Abstract: On the basis of concentrations of 21 major and minor elements in a well-dated sediment core from the deepwater part of Lake Erhai, principal component analysis (PCA) reveals three main factors controlling the inorganic chemical composition of lake sediments. These are physical erosion in the watershed (Component 1), autochthonous calcite precipitation in lake water (Component 2) and early diagenesis in sediments (Component 3). Variations of factor scores of Component I and Component 3 may reflect fluctuations in rainfall and temperature, respectively in the lake region. High factor scores of Component 3 correlate with low factor scores of Component 1 in sediments within the intervals AD 1340-1550 and AD 1890-1950, indicating two warm-dry episodes. Low factor scores of Component 3 correlate with high factor scores of Component 1 from AD 1550-1890, indicating a cold-wet climate corresponding to the 'Little Ice Age' in Europe. Our study provides a new approach to reconstructing palaeoclimate, and adds to a growing body of evidence for a widespread cooling during the 'Little Ice Age'. The alternation between warm-dry and cool-humid conditions possibly implies different climate change characteristics between the southwest monsoon zone and the southeast monsoon zone where the climate pattern is warm-humid and cool-dry.
Abstract: The paper explores the use of Resilience Theory to provide an improved theoretical framework for the analysis of socio-ecological interactions over decadal–millennial timescales. It identifies landscape system behaviour through analysis of proxy records for land use, erosion and monsoon intensity over the past 3000 years in the Erhai lake-catchment system, Yunnan, SW China. Analysis of the records shows the possibility of alternative steady states in the landscape, as expressed by the relationship between land use and erosion. In particular, a period of agricultural expansion ~1400 cal. yr BP triggered rapid gully erosion that led to the formation of an eroded landscape state that has existed since ~800 cal. yr BP to the present day. Comparison of detrended time-series data suggests that over 3000 years erosion and land use should be considered ‘slow’ processes relative to the ‘faster’ monsoon intensity and flooding. In the past, the effects of high monsoon variance on flooding have been suppressed by paddy farming and the maintenance of terraced field systems. Mapping the Adaptive Cycle on to the millennial record of land use and erosion suggests that the modern landscape may be approaching a ‘conservation’ phase characterized by minimum resilience. Such ‘historical profiling’ of modern landscapes offers a new dimension for hypothesis testing, for the development and testing of simulation models and for the creation of appropriate management strategies.
Abstract: Differences in microenvironments---defined by geology, geomorphology, and hydrology-led to major differences in the nature of the environmental problems created by economic development in different parts of the Erhai catchment in southwestern China during the premodern period. In particular we show that the second half of the eighteenth century was the critical period for the onset of rapid environmental degradation in the northern part of the catchment. From this it is established that premodern Chinese irrigated farming cannot be defined as indefinitely 'sustainable' without major qualifications.
Abstract: The southwestern Chinese provinces and neighbouring upland areas in Burma, Thailand, Laos and Vietnam form a geographical region with an expanding Palaeolithic record. The area was a gateway for the dispersion of populations into East Asia and Island Southeast Asia. It is therefore important to examine the diversity of environments and resources that the earliest inhabitants encountered, and to identify adaptations and technologies that may have shaped subsequent exploitations of Asian environments. This paper synthesizes the evidence for the early human occupations of the region, beginning over one million years ago and continuing through the Upper Pleistocene.
Every year archaeologists in China discover numerous rich sites
demonstrating significant regional variability in Neolithic cultures,
primarily from about 6500 B.C. to 1900 B.C. This paper discusses a topic
not covered in detail in current or forthcoming publications, the
origins and development of agricultural systems. Recent fieldwork in
both northern and southern China suggests that initial steps toward
settled agricultural villages began circa 11,000 B.P. I review evidence
for the cultivation of millet, rice, and other plants as well as animal
husbandry in different regions of China. There are several later
Neolithic sites in northern China with evidence for rice cultivation. I
suggest how future research projects can investigate regional variation
and change over time in subsistence and settlement during the Neolithic