Water loss due to increasing planted vegetation over the Badain Jaran Desert, China

© 2018 by the authors. Water resources play a vital role in ecosystem stability, human survival, and social development in drylands. Human activities, such as afforestation and irrigation, have had a large impact on the water cycle and vegetation in drylands over recent years. The Badain Jaran Desert (BJD) is one of the driest regions in China with increasing human activities, yet the connection between human management and the ecohydrology of this area remains largely unclear. In this study, we firstly investigated the ecohydrological dynamics and their relationship across different spatial scales over the BJD, using multi-source observational data from 2001 to 2014, including: total water storage anomaly (TWSA) from Gravity Recovery and Climate Experiment (GRACE), normalized difference vegetation index (NDVI) from Moderate Resolution Imaging Spectroradiometer (MODIS), lake extent from Landsat, and precipitation from in situ meteorological stations. We further studied the response of the local hydrological conditions to large scale vegetation and climatic dynamics, also conducting a change analysis of water levels over four selected lakes within the BJD region from 2011. To normalize the effect of inter-annual variations of precipitation on vegetation, we also employed a relationship between annual average NDVI and annual precipitation, or modified rain-use efficiency, termed the RUEmo. A focus of this study is to understand the impact of the increasing planted vegetation on local ecohydrological systems over the BJD region. Results showed that vegetation increases were largely found to be confined to the areas intensely influenced by human activities, such as croplands and urban areas. With precipitation patterns remaining stable during the study period, there was a significant increasing trend in vegetation greenness per unit of rainfall, or RUEmo over the BJD, while at the same time, total water storage as measured by satellites has been continually decreasing since 2003. This suggested that the increased trend in vegetation and apparent increase in RUEmo can be attributed to the extraction of ground water for human-planted irrigated vegetation. In the hinterland of the BJD, we identified human-planted vegetation around the lakes using MODIS observations and field investigations. Four lake basins were chosen to validate the relationship between lake levels and planted vegetation. Our results indicated that increasing human-planted vegetation significantly increased the water loss over the BJD region. This study highlights the value of combining observational data from space-borne sensors and ground instruments to monitor the ecohydrological dynamics and the impact of human activities on water resources and ecosystems over the drylands

Integrated Ecosystem Assessment of Western China

Western Development is an important strategy of China Government. The ecological environment in the western region of China is very fragile, and any improper human activity or resource utilization will lead to irrecoverable ecological degradation. Therefore, the integrated ecosystem assessment in the western region of China is of great significance to the Western Development Strategy. This project, Integrated Ecosystem Assessment of Western China (MAWEC), will provide very important scientific foundations for both the central and local governments to make decisions on ecological construction, thus assuring the successful implementation of the Western Development Strategy. Meanwhile, MAWEC as one of the MA sub-global assessments is contributing to strengthen capability in boosting the development of the ecological science, interaction between different subjects, and combination between scientific research and practice, and pushing forward international cooperation in the relevant fields

Bioarchaeology of Adaptation to Climate Change in Ancient Northwest China

The 4000 BP climate event was a time of dramatic change, including a cooling and drying climate and the emergence of pastoral practices and a distinct cultural identity across northern Eurasia. However, the link between the climatic changes and the cultural changes has not yet been thoroughly explored. This dissertation therefore assesses human biological measures such as frailty, physiological stress, and nutritional status to ask whether late Holocene climate change precipitated a crisis and collapse of subsistence practices, as has been claimed. The dissertation employs the theoretical framework of the “adaptive cycle,” an understanding of complex systems that incorporates both change and continuity. The dissertation asks whether the Bronze Age transition, in which humans adapted to the arid climate of the second and first millennia BCE, constituted a “collapse” or “transformational adaptation,” in which the human-environment system changed categorically; or an “incremental adaptation,” in which defining system elements persisted with only peripheral changes. Skeletal samples from six populations (spanning 2600-221 BCE) were examined for bioarchaeological markers of oral health, nonspecific infectious lesions, trauma, stature, and fertility. There was broad continuity and some improvement in population health measures in the Bronze Age study populations, with a decline in health in the Iron Age groups. Bronze Age subsistence systems therefore seem to have been resilient enough to adapt to the new climate, while the sociopolitical conditions of the Iron Age led to poorer health outcomes. The Bronze Age transition has often been described in terms of “collapse,” and by critically engaging with this narrative, the current project demonstrates that the transition in fact entailed an incremental adaptation, rather than a collapse. These findings also point to how sociocultural factors can serve as a buffer against environmental stressors in some groups, while themselves serving as stressors in others.Doctor of Philosoph

