Biomedical subjects

Zhenliang Yu

Publications and source records attributed to Zhenliang Yu.

5 recordsLinked to original sources

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↗

PubMed2002

[Important ecological topics on regional scale ecosystem management in China].

Ecosystem management is a synthetic applied ecology concerning ecosystem management theories, practical technologies, relevant policies and management strategies. It is not only an urgent need for the sustainable development of human society, but also an important tendency and scientific task of ecosystem management to develop integrated studies on models of global or regional scale ecosystem management and the relevant scientific problems. For this reason, we systematically expounded a series of important ecological topics, such as the synthetic evaluation and ecological mechanism of the services, sustainability, complexity, and indeterminacy of ecosystem, the ecological basis of natural resources conservation, ecosystem health, and the rehabilitation of degraded ecosystem, basic ecological processes for ecosystem management, theories and practice on adaptive management of ecosystem, ecosystem network study, monitor, and achievement integration, as well as synthetic special topic studies on regional scale ecosystem management etc. Research advances and tendencies of these topics at home and abroad were also reviewed.

China↗