Arno Kleber

Stratification of the Regolith Continuum – a Key Property for Processes and Functions of Landscapes

Regolith may be regarded as a continuum, but has a pronounced internal structure (stratification). It is thus a key element controlling processes, properties, and functions of landscapes. However, so far research has focused mainly on regolith genesis and only few investigations explicitly deal with the relationship between regolith structure and site/landscape properties. The need to deal with environmental problems at landscape scale has increased substantially the demand for the investigation of the regolith continuum and its internal structure. Stratification of regolith is a ubiquitous phenomenon not only affecting properties of soils and sites, but also of landscapes. The effects of regolith structure on (i) depth functions of soil properties, (ii) slope hydrology, and (iii) vulnerability against erosion will be shown. The aim of this contribution is to point out the vital position of regolith within landscape ecosystems and to stress the need for an interdisciplinary regolith science emphasizing a geo-hydro-ecological approach.

Influence of Cover Beds on Slope Hydrology

Abstract Numerous case studies carried out in the subdued mountains of Germany during the last decades have revealed that periglacial cover beds play a decisive role in hillslope hydrology. Considering the omnipresence of cover beds in sloped terrain of the mid-latitudes, knowledge of slope-water paths is crucial not only for flood forecast but also for understanding how contaminants pass through ecosystems. Since periglacial cover beds are usually composed of different sedimentary layers, they show a high spatial variability of physical soil parameters, which are, in turn, responsible for small-scale variations of the hydraulic properties. Regardless of bedrock type, the observations reported in this chapter from different regions lead to the conclusion that there is a clear relationship between subsurface layering and runoff-generation processes. The hydraulic anisotropic structure of the deepest (basal) layer is the major factor controlling subsurface water-flow paths. On one hand, this layer acts as an aquitard for seeping water because of its high bulk density. On the other hand, once water has percolated into this layer, it is able to flow in lateral directions because of the coarse clasts oriented parallel to the slope. Therefore, such a cover bed may be treated neither as an aquifer nor as an aquiclude. Besides, as a function of pre-moisture, a nonlinear runoff response to precipitation or snow-melt of the investigated catchments was identified.

Heavy-mineral analysis as a tool in tephrochronology, with an example from the La Sal Mountains, Utah, U.S.A.

Abstract An essentially pure tephra layer on a steep slope in the La Sal Mountains, Utah, U.S.A., is correlated with the 1.65 Ma old Guaje Tephra derived from the Jemez Mountains, New Mexico, U.S.A. The heavy-mineral contents and glass shards in sediments beneath the La Sal tephra layer indicate that tephra constituents are contained in deposits considerably older than the pure layer. This suggests that tephra material may become reworked while retaining its pure character, possibly due to laminar transport or to dislocation in a frozen condition. This raises the need to handle tephrochronological findings with great care.

Effect of Sky Lark plots and additional tramlines on territory densities of the Sky Lark Alauda arvensis in an intensively managed agricultural landscape

ABSTRACT Capsule: Sky Lark plots and additional tramlines increase Sky Lark Alauda arvensis territory densities in winter crops. Aims: To analyse the effects on Sky Lark territory density of Sky Lark plots and additional tramlines in winter cereals and oilseed rape. Methods: We mapped Sky Lark territories on fields with Sky Lark plots or additional tramlines as well as on adjacent control sites, from 2010 to 2013 in Saxony, Germany, where agricultural land use is intensive, dominated by winter-sown crops and takes place in large fields. Results: In test sites with Sky Lark plots, 5.6 and 3.1 territories per 10 ha were found in the early (April/May) and late periods (June/July) respectively, compared to 3.3 and 1.4 territories per 10 ha in control sites. Sky Lark territory densities in fields with additional tramlines were 1.6 times higher in the early period (4.2 versus 2.6 territories per 10 ha) and 2.2 times higher in the late period (3.6 versus 1.6 territories per 10 ha). Conclusion: Sky Lark plots and additional tramlines improve large fields for the Sky Lark and have the potential to increase the Sky Lark population.