Pottery Production, Mortuary Practice, and Social Complexity in the Majiayao Culture, NW China (ca. 5300-4000 BP)

The Majiayao Culture: ca. 5300-4000 BP) is famous for its stunning painted pottery vessels. First discovered in the 1920s in northwestern China, these Neolithic painted pottery vessels have become one of the most popular icons used to depict the rich material culture of ancient China. Today, many museums throughout the world hold Majiayao painted pottery vessels in their collections. We know much about the pottery, but research on the associated Majiayao Culture has been limited to cultural histories that emphasize chronology and trait-list classification. These approaches present the Majiayao Culture as static and simplify the social and economic complexity of the people who composed this society. Although scholars commonly assume that Majiayao painted pottery vessels were made by specialized craftspeople, the social and economic processes behind the production of these vessels have long been overlooked. Materials discussed in this dissertation include firsthand attribute and physicochemical analyses of hundreds of ceramic vessels and samples selected from multiple sites in Gansu, Qinghai, and Sichuan provinces. These data are supplemented with settlement pattern and mortuary analyses of thousands of published sites and burials. By synthesizing these data, this study illustrates a positive correlation between regional density of settlement distribution, intensification of pottery production, and degree of social inequality in each phase during the Majiayao Cultural period. Rather than showing a simple linear process of social complexity, however, there are distinct regional variations in each phase and significant regional fluctuations over time. Results of this study demonstrate economic and social patterns related to Majiayao ceramics were far more complex than we have previously thought. Specifically, intensive ceramic production among these Neolithic agricultural communities was primarily driven by the increasing demand to offer large quantities of painted pottery vessels at funerals. These Neolithic communities fulfilled the increasing demand for painted pottery vessels in mortuary practices by sacrificing vessel quality to promote production efficiency. When the demand for vessel quantity reached its peak, no products were made with the skill and care comparable to the most high-quality vessels dated to earlier phases. Further, the great demand also encouraged the development of inter-regional exchange involving painted pottery vessels. Certain production groups in the core area of site distribution in each phase were able to make relatively high quality vessels and successfully increased their output to best meet the needs of both internal and external consumers. Therefore, I argue that the distribution and consumption of these craft goods was not limited by kin organization. I emphasized these vessels were marketable objects--commodities. The way these craft goods moved from the hands of potters to the consumers was associated with complicated social and economic interaction/exchange, about which we still have limited understanding. The development of social hierarchy in this region is indicated by the disparity of painted vessels unearthed from graves. The preference for painted storage jars may relate to the development of agriculture in this region. These vessels seem to be used as a symbol of wealth. However, these craft goods were generally available for most social members of different ranks. Exchange of goods also led to an exchange of cultural and social experiences. Diverse social values might have been delivered and structured through the circulation of Majiayao painted pottery vessels among the living and between the living and the dead. Patterns identified in this study shed new insights into conceptualizing the dynamic social and economic relationships among Neolithic village-scale communities

Factors limiting sand dune restoration in Northwest Beach, Point Pelee National Park, Canada

