Rodenticides now ubiquitous in wildlife of Italian landscapes

Jacopo Cerri , Carmela Musto, Annalisa Santi, Dario Capizzi, Patrizia Bassi, Giuseppe Merialdi, Giovanni Pupillo, Silvia Rubini, Caterina Siclari, Gianluca Rugna, Camilla Torreggiani, Luisa Loli Piccolomini, Elena Faggionato, Chiara Anna Garbarino

Second Generation Anticoagulant Rodenticides (SGARs) are used to control synantropic rodents and therefore also affect non-target wildlife. However, no study tested for their presence across a whole assemblage of wildlife, limiting our understanding of their overall circulation and exposure pathways. We tested for SGARs in a large sample of terrestrial mammals (n = 403) and birds (n = 189), that were recovered in Northern Italy. Species included herbivores, facultative scavengers as well as small, medium and large predators. Almost all small carnivores, owls, diurnal raptors, mesocarnivores and large carnivores tested positive to at least one SGAR. We also detected SGARs in non-target rodents, such as the crested porcupine (Hystrix cristata), the coypu (Myocastor coypus), the edible dormouse (Glis glis) and the red squirrel (Sciurus vulgaris). Our findings indicate that SGARs could now be widespread between different mammals and birds in Europe. While early studies pinpointed their presence in predators, we detected them in different functional groups, including facultative scavengers and herbivores. This exposure also affects areas with limited human settlements. This pervasive exposure to SGARs can potentially destabilize interspecific relationships, such as prey-predator dynamics, and have cascading effects on ecosystems. It is therefore necessary to estimate its demographic impacts on target and non-target species, while also implementing rules i) restricting the use of SGARs to professional pest control operators, ii) obliging competent authorities to monitor their application, selectivity and circulation in the food chain and iii) prioritizing alternative measures under an integrated pest management framework.