The Historical and Overlooked Collapse of Medicinal Leeches in Spain

Leeches in genus Hirudo have been used in medicine since ancient times, but increased exploitation during the 19th century led to the depletion of several populations in Europe. A compilation of Hirudo records in Spain ( H. troctina Johnson, 1816 and H. verbana Carena, 1820) show that the genus was more commonly mentioned and widely distributed in the past. Only 11% of the available records correspond to the 21st century. We highlight the overlooked decline of Hirudo leeches in Spain and call for an effort to better characterise their status, as an essential tool to design conservation measures.