Landscape-level impact and habitat factors associated with invasive beaver distribution in Tierra del Fuego

J HENN; CB ANDERSON; G MARTÍNEZ PASTUR

BIOLOGICAL INVASIONS

SPRINGER

Lugar: Berlin; Año: 2016

1387-3547

Understanding the amount of impact anddistribution of invasive species is important for bothbasic ecological research and making managementdecisions. Because of their extensive impacts insouthern Patagonia, invasive North American beavers(Castor canadensis) are considered both a scientificand conservation priority. However, little is knownabout the landscape-scale effects of these exoticecosystem engineers. Using satellite imagery, weestimated the impact of beavers in the Argentineportion of Tierra del Fuego Island and determined thehabitat factors (vegetation cover, forest type, streampresence and topography) related to their presenceusing both non-parametric statistical and informationtheoreticapproaches. Results indicated that more than31,000 ha (1.6 % of the study area) were impacted bybeavers and that the presence, but not the amount, ofbeaver impacts were spatially clustered. Impacts weregreater in the Mountain ecoregion (2.8 % of theecoregion) and lower in the Steppe (0.1 %). The bestmodel for predicting beaver presence included variablesrelated to water availability (presence of peatlandsand streams), forage availability (forest typecover), and topography (slope and elevation). Thesefindings support previous assertions that this invasionis the largest alteration to the sub-Antarctic forests inthe Holocene. They also serve as a foundation for thedevelopment of maps based on habitat- and landscapescaleconditions to assist with the orientation ofcontrol, eradication, and restoration efforts currentlybeing planned.