Erosion Through Time: Causes and Consequences

Eine komplexe Grafik, welche räumliche und zeitliche Dimensionen von Bodenerosion und damit verbundenen Sedimenten darstellt / A complex graphic illustrating temporal and spatial relations of soil erosion and corresponding sediments
Geo-ecosystems are shaped by alternating phases of landscape stability and erosion. Climatically induced ecosystem degradation and anthropogenic impacts on the landscape system are among the major causes of erosion. Soils form from surficial rocks and sediments in stable ecosystems, but may be eroded as a result of changes within the landscape system. The cluster studies landscape development that occurred from the last glacial period until today.

Erosion has shaped landscapes throughout the earth’s history; since a few millennia, human activities have been identified to be a major cause. Soil erosion is a rather silent and often underrated problem of global relevance. In addition to its central function within ecosystems and the water-, carbon-, nitrogen cycle, soil is the basis for food production. Past societies and their excessive land use, like the Mayas in Central America, exemplify impressive and complex human-environment interactions. Soil loss is almost irreversible, because the transformation of rock to soil is magnitudes slower than measureable soil erosion. Furthermore, most soils worldwide contain products of earlier phases of erosion and do not solely consist of in situ weathered rock. Within applied erosion research, this factor is inadequately accounted for and unrealistically high soil neoformation rates are assumed. The cluster “Erosion Through Time: Causes and Consequences” unites scientists from the units Paleo-Geoecology, Soil Science, Remote Sensing and Sustainable Land Management and aims to combine fundamental research on soil formation with applied research on soil erosion. The understanding of past climate and land use changes plays a central role within this integrated framework.

Beispielfotos von Erosionsformen / photographic examples for erosion forms
Left: Small-scale erosion in a soy field in SW-Brazil. Right: Large-scale erosion in volcanic deposits in Central Mexico (photos: T. Sprafke)

The aim of the cluster is to develop an integrated model to effectively describe mutual relationships of past and present soil genesis and erosion. Experience from applied erosion research, including socioeconomic consequences, is combined with fundamental research on past erosion and soil genesis, with varying influence of natural processes and human influences. Within this complex framework, we want to gain a better understanding about the following aspects:

  • The modern soil-landscape geosystem and the influence of land management and climate change
  • The role of past erosional processes on current soil properties
  • Contemporary measured erosion rates compared to estimates from (pre)historic archives of erosion (colluvia, lake sediments)
  • Natural vs. anthropogenic causes of erosion (archives with/without human influence)
  • The consequences of current and past erosion for natural systems and societies

Soil formation, erosion and accumulation are cyclical processes related to environmental conditions, and have been strongly influenced by humans since millennia. The cluster “Erosion Through Time” focuses on three phases from the Last Glacial Maximum until today.

  • I - From the Late Pleistocene to the Early Holocene, characterized by profound climate and landscape changes
  • II- From the onset of agriculture to the early modern period, characterized predominantly by human induced erosion
  • III - Modern soil erosion with the possibility to work with direct observations, measurements and mitigation strategies
Fotos von Archiven vergangener Erosion und rezente Erosion / photos illustrating archives of past erosion and present erosion forms
I: Tropical hillwash in Cameroon. Profound climate shifts and landscape changes during the Late Pleistocene and Early Holocene resulted in widespread erosional products, which constitute the parent materials for present-day soils (cover beds, loess, hillwash). II: Soil sediments in Lower Austria. Forest clearance and agricultural activity have a fundamental impact on the landscape system. Bare soil is eroded and accumulates downslope as colluvial deposits. III: Recent soil erosion on the Swiss Plateau. Modern erosion is measurable and visible events may help to improve the general awareness towards the necessity of soil protection (photos: H. Veit, T. Sprafke, T. Lemann)

Soil erosion is a topic of global relevance. While the “Erosion Through Time” cluster is not restricted to a specific study area, there are two main regions of interest.

  • Central Europe, especially Switzerland. The region is studied intensively, with a relatively high local awareness of present soil erosion. It is home to the Geographical Institute and its group of researchers. The integration of fundamental research on soil genesis and applied research on soil erosion and socio-economic consequences are just beginning.
  • In the tropics, quaternary landscape development and pedogenesis, as well as past human influences on erosion and present day soil distribution are still poorly understood. There is the need to increase general awareness about soil erosion and its associated challenges. Furthermore, the integration of fundamental and applied research can still be improved upon.
Fotos von Feldern mit Bodenschutzmassnahmen / Photos of agricultural fields and erosion measures
Left: Potato field in the Swiss Plateau after treatment with a dyker, to minimize soil erosion. Right: Soil protection terraces in SW-Brazil (photos: T. Lemann, T. Sprafke)

The “Erosion Through Time” cluster has a chronological structure, with methods adapted to the respective modules

Grafik über die Untersuchungsmethoden in Abhängigkeit von Zeitskala und Disziplin / Graphic illustrating the relevant methods in relation to temporal scale and scientific discipline
Methods to study causes and consequences of natural and anthropogenic erosion from the past to the present (T. Sprafke)

Cluster coordination

Unit Leaders

You can find several courses related to the cluster and its respective units within the CTS (core teaching system). The following courses are particularly relevant:

Bachelor studies

  • Paleosols, sediments and Paleolimnology (Veit, Grosjean) - every HS
  • Paleo II - every FS
  • Ecology of Tropical and Subtropical Areas (Veit) - every HS

Master studies

Regularly:

  • Challenges in Geography II (e.g. Veit, Grosjean) - every FS
  • Colloquium in paleo-geoecology (Veit, Sprafke) - every semester
  • Sustainable Land Management and Land Systems (e.g. Ifejika, Messerli, Liniger)

Only HS 2017:

  • Archaeological, geomorphological and soil-scientific aspects of a late glacial settlement in the Swiss Midlands (Moosbühl, Magdalenien). (Nielsen-Bigler, Veit, Hafner)

Master theses

Running master theses

  • Manuel Schläpfer: Bodenentstehung, -nutzung und –erhaltung in der Region Frienisberg (BE). Supervisors: Sprafke, Lemann

Topics for master theses

  • Soil genesis and -erosion in South Cameroon
  • Soil erosion in South Nigeria

Bachelor theses

Topics for bachelor theses

  • Soil genesis and distribution in the Region Frienisberg (BE).
  • Loess distribution in Switzerland - literature and reality.

 

Topics customized to personal interests that fall within the scope of the cluster’s domain are also welcomed. If you are interested, just send a message to Tobias Sprafke. We look forward to hearing from you!