When Processes Meet Events: Late Holocene Degradation and the Collapse of Temperate Forest Ecosystems
Abstrakt
This chapter aims to show that collapse dynamics can be a part of natural processes at landscape level. To illustrate this phenomenon, we chose an example of the transformation of forest communities in prehistory.
During 2nd millennium BC, productive, nutrient-rich broadleaf deciduous forests, which formed at the end of the Older Holocene, and which survived relatively steadily over the Middle Holocene, came to sudden decline in Central Europe. "Modern" types of less productive and nutrient-poor beech, fir and pine forests have replaced them. The working hypothesis, which has succeeded in supporting rich documents, points to a natural change in connection with the progressive depletion of the ecosystem through decline in biologically active mineral compounds.
It is the same kind of development that was characteristic of the temperate ecosystems of our planet during all previous interglacial stages of the Quaternary. Nutrients, especially biologically active forms of phosphorus, have arrived to the ecosystems in the form of a wind-transported dust during the loess accumulation phase of the Last Ice Age.
The humid and warm Holocene climate, which has been acting for many millennia to soil substrates enriched with this wind-transported dust, has resulted in progressive soil degradation due to the successive loss of nutritive compounds; surface acidification thus resulted in a retrogressive soil and biological successions. Against the backdrop of such gradual controlling climatic and related geochemical processes, numerous biotic and abiotic events can be observed - forest fires, windswept occurrences, erosion, immigration and expansion of new organisms.
Were also people responsible? To answer this question, a comprehensive environmental-archaeological research has been conducted in the Czech Republic. Indeed, correlations suggest that people really could participate in the changes, especially through logging and nomadic animal herding.