Research overview: prey depletion and the empty forest syndrome

Many forests across tiger range remain structurally intact yet hold few or no tigers because their large prey have been hunted out, a condition often called the empty forest syndrome. This overview surveys research quantifying how snaring and subsistence hunting strip deer, wild pig, and other ungulates from apparently healthy habitat, removing the prey base tigers require. Studies in Southeast Asia document landscapes where tigers vanished despite protected status, driven primarily by collapse of prey rather than direct poaching of cats. The work shows that habitat protection alone is insufficient and that prey recovery, through snare removal and hunting control, is frequently the binding constraint on tiger restoration. It matters because it reframed defaunation, not just deforestation, as a leading cause of regional tiger extinction.