Biomedical subjects

Shidong Zhao

Publications and source records attributed to Shidong Zhao.

6 recordsLinked to original sources

PubMed2004

[Temporal and spatial change of land use in Horqin Desert and its outer area].

Based on two sets of land use data (1985 and 2000), the land use change in Horqin Desert and its outer area, in both spatial and temporal aspects, was studied with the tools of geographical information system (GIS) and statistics in this paper. Conclusions of this study are drawn as follows: From 1985 to 2000, the area order of individual land use changes was grassland > plough land > forestland > unused land > water body > residential and industrial land. As to the form of changes, the swapping area was greater than its quantitative change for forestland while the quantity change was greater, with different degree, than swap for the rest 5 land use types. As a whole, the quantity change was far greater than its swap. The analysis of land use dynamics showed that the speed of individual land use changes was in order of cultivated land > water body > grassland > forestland > unused land > residential and industrial land in sequence. Meanwhile, there was notable difference of land use change among counties in the region. For plough land change, Zhalute county was the greatest. Naiman the smallest. For forest change, Naiman was the greatest, Kalaqin the smallest. For grassland change, Tongliao city was the greatest, Alukerqin the smallest. For water change, Kezuozhongqi was the greatest, Balinzuoqi the smallest. For residential and industrial land change, Naiman was the greatest, Alukerqin the smallest. Finally, the change of unused land is more obvious in Chifeng city. As to the spatial change, 9 major land use change types were identified. Wherein, the change from grassland to plough land, expanding from the center of Horqin desert towards its outer counties, was still the most important land use change for the whole study area. In addition, the construction of protective forest for grassland in Naiman, the return from plough land to forestland in Kezuozhongqi, the return from plough land to grassland in Tongliao city, the deforestation for plough land in Kukun county, the degradation of grassland in Zhaluteqi, the exploit of river beach in Kailu, the reclamation of unused land in Kezuobouqi, and the regeneration of natural vegetation in Alukerqin were all important regional characteristics of land use change during the past 15 years.

Agriculture↗

PubMed2004

[Ecosystem approach: a new concept for ecosystem management].

Ecosystem approach (EA) was firstly proposed by ecologists in developed countries and then supported by a number of international institutions and NGOs, among which, CBD, IUCN and WWF played important roles. Ecosystem approach is an integrated strategy for the management of land, soil and bio-resources. The application of EA will help to reach a balance between conservation, sustainable use, and fair and equitable sharing of the benefits arising out of the utilization of biological resources. Ecosystem approach is a methodology of ecosystem management, focusing on the biological organisms and recognising that human beings, with their cultural diversity, are an integral component of many ecosystems. The decision V/6 adopted by the Conference of the Parties to the CBD at its fifth meeting in 2000 concretized the EA in the form of twelve principles and five operational guidelines. Our government has recently made a lot of efforts in ecosystem management at large scale with many important measures and obtained significant achievements, but the potential role of local governments, institutions and individuals has not been fully played. In the attempts of managing a specific ecosystem, there are many successful cases done by our ecologists, for example, the ecological management of Chinese fir plantation forest in central subtropical China. However, the whole ecosystem at national or regional level is confronted with a lot of serious problems, mainly because there is a lack of complete understanding of the significance of ecosystem management and a lack of guidelines or principles from an integrated scientific theory. The introduction and implementation of ecosystem approach will play an important role in improving the ecosystem management in China.

China↗

PubMed2003

[Carbon budget of ecosystem in Changbai Mountain Natural Reserve].

The study used EPPML, a biological geochemistry cycle model that was built, to simulate the carbon budget for ecosystems in Changbai Mountain Natural Reserve. The results indicated that the annual net primary productivity [NPP (carbon)] of the natural reserve was 1.332 x 10(6) t.a-1. The annual NPP of mixed broad-leaved and Korean pine forest and spruce-fir forest were maximal, 0.540 x 10(6) t.a-1 and 0.428 x 10(6) t.a-1 respectively. The area and productivity of the two stands were maximal in Changbai Mountain, therefore, the simulating productivity of the two stands most greatly affect carbon cycle and carbon budget of the natural reserve, and the veracity of the former decides the security of the latter. To sum up, not only did the simulations accord with routines in the relative comparisons between different vegetation belts and climate belts in the whole natural reserve, but also was exact in the absolute comparisons with very disperse data from field survey. Vegetations in the natural reserve had evident carbon sink functions, mainly exhibiting in the increasing of carbon, about 1.058 x 10(6) t.a-1. The annual carbon of mixed broad-leaved and Korean pine forest increased greatest (0.452 x 10(6) t.a-1), secondly spruce-fir forest (0.339 x 10(6) t.a-1). The two stands played crucial roles in the carbon sink for Changbai Mountain, others being Changbai larch forest, broad-leaved forest, meadow, shrub, alpine tundra, subalpine Betula ermanii forest and alpine grass. In 1995, the decomposing carbon of soil organic matter was 0.169 x 10(6) t.a-1 higher than the littering carbon in the natural reserve. There was accumulation of organic matter in the meadow soil and shrub soil. The decomposition and accumulation of soil organic matter was in the nearly balancing condition in the alpine tundra soil and alpine grass soil. The decomposition of organic matter was as one and a half time or double as litterfall in the arbor forest soil.

Carbon↗

PubMed2003

[Ecosystem productivity process model for landscape based on remote sensing and surface data].

In this paper, the a ecosystem productivity process model for landscape (EPPML) reflecting carbon and water cycles of system was described and discussed. In EPPML, leaf area index (LAI) that greatly influenced vegetation productivity was received from remote sensing images, the spatial distribution and temporal dynamics of net primary productivity (NPP) and evapotranspiration were simulated. Geographical information system (GIS) was used to process, analyze, and display spatial data. Thus, the studies on physiological ecology could be extended, and converted from small scale to larger scale. Using EPPML, the vegetation productivity in Changbai Mountain Natural Reserve in 1995 was simulated. EPPML could well and truly simulate the NPP of main vegetations in the natural reserve. NPP was estimated to be 0.680 kg Cm.-2.yr.-1, mostly ranging from 0.105 to 1.241 kg C.m-2.yr.-1, accounting for 82.1%. The highest NPP (1.084 kg C.m-2.yr-1) appeared in mixed broad-leaved and Korean pine forests. The total NPP was estimated to be 1.332 x 10(6) t C.yr-1. The highest total NPP appeared in mixed broad-leaved and Korean pine forests and spruce-fir forest, which were 0.540 x 10(6) t C.yr.-1 and 0.428 x 10(6) t C.yr.-1, respectively. The seasonal variation of NPP appeared obvious single peak with peak value in July (6.13 g C.m-2.d-1). The most NPP accumulated in the summer, which was 0.465 kg C.m-2, secondly in the spring, and least in the winter.

Conservation of Energy Resources↗

PubMed2003

[Simulation of temporal-spatial variation characteristics of surface runoff in Changbai Mountain based on process model for landscape scale].

The seasonal dynamics and spatial distribution characteristics of surface runoff in Changbai Mountain simulated by the process model (EPPML), and the relationships between surface runoff and environmental conditions were analyzed. The results showed that the seasonal variation of surface runoff in Changbai Mountain presented obvious three-peak pattern, i.e., the lowest values in June and September, peak values in August (2.58 mm.d-1), similar to that of soil water content. Total trend of surface runoff for different vegetations in the growing season was in order of grass and shrub > coniferous forest > broad-leaved forest > mixed broad-leaved and Korean pine forest, highly correlated to LAI. Annual surface runoff in 1995 was estimated to be 0.203 m.yr.-1, mostly ranging from 0.0 to 0.246.m.yr.-1, accounting for 69.3%. The trend of spatially increasing annual surface runoff along with increasing altitude was obvious. The maximum annual surface runoff appeared in alpine grass (0.619 m.yr.-1), minimum in mixed broad-leaved and Korean pine (Pinus koraiensis) forest (0.081 m.yr.-1), others being alpine tundra, Betula ermanii forest, meadow, shrub, mixed spruce (Picea asperata) and fir (Abies nephrolepis) forest, Changbai larch (Larix olgensis) forest and broad-leaved forest. Vegetation and environmental conditions controlled the main trend of the spatial distribution of annual surface runoff in Changbai Mountain. There was very strong negative exponential correlativity between annual surface runoff and LAI (R2 = 0.857). The more LAI, the more literfall, the more precipitation intercepted by litter, thus, the less surface runoff. Annual surface runoff was highly negatively correlated with air temperature and total solar radiation (R2 being 0.965 and 0.836 respectively), however, it was highly positively correlated with precipitation, relative humidity and wind speed (R2 being more than 0.950). And annual surface runoff was also strongly correlated to soil characteristics.

Conservation of Natural Resources↗

PubMed2003

[Analysis on factors affecting net primary productivity distribution in Changbai Mountain based on process model for landscape scale].

Based on the data received from remote sensing images, the spatial distribution of annual net primary productivity (NPP) was simulated by the process model (EPPML), and the relationships between annual NPP and environmental conditions were analyzed. The results showed that NPP in 1995 was 0.680 kg C.m-2.yr.-1, mostly ranging from 0.105 to 1.241 kg C.m-2.yr.-1, accounting for 82.1%. The highest NPP (1.084 kg C.m-2.yr.-1) appears in mixed broad-leaved and Korean pine forest. Environmental conditions decide the main trend of the spatial distribution of annual NPP (Carbon) in Changbai Mountain. Soil water content had a negative correlativity with NPP, and the correlation coefficient (R) was -0.65. Therefore, water was sufficient for the growth of plants in Changbai Mountain. NPP was highly correlated with LAI (R = 0.81). When LAI was greater than 4-5 m2.m-2, NPP became saturated. NPP was also highly correlated with canopy transpiration (R = 0.77). The response of NPP on environmental conditions, LAI and canopy transpiration in Betula ermanii and broad-leaved forests were different from those in other vegetation.

Conservation of Natural Resources↗