Late Quaternary Beetle Faunas of Southwestern Alaska: Evidence of a Refugium for Mesic and Hygrophilous Species

Abstract

Recent investigations of fossil insect assemblages from 11 late Quaternary sites in the southwestern Alaska region of Eastern Beringia demonstrate the survival of an abundant mesic to hygrophilous beetle fauna in this refugium before, during, and after the last glacial interval. These faunas contrast sharply with late Quaternary fossil insect assemblages described from interior and northern sites in Eastern Beringia, where xeric and steppe-tundra species dominated regional faunas. Proximity of southwestern Alaskan to maritime sources of moisture may have played a role in the development of a refugium for mesic and hygrophilous species by maintaining wet habitats even through the last glaciation.