The impact of prehistoric agriculture and land occupation on natural vegetation.

Paleoecological and paleoethnobotanical evidence from Europe and North America indicates that prehistoric human populations affected the biota by: (1) changing the dominance structure within forest communities; (2) extending or truncating the distributional ranges of both woody and herbaceous plant species; (3) providing opportunities for invasion of ruderals into disturbed areas, with their subsequent population expansions as they became weeds; and (4) changing the pattern of the landscape mosaic, especially the proportion of forested to nonforested land.