The role of the montane water vole (Arvicola scherman) as a crop pest in NW Spain: since when?

61 The montane water vole, Arvicola scherman (Shaw, 1801), mainly inhabits meadows, grasslands and fruit orchards (Giraudoux et al. 1997, FichetCalvet et al. 2000) of the main mountainous areas of Europe (Kryštufek et al. 2015 and reference therein). This species lives underground in extensive burrow systems (Airoldi 1976), consuming both epigeic and hipogeic parts of plants (Airoldi 1976, Kopp 1993). Due to its relatively high energy demand, each individual should daily ingest the equivalent of its body mass in food (Quéré 2009). As a consequence, important damage to grasslands, fruit orchards (apple, cherry, plum and pear trees) (Meylan 1977, Somoano et al. 2016) and annual crops (Braña 2001) can occur, but also damages to kiwi trees and grass silages may be observed (Somoano 2017). Additionally, vegetation is covered by earth mounds because of its activity, which interferes with farming practices (Meylan 1977). It was as a result of first records of A. scherman in NW Spain when agricultural damages produced by this species were well described (García-Dory 1974, Noval 1976, 1981, Nores 1986). The first study on A. terrestris (read A. scherman) reported its presence in the Cantabrian Mountain range (Niethammer 1964). Shortly after, a study of barn owl (Tyto alba) pellets from Picos de Europa (Heim de Balsac & Beaufort1 969) verified the existence of established populations of this species in Asturias, Cantabria and Galicia. By the same methodology, A. scherman was revealed to occur in a relatively wide distribution in Asturias (Braña 1974, Nores 1989). Also in 1970s, Garzón-Heydt et al. (1971) and Gosálbez (1976) detected this species in mountains of Los Ancares (Galicia) and in southern Cantabrian Mountain range (Castilla y León) respectively. However, it could be probably that crop damages caused by A. scherman in Cantabrian mountain range had been historically well-known by farmers before the species was described (García-Dory 1974). The presence of montane water voles in the NW Iberian Peninsula goes back to the Mousterian (Middle Palaeolithic, about 39,110 years BP) as showed the dentitions of several specimens found in Cueva del Conde, an archaeo-palaeontological deposit located in Asturias (Lopez-García et al. 2011). In Upper Paleolithic, this species seemed to be present along NW coastal Spain, from Donostia to at least Oviedo (García-Ibaibarriaga et al. 2013). Nevertheless, there seems to be no information on agricultural damages caused by montane water voles until the beginning of the XVII-century. In that sense, the first reported case encountered to date which suggests crop losses arguably caused by montane water voles occurred in uplands from Villaviciosa (Asturias) between 1616 and 1622 (Fig. 1). The author, Gaspar de Villarroel (1738), mentioned an overabundance of mice that cut down the fruit trees and crops, with negative consequences for farmers. It is worth noting that, far from applying demographic control practices, protective measures were accomplished under the guidelines of clergy, upholding mice rights as animals of God. The agricultural activity developed since prehistory in this geographic area would have propelled the substitution of deciduous forests by meadows (Díaz-Maroto 2009), whereas most natural grasslands were restricted to elevated areas The role of the montane water vole (Arvicola scherman) as a crop pest in NW Spain: since when?