Black Death reduced plant diversity across Europe

Between 1347 and 1353, the Black Death killed between one-third and half of Europe’s population, and new research shows this disaster also decreased plant diversity.

Scientists analysed fossil pollen from over 100 sites across Europe to understand how plant life changed before, during, and after the plague. They discovered that plant diversity had been increasing for 2,000 years, peaking in the High Middle Ages, but then sharply declined for roughly 150 years following the Black Death’s arrival in 1348.

The decline happened because the plague caused widespread abandonment of farmland. Where people stopped farming, landscapes became less varied and fewer plant species could survive. Surprisingly, areas with continued farming actually maintained higher plant diversity. This suggests that, for much of the last two millennia, human activity, specifically mixed agricultural systems, created the patchy landscapes that supported a wider range of plant life.

Researchers also point to similar patterns in other regions, like the forest gardens of the Pacific Northwest and the satoyama of Japan, demonstrating that long-term human interaction can actually boost biodiversity. They caution against conservation efforts that aim to completely remove human influence from landscapes, suggesting that low-intensity, traditional farming practices can be valuable for preserving both natural and cultural diversity.