Alexander Fülling

The influence of historic land-use changes on hillslope erosion and sediment redistribution

Agricultural societies around the world have dramatically altered the natural landscape, particularly through accelerated soil erosion. The expansion of agricultural land use into steeper headwater areas during the Medieval period in central Europe is known to have caused large increases in soil erosion and sediment redistribution downstream. Although land-use practices changed and improved following this initial impact, it is currently unknown whether changes in land-use techniques also improved hillslope soil erosion and sediment redistribution rates. In this paper, we use a variety of techniques, including chrono-stratigraphy, wood charcoal analysis and a geostatistical model, to reconstruct land-use and erosion rates for the period spanning the Medieval Period to the present (1100–300 years ago) in a small headwater catchment in central Europe. Coupling land-use, hillslope erosion and sediment redistribution fluxes, we find the largest flux change occurs because of the initial deforestation at the beginning of the Medieval Period (1100 years ago). Following deforestation, we identified three main types of land-use techniques that were practised between ~1100 and 300 years ago: Horticulture, cropping agriculture and rotational birch silviculture, the last of which represents the earliest evidence for this practice found in central Europe to date. However, we find only small differences in hillslope fluxes throughout the catchment despite the variable land-use techniques employed. This is because the land-use techniques primarily influenced and increased the hillslope sediment storage capacity rather than erosion rates directly, which is an important distinction to consider for future work attempting to link changes in human land use and hillslope erosion.

The formation of alluvial fans and young floodplain deposits in the Lieser catchment, Eifel Mountains, western German Uplands: A study of soil erosion budgeting

This study deals with the exploration and spatiotemporal quantification of the young Holocene, nearly skeleton-free floodplain sediments of the Lieser River, a tributary of the Mosel River in the Eifel Mts. The deposits are primarily a consequence of anthropogenic-triggered soil erosion in the catchment. To observe the phenomenon of corresponding soil erosion on multiple levels two small alluvial fans of tributary catchments were investigated. For comparison, one location in the neighboring Salm valley was described. The results were compared with those of other streams. With extensive fieldwork more than 100 drillings and pits were made at 12 locations. For dating the sediments OSL dating, 14C dating of organic contents and archaeological artifacts were used. In the floodplains of the Lieser and its tributaries, 35.1 × 106 t of overbank fines are stored. To achieve this, an average soil erosion of 61.4 mm in the whole catchment would have been necessary. About 28% of young floodplain sediments in upper and lower course were deposited before ad 1000. However, prehistoric deposits could not be positively proven. Only 18% of floodplain sediments were deposited between ad 1000 and 1320 (early and high Middle Ages) and 54% during late Middle Ages and early Modern Time (ad 1320–1850), respectively. The thickness of floodplain sediments is mostly independent of the valley gradient. The largest sediment thickness (> 5 m) was found by drilling in the upper reaches. However, a part of this could be dated to the early Holocene. In the narrow middle reaches, the maximum thickness of the skeleton-free deposits was only 1.2–2 m. The average thickness of the floodplain sediments rose again in the depression of Wittlich up to 2.4 m. The formation of the investigated small fans was quite different. Sedimentation occurred within limited periods as a result of single events.

Evolution of an Upper Pleistocene aeolianite in the northern Mediterranean (Liguria, NW Italy)

Based on a 19th century scientific report, a recent geological survey has highlighted the presence of a complex, mostly Aeolian deposit along the coast of Liguria (Laigueglia, Savona Province, NW Italy). This finding was recognized to be a relevant palaeoclimatic marker, being the northernmost aeolianite outcrop ever reported from the Mediterranean Basin. The investigated deposit is spread along a steep sea-facing slope from 2-3 m up to almost 60 m a.s.l.; it is strongly reworked due to recent urbanization of the area. Its stratigraphic features were recognized thanks to its exposure in different sections and analysed in order to obtain reliable indications on the sedimentary environments. Facies analysis suggests that the sedimentary body is a relict cliff-top dune evolved on top of a foreshore deposit in temperate-cold and moist climate conditions. Two samples from the upper, strictly aeolian part of the sequence were subjected to OSL (Optically Stimulated Luminescence) dating and yielded an age consistent with its deposition during the Marine Isotopic Stage (MIS) 5.2 and 5.1 substages (88-83 and 83-71 ka). This paper contributes to the increase of the number of Upper Pleistocene coastal aeolianites accounted for in literature. Being located at the northern border of the occurrence of aeolianites in the northern Mediterranean, it helps to outline climatic and environmental boundary conditions for the formation of this type of deposit.