For 2,000 years before the Black Death, plant diversity across Europe rose. Not despite farming — because of it. Mixed agriculture created a lattice of cropland, pasture, hedgerow, fallow, and woodland edge. Each patch was a different habitat. Each transition was an opportunity. The patchwork was the mechanism.
Then the plague killed between a third and half of Europe's population. Fields went untended. Grazing stopped. The expectation — the modern expectation — is that nature recovers when humans leave. Rewilding should increase biodiversity.
It didn't. Over 100 fossil pollen records from lakes and bogs across Europe show plant diversity collapsing after 1348. The decline lasted 150 years. Only when populations recovered and farming resumed did species begin to return. Recovery took three centuries.
The critical detail: the biggest losses occurred where arable farming was abandoned. Where farming continued or expanded, biodiversity grew. The relationship isn't correlative — it's architectural. The diverse lattice of farming practices maintained habitat heterogeneity. When farmers disappeared, the lattice collapsed into uniform woodland. Homogenization killed species that had evolved to exploit the edges.
The intuition that nature needs us to leave is based on a temporal error. It assumes the pre-disturbance baseline is wilderness. But after 2,000 years of mixed agriculture, the disturbance was the baseline. The farming hadn't been imposed on an ecosystem — it had become the ecosystem's load-bearing structure. Removing it wasn't restoration. It was demolition.
The Black Death was a natural experiment in rewilding at continental scale, and it proved the opposite of what rewilding advocates assume: that the scar can become the scaffold, and removing the scaffold collapses what it holds.