In the early 1800s, the European roe deer (Capreolus capreolus) was probably extirpated from Switzerland, due to overhunting and deforestation. After a federal law was enacted in 1875 to protect lactating females and young, and limiting the hunting season, the roe deer successfully recovered and recolonised Switzerland. In this study, we use mitochondrial DNA and nuclear DNA markers to investigate the recolonisation and assess contemporary genetic structure in relation to broad topographic features, in order to understand underlying ecological processes, inform future roe deer management strategies and explore the opportunity for development of forensic traceability tools. The results concerning the recolonisation origin support natural, multidirectional immigration from neighbouring countries. We further demonstrate that there is evidence of weak genetic differentiation within Switzerland among topographic regions. Finally, we conclude that the genetic data support the recognition of a single roe deer management unit within Switzerland, within which there is a potential for broad scale geographic origin assignment using nuclear markers to support law enforcement.

Roe deer samples were collected in Switzerland between 2004 and 2017, by local hunters. Additional tissue samples were collected from Northern Italy close to the Swiss border (Lombardy) and Central Italy (Emilia-Romagna region). Samples were grouped into six regions based on broad landscape features, primarily according to topographic variation, as follows: Swiss regions: North, n=25; Central-East, n=106; Central-West, n=102; South-West, n=20; South-East, n= 54. The samples from Lombardy were included in the southeastern Swiss region as they originated close to the Swiss border with no barrier to free movement.The sixth group consisted of 9 individuals from central Italy, resulting in a total of 316 samples. DNA from tissue and blood samples was extracted using the DNeasy® Blood and Tissue kit (Qiagen). DNA from blood swab samples was extracted using a chelex protocol followed by a Qiagen PCR purification kit (Qiagen, Switzerland) as described in Morf et al. (2021).

Microsatellite genotypes for Capreolus capreolus

CSV file which contains original individual genotypes

README_roe_deer_genotypes