture it as a garden, maintaining it in health, beauty and diversity for whatever glorious future its denizens may together share." -- Stan Rowe
"The care of the earth is our most ancient and most worthy and, after all, our most pleasing responsibility. To cherish what remains of it, and to foster its renewal, is our only legitimate hope." -- Wendell Berry
"Unlike our ancestors, those of us alive today comprise the generations running headlong into the limits of our use of natural systems while observing permanent loss of much of our natural heritage. The bottom line is that people have the freedom to change their behavior, whereas fish do not. If we are to save wild salmon, then some people will lose money or the ability to do things they wanted to do. But we all lose if we lose the salmon." (p. 245) -- King of Fish: The Thousand-Year Run of Salmon by David R. Montgomery
"...if we can silence our egos for a moment and set aside our preconceptions about who we think we are, we may begin to perceive some of the lessons that the rest of nature has to teach: lessons not of personality but of relationship, not of order but of complexity, not of private property but of shared responsibility, not of rationality but of mystery, not of the ultimacy of the human enterprise but of the interdependency of all life." (p. 47) -- Cathedral of the World: Sailing Notes For A Blue Planet by Myron Arms
"... is the story we've been telling ourselves about our 'progress' as a species during the last ten thousand years really upside-down? Have we actually regressed, psychologically, from a state of harmony with our natural surroundings to a state of boredom, contentiousness, and alienation?" (p. 122). -- Cathedral of the World: Sailing Notes For A Blue Planet by Myron Arms
"... we have learned to adapt, by increments, to the humanscapes around us until we can hardly remember what a natural landscape looks like any longer.... Most dangerous of all, we convince ourselves, perhaps because of the pervasiveness of the humanscape, that we are at the center of things -- that we are the controllers, the 'managers' of the planet." -- Cathedral of the World: Sailing Notes For A Blue Planet by Myron Arms
"... while engineers can reproduce fish, they cannot replace nature. Hatcheries are technological marvels and they may be a necessity in the modern world, but they are not signs of progress; they are monuments to our failure to protect rivers." -- The Run of the River: Portraits of Eleven British Columbia Rivers by Mark Hume
"A river is water in its loveliest form, rivers have life and sound and movement and infinity of variation, rivers are veins of the earth through which the life blood returns to the heart." -- Roderick Haig-Brown A River Never Sleeps