Known as home to rare species of flora and fauna, and their critical habitats, Northwest beach of Point Pelee National Park has undergone significant ecological and infrastructural changes in the past decades. A number of important management challenges have emerged, including conservation of endangered Five-lined Skink (Plestiodon fasciatus) which inhabit the extensive dune system within the park. This research investigates key factors for sand dune ecosystem restoration in Northwest beach of Point Pelee with particular attention to the conservation of Skink habitat. Random stratified sampling method was used to collect sand and vegetation samples from the disturbed and natural areas. Sand samples were also collected from the sand piles, which is a part of dune restoration process initiated by the Parks Canada. Three aspects were considered: grain size distribution of dune sediments, vegetation assemblage and character of the dune associated species, land use and land cover change. Grain size distribution indicated that samples from most of the sand piles contained some amounts of clay/silt and pebble sized grains making it unfavourable for wind action, resulting in no significant contribution to dune formation. Most of the sand samples collected along the foredunes and water edge were appropriate for sediment transport. Shannon and Simpson’s Diversity Index was calculated as 1.48 and 0.67 for natural area as compared to 0.71 and 0.35 for the disturbed area, which indicate unfavourable species diversity for dune restoration in disturbed areas. The research also focused on the spatial and temporal changes in land use and land cover in NW beach area of Point Pelee using aerial photos for 1959, 1977, 2006 and 2015. Different time series of the aerial photos were chosen based on their availability. The Ecological land classification system for Southern Ontario were used to classify the aerial photos for land use and land cover (LULC). LULC classes included Shoreline vegetation, Deciduous thicket, Sand Barren and Dune Type, and Infrastructures (includes Transportation and services) for the entire Northwest Beach area. Segmentation and classification tools was used to classify four different time series of aerial photos. Grain size distribution and vegetation assemblage for dune associated species were calculated to determine the factors limiting habitat restoration process. Based on the results alternate management strategies for dune restoration in Point Pelee were recommended. The study offers key insights on the importance of timely detection, analysis and visualisation of dynamic changes for habitat restoration and maintaining ecological integrity of the Northwest beach area of Point Pelee

Does intercropping have a future in China? : insights from a case study in Gansu Province

Intercropping is the simultaneous cultivation of two or more crop species in the same field. It has been practiced in China for thousands of years. In recent decades, researchers in several disciplines have shown increasing interest in intercropping systems, due to their potential to generate higher yields and counteract resource degradation. Much research on intercropping has been carried out from an eco-physiological perspective in China in recent decades. However, a socio-economic analysis is critically needed to obtain more insight into why farmers adopt intercropping or not and why they shift from one production system to another. This study tries to fill this gap in the existing literature. Its main aim is to obtain a better understanding of farmers’ decisions on intercropping in China. The analysis conducted in two distinct perspectives. The first empirical study aims to present an overview of the current prevalence of intercropping, and its recent trends in China, using national survey dataset. The other empirical studies focus on (relay) intercropping in small-scale farming, using a case study on household decision-making in Gaotai County, Gansu Province, northwest China. Results from the first study show that intercropping was practiced on approximately three percent of the arable land in the surveyed villages, while agroforestry was practiced on approximately one percent of the arable land and one percent of the area of plantation plus forest land. The use of both these systems did not significantly change between 2009 and 2014. An explorative village-level analysis of factors associated with mixed species cultivation practices (intercropping and agroforestry) reveals a significant positive association with labour availability, and a smaller, but mostly significant, negative association with agricultural machinery power. In the case study, results reveal that technical efficiency scores are positively affected by the share of land assigned to intercropping. Other findings are that natural assets (land and irrigation water) are important determinants of the use of intercropping, while human assets (including labor-land ratios) and financial assets do not have a significant effect. Water and labor scarcity and declining maize prices all affect negatively the potential use of intercropping in the future; among the aforementioned three factors, (rural) labor scarcity has the most negative impact on intercropping. To conclude, intercropping is practiced on a small but non-negligible proportion of China’s arable land, and has not declined in recent years. Policies aimed at dealing with resources scarcity and liberalizing maize market should take the impact on use of intercropping into account, and appropriate machinery for intercropping should be developed. Given its relatively high land use efficiency, and its relatively high profit in the case study region in northwest China, intercropping may continue to provide pathways for the intensification of agricultural food production and to contribute to the growth of farmers’ income in China.</p

Dynamics of Disintegration: The Later Han Empire (25-220CE) & Its Northwestern Frontier

