Medieval Farms Were a Boon for Biodiversity, Research Finds
In Europe, plant diversity was greatest in the years before the Black Death, a time when small farms and pastures coexisted with meadows and forests, new research reveals. The results show how, under the right conditions, farms can be a boon for nature.
The researchers focused on the land around Lake Constance, which lies on the borders of Germany, Austria and Switzerland, and tracked changes in the local flora from 2000 BC to the present day. For this study, they gathered, among other sources, data from thousands of fossilized pollen grains, plant remains recovered from hundreds of archaeological sites and numerous legal documents held at the nearby St. Gallen Monastery.
Researchers found that plant diversity increased steadily from 500 AD until around 1000, as farms expanded and trade expanded. Over time, farmers created a mosaic of fields, pastures, and forests that supported a greater range of plants than the closed forests that preceded them or the industrial farms that followed.
Around Lake Constance, researchers discovered not only a greater variety of crops, but also weeds, grasses and even shrubs and trees. The process was additive, said lead author Adam Spitzig, a doctoral student at Stanford University. Old plants persisted while new plants adapted to open or disturbed landscapes took root.
When the Black Death struck Lake Constance around 1350, it decimated the population, wiping out half the inhabitants of some villages. Farms collapsed and plant diversity declined. As the region recovered, diversity rebounded, but it never returned to previous highs. The development of flax manufacturing meant that farms became increasingly devoted to growing flax and raising cows, whose milk was used for bleaching.
The study, recently published in Proceedings of the National Academy of Sciencesfollows previous research showing how the growth of agriculture in medieval Europe led to a “honeymoon” period, during which small farms fostered plant diversity. The findings were corroborated by a study published this month in Ecology letterswhich found that biodiversity declined during the Black Death, even as large areas of land were once again wild.
“The broader lesson is that in modern conservation the choice is not simply between agriculture and biodiversity,” Spitzig said. Yale E360. Small, diversified farms “can boost and maintain biodiversity while supporting food production.”
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