The Origin and Affinity of the Biota of the Kodiak Island Group, Alaska

Abstract

Kodiak Island occupies an important biogeographical position. Situated along the northwestern border of the Gulf of Alaska, this island and its neighboring lesser islands have biogeographic relationships that radiate in three directions: westward along the Aleutian Islands, northward toward interior Alaska, and southeastward toward the temperate Pacific Coastal and Rocky Mountain regions of North America. The Aleutian and Bering Strait migration routes tend to funnel through this strategic area. Furthermore, the Island Group was probably severely glaciated during at least the later part of the Pleistocene. Karlstrom (1%0) found geological evidence of a small late Pleistocene refuge on southwestern Kodiak Island. Nearly all subsequent biota, besides that which may have persisted on the refuge or on nunataks, would have had to originate as reinvaders from adjacent land or sea areas. A third peculiar feature in addition to location and glacial history is the possible significance of major habitat change caused by an encroaching timber line across the northeastern part of Kodiak Island.