As a frontier region of the Qin-Han (221BCE-220CE) empire, the northwest was a new territory to the Chinese realm. Until the Later Han (25-220CE) times, some portions of the northwestern region had only been part of imperial soil for one hundred years. Its coalescence into the Chinese empire was a product of long-term expansion and conquest, which arguably defined the region\u27s military nature. Furthermore, in the harsh natural environment of the region, only tough people could survive, and unsurprisingly, the region fostered vigorous warriors. Mixed culture and multi-ethnicity featured prominently in this highly militarized frontier society, which contrasted sharply with the imperial center that promoted unified cultural values and stood in the way of a greater degree of transregional integration. As this project shows, it was the northwesterners who went through a process of political peripheralization during the Later Han times played a harbinger role of the disintegration of the empire and eventually led to the breakdown of the early imperial system in Chinese history. In this study, the author adopts a regional perspective by focusing on the role of the northwestern frontier region vis-Ã -vis the imperial center to explain the collapse of the Later Han empire. The author emphasizes the role that regional conflicts played in the decline and fall of the dynasty, and paid particular attention to the incompatibility between the militarized culture of the northwest and the civil values promoted by the imperial center, which was dominated by the eastern-based scholar-officials. Through this analysis, the author provides a case study of the relationship between the imperial center and the regions with different cultures and identities, and the variations of the conception of such a relationship in the period of early imperial China

Construction and optimization of ecological security patterns in the songnen plain

To address the ecological security issues in the Songnen Plain, this study constructs the ecological security pattern by using the Multi-Criteria Evaluation Method, Minimum Cumulative Resistance (MCR) model, and Circuit Connectivity Model. Results show that: 1) The ecological source areas were 66, 52, and 56 blocks in 2000, 2010, and 2020 respectively, which are composed mainly of forests, water bodies, and wetlands. The distribution of resistance values of the ecological resistance surface shows a gradually increases trend from the source areas to the outward surrounding regions. The high and low value areas are more dispersed, consisting with the overall spatial distribution; 2) The numbers of ecological corridors show a temporal declining trend from 178 in 2000 to 159 in 2020 with a reduction of 645.46 km in total length. Node areas are mainly distributed in the southwestern and central-eastern regions and its number decreased from 232 in 2000 to 229 in 2020. The sizes of obstacle areas are 74029.52 km2, 70203.72 km2, and 75529.72 km2 in the three periods; 3) The size of important ecological source areas has decreased by 5779.16 km2, the area of medium ecological source areas has increased by 11466.44 km2, and the area of general ecological source areas has increased by 9509.16 km2. The areas being classified as ecological conservation, ecological enhancement, ecological restoration, and ecological control are 30346.68 km2, 8480.56 km2, 51473.92 km2, and 122047.48 km2, respectively. The multiple spatial pattern optimization strategies are proposed based on the identified ecological source areas, corridors, node points, and other comprehensive ecological security patterns. It not only provides practical reference for the ecological restoration and ecological protection in the Songnen Plain, but also can be used for the ecological security pattern investigations in other study regions in the world

Sustainability in China: Bridging Global Knowledge with Local Action

China’s road to sustainability has attracted global attention. Since the “Reform & Opening Up” policy, China’s rapid pace of both urbanization and industrialization has made its being the second largest economy but meantime a heavy environmental price has been paid over the past few decades for addressing the economic developmental target. Today, as the biggest developing country, China needs to take more responsibilities for constructing its local ecological-civilization society as well as for addressing the global challenges such as climate change, resources scary and human beings well-fare; therefore, we need to have deeper understandings into China’s way to sustainability at very different levels, both spatially and structurally, concerns ranging from generating sustainable household livelihoods to global climate change, from developing technological applications to generate institutional changes. In this spirit, this publication, “Sustainability in China: Bridging Global Knowledge with Local Action” aims to investigate the intended and spontaneous issues concerning China’s road to sustainability in a combined top-down and bottom-up manner, linking international knowledge to local-based studies