Recent research in nature reserve Laarder Wasmeren, close to Hilversum, has led to new insights with regard to the use of large herbivores in nature management in the Netherlands. Physical geographers and paleoecologists of the UvA Institute for Biodiversity and Ecosystem Dynamics have discovered that characteristic Dutch drift sand landscapes originated earlier than previously assumed, as far back as 10.000 years ago.These findings have resulted in an alternative hypothesis: that instead of large herbivores, forest fires are the main cause of open forests and drift sands.
Drift sands in the Netherlands are a special type of ecosystem that belong to the characteristic higher, dry sand landscapes. The prevailing theory is that these drift sands originated because of high grazing pressure, burning and sod cutting since the late Middle Ages. However, earlier research in nature reserve Laarder Wasmeren had already indicated that the link between sand drifting and intensive premodern agriculture was less strict than assumed, revealing that sand drifts already occurred centuries before the earliest forms of agriculture (4000 B.C.).
Recent research by the University of Amsterdam and Wageningen UR in Laarder Wasmeren revealed an unexpected result: sand drifts appear to have occurred much earlier, as far back as 10.000 years ago (early Holocene). As Jan Sevink, emeritus professor in Physical Geography at the UvA, explains, ‘This means that sand drifts occurred thousands of years before the introduction of agriculture. Moreover, it turned out that in that early period – the Mesolithic or Middle Stone Age – forest fires occurred repeatedly, apparently damaging soil and vegetation in such a way that soil degradation and sand drift occurred.’
The Laarder Wasmeren is the first area in the Netherlands where indications have been found of these very early sand drifts and forest fires. Research in other European countries has shown that these forest fires were deliberately lit by Mesolithic hunters-gatherers, to create open vegetation and an increase of common hazels, as hazelnuts were an important source of preservable food. This probably also applies to the Laarder Wasmeren and other dry sand areas in the Netherlands.
The hypothesis that in the Mesolithic open forests were the result of forest fires lit by humans offers an alternative hypothesis to that of Frans Vera, which states that forests in the Mesolithic were open due to the grazing of wild large herbivores. The theory put forward by Vera, who is seen as one of the most influential nature conservationists in the Netherlands after the Second World War, forms the basis for the experiment with large herbivores in the Oostervaardersplassen and the introduction of highland cattle in many other nature reserves.
This research, published in the scientific journal Catena, shows that, instead of large herbivores, the main cause of open forests and sand drifts were probably human-lit forest fires. This new hypothesis is strengthened by archeological research that already indicated that settlement by Mesolithic hunter-gatherers and intensive grazing by large herbivores do not go together well. Sevink: ‘Our hypothesis, in which human-lit fires are the cause of prehistorical sand drifts, therefore forms an interesting alternative and forces us to take a new look at current nature management practices.’
Jan Sevink, Bas van Geel, Boris Jansen, Jakob Wallinga (2018). ‘Early Holocene forest fires, drift sands, and Usselo-type paleosols in the Laarder Wasmeren area near Hilversum, the Netherlands: Implications for the history of sand landscapes and the potential role of Mesolithic land use’ in: Catena. https://doi.org/10.1016/j.catena.2018.02.016