The rise and fall of wild boar in a northern environment: Evidence from stable isotopes and subfossil finds

Abstract

Here we use long-term data from Holocene archaeological bone assemblages in order to investigate how changes in climate, vegetation and human land use might have influenced the distribution of wild boar (Sus scrofa) in Norway during the Holocene. We combine four lines of evidence: an analysis of stable isotopes of carbon and nitrogen in a time series of subfossil teeth, distribution data of bone finds from 31 archaeological sites, changes in the relative abundance of wild ungulates from four of these sites and historical documents. A significant change in Sus diet, indicated by δ¹⁵N levels, was found. This coincided with the spread of agriculture and indicates a change from wild boar to domestic pigs. Based on this finding the distributional data show that the Norwegian wild boar was limited to the coastal broadleaved forests even during the most optimal climatic period. A reduction in the relative abundance of wild boar, and later extinction, seems to coincide with a reduction in such habitat, caused partly by climatic change but more pronouncedly by human habitat alterations, and competition with domestic animals. The data indicate that the primary factor limiting the northern distribution of wild boar is the availability of food resources.