March 4, 2014
Fossilized Dung Beetles Reveal Link Between Prehistoric Herbivores And Vegetation Diversity
redOrbit Staff & Wire Reports - Your Universe Online
Analysis of fossilized dung beetles has revealed that prehistoric temperate ecosystems were comprised not just of dense forest, but a mosaic of closed forest and wood-pasture vegetation, according to new research appearing in the March 3 edition of the Proceedings of the National Academy of Sciences.In the study, researchers from the Aarhus University Department of Bioscience and Natural History Museum Aarhus reviewed decades of research on fossil beetles, focusing specifically on those associated with the dung of large animals in the past or with trees and woodland environments.
They discovered that beetles associated with herbivore dung were better represented during the previous interglacial period (from 132,000 to 110,000 years ago, prior to the arrival of humans) than with the present interglacial period (the early Holocene, the period pre-dating agriculture, from 10,000 to 5,000 years ago).
“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,” study author and postdoctoral fellow Chris Sandom said in a statement Monday.
“Large animals in high numbers were an integral part of nature in prehistoric times. 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,” added Professor Jens-Christian Svenning.
As a result, the landscape developed into primarily dense forest that was not cleared until humans started using the region for agricultural purposes, Svenning and his co-authors noted. Following the loss of that vegetation, large herbivores were typically less abundant, causing closed woodland to be more prevalent in the early Holocene.
“An important way to create more self-managing ecosystems with a high level of biodiversity is to make room for large herbivores in the European landscape – and possibly reintroduce animals such as wild cattle, bison and even elephants,” senior scientist Rasmus Ejrnæs said. “They would create and maintain a varied vegetation in temperate ecosystems, and thereby ensure the basis for a high level of biodiversity.”
The research was funded in part by the 15 June Foundation and a grant from the European Research Council, and according to Aarhaus University, it advocates the expanded use of the rewilding-based nature management approach in European nature policy, particularly when it comes to national parks and other large ecological reserves.
Image 2 (below): Dung beetles are associated with sun-exposed, dung-rich habitats that are well represented in interglacial beetle assemblages. Examples are Copris lunaris (A) and Onthophagus vacca (B), with (C) their modern habitat (Røsnæs, Denmark). Credit: Morten D.D. Hansen