Large mammals were architects of prehistoric ecosystems
Researchers' studies on fossil dung beetles has shown that large mammals were the chief architects of prehistoric ecosystems.
Researchers from Denmark demonstrate in a study that the large grazers and browsers of the past created a mosaic of varied landscapes consisting of closed and semi-closed forests and parkland.
The biologists behind the new research findings synthesized decades of studies on fossil beetles, focusing on beetles associated with the dung of large animals in the past or with woodlands and trees.
Their findings reveal that dung beetles were much more frequent in the previous interglacial period (from 132,000 to 110,000 years ago) compared with the early Holocene (the present interglacial period, before agriculture, from 10,000 to 5,000 years ago).
Postdoctoral fellow Chris Sandom said that one of the surprising results is that woodland beetles were much less dominant in the previous interglacial period than in the early Holocene, which shows that temperate ecosystems consisted not just of dense forest as often assumed, but rather a mosaic of forest and parkland.
Professor Jens-Christian Svenning said that large animals in high numbers were an integral part of nature in prehistoric times.
He said that the composition of the beetles in the fossil sites tells us that the proportion and number of the wild large animals declined after the appearance of modern man. As a result of this, the countryside developed into predominantly dense forest that was first cleared when humans began to use the land for agriculture.
The study has been published in journal PNAS (Proceedings of the National Academy of Sciences of the United States of America).
(Posted on 04-03-2014)