Rhetorical question on wilderness vs. development.

So I'm driving to the beach yesterday through one of our scenic canyons here on the coast of California. I hadn't been down this one in several years. Now this canyon, other than some ugly oil derricks was pretty pristine otherwise in native vegetation and wildlife. I was dismayed to see that a large portion of the land had been cleared and a new vineyards for wine planted. When I first moved here, there were no vineyards, then the wineries started coming in. Just how much wine is needed in the world? Granted vineyards are an attractive replacement, but they way they are done is not ecological and I believe it stresses and marginalize the wildlife even more than it is already.

My question is, although I know it's a fool's errand to try to stop development, just what should the ratio be between development, whether agricultural or structure and land left as wildlife preserves for the original residents of these lands of other species? I say we shouldn't develop more than 30% and leave the rest alone and definitely, we should create wildlife preserves around the waterways, like rivers, creeks and lakes. Are there any studies out there or anyone in the field who has studied this to give me a shove in the right direction to learning more about this?