Effective cooperation between ecologists and historians for conservation: Documenting a 16th century crayfish introduction

Humans have moved species across biogeographical barriers for millennia, but ancient introduction events often remain unknown due to the lack of primary information. Here, we show that the cooperation between ecologists and historians can undercover relevant past ecological processes, such as species introductions, with high temporal and spatial precision. We were able to locate and study over a dozen 16^th century documents hosted in historical archives and spanning 25 years (1563–1588) that dealt explicitly with crayfish introduction into Spain. Those documents allowed identifying the aims, negotiations, actions and people involved in both failed and successful introduction attempts in king Philip II's court. In the 1560s the Spanish court unsuccessfully tried to import crayfish from Flanders and France to be stocked in Philip II's garden ponds. The king's desires were not fulfilled until 1588, when several Italian crayfish (Austropotamobius fulcisianus) were shipped from Tuscany and successfully transported alive to Madrid. The narrative developed from historical documents fits parsimoniously known biogeographical patterns (i.e. explains widespread the presence of a NW Italian crayfish lineage in Spain) and have straightforward implications for present-day biodiversity management, as the Italian crayfish is currently a conservation priority in Spain. Our work highlights the potential of historical sources to describe long-term human-nature relationships, and calls for collaborations among historians, scholars from other disciplines in the humanities and natural sciences researchers for the development of robust multidisciplinary knowledge.