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Land degradation and mitigation in northern China. Evaluated from the biological production

Publiceringsår: 2003
Språk: Engelska
Sidor: 126
Dokumenttyp: Doktorsavhandling
Förlag: UB LUND; Micael Runnström, Sölvegatan 12, LUND;,
Ytterligare information: Article: Runnström M., 2000. Is northern China winning the battle against desertification? Satellite remote sensing as a tool to study biomass trends on the Ordos plateau in semiarid China. Ambio 29: 468-476. Article: Runnström M., 2003. Rangeland development in the Mu Us Sandy Land in semi-arid China. An analysis using Landsat and NOAA remote sensing data. Land Degradation & Development 14: 189-202. Article: Runnström, M., Brogaard, S. and Olsson, L., 2003. Estimation of PAR over Northern China in the context of NOAA AVHRR vegetation modelling. Geocarto International. (submitted August 2003). Article: Brogaard, S., Runnström, M. and Seaquist, J., 2003. Primary Production of Inner Mongolia, China, between 1982 and 1999 estimated by a satellite-driven light use efficiency model. Global and Planetary Change (accepted).

Sammanfattning

Land degradation is commonly perceived to be severe in many parts of semi arid China. The transition towards market economy since the 1978 reforms, have set marginal dry lands under added pressure in the form of increased livestock numbers and expanding cultivation on erosive soils. To evaluate land degradation since the reforms, this study focuses on mapping and analysing the biological production of the Mu Us Shamo on the Ordos Plateau in the Inner Mongolia Autonomous Region (IMAR). Time series of satellite data are examined for analysing the seasonal dynamics of biological production, annual variability and trends. Images with high geometric resolution are used to study the small-scale changes in land use and vegetation cover. A Light Use Efficiency (LUE) model is further adapted to the steppe regions of the IMAR. The model is driven by NOAA AVHRR and climate data, producing monthly estimates of Gross Primary Production (GPP) from 1982 through 1999. Although there have been rapid increases in livestock numbers, the trend of GPP since 1982 is generally positive. The annual variability of GPP is high resulting from the erratic monsoon climate. In Wushen Banner, a central county in the Mu Us Shamo, the area indicating improved vegetation cover between 1987 and 1996 is nearly ten times that of declining vegetation cover. The area of cultivation expanded almost five-fold, to about 2% of the county area, of which, nearly all is irrigated. No abandoned farmland could be detected, indicating short-perspective strategies from intensive farmland reclamation. Severe degradation causing declining biomass production rates and expansion of the desert area cannot be drawn from this investigation. Re-vegetation activities to mitigate land degradation such as the Green Wall, farmland lee-shelters, aerial seeding etc., are likely to be contributing to the increase in biological production in this region, and may act as a balance to the increased utilization of these pastures.

Disputation

2003-10-10
10:15
F209 Sölvegatan 12, LUND
  • Qiming Zhou (Dr)

Nyckelord

  • Earth and Environmental Sciences
  • marklära
  • geomorfologi
  • Fysisk geografi
  • climatology
  • kartografi
  • klimatologi
  • cartography
  • pedology
  • desertification
  • China
  • GPP
  • Mu Us
  • LUE-model
  • overgrazing
  • Physical geography
  • geomorphology

Övriga

  • ISSN: 0346-6787
  • ISBN: 91-973857-6-X

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