… okay this somehow both makes perfect sense and is completely not what I was expecting, all at the same time.
… do they have a long-term impact on the landscape?
Tl;dr, yes, yes they do. Content warning that the link contains video and images of rotting pig carcasses and attendant scavengers, e.g. maggots. Loads and loads of maggots. I didn’t find it particularly gross–nothing is suffering, it’s just nature doing its thing–but YMMV.
Why the hell would you dump three tons of pigs in a forest, you ask? Basically, some scientists wanted to study the impact of mass die-offs, e.g. the sort of things that can occur with, say, global warming. Or lightning strikes on really, really unlucky animal herds, apparently. To do this, they spent several years collecting the carcasses of culled feral pigs, then had to beg around to try and find someone who’d let them dump all the meat in a suitable location. A university finally agreed to allow the scientists to use its research forest, much to the delight of the local vulture population…