Northwest China, including the provinces of Shaanxi, Gansu, Ningxia, and a small part of the Inner Mongolian Autonomous Region,
was not only one of the earliest developed areas in history, but also one of the most ecologically fragile belts. The traditionally
sustainable land reclamation and cultivation policies for the development of an agricultural economy adopted and implemented
in administrations during different periods of the Qing dynasty, greatly raised farming and stock production. However, this
led to imbalances in the originally fragile ecological environment. The negative effects such as rapidly expanding desertification,
worsening water and soil erosions, increased cost of production, enlarged investment, vicious cycles and failing economy can
serve as a lesson for contemporary development.
__________
Translated from: Qingshi Yanjiu 清史研究 (Studies in Qing History), No. 1, 2004 相似文献
Agricultural land‐cover changes in Eastern Ontario from 1826 to 2006: environmental effects. Stormont, Dundas and Glengarry (SDG) counties, Eastern Ontario, are among the first areas in Ontario to welcome settlers. In 1784, they established themselves in a forested land where wetlands are very important. Today, a large part of the wetlands has disappeared, but the landscape is wooded, masking the radical changes that took place over the course of the last two centuries. Analysis of census data from 1826 to 2006 allows the reconstruction of the history of land‐cover changes. It reveals the nature and rates of change for which a first analysis is presented. Four periods are identified. First, agriculture conquers the land and establishes its dominance. A plateau is reached in 1891 as agriculture maintains its supremacy until 1941. Then, as fast as agriculture invaded land, it fades away until 1986 when agricultural land‐cover stops shrinking. The opening of forest for cultivation was relatively slow in SDG because of biophysical and socio‐economical conditions associated with an absence of growth of agricultural population. Deforestation and wetland drainage led to a degradation of agricultural life but resulted in consideration of the environment in agriculture. Today, wooded and agricultural land covers are more balanced and environmental effects less acute. 相似文献
This paper investigates the establishment of trading regions in the global economy at the national level using a measure of trade intensity and a regional assignment algorithm that generates economically meaningful trading regions. Although there is definite regionalization in the global economy with regard to international trade, there is no evidence of an increase in the concentration of that regionalization over time. The geography of international trade is incredibly dynamic, with change related to political, historical and economic forces. Overall, trading regions have relatively few members and are increasingly a set of geographically close countries. 相似文献
Inspired by recent environmental historical studies on animal extinctions and human-animal relations, this paper shifts scholarly attention from the plague-centered narrative of the great Pneumonic Plague Epidemics (1910-11) to the fate of the plague host animals, Tarbagan marmots (Marmota sibirica), and examines their near-extinction in Northwest Manchuria (Hulunbuir) from the 1900s to 1930s. Focusing on changing images of Tarbagan marmots from “inexpensive,” “sacred,” and “beneficial” in the pre-modern period to “valuable,” “dangerous,” and “noxious” in the early twentieth century, it argues that three interrelated factors: the international fur trade, pneumonic plagues, and environment changes together resulted in the “retreat of the marmots.” It also uses this case study to help us better understand larger historical changes that occurred by contextualizing them in terms of human-marmot relations in Manchuria, China and beyond. 相似文献
Li, L., Shih, C. & Ren, D., February 2017. New fossil helorid wasps (Hymenoptera, Proctotrupoidea) from the Early Cretaceous of China. Alcheringa 41, 474–486. ISSN 0311-5518
Two new genera with two new species, Bellohelorus fortis and Novhelorus macilentus, and one new species, Protocyrtus parilis, within an established genus are described. Laiyanghelorus erymnus is re-described based on well-preserved specimens from the Lower Cretaceous Yixian Formation at Huangbanjigou Village, Beipiao City, Western Liaoning Province, China. Three taxonomic changes are proposed: Liaoropronia Zhang & Zhang is transferred from Roproniidae to Heloridae, and Novhelorus saltatrix (Shi, Zhao, Shih & Ren) and Spherogaster beipiaoensis (Shi, Zhao, Shih & Ren) are recombined. In addition, Gurvanhelorus mongolicus Rasnitsyn is tentatively considered a synonym of Protocyrtus validus Zhang & Zhang. A key to all genera of Heloridae is provided. All described helorid fossils with their distribution and geological age are summarized. Key forewing characters are compared for all fossil species to show the interspecific venational differences, which highlight a high level of genus-level diversity among Mesozoic helorids.
Longfeng Li [fenger4499@163.com], Chungkun Shih* [chungkun.shih@gmail.com] and Dong Ren [rendong@mail.cnu.edu.cn], College of Life Sciences, Capital Normal University, Beijing 100048, PR China. *Also affiliated with Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013, USA. Received 20.4.2016; revised 19.9.2016; accepted 11.11.2016.相似文献
