Range expansion of nonindigenous caribou in the Aleutian archipelago of Alaska

• Published in: Biological invasions Vol. 14; no. 9; pp. 1779 - 1784
• Main Authors: Ricca, Mark A., Weckerly, Floyd W., Duarte, Adam, Williams, Jeffrey C.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.09.2012; Springer Nature B.V
• Subjects: Animal migration; Animal populations; Archipelagoes; Biodiversity; Biomedical and Life Sciences; Caribou; Developmental Biology; Ecology; Freshwater & Marine Ecology; Invasion Note; Islands; Life Sciences; Nonnative species; Plant Sciences; Rangifer tarandus; Summer; Wildlife conservation; Ocean crossing; Dispersal; Immigration; Emigration; Reindeer; Invasive; Swim
• ISSN: 1387-3547; 1573-1464
• DOI: 10.1007/s10530-012-0195-z

Caribou ( Rangifer tarandus ) are nonindigenous to all but the eastern-most island of the Aleutian archipelago of Alaska. In 1958–1959, caribou were intentionally introduced to Adak Island in the central archipelago, and the population has at least tripled in recent years subsequent to the closure of a naval air facility. Although dispersal of caribou to adjacent islands has been suspected, no historical documentation has occurred to date. Herein, we report consistent detections of caribou sign on the adjacent island of Kagalaska over 2 summer field seasons (2010–2011), and visual detection of caribou on that island during the summer of 2011. Ecological impacts of caribou on Kagalaska are not strongly apparent at the present time and we do not know how many animals permanently occupy the island. However, establishment of a reproductively viable resident population on Kagalaska is worrisome and could set the stage for a step-wise invasion of additional nearby islands.