Climatic change, and with it changes in melt season duration, snow and rainfall and thermal balance are expected to cause changes in the surface water environments which in turn will have an impact on sediment budgets and their dynamics in these cold environments.

The current volume presents a set of nine reviewed papers presented at the fourth ESF Sediflux meeting and the first IAG-workshop of the IAG-Working group SEDIBUD at Trondheim in 2006. The papers of this issue deal with supraglacial debris systems, the spatial scale of glacial weathering and its impact on landscape evolution, hydrogeomorphological characteristics and fluvial sediment transport of a high mountain river, matter fluxes in small tundra lakes, sediment budget and morphodynamics of alpine talus cones at different time scales, changes of sediment budget under accelerating global change conditions.
A study of on mass transfers, sediment budget and relief development in a catchment in Swedish Lapland and an evaluation of detailed geomorphological mapping as a potential basis for sediment flux assessments conclude the volume.

Geomorphic systems in cold environments are characterised by a high sensitivity with respect to environmental changes. Understanding and predicting changes of sediment fluxes in response of environmental impacts is not straight forward due to the lagged and off site responses of geomorphic systems, reflecting the structure and the connectivity of their compartments. Studies of sedimentary sources-to-sink-fluxes and sediment budgets provide a platform to analyse the impact of environmental changes on geomorphic responses. The I. A. G./ A. I. G. (International Association of Geomorphologist) Working Group SEDIBUD (Sediment Budgets in Cold Environments) addresses these issues in the ZfG-Supplementary Issue 1 “Sedimentary Source-to-Sink-Fluxes and Sediment Budgets in Changing Cold Environments”, which contains nine papers and posters presented at the Fourth ESF – SEDIFLUX Science Meeting and the first I. A. G./A. I.G. SEDIBUD Working Group Workshop at Trondheim, Norway, from Oct 29th to Nov 2nd 2006.

In the first paper Beylich et al. (p. 1–2) provide a short overview concerning the main issues and central research questions of the SEDIBUD-Working Group. A map with the 37 sites, which are currently part of the SEDIBUD-network, would have been appreciated to identify the spatial distributions of these case studies.

Kellerer-Pirkelbauer (p. 3–25) presents results on the spatial distribution, characteristics and transport of supraglacial tills at the Pasterze Glacier (Austria). The spatial distribution of the debris cover was analysed based on topographic maps and orthophotos since 1964. In conjunction with velocity data measured between 1970 and 2006, the author was able to estimate a six fold decrease of debris transport. This decrease was caused by declining flow velocities of the glacier, which overbalanced the increase of the debris cover.

Dixon et al (p. 27–49) discuss the controlling factors of chemical weathering in Kärkevagge (Sweden) and their influence on landscape evolutions. The authors consider geological, hydrological, biological and climatological controls on five different scales: the micrometer, millimeter, centimeter, meter and kilometer scale. Therefore, they are able to identify sources of, and controls on dissolved loads at different scales. This paper presents important conceptual considerations on the nature and to a lesser extend on the rates of chemical weathering. Extending these considerations to rates of chemical weathering will establish a better understanding of sediment budgets in cold climate regions.

Morche et al (p. 51–77) investigates the hydrogeomorphological characteristics and fluvial sediment transport in the Reintal Valley (Bavarian Alps, Germany). The authors measure the hydraulic geometry and grain size along the Partnach River in combination with a sediment budget approach (overbank storage and sediment yield) applied to an extreme discharge event in 2005, which caused large amounts of sediment input into the channel due to bank failures and debris flows. The debris flow and therefore the coupling between hillslopes and channels during extreme events interrupted the general downstream fining of the river bed sediments that is characteristic of selective sorting of fluvial sediment transport.

Zwolinski et al (p. 79–101) measured the hydrological, hydrochemical and sedimentological properties of tundra lakes of the Petuniabukta coast (Central Spitzbergen), which are subjected to strong environmental changes. Based on their measurements, the authors suggest a conceptualization of input, transformation and output of water, solutes and sediments during seasonal cycles. Unfortunately, this paper lacks a statement regarding sedimentary sourceto- sink fluxes and sediment budgets in changing environments.

Heckmann et al (p. 103–121) present the results of a sediment budget analysis and discuss the internal controls of the morphodynamics of an alpine talus cone. Similar to the contribution of Morche et al (p. 51–77), their study site is also located in the Reintal (Bavarian Alps, Germany). The authors assess the changes of a dissected talus cone, which was affected by channel incision and gullying during the 2005 discharge event. On the timescale of the 2005 flood-event, Heckmann et al. use geodetic measurements to estimate the eroded volumes. On a decadal scale, they reconstructed debris flow activity based on orthophotos, which indicate a strongly intensified activity since 2003. However, based on the interpretation of a historical map from 1815 and an interpolation of recent debris flow rates, the authors suggest that the dissection of the talus cone by debris flows started already ~150 years ago as a consequence of internal reorganization within the talus system (changes in catchments size) rather than external climatic changes.

Slaymaker (p. 123–148) highlights the importance of sediment budgets to evaluate the impacts of climate and humans on geomorphic systems in cold environments. He proposes a classification of cold environments based on relief and ice into classes of polar ice caps, glaciered high relief, non-glaciered high relief and low relief tundra. In spite of the large variability of sediment fluxes within these classes, the classification is characterised by larger differences between these classes. Based on a listing and a description of sources of error in sediment budgets, Slaymaker concludes that a strong focus on sediment storage helps to reduce the degree of uncertainty and to increase the knowledge of complex response and landscape resistance.

The contribution of Beylich (p. 149–197) presents a sediment budget for the 9 km2 sized Latnjavagge catchment (Swedish Lapland) based on the monitoring of recent denudational processes (gravitational hillslope processes, debris flows and fluvial sediment yield). The monitoring, which started in 1999, provides an impressive data set on the relative importance of different processes. While creep/solifluction and rock/boulder falls transfer the largest amount of volumes, the fluvial transport dominates in terms of mass transfer, which includes the averaged transport distance of each process. Similar to the results of Morche et al. (p. 51–77), fluvial solute transport significantly overbalances suspended sediment yield and bed load transport. The results suggest a low postglacial modification of the glacial relief due to low denudation rates and a limited hillslope-channel coupling.

Nygaard & Kolstrup (p. 199–210) introduce a geomorphological mapping system and present a geomorphological map of the Vattholma test area (E Sweden), which covers an area of about 8 km2. While the authors discuss the potential application of their mapping system, they unfortunately do not discuss the advantages and disadvantages compared to existing geomorphic mapping systems.

The ZfG-Supplementary Issue 1 contains a collection of case studies of the I. A. G./ A. I.G. SEDIBUD Working Group and presents comprehensive data from cold environments on a hot topic. The presented case studies cover a broad range of geomorphic processes, methods, spatial and temporal scales and will offer a solid data basis to asses the impacts of climate change on arctic and alpine environments. However, besides the individual case studies more integrating research efforts (compare Slaymakers contribution) and integrated sediment flux models are necessary.

Thomas Hoffmann, Bonn

Zeitschrift für Geomorphologie vol. 54, 1