Understanding the impact of wild boar on the European wild rabbit and red-legged partridge populations using a diet metabarcoding approach

Abstract

European wild rabbit (Oryctolagus cuniculus) and red-legged partridge (Alectoris rufa) are main small game species of conservation concern in Mediterranean ecosystems. To date, their presence in wild boar’s (Sus scrofa) diet and factors driving their consumption have been little investigated. A genetic metabarcoding approach was used on 80 wild boar faeces collected from four hunting estates devoted to small game hunting during two different seasons. Abundances of wild boar, rabbits and partridges were first estimated. Results showed DNA of seventeen chordate species. The highest frequency of occurrence (FO) corresponded to mammals and birds, with 77.6 and 22.3%, respectively. DNA of game species was detected in 39/71 (FO = 55.0%) samples, highlighting the presence of European wild rabbit in 27 (FO = 38.0%) and red-legged partridge in eight (FO = 11.3%). Dietary composition varied between seasons and estates, being rabbit the main responsible (explaining 35.26% and 39.45% of differences, respectively). Rabbit FO in the diet was positively related to the abundance of wild boar and rabbit density on the estate. It was greater in autumn and in estates where rabbits were hunted. Regarding red-legged partridge, a significant and positive relationship between its population density and its diet FO was observed, without significant differences between seasons or estates. Overall, our results suggest wild boar as an opportunistic species whose diet is largely determined by the relative availability of different food resources. Its ecological role concerning small game species in Mediterranean agroecosystems seems to be more related to consumption of carrion during the hunting season than to direct predation.

Using DNA metabarcoding to separate natural and human provided food in wild boar diet at the northern distribution range of Europe

“…There were signs of 'accidental bycatch' taxa being consumed during foraging, as many microscopic soil fungi, rotifers and tardigrades were detected, but are unlikely to represent significant energetic components of the wild boar diet. In addition, while wild boar can exhibit scavenging behaviour (Carpio et al 2023), the samples used in this study were provided by hunters, and we cannot unequivocally determine if the presence of commonly harvested taxa like roe deer, red deer, and moose represent cadaver consumption or if DNA from these species was introduced from hunting implements previously used in the harvest of these species. Similarly, the detection of salmon in eight individuals at proportional abundances < 2% could represent foraging of human garbage by wild boar, or may represent low level laboratory contamination, as samples were handled in a lab that routinely also isolates DNA from salmon.…”