Shifting Baselines and the Conservation of Non‐Native Species

Abstract

The shifting baseline syndrome occurs because humans adapt the notion of healthy ecosystems to the characteristics of contemporaneous environments, either because of an inefficient intergenerational transmission of knowledge or the deformation of personal memories (Pauly 1995; Papworth et al. 2009). In altered systems, the shifting baseline syndrome may lead to constant downgrading of environmental reference conditions (Pauly 1995). Introductions of non-natives species by humans have occurred for millennia. Cultural traditions tend to embrace newly introduced organisms progressively, by attributing to them the values originally associated with native species (Trigger et al. 2008; Schuttler et al. 2011). This cultural integration represents a form of shifting baseline syndrome, through which the new species are included in the assumed normal or desirable state of natural systems (Speziale et al. 2012). Consequently, if these widely accepted introduced species decline, societies may feel compelled to restore them. For example, the European Habitats Directive mandates the protection of the European mouflon (Ovis orientalis musimon), introduced to Corsica and Sardinia (Poplin 1979), and the porcupine (Hystrix cristata), introduced to Italy (Masseti et al. 2010), whereas in Australia there are initiatives to reintroduce dingoes (Canis lupus dingo) in areas from which the species had been extirpated (Allen & Fleming 2012). Already introduced, established species can be threatened by newly introduced ones (e.g. Carpentier et al. 2007). When the former are valued species the shifting baseline syndrome may be manifested in a clear preference toward the species that was introduced first. These processes are illustrated here with 2 examples from Spain, showing how societies may promote the control or eradication of introduced species with the aim