Holocene land-use evolution and associated soil erosion in the French Prealps inferred from Lake Paladru sediments and archaeological evidences

A source-to-sink multi-proxy approach has been performed within Lake Paladru (492 m a.s.l., French Prealps) catchment and a 6-m long sediment sequence retrieved from the central lacustrine basin. The combination of minerogenic signal, specific organic markers of autochthonous and allochthonous supply and archaeological data allows the reconstruction of a continuous record of past human disturbances. Over the last 10,000 years, the lacustrine sedimentation was dominated by autochthonous carbonates and the watershed was mostly forest-covered. However, seven phases of higher accumulation rate, soil erosion, algal productivity and landscape disturbances have been identified and dated from 8400 to 7900, 6000 to 4800, 4500 to 3200, 2700 to 2050 cal BP as well as AD 350–850, AD 1250–1850 and after AD 1970. Before 5200 cal BP, soil erosion is interpreted as resulting from climatic deterioration phases towards cooler and wetter conditions. During the Mid-Late Holocene period, erosion fluxes and landscape disturbances are always associated with prehistorical and historical human activities and amplified by climatic oscillations. Such changes in human land-used led to increasing minerogenic supply and nutrients loading that affected lacustrine trophic levels, especially during the last 1600 years. In addition, organic and molecular markers document previously unknown human settlements around Lake Paladru during the Bronze and the Iron Ages.     

An assessment of blanket mire degradation and Peatland Gully development in the Cheviot Hills,Northumberland

This paper provides the first systematic assessment of blanket mire degradation in the east Cheviot Hills, Northumberland. The extent of erosion is mapped over a 32 km² area of peat. Erosion affects 37% of the blanket peat. Erosion forms consist of anastomosing (7%), linear (21%) and dendritic (9%) gully systems together with peat slides (<1%). Topography is the primary influence on gully system pattern. Spatial variations in gully form can be partly explained by position in the stream network (stream order) and local variations in the depth of peat. A sequential scheme of gully development is described. Gullies evolve initially through a phase of rapid downcutting to the peat base, followed by lateral erosion and gully widening becoming dominant through a process of roughly parallel wall retreat. As gully width increases re‐deposition of peat occurs and re‐vegetation occurs on the gully floor. Comparative photography reveals that gully patterns have been stable over the past 32 years and in some areas for over 70 years. It is possible that gully systems in places are in excess of 500 years old.     

Lake Dwellings in Baden-Württemberg. Conservation Projects In Situ at Lake Constance and the Federsee Moor

The Baden-Württemberg shoreline of Lake Constance and the lakes and moors of Upper Swabia contain important prehistoric wetland sites. From 1979, new research has brought up not only important finds and scientific results but also increasing information about bank erosion in the lakes and desiccation in the moorlands. At Lake Constance, early attempts were made in the 1980s to protect sites threatened by erosion by covering them with geo-textile and gravel. With further protective projects the know-how improved, but crucial questions still remained: What are the best practical solutions? How about ecological compatibility? Do we have other options? The INTERREG IV 2008–2011 international project ‘Erosion and Archaeological Heritage Protection in Lake Constance and Lake Zurich’ brought deeper insights and opened the field for new experiments with protective measures. At the Federsee Moor a long-term project started in 1980 with close collaboration between nature conservation and archaeological heritage management. With archaeological stocktaking, acquisition of land, establishment of new nature reserves, exchange of landholding and hydrographic engineering, the project was completed with the help of European Union funding by LIFE+in 2013.     

Laboratory Experiments as Support for Development of In Situ Conservation Methods

Abstract

Within the EU-Project BACPOLES (EVK4-CT-2001-00043) bacterial wood degradation could be simulated in laboratory experiments to investigate the living conditions of the up to now unknown bacteria consortia, named erosion bacteria (EB), which cause considerable decay on waterlogged archaeological wood. In these Microcosm (MC) experiments the role of oxygen and chemical composition of the sediment were investigated. Therefore, the microcosms were subjected to different gassing treatments and the free dissolved oxygen was measured in different depths of the microcosms by special oxygen sensors (optodes). In further experiments the chemical composition of the sediment was verified to investigate the influence of different nutrient concentrations to the degradation process by EB.

From the findings it can be concluded that bacterial wood decay can proceed without free oxygen present but that it is more intense if oxygen is available. A water flow like streams in the sea, simulated by vertical water circulation, seems to stimulate the degradation activity and the degradation of wood by EB seems to be a result of low nutrient levels in the surrounding area.     

The Role of Fire Disturbance on Runoff and Erosion Processes – a Long‐Term Approach,Mt. Carmel Case Study,Israel

The Mediterranean ecosystem of Mt. Carmel, Israel, is subjected to an increasing number of forest fires of various extents and severities. The impacts of forest fires on runoff and erosion are widely documented and include increased peak flows and soil loss until the return of a vegetation cover. Most studies, however, treat fire as a single event, whereas the present study is aimed at exploring the long‐term effects of repeated forest fires on eco‐geomorphic processes. The study integrates the results of plot‐based, detailed analysis of post‐fire runoff and erosion with vegetation recovery analysis, at a temporal‐spatial scale which includes the effect of reburning. Our results indicate that forest fires lead to a significant increase in runoff and sediment yields, particularly during the first two years following the disturbance, up to five orders of magnitude higher than from the adjacent unburnt control plots.     

