Historische landschapsecologie van Noordoost-Twente
|PhD ceremony:||ir. H. (Harm) Smeenge|
|When:||October 15, 2020|
|Supervisors:||prof. dr. ir. M. (Theo) Spek, prof. J.H.J. Schaminée|
|Co-supervisor:||dr. A.J.M. Jansen|
|Where:||Academy building RUG|
In this thesis, I have tried to develop an interdisciplinary research method that combines ecology, cultural history and earth sciences into a coherent analysis and reconstruction of landscape development. This study shows that profound physical-geographical change processes took place in the Late Paleolithic period, Iron Age, Middle Ages and modern period, largely as a result of human activity since the Iron Age. This also means that natural processes were still occurring in many places from the Late Paleolithic period to the Bronze Age and that, between the Neolithic period and the Bronze Age, people had an impact on the ecosystem only at a local level. From the Iron Age onwards, there are indications that changes occurred at the river basin level and that local effects were compounded as a result of erosion and sedimentation processes. Ecosystems disappeared from the Middle Ages onwards (as a result of deforestation, sod cutting and drainage), while drainage and reclamation in the modern period created a ‘makeable’ landscape, in which features of historical ecosystems have been preserved to only a limited extent. One profound change is that agricultural practices resulted in immense diversity from prehistory to the early modern period, but have moved in a new direction since the twentieth century. Current social developments offer excellent opportunities for restoring the millennia-old connection between people and nature.
An important added value over established research methods is that this method is better able to explain geological, ecological and cultural historical developments. Various studies rely far too readily on general assertions and explanations that are poorly substantiated (e.g. ‘it became colder, wetter, it was the plague, wild grazing, the introduction of agriculture’). While all these factors played a role in the picture that I present, their impact differed significantly in each location because of regional differentiation. By applying the new landscape model, we have looked at the landscape from three perspectives, which has often led to much stronger process factors being identified. Supraregional developments such as population growth, the advent of agriculture and the introduction of plaggen agriculture had regional consequences for landscape formation. In various cases, local factors such as the construction of water mills, the building of a castle and the transportation of sandstone were the dominant influences.
This new historical landscape ecological approach is a useful method for understanding both contemporary and historical ecosystems. The major advantage of this approach over traditional landscape ecology is that it utilizes more disciplines and spans a much longer period of time. This broader approach produces a picture of what type of nature arose within a particular area, showing how this nature developed through interaction between earth and people and identifying the ecological turning points over time. This has the significant added value that we are able to assess with far greater accuracy whether the current conservation objectives in the area are achievable and what measures will be most effective when it comes to solving today’s problems of biodiversity loss and climate change.Because this methodology is costly and time-consuming, it is important to estimate in advance which of its research aspects are necessary. In addition to an overall desk study involving easy-to-consult open sources, a field visit – preferably with the parties involved or the necessary experts – is invaluable. Clearly, a low investment of this kind will save considerable time and expense in the follow-up process, as it means that assignments can be fulfilled in a more targeted fashion. This thesis reveals that more extensive research is recommended in high-value landscapes or nature reserves in order to maintain and bolster the balance between geological, ecological and cultural historical values. In current practice, an overly sectoral and focused approach can sometimes inadvertently detract from the layeredness of the landscape because researchers think and work on too high a scale or level of abstraction, and in doing so, overlook the local variation in values.