Biomedical subjects

Rencang Bu

Publications and source records attributed to Rencang Bu.

3 recordsLinked to original sources

PubMed2004

[Dynamics of forest landscape boundary at Changbai Mountain].

By using Geographic Information System (GIS) and Remote Sensing (RS) technology combined with field investigation and correlation analysis, this study was aimed to explore the dynamics of forest landscape boundary at Changbai Mountain, and to reveal the relationships among landscape fragmentation and changes of landscape boundary indices. The results showed that in the last 20 years or so, tundra decreased by 3694.8 hm2, spruce and fir forest reduced by 130482.03 hm2, and Korean pine-hardwood and mountain birch forest increased by 41610.4 hm2 and 669.78 hm2, respectively. The forest landscapes at Changbai Mountain tended to be more fragmented, and the shape of the landscape boundary became more complicated due to timber harvesting, forest cutting for cropping, and other human activities such as tourism. The changes of landscape shape index (LSI), contrast weighted edge density (CWED), total weighted edge length (TE-WGT) and weighted landscape shape index (LSI-WGT) could be used as good indicators for the degrees of forest landscape fragmentations, which was approved by correlation analysis among landscape fragmentation and changes of landscape boundary indices. The degree of human activities on landscape could be reflected by landscape shape index.

China↗

PubMed2003

[GIS and RS determination of abiotic range of forest landscape distribution in Changbai Mountain Natural Reserve].

Based on landscape classification of remote sensing data and spatial expression of environmental factors, the abiotic ranges of forest landscape distribution in Changbai Mountain Natural Reserve were determined by using GIS. The results showed that the optimum elevation range of tundra, mountain birch forest, evergreen coniferous forest, and broad-leaved Korean pine forest were 1780-2212 m, 1705-1956 m, 1042-1625 m, and 823-1184 m, respectively. The corresponding optimum annual average temperature ranges were -4.75(-)-2.40 degrees C, -3.42(-)-2.07 degrees C, -1.49-1.39 degrees C, and 0.71-2.37 degrees C, and the optimum ranges of annual precipitation were 1034-1110 mm, 1014-1060 mm, 883-1017 mm, and 824-925 mm, respectively. The forest landscapes in Changbai Mountain Natural Reserve were mainly distributed in flat and gentle areas. This distribution pattern was closely related to aspect. Tundra was almost evenly present in various aspects. In northern and northwestern direction, most forest landscapes were distributed, including mountain birch forest, evergreen coniferous forest, broad-leaved Korean pine forest, aspen and Betula forest. Most larch forest was in favor of northeastern direction with small amount facing eastern and northern way. Sparse forest briefly occupied west aspect with some orienting in southwest, northwest and south, while all wind-thrown areas were facing west, southwest and northwest aspects.

Conservation of Natural Resources↗

PubMed2003

[Scaling effects on landscape pattern indices].

The methods of spatial data aggregation based on majority and random rules were used in this study to reveal the scaling effects on landscape pattern in a classified TM imagery with 8 land cover types. For the majority rule-based aggregations, the proportion of most common cover types increased slowly, while that of less common cover types decreased rapidly with increasing grain. For random rule-based aggregation, each cover remained its original area on the aggregated maps. The largest patch sizes of shrub decreased, and those of the others increased in the majority rule-based aggregations with increasing scales. For random rule, the largest patch size of water (smallest cover type) decreased, but that of the others increased. The smallest patch size of each cover type was equal to the square of grain sizes. The average patch size of each cover type increased with increasing scales. However, the average patch size of dominant cover types increased rapidly in majority rule-based aggregations, while that of less common cover types increased rapidly in random rule-based aggregation. The patch count of each cover types decreased substantially with increasing grain. Random rule-based aggregation made landscape more fragmented and remained more patches. The diversity decreased in majority rule-based aggregation, and maintained its original value in random rule-based aggregation with increasing scales. Aggregation indices decreased with increasing map and measurement resolution, and the landscape became more aggregated in majority rule-based aggregation. However, under fixed measurement resolution (e.g., 30 m), aggregation indices increased and cover types were more clustered with increasing resolution. Moran's I decreased rapidly with increasing measurement and map resolution, and each cover type tended to be arranged randomly and independently in space. However, under fixed measurement resolution (e.g., 30 m), Moran's I increased and cover types were more clustered on aggregated maps than on original map with increasing map resolution.

Ecosystem↗