Wild carnivore occurrence and models of hunting yield abundance at European scale: first models for red fox and badger

Abstract

The goal of this report is modelling the occurrence for carnivores at the European scale and to compare the output of occurrence with observed hunting yield (HY) density models for red fox (Vulpes vulpes) and badger (Meles meles). Random Forest function was used for modelling occurrence of species. Occurrences available from the past 30 years (1990-2020), and HY data (period 2012-2021) from records submitted to ENETWILD were considered for modelling. Like previous models based on HY for ungulates, the response variable was the maximum number of carnivores hunted in that period divided by the area in km2 of the corresponding administrative unit (HY density). Models based on HY were statistically downscaled to make predictions to 10x10 km2. Occurrence data models indicated a good predictive performance for most species, showing that the model framework proposed for ungulates can also be applied for carnivores. Realistic distribution maps of carnivore species were achieved under this framework, except for those ones which are expanding their range, the golden jackal (Canis aureus), or those considered alien species, raccoon (Procyon lotor) and raccoon dog (Nyctereutes procyonoides); or those having a very limited distribution as the Iberian lynx (Lynx pardinus) or the steppe polecat (Mustela eversmanii): in those cases the obtained models were underestimating their suitability in Europe. Suitability has potential to be used as a proxy for abundance of red fox and badger. Validation of suitability on HY suggested the potential to be used as a proxy for abundance of red fox and badger but depending on each species. The calibration plots for HY models showed a good and linear predictive performance for fox and badger as well as an expected pattern of abundance of species, according to the data. However, differences in type of hunting and regulations in game carnivores between countries must be playing an important role in the patterns obtained. We conclude that (i) the framework developed for modelling ungulates distribution generally well fit to carnivores species, (ii) the predicted suitability were realistic for all carnivores, but alien invasive species, limited distributed species and species expanding its range, and (iii) HY model projections displayed good abundance patterns for red fox and badger, showing that the frameworks proposed for wild ungulates were a good approximation for modelling the distribution of carnivores HY. As a future step, we need to explore how to improve the results when the unavailability of hunting activity for some species limits the extrapolation to other regions.