Li Xiuzhen

Long-term effect of different planting proportions on forest landscape in Great Xing’an Mountains, Northeast China after the catastrophic fire in 1987

A landscape model (LANDIS) was used to study the long-term forest dynamics under five planting types (100% larch (P1); 70% larch and 30% Mongolian Scotch pine (Pinus sylvestris var. mongolica) (P2); 50% larch and 50% Mongolian Scotch pine (P3); 30% larch and 70% Mongolian Scotch pine (P4); 100% Mongolian Scotch pine (P5)), which were also employed in severely burned area under current planting intensity, and under natural regeneration (as a comparison) in Tuqiang Forest Bureau in the northern slopes of Great Xing’an Mountains after the catastrophic fire in 1987. Results showed that different planting types had a significant influence on the abundance of larch, Mongolian Scotch pine and white birch. The abundance of larch increased with time, whereas the abundance of Mongolian Scotch pine was in a converse way. The abundance of larch and Mongolian Scotch pine under these planting scenarios was higher than that under natural regeneration. Under these planting scenarios, the abundance of larch increased with the increasing proportion of larch, and the abundance of Mongolian Scotch pine was in a similar way. Contrary to larch and Mongolian Scotch pine, white birch had higher abundance under natural regeneration than that under these planting scenarios. Also, the different proportions of larch and Mongolian Scotch pine had an influence on the abundance of white birch. White birch had higher abundance with the increasing proportion of Mongolian Scotch pine. As for the total abundance of larch and Mongolian Scotch pine, the difference was not significant under P2, P3 and P4 scenarios, but was higher than that under P1 and P5 scenarios, which indicated that individual-species planting should not be used in the forest landscape.

Forest crown density restoration and influencing factors in the burned area of northern Great Hing′an Mountains of China

Abstract Fire in the Great Hing′an Mountains in 1987 affected an area of more than 1.33×106 hm2, creating a mosaic of burn severities across the landscape, which strongly affected the postfire vegetation succession. In addition, undulate landform and anthropogenic disturbance inevitably influenced the postfire vegetation succession. In this paper, a typical area was selected for a case study, including two forest farms, covering more than 1.2×105 hm2. In order to reveal how the forest changed in 2000 (13 years after the fire) by comparing with 1987 (prefire) and to find out the relationship between the forest succession and the affecting factors, forest crown density was selected as the criterion, and forest type, fire severity, silviculture practice, elevation and topography gradients were designed as the affecting variables. With the support of GIS software, each variable was classified and entered into the multivariate regression model. The result showed that the forest crown density changed notably in 2000 compared with that of the prefire, and all the variables significantly affected the forest crown density. The most important affecting variable was elevation, which was positively correlated with the forest crown density. The next was fire severity, which was negatively related with the forest succession. The effects of topographic factors and silviculture practices on forest crown density were relatively small.

Comparison of Two Approaches for Detecting the Depth of Edge Influence on Vegetation Diversity in the Arid Valley of Southwestern China

Three types of landscape boundary (forest/pepper field, forest/cabbage field, and forest/grassland) were selected in the aird valley of upper reaches of Minjiang River, southwestern China. On the basis of vegetation diversity, the depth of edge influence (DEI) on different types of landscape boundaries was estimated using principal components analysis (PCA) method and moving split-window techniques (MSWT). The results showed that in the 5 transects, PCA method was able to detect the edge influence depth with 3 transects, while MSWT could explain 4 transects. It is concluded that PCA and MSWT both can be used to detect the depth of edge influence within 50 m from the edge to the interior. Similar conclusions were drawn in the forest of each transect with the two methods, but no similar conclusions were drawn in the pepper field of each transect. Although the two methods have advantages and disadvantages respectively, they are useful tools for characterizing edge dynamics. Comparing the two methods, MSWT is more successful.

Deformation and development tendency of Shiliushubao landslide by numerical modeling

On the basis of analysing basic features of Shiliushubao landslide, the landslides deformation and development tendency are quantitatively studied by using FLAC3D program. The results accord with monitoring results. The results are indicated that reservoir impounding accelerates the landslides deformation, and the variation of reservoir water level is key factor of affecting the deformation; The landslide has the characters of pull-behind movement according to the displacement of the landslide body gradually reducing from leading edge to trailing edge; Excavating and deloading slow down the landslides deformation in the certain degree. On the basis, the deformation developmental tendency of Shiliushubao landslide is predicted by the established simulating model.

