Ecological Impact of Wild Boar in Natural Ecosystems

Introduction The presence of wild boar (Sus scrofa) (also known as feral pigs or wild hogs), in many ecosystems of the globe, has raised concerns about the impacts of this species on agriculture, collisions with vehicles, and because of the expected strong impact on wild ecosystems and biodiversity. Problems are exacerbated where this species is alien or in insular ecosystems where the presence of wild hogs can be devastating. Several review papers have focused on different aspects of the ecology of wild boar in native or introduced populations (Massei & Genov 2004; Barrios-Garcia & Ballari 2012; Bengsen et al. 2014). With respect to ecological/biodiversity impacts, Barrios-Garcia and Ballari (2012) have set the scene. This species has a native distribution ranging from the tropical region of Asia to Siberian forests, including semi-desertic and temperate ecosystems. The possibility of colonizing this large ecological range is probably linked to the particular life-history traits of the species, which is characterized by high population turnover, a peculiar pattern of elasticity of demographic parameters (Servanty et al. 2011), and resilience in the face of predation and harvest (Gamelon et al. 2012). Its demographic strategy appears atypical among ungulates of similar size and with similar sexual dimorphism. Focardi et al. (2008) suggested that these features are linked to its diet because wild boars consume other animal species when available, by scavenging or actively preying upon both vertebrates and invertebrates. So it is not a big surprise that the wild boar was able to invade many different habitats in America and Australia, while high predation risks or interspecific competition appear to have reduced its capacity to colonize African ecosystems. Barrios-Garcia and Ballari (2012) noted that most of research was devoted to negative impacts, but they also pointed out some examples of positive effects on biodiversity. It is not worth repeating arguments well developed in the existing literature. Previous researches have clearly pointed out that wild boar can be considered an ecosystem engineer. According to Jones et al. (1997), 'physical ecosystem engineering by organisms is the physical modification, maintenance, or creation of habitats'. It is important to note that 'trophic interactions and resource competition do not constitute engineering'.