Anthropogenic pressures on coastal dunes, southwestern Newfoundland

Sand‐dominated coastlines backed by transverse foredunes, dome dunes, and parabolic dunes occur at several sites along the coastline of southwest Newfoundland, extending from Sandbanks Provincial Park (Burgeo) to Grand Bay West (Channel‐Port‐aux‐Basques) and north to J.T. Cheeseman Provincial Park. The coastal dunes developed during the mid‐Holocene in response to enhanced sediment availability and flux, coupled with effective sediment retention. Under present environmental conditions, development of aeolian dunes is hindered. Recent changes in the geomorphology of these coastlines provide evidence of the impact of anthropogenic activity. Differing time scales of both weather/climate events and landform response complicate interpretation. Anthropogenic modification, both intentional and accidental, represents a locally dominant geomorphic influence, and these dunes have evolved rapidly in response to anthropogenic pressure coupled with storm events. Changes in the southwest Newfoundland economy have led to increased interest in tourism, and consequent pressure on the sandy coastlines and backing dunes. Increased anthropogenic utilization of the coast for recreational purposes, both by residents and tourists, and limited offshore winter ice and onshore snow cover have resulted in accelerated erosion and degradation of the dunes and coastlines. The influx of sand from the beaches is insufficient to replace that removed through natural and anthropogenic causes. Consequently, the coastal dunes of southwest Newfoundland are essentially relict and will not regenerate following anthropogenic disturbance. On trouve à plusieurs endroits le long des côtes sud‐ouest de Terre‐Neuve, du parc provincial Sandbanks (Burgeo) à Grand Bay Ouest (Channel‐Port‐aux‐Basques) et vers le nord jusqu'au parc provincial J.T. Cheeseman, des littoraux à prédominance de dunes où se sont formées des avant‐dunes transversales, des dunes en forme de dôme et des dunes paraboliques. Les dunes maritimes sont apparues vers le milieu de l'ère holocène en réaction à la disponibilité accrue de sédiments et à leur flux alliés à leur rétention efficace. Ainsi, les conditions environnementales actuelles entravent la formation de dunes éoliennes. Des changements récents à la géomorphologie de ces littoraux fournissent la preuve que l'activité anthropique a des conséquences. Les événements météorologiques et climatiques ainsi que la réaction topographique étant reliés à des échelles de temps différentes, compliquent l'interprétation. Une modification anthropique, qu'elle soit intentionnelle ou accidentelle, constitue une influence géomorphologique locale dominante. Ces dunes ont évolué rapidement en raison de ces pressions anthropiques alliées à des événements pluvio‐hydrologiques. Des changements dans l'économie du sud‐ouest de Terre‐Neuve ont suscité un regain d'intérêt pour le tourisme, ce qui a eu pour effet de créer des pressions sur les littoraux sablonneux et les dunes. L'accroissement de l'utilisation du littoral à des fins récréatives, tant par les résidents que les touristes, et l'accumulation limitée de glace en mer et de neige sur les côtes ont accéléré l'érosion et la détérioration des dunes et des littoraux. L'afflux de sable des plages est insuffisant pour remplacer celui qui disparaît pour des raisons naturelles ou anthropiques. En conséquence, les dunes maritimes du sud‐ouest de Terre‐Neuve sont essentiellement des reliques et ne se régénéreront pas si elles sont perturbées par des causes anthropiques.     

Agricultural slope management and soil erosion at La Laguna,Tlaxcala, Mexico

Several superimposed systems of agricultural terracing are preserved at the archaeological site of La Laguna in central Mexico. Excavations uncovered complex stratigraphic sequences of terrace fills and colluvial deposits. Their chronology was established by radiocarbon, optically stimulated luminescence (OSL), and the presence of diagnostic features and artifacts. The Formative occupations of the site (ca. 600–400 BC and 100 BC–AD 100) resulted in severe erosion and exposure of indurated subsoil horizons. In the Middle to Late Postclassic (AD 1150–1520) stone-walled terraces were built to recover the degraded slopes for cultivation. Renewed reclamation works have been undertaken since the Colonial period, eventually taking the form of sloping-field terraces with berms planted in maguey. The reconstructed sequence of local land use underscores the risks of dating agricultural features by association with sherd scatters, as well as the complexity of the relationships between demographic variables, agricultural intensity and terracing.     

河南信阳战国楚墓出土彩席漆膜的成分、表面形态及髹漆工艺分析

河南信阳城阳城遗址M8为高等级战国晚期楚国贵族墓,该墓出土了以漆木器为主的各类文物400余件,其中尤以黑、红两色竹蔑编织而成的髹漆竹席最为精美。为开展彩漆竹席脱水保护提供基础数据,采用激光共聚焦显微镜、拉曼分析仪和傅里叶红外吸收光谱仪(FTIR)及扫描电镜-能谱(SEM-EDS)等现代分析仪器对竹席漆膜的成分及表面形态进行了分析,并在此基础上,结合传统髹漆文献资料探讨了漆膜的制作工艺。结果表明:城阳城彩席中的黑色漆膜为大漆自然显色,红色漆膜是大漆掺加朱砂调制而成;黑色漆膜表面较为平整,漆膜与胎体结合紧密,红色漆膜表面相对粗糙,结构较为疏松;竹席漆膜的厚度在0.02~0.03 mm之间,应是由大漆涂刷至少3~5次制备而成。研究结果可为下一步的彩漆竹席的脱水保护及展示提供基础数据。     

Moisture content measurement and surface water absorption test in the inner gallery of Bayon for the conservation of the bas-relief

The bas-relief carved on the sandstone wall in the central part of the inner gallery of Bayon in the Angkor monuments, Cambodia, has been severely damaged mainly due to calcite crystallization. In order to confirm the mechanism of salt weathering and help determine conservation measures for the bas-relief, measurements of the annual change in the moisture content in the bas-relief were conducted. We found that water supplied from the platform behind the bas-relief is the cause of calcite crystallization. It is therefore indispensable for the conservation of the bas-relief to prevent the water permeating from the inside of the platform behind it. As precipitated calcite from the water block pores near the surface of the sandstone, the surface water absorption test is a useful method to evaluate the degree of the salt weathering.     