Post-fire habitat restoration of sables during winter season in northern slope of the Great Xing′an Mountains

Habitat loss and fragmentation have been associated with the decline of endangered species. In 1987, a catastrophic fire in the northern Great Hing’an Mountains of China, where the main habitat of sables. (Martes zibellina) is located, aggravated the loss and fragmentation of the forest landscape. Due to restricted distribution and low population density, sables were listed in the national first-grade protected species in China. The objective of this paper was to identify to what extent the habitat of sables had been restored 13 years after the fire. Based on the behavioral data, which came from field survey information by radio-tracking, GPS (Global Positioning System) and forest inventory data, suitability habitat maps were derived using the Ecological Niche Suitability Model (ENSM). In addition, the habitat structure was analyzed with selected landscape indices. Although forest cover mostly had been restored by 2000, the results indicated that, compared to the pre-fire situation, the areas of suitable habitat had been reduced significantly, especially those of less suitable, marginally suitable and moderately suitable designation. Fragmentation was aggravated, and suitable patches were found to be further isolated with the exception of those in most suitable areas. The ratio of the patch perimeter to area in unsuitable, moderately suitable and suitable areas decreased, while the ratios within other suitability types increased. Moreover, the percentage of soft boundaries decreased slightly, which can influence the redistribution of sables. The results above indicated that the suitable habitat had deteriorated, and the restoration of the sables’ habitat remained to be done.

Literature analysis and research progress of the landscape ecology in China in the 1990s

This paper makes analysis of published articles and books on landscape ecology in the 1990s through literature collection. The analytical results showed that the study of landscape ecology had made a great advance during the past decade in China. By incomplete survey, Chinese researchers at home and abroad published 619 scientific articles and 13 monographs on landscape ecology in the 1990s, and most of them (more than 90%) were published in Chinese with English abstracts. The published articles on basic theory accounted for 39.6% (245 articles), and those concerning application and methods accounted for 36.8% (228) and 23.6% (146), respectively. According to the objects of research, the published articles on landscape ecology were classified into nine catalogues. The urban landscape ranks first in terms of number of published articles, accounting for 13.4% of the total, followed by regional and river basin landscape, cold and arid landscape, forest landscape, habitat and bio-diversity landscape, agricultural landscape, wetlands, suburban landscape, and vegetation landscape. Based on the analysis, some discussions were made on the existing problems and development trend of landscape ecology study in China.

Spatial pattern and function of corridors in wetlands of Liaohe delta

Corridors are special patches with narrow and long shape, and often have the functions as transportation, protection, resources and aesthetics. Corridors in the study area can be classified into 8 types, with a total length of 5167.2 km, and corridor density of 1.25 km/km2. The corridors are mainly composed of irrigation and drainage canals, the total length of which is 2794 km, about 54.1% of all the corridors. The corridors have segmented the landscape, and changed the original situation of the natural landscapes. The types of corridors are closely related to the landscape types they are distributed in. Canals are mainly distributed in the wetland landscapes, while roads are mainly in the buil-up area. Dikes are always along rivers or coastlines. The corridors are most densely distributed wherever human activity occurs most frequently, such as in the artificial wetlands of paddy fields.

Criterions and Measures of Route Selection of Shallowly Embedded Long-distance oil and Gas Pipeline in Mountain Areas

According to the engineering investigation of long-distance oil and gas pipelines, the criterions and measures of route selection are drawn as follows: the flat landform is the first choice in route alignment. The foot of mountain is the first choice when the route passes by the valley. The route should pass by but the shady and deposited slope and not in sunny and erosive slope as possible as it can. The pipeline should be vertical to contour climbing and descending the mountain except steep slope. Tunnel can be used in crossing foothill. Perpendicularly traversing the river is better than beveling; the worst choice is to put the pipeline along the river. Bypass is the best choice in karsts area. The order of route selection should be pre-choosing, investigation, optimization and adjustment.