Long-term decline of the European wild rabbit (Oryctolagus cuniculus) in south-western Spain

The European wild rabbit (Oryctolagus cuniculus) is a species native to the Iberian Peninsula, where it was once extremely abundant. It is considered the most important prey item for the peninsula's assemblage of Mediterranean vertebrate predators, which includes two endangered specialist rabbit feeders, the Spanish imperial eagle (Aquila adalberti) and the Iberian lynx (Lynx pardinus). However, rabbit population trends in Spain have not been accurately documented. In the present study, we analysed trends in a population of European rabbits monitored over 23 years in the Donana National Park, home to one of the most diverse and densest predator communities in Europe. Rabbit abundance and population trends were estimated using roadside counts. Results show that the rabbit population declined sharply by similar to 60% during the first wave of epizootic rabbit hemorrhagic disease (RHD) in 1990. Since then, rabbit numbers have declined at a relatively constant rate and the species has become progressively scarcer in the area. The current population is less than 10% of that before the arrival of RHD. However, after the RHD epizootic we observed increasing intra-annual population recruitment. We hypothesise that density-dependent factors caused by enzootic viral diseases (myxomatosis, RHD) and higher predation of rabbits are the main factors preventing recovery of rabbit numbers. The effects of a decline in the prey species on the ecology of sympatric rabbit predators are discussed, and measures to improve ongoing rabbit conservation efforts are suggested.