The only thing needed? People shouldn't interfere with nature so much. Let it all balance naturally and optimality by doing: nothing. No research needed, no plans, no guidance, just let the earth do it's thing and Paradise returns quickly.
That's a lot of Lyme disease, deer in your windshield and 10ft tall garden fencing whilst waiting for evolution to turn bobcats into deer eaters. I prefer to turn back the clock and just restore what was removed.