Human Impact on Historical Fluvial Sediment Dynamics in Europe

by

Gert Verstraeten

• LAST REVIEWED: 30 October 2019
• LAST MODIFIED: 30 October 2019
• DOI: 10.1093/obo/9780199363445-0122

Introduction

Rivers and floodplains are dynamic environments formed through hydrologic and geomorphic processes that are in turn governed by environmental conditions in the river catchment, such as climate, tectonics, lithology and soils, vegetation cover, and topography. At longer timescales, river landscapes are in a state of dynamic equilibrium with these controlling factors. However, over the last few thousand years, humans have become another important factor in controlling fluvial-landscape dynamics that in many regions has now overwhelmed the importance of natural controlling factors. This is in particular true for many river catchments in Europe that have a long history of human impact. Anthropogenic changes in land cover (e.g., deforestation and the rise in agriculture) have resulted in increased rates of hillslope erosion and amounts of sediment delivered to river systems. As a result, many floodplains have witnessed increased rates of aggradation. Furthermore, these changes also led to the development of typical anthropogenic fluvial landscapes. In temperate Europe, rivers often changed from anastomosing channels in wetland environments to single-thread meandering rivers with levees and overbank deposits. In Mediterranean Europe, many river valleys also became silted up, creating more-extensive, relatively flat valleys. With the increasing industrialization and urbanization of Europe since the 19th century, but also through the implementation of erosion control measures, many regions experienced a greening of the landscape and a return to less erosive land cover. Several rivers, often in mountainous environments, saw again a reduction in sediment loads and river incision and a return in fluvial style. Humans also impacted European river systems through direct interventions such as mining of river sands and gravel, damming of rivers, artificial straightening, or the hunting and later reintroduction of river-engineering animals such as the beaver. Changes in floodplain sedimentation and floodplain ecology following human impact also affected the amount of carbon sequestered and buried within European floodplains.

General Overviews

Numerous case studies on past erosion and sediment dynamics in relation to human-induced land cover changes have been performed across Europe since the late 20th century. This wealth of local information has been synthesized in a few review papers that address the spatial and temporal variability in human impact on river systems and the relative importance of human versus climatic impacts on fluvial-system dynamics. Many of these review studies have a strong regional focus whereby it is clear that large differences in impact-response can be seen between Mediterranean Europe and more-temperate regions in northwestern and central Europe. Both Bintliff 2002 and Butzer 2005 challenge older studies that focus on either climate or humans in controlling fluvial systems (see Vita-Finzi 1969 and Van Andel, et al. 1986, both cited under Pioneer Studies). They both stress the importance of multicausal drivers of changes in river systems and urge for interdisciplinary research. Dusar, et al. 2011 and Bellin, et al. 2013 provide a synthesis of data for the Eastern and Western Mediterranean regions, respectively, and corroborate the findings of Bintliff 2002 and Butzer 2005. For drier regions in the Mediterranean, the sensitivity to climate change is much higher and also internal feedbacks in the river system can be important, thereby obscuring the relation with human impact. This is different for temperate Europe and in particular for western and central Europe, where human impact on fluvial systems throughout the Holocene increases until it becomes the dominant driver of change. For temperate Europe, Zolitschka, et al. 2003 is one of the first reviews stressing the different responses of colluvial, fluvial, and lacustrine environments toward human and climatic impact. More information on changes in hillslope erosion throughout the Holocene for central Europe is provided in Dotterweich 2008, whereas Notebaert and Verstraeten 2010 provides a synthesis for rivers in northwestern and central Europe. The authors show that humans impacted mainly the rates of erosion and sedimentation but that changes in fluvial stability or morphological changes are also controlled by climatic changes. Foulds and Macklin 2006 comes to similar conclusions for the United Kingdom and Ireland. Hoffmann, et al. 2010 synthesizes information on fluvial-system dynamics to identify major research needs with respect to human interactions in fluvial systems.

• Bellin, N., V. Vanacker, and S. De Baets. 2013. Anthropogenic and climatic impact on Holocene sediment dynamics in SE Spain: A review. Quaternary International 308–309 (2 October): 112–129.

  This review of high-resolution paleoenvironmental studies analyzes how Holocene sediment dynamics can be related to regional climate histories, and changes in land cover and human occupation for southeastern Spain. It shows that for these semiarid environments there is no straightforward relation either between human impact or climate change and geomorphic dynamics.

