Molecular evidence reveals unsustainable harvest of wild orchids

Human use of wild species has long reshaped biodiversity, but the historical dynamics of exploitation are often poorly documented. One region where this is particularly concerning is the eastern Mediterranean, where orchids are harvested for the production of salep, a traditional beverage made from dried orchid tubers. Collections of these tubers held by pharmaceutical and natural history museums provide a record of their centuries-long use, but their provenance and species identity remain largely unknown. Here, salep tubers spanning nearly 200 years were analyzed using targeted capture of orchid-specific loci to identify their likely source among 80 regional candidate species. Our approach confidently identifies up to 85% of highly degraded tubers, enabling temporal and spatial reconstructions of harvesting patterns. We reveal a rapid expansion in the diversity of collected species in recent decades that is linked to variation in flowering time. Longer harvesting seasons and universally declining tuber sizes are consistent with a scenario of intensifying exploitation. Species distribution models indicate that the diversity of salep sold in markets today exceeds local orchid availability, implying long-distance trade—while comparative phylogenomics identifies the lineages that are increasingly targeted today and are at an elevated risk of future depletion. Combined, our results show that traditional salep orchid populations are declining, driving shifts toward new species and harvesting territories. This escalating trade poses a significant and growing threat to orchid diversity.

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