Increasing livelihood vulnerabilities to coastal erosion and wastewater intrusion: The political ecology of Thai aquaculture in peri-urban Bangkok

Most livelihood research focuses on micro-level decisions affecting occupations but fails to examine wider scale processes that shape markets, institutions, and thus livelihood choices. A political ecology framework can help address this gap by providing ways to analyse how multi-scalar and extra-local practices, policies, and discourses affect local-level socio-environmental outcomes. In the qualitative research reported here, that framework is applied to Tha Kam, a peri-urban coastal sub-district of Bangkok, where most residents are small-scale aquaculture farmers. These farmers have experienced precipitous drops in incomes because of two major environmental changes: coastal erosion and wastewater intrusion. The causes are multiple and complex, and many originate not from practices within Tha Kham but from challenges present at a larger scale or that start upstream. The political and economic drivers of these problems stem from Thailand’s fragmented vertical and horizontal governance structure, unequal class relations in which smallholder farmers and peri-urban residents are marginalised, and lack of accountability and representation. This combination of multi-scalar factors and power imbalances has contributed to evolving injustices of peri-urbanisation, all of which are profoundly geographical in their significance.     

Tianshui’s three treasures: water and soil conservation in wartime northwest China

ABSTRACT

In addition to examining how wartime imperatives shaped the agricultural research, demonstration, and extension programs undertaken by the Nationalist government’s Tianshui Water and Soil Conservation Experiment Area (the Experiment Area) after its founding in 1942, this article assesses the rural populace’s responses to these conservation measures. While the Experiment Area’s plans to construct terraces and ditches were not well suited to the socioeconomic and environmental conditions that existed in rural Gansu during the 1940s, its introduction of non-native tree and grass species to check water and soil loss met with an enthusiastic response from Tianshui’s populace. Water and soil conservation specialists aspired to rationalize human interactions with the environment as part of wartime efforts to develop the northwest, but to realize these goals they had to take socioecological realities in the region and the needs of rural residents into account. Wartime conservation’s environmental legacies, the article also shows, extended into the period after 1949.     

A review of lessivage and neolithic cultivation in southern England

A critical re-examination is undertaken of a model for soil development which has been put forward to explain the occurrence of buried sols lessivés (Argillic brown earths) under several neolithic earthworks in southern England. The model attributes the formation of sols lessivés to neolithic agricultural activity, and is based on the assumption that lessivage will not occur under woodland, but will be facilitated by clearance and cultivation. A review of the pedological literature shows both these assumptions to be unsubstantiated, and a survey of the sites used in the development of the model reveals that at only one is there any independent evidence for neolithic agriculture. An alternative hypothesis for sol lessivé development is put forward which associates it with the post-glacial forest. The original model was taken as an environmental cause of the change in the neolithic economic base. In view of the arguments presented here this explanation is no longer tenable.     

Pretos Novos: Evidence for African Oral Hygiene Practices in Brazil, 1769–1830

Fine, polished abrasion of teeth provides evidence for use of traditional oral hygiene practices in 32 fragmentary dentitions from a cemetery for newly arrived enslaved Africans who died before leaving Valongo, the slave port and market of Rio de Janeiro. We infer that chewing sticks were used before these people were enslaved. Cosmetic dental modification and abrasion of tooth roots occur in some individuals. High caries frequency, tooth loss and hypercementosis characteristic remains of enslaved Africans with longer residence in the New World were not found in this unique collection. We review evidence that the practice of using chewing sticks persists in some regions of the Americas. Copyright © 2012 John Wiley & Sons, Ltd.     

Beached swords from Marano Lagoon (northern Adriatic) reveal ancient land–sea connections and recent coastal evolution

Depositional and erosional processes, subsidence and sea-level changes have strongly modified the coastal landscape of northern Adriatic lagoons. Such rapid transformations have induced significant consequences on human settlements and, thus, on the archaeological visibility of the area, still largely unexplored. We present here six metal swords fortuitously retrieved by fishermen over the last decades in front of the barrier islands of Marano Lagoon (north-eastern Italy). Multi-analytical analyses carried out on the artefacts (X-ray radiography and computed micro-tomography, radiocarbon dating and typo-chronology) combined with the study of the coastal paleo-environment (mainly based on historical cartography and remote sensing) allowed the items’ main features to be defined, and highlighted both the historical importance of the area and the significant morphological changes that have occurred there over the last millennium. Data presented indicate that Marano Lagoon was a major hub in the northern Adriatic in the Late Middle Ages, during the crucial period of the Crusades, and in Early Modern times, connecting inland Europe with the Mediterranean Sea. Moreover, the research highlights the onset of coastal erosion that occurred in the last century after a phase of relatively geomorphic stability, possibly deriving from the intensification of human impact and climate change.