• Bintliff, J. 2002. Time, processes and catastrophism in the study of Mediterranean alluvial history: A review. World Archaeology 33.3: 417–435.

  DOI: 10.1080/00438240120107459

  Provides an important contribution to the longstanding debate on the respective role that humans and climate played in shaping Mediterranean river valleys. Emphasizes the importance of multicausal explanations and interactions among the environment, climate, and human impact to explain the observed changes in alluvial landscapes.

• Butzer, K. W. 2005. Environmental history in the Mediterranean world: Cross-disciplinary investigation of cause-and-effect for degradation and soil erosion. Journal of Archaeological Science 32.12: 1773–1800.

  DOI: 10.1016/j.jas.2005.06.001

  Critically reviews the notion that Mediterranean environments are degraded due to long-term, intense human impact, and calls for more cross-disciplinary research to examine cause-effects relations with respect to ecological changes, including soil erosion and stream (in)stability. Uses examples from Greece and southern Spain.

• Dotterweich, M. 2008. The history of soil erosion and fluvial deposits in small catchments of central Europe: Deciphering the long-term interaction between humans and the environment—a review. Geomorphology 101.1–2: 192–208.

  DOI: 10.1016/j.geomorph.2008.05.023

  Provides a detailed review of more than forty studies focusing mainly on soil and gully erosion in smaller catchments, but also discussing its impact on nearby fluvial systems in central Europe, including Belgium, the Netherlands, Germany, Poland, the Czech Republic, and the Slovak Republic.

• Dusar, B., G. Verstraeten, B. Notebaert, and J. Bakker. 2011. Holocene environmental change and its impacts on sediment dynamics in the eastern Mediterranean. Earth-Science Reviews 108.3–4: 137–157.

  DOI: 10.1016/j.earscirev.2011.06.006

  Synthesizes information on Holocene paleoenvironmental changes for the eastern Mediterranean region (Greece, Turkey, Cyprus, Levant) and discusses the temporal dynamics of various sedimentary systems (soil, floodplains, coastal environments). Provides a conceptual framework of changes in sediment dynamics and driving factors. Also discusses the main challenges in identifying the causes of changes in sedimentary systems and the shortcomings of existing studies.

• Foulds, S. A., and M. G. Macklin. 2006. Holocene land-use change and its impact on river basin dynamics in Great Britain and Ireland. Progress in Physical Geography 30.5: 1–16.

  Critically reviews the sensitivity of Holocene land use on hillslope and floodplain stability for the United Kingdom and Ireland. Highlights that there is little evidence that anthropogenic activities led to fluvial instability, largely due to a lack of secure dating control. Argues that a better understanding of catchment sensitivity is needed to know the role of land use change.

• Hoffmann, T., V. R. Thorndycraft, A. G. Brown, et al. 2010. Human impact on fluvial regimes and sediment flux during the Holocene: Review and future research agenda. Global and Planetary Change 72.3: 87–98.

  DOI: 10.1016/j.gloplacha.2010.04.008

  Reviews studies and methods that enable a determination the natural status of river systems as well as the quantification of human-environment interaction in fluvial systems. Proposes key research strategies to increase our understanding on human-riverine interactions and to link this knowledge to river basin management for the future.

• Notebaert, B., and G. Verstraeten. 2010. Sensitivity of West and central European river systems to environmental changes during the Holocene: A review. Earth-Science Reviews, 103.3–4: 163–182.

  DOI: 10.1016/j.earscirev.2010.09.009

  Synthesis research on fluvial sedimentation histories from various western and central European countries (i.e., from France to Russia), thereby focusing on changes in fluvial (in)stability as well as changes in rates of floodplain aggradation. Discusses that while climate had an impact on changes in fluvial activity, rates of sedimentation are mainly linked to land use.

• Zolitschka, B., K. E. Behre, and J. Schneider. 2003. Human and climatic impact on the environment as derived from colluvial, fluvial and lacustrine archives—examples from the Bronze Age to the Migration period, Germany. Quaternary Science Reviews 22.1: 81–100.

  DOI: 10.1016/S0277-3791(02)00182-8

  One of the first studies that synthesizes information from various colluvial, fluvial, and lacustrine sediment archives at regional scales (here, Germany). It also stresses the need for multiproxy approaches, including archaeological and paleovegetation proxies, to understand the role that humans have played in controlling sedimentary systems.