Demographic plasticity in an invasive species: time since invasion and population management of beavers in Tierra del Fuego, Argentina

GONZÁLEZ CALDERÓN, A; ESCOBAR, J; DEFERRARI G; SCHIAVINI,A

JOURNAL OF ZOOLOGY (1987)

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2023 vol. 319 p. 175 - 187

0952-8369

The beaver (Castor canadensis), an invasive species in the Tierra del Fuego archipelago since 1946, impacted severely different environments in a way that the eradication is tested as a management alternative. We assessed how vital rates of beavers were affected by the time since invasion and by the population management history (lethal control). We built vertical life tables and compared the survivorship, age-specific survivorship, generation time, and life expectancy for different landscapes and management histories, from 922 beavers massively removed as part of an eradication pilot program conducted between 2016-2018 in seven pilot areas of the Isla Grande de Tierra del Fuego, Argentina. Areas with long-term occupation, areas without hunting pressure and areas previously cleared of beavers presented higher survivorship, generation time, and life expectancy. Areas where beavers were managed, presented lower life expectancy and generation time, and advanced age at first reproduction. Beavers showed demographic plasticity both in relation to time since invasion (vital rates consistent with populations close to carrying capacity in areas with low or null management), as well as with management histories (vital rates in managed areas similar to those from managed populations at their native range). We give management implications from the demographic perspective, for a future eradication-control program of beavers. We also highlight the relevance of landowners in shaping beaver demography for the future management of the species. In the end, beaver demography reacts dynamically and rapidly to local removal, challenging management outcomes based on the removal of beavers.