Post-depositional surface whitening of ceramic artifacts: alteration mechanisms and consequences

Surfaces on ceramic artifacts that are paler than the main sherd body are commonly interpreted as slips that were intentionally applied by the potter during the manufacturing process. However, due to post-depositional alteration, sherds that were not originally coated with a slip may macroscopically appear with deceptively similar pale surfaces. This paper presents a comparison of two sherds, both with pale to white surfaces, one of which is a real slip and the other a surficial corrosion that occurred during the burial stage. Observations using optical and scanning electron microscopy, as well as electron-probe image- and microanalysis, clearly illustrate the features of the two surfaces, as well as demonstrating their causes and effects. The superimposed slip is clearly delimited from the sherd body by a denser and much finer-grained fabric, in which clay minerals predominate and porosity is reduced by about 20% compared to the body. In the other sample, surface corrosion, due to invading fluids, has led to leaching of calcareous constituents and results in a remarkable increase in porosity close to the rim (ca. 25%). Sometimes called the “espresso crema effect” (Tschegg et al., 2009b), the surface becomes considerably brighter than the core and can easily be confused with intentional slips. This, as a consequence can lead to significant misinterpretations, to erroneous sherd characterizations and classifications, as well as to incorrect assignments to specific ware groups.     

Estimation of Soil Erosion Using Field and Modelling Approaches in an Undisturbed Arnhem Land Catchment,Northern Territory,Australia

An assessment of slope erosion at Tin Camp Creek catchment, Arnhem Land, Northern Territory, Australia, was carried out using the fallout environmental radioisotope caesium‐137 (¹³⁷Cs) as an indicator of soil erosion status, two numerical models (SIBERIA and the Revised Universal Soil Loss Equation (RUSLE)) and erosion pins. This undisturbed drainage basin is situated in the seasonally wet‐dry tropics, with high energy storms and a mean annual rainfall of 1389 mm. Tin Camp Creek catchment is unaffected by European agriculture or pastoral activities, but often experiences fire during the dry season. Two transects were sampled for ¹³⁷Cs in 2002 and 2004, and two models were used to convert ¹³⁷Cs measurements into soil loss estimates. Two methods using the theoretical Profile Distribution Model (PDM) gave net soil redistribution rates between +2.72 and –22.19 t ha^?1 yr^?1 and +2.95 and –24.06 t ha^?1 yr^?1, respectively, while an Australian empirical model (AEM) for uncultivated soils produced estimates between +1.84 and –7.00 t ha^?1 yr^?1 (negative values indicate soil erosion, positive, deposition). The RUSLE gave estimated soil losses for the two transects of approximately 10 t ha^?1 yr^?1, while the SIBERIA model produced values between 0.5 and 2 t ha^?1 yr^?1 for the transects and between 3.5 and 11 t ha^?1 yr^?1 for the total catchment. Average net soil losses of 14 and 15 t ha^?1 yr^?1 for the total catchment and slopes, respectively, were measured by erosion pins. The soil losses in the catchment are similar to those for some other transects in the Northern Territory and the Kimberley region of Western Australia (measured by the ¹³⁷Cs AEM), even though these areas are affected by pastoral activities. This may be at least partly explained by erosion in Tin Camp Creek catchment during high intensity rainstorms at the commencement of the wet season, especially if the slopes have been affected by fire during the previous dry season.     

土遗址病害的评估体系研究

土遗址病害评估是对土遗址进行科学保护、管理、利用的一项基础性工作,但土遗址病害评估的体系还没有建立。为此,通过对土遗址病害的分析,借鉴地质工程、岩土工程的相关理论和方法,采用逐次分析的方法评估土遗址的载体和本体病害,探讨了土遗址病害评估体系。通过研究认为,可以从地质灾害、稳定性、表面风化三方面对土遗址病害程度进行评估。地质灾害和稳定性有其它学科相对成熟的理论和方法可以借鉴和采用。表面风化评估应考虑到风化剥蚀速率、遗址保存程度和文物价值三个方面,引进风化度和文物价值权重系数的概念,利用模糊数学原理对表面风化的危险程度进行综合评估是一种新思路。     

陕北明长城夯土密度与雨蚀破坏的量化研究

为量化研究夯土性质对陕北明长城遗址雨蚀破坏模式的影响作用,采用室内模拟降雨试验的方法对夯土密度和雨蚀量间的关系进行定量化分析。研究结果显示,大到暴雨条件下,干湿作用产生的破坏是低强度夯土(密度1.5 g·cm^-3、1.6 g·cm^-3)最主要的雨蚀破坏模式,冲刷破坏造成的雨蚀量较小;水力侵蚀产生的冲刷破坏和重力侵蚀引起的小范围掉块是高强度夯土(密度1.7~1.9 g·cm^-3)最主要的破坏模式,冲刷破坏造成的雨蚀量较大;当土体含水率在3%~7%区间时,夯土的雨蚀量和密度呈指数函数关系,二者呈现正相关性。研究结果为探索多因素作用下夯土雨蚀的破坏机制提供方法借鉴,是土遗址病害研究的重要组成部分。