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Current estimates of land cover and land use are important aspects in understanding the flux of material and energy from terrestrial ecosystems into hydrological and atmospheric components of the earth system. These land use characteristics define the various dimensions of human impacts on ecosystem processes and resource use. The recent availability of global remote sensing data and agricultural census data from various regions of the world, including portions of Asia such as China and Mongolia, now makes it feasible to evaluate differences in the physical environment and land use patterns affecting land cover and land use changes. In addition, recent research involving transects studies along gradients of climate, soil, and land use intensity has been carried out during the past decade to allow more careful regional comparisons. Using the analysis of the Mongolian-North East China Transect (NECT), we can estimate the effect of land cover differences on ecosystem dynamics. The 30 m-Thematic Mapper data provides a way to identify fine scale features of the regional landscape patterns which are not captured by the 1-km AVHRR data.
The focus of this paper is to evaluate the scale of land use and cover changes in the Asian region and the biogeochemical implications of these changes. The estimates of land cover and land use can vary depending on the spatial scale of the features represented across the land surface. Both physical and social factors influence the spatial extent these features represent. Therefore, the scale of land use intensification can affect the accuracy of land use area estimations. In particular, those regions of the world where land use practices are implemented via small individual holdings may be underestimated when using coarse scale remote sensing data such as AVHRR, where as the Thematic Mapper satellite data at 30 to 50 m resolution can provide a better estimate of land cover and land use area. The accuracy of the extrapolated fluxes of ecosystem dynamics and biogeochemical cycles are directly proportional to the accuracy associated with the land estimates. We will evaluate the land cover estimates in this region of Asia using these data sources. This region encompasses a broad set of precipitation and temperature regimes and includes characteristics of regional land cover and land use related to grazing systems and grain cultivation.
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