Historical data to plan the recovery of the European eel

1. Long-term perspectives are critical to understand contemporary ecological systems. However, historical data on the distribution of biodiversity have only rarely been used in applied environmental sciences. 2. Here, we use historical sources to reconstruct the historical range of the European eel, a critically endangered species. We then use this baseline range to set range targets for the recovery of the European eel, as opposed to the abundance-based targets established by the European Union, which are constrained by the poor information on pre-collapse stocks. 3. We collected over 10 000 historical freshwater fish records from Spain in the 19th and 16th centuries, as well as over 25 000 records from the global biodiversity information facility (GBIF) to characterize historical and current European eel distribution in the Iberian Peninsula. We converted fish records into an eel presence–absence data set using subcatchment as spatial unit of analysis and modelled eel distribution in ...