During the interglacial period from 132,000 to 110,000 years ago, dung beetle fossils abounded, which implied plenty of unshaded, treeless territory. Giant animals likely served as natural landscapers in this ecosystem. During the interglacial period, more than half of the sites examined by the study held beetle species found in mixed woodland and pasture landscape.
After 110,000 years ago, ice conquered Europe once again, then re-thawed approximately 15,000 years ago. However during the warm period from 10,000 to 5,000 years ago, there were few dung beetles, possibly because another species had moved north as the glaciers retreated.
Modern Homo sapiens migrated north as they hunted elephants. That predatory pressure from humans may have stopped the lumbering landscapers from pruning the edges of the forest, suggested the authors of the PNAS study. In this period, called the early Holocene, forest beetle species dominated more than half of the sites.
ANALYSIS: Humans Acquitted of Mammoth Murder