Roe deer population trend after reintroduction of Eurasian lynx within the Palatinate Forest: a first insight into a long-term study

After becoming extinct approximately 250 years ago in the Palatinate Forest, the first Eurasian lynx (Lynx lynx) were reintroduced within this area in 2016, with 20 lynx reintroduced in the following five years. We observed the roe deer population within the Palatinate Forest before (2016) and during (2017–2019) the lynx reintroduction by estimating the population and evaluating the hunting bag. The roe deer population estimation based on the distance sampling method was conducted on ten defined transects with an average length of 48 km from 2016 to 2019, observing a 6,000 km transect length for 120 nights overall. An average of 6.54 ± 1.28 roe deer km-² was estimated over the course of the four years (2016 – 2019). Since we suspect that our estimations might underestimate the roe deer population within the Palatinate Forest, hence we preferred to use the roe deer count index for further analysis. Over the first four years (2016–2019), significant differences were neither found in the roe deer count index nor for the hunting bag in relation to the reintroduction of the lynx. The data and findings presented in this study provide a first insight into a long-term observation of a predator-prey system within the Palatinate Forest, with roe deer not having experienced a natural predator over a long time. In order to make coherent interpretations, long-term data is needed to estimate the population trends of both species within the Palatinate Forest.