Chelonoidis chilensis (Chaco tortoise). Predation

KUBISCH, ERIKA; ECHAVE, MARIA EUGENIA; ECHAVE, LUIS ALBERTO

HERPETOLOGICAL REVIEW

Herpetological review

Año: 2014 vol. 45 p. 684 - 685

0018-084X

Chelonoidis chilensis is the southernmost continental tortoise in the world (Cei 1986), Reptiles del Centro, Centro-oeste y Sur de la Argentina. Herpetofauna de las Zonas Áridas y Semiáridas Museo Regionale di Scienze Naturali, Mongr, 4, Torino, Italy). It is distributed from southwestern Bolivia and Western Paraguay to northern Chubut, Argentina ( Richard 1999. Tortugas de las Regiones Áridas de Argentina, L.O.L.A., Buenos Aires, 200 pp). This especies is threatened by reduced availability of suitable hábitat due to agricultural expansion of the Espinal and Chaco forest, which are replaced by crops or ranching. Other threats include competition with sheep and goats (Prado et al. 2012, Cuad. Herpetol. 26:375-387), soil compaction by livestock (degrading tortoise nesting sites ) (Waller and Micucci 1997, In J. Van Abbema [ed.], Proceedings: Conservation, Restoration and Management of Tortoises and Turtles- An International Conference, pp. 2-9. New York Turtle and Tortoise Society, New York); fires set to promote the regrowth of pasture (Richard 1999, op. cit.), and the illegal pet trade, as this species is the most traded native reptile in Argentina. This species is included on Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) and is considered to have a conservation status of Vulnerable by the IUCN (The IUCN Red List of Threatened Species. Version 2014.2. www.iucnredlist.org, accesed 07 August 2014). During the juvenile stage, this species is especially vulnerable to attack by natural predators such as ferrets, skunks, small cats, Tupinambis lizards, and many species of birds. Adults have fewer natural predators, which include foxes, Cougars, and Crowned Eagles (Chebez 2008, Fauna Argentina Amenazada 1:219-231). Here we report evidence of predation of C. chilensis by Wild Boars (Sus scrofa) in a natural environment located 45 km N of San Antonio Oeste, Rio Negro Province, Argentina (40º.396ºS, 64.750ºW. datum WGS84; elev. 125 m). Since the introduction of the Wild Boar in La Pampa Province in the early twentieth century (Jaksic et al, 2002. Biol. Invasions 4:157-173), the Wild Boar population has expanded and become established in a variety of enviroments, and currently inhabits al least nine provinces of Argentina. In the study site, the presence of Wild Boar increased since 1972 with the construction of the Pomona Channel (pers. Obs.), built to supply drinking water to San Antonio Oeste. Until that time, adult tortoise shells found were always intact. In constrast, following the stablishment of Wild Boar at the site, we now find shells of adult tortoises with the plastron opened indicative of attack by Wild Boars. We can include the Wild Boar as another potential threat to the Chaco Tortoise and urge that the presence of Wild Boar be considered during the development of strategies and priority actions to conserve this vulnerable species.