Land degradation in the arid Aletai Region in northern China is not only detrimental to animal production, but also reduces the ability to conserve water resources by destabilising the catchments of rivers which affects runoff, thus, threatening the sustainable use of these grasslands. A new approach to grassland management based on carrying capacity and ecological services value of grassland types, using an index of classification management (ICG), was designed to ensure the sustainability of grassland ecosystems. