Schematizing a historical demographic collapse on a large time span using local, secondary and grey data: The case of Italian roe deer Capreolus capreolus italicus in Central Italy

In this work we attempt to reconstruct the dynamic collapse over time of a regional population of Italian roe deer in central Italy (Latium and Abruzzi) from 15th Century to the present day. To meet this aim, both historical and grey literature (both primary and secondary) has been investigated, and the DPSIR model and a standardized threat taxonomy have been applied. Historically, different driving forces and threat pressures changed the status of roe deer and different conservation responses were promoted. Biological resource use (5.1—“Hunting and collecting terrestrial animals” and 5.3—“Logging and wood harvesting”), Natural system modification (7.1—“Fire” and 7.3—“Other ecosystem modifications, as land reclamation) and Invasive and other problematic species (8.3 “Introduced genetic material and genes”) were the main threats (IUCN standardized taxonomy). We recognized three historical phases and one sub-phase of demographic reduction and collapse: “Aristocratic hunting” phase (15th Century), “Fire weapons and people hunting” phase (from 16th to 18th Century), “Habitat collapse” phase (19th and 20th Century), with a sub-phase of “genetic introgression” beginning in the 1940s. Our analysis highlighted: (i) the role in conservation biology of primary and secondary grey sources of data; and (ii) the use of the DPSIR approach to schematically reconstruct the local factors and processes acting on the demographic collapse of a below-species taxon.