The utility of herbarium collections for genetic monitoring.

Despite growing evidence of widespread genetic responses to anthropogenic activity, data shortfalls constrain genetic monitoring efforts and preclude the widespread use of genetic data to inform conservation. For flora, one option is to leverage the wealth of genetic material preserved in Earth's vast herbarium collections, but the extent to which herbarium specimens can supply the population-level data required to monitor genetic change remains unclear. Using the Essential Biodiversity Variable (EBV) framework developed to monitor population-level genetic change, we show that digitized herbarium specimens could be used to quantify ∼162 K measures of genetic EBVs representing over 41 K species, 86% of regions on Earth, and spanning the past 250 years of global change. As such, we find that herbarium collections offer an invaluable source of historical genetic data, the mobilization of which could transform global efforts to monitor and conserve plant diversity.