In many places, especially near the coasts, fishing and collecting grounds still rich with life only a generation ago are now utterly depleted. But all is not lost. Thankfully, in many of these same places, people are making an effort to restore diversity. It isn't easy. Farming is much more expensive than hunting.
Nature works for free, it is true.
But once an ecosystem has been destroyed, it takes massive inputs of energy and money to get it going again, or to replicate its services. That hasn't stopped clam farmers in Fiji and Palau. Giant tridacna clams have been hunted relentlessly for generations. With our population growth, the pressures increased exponentially, and the clams literally could not reproduce fast enough to stay ahead of the onslaught. To restore damaged clam populations in Fiji, the clams are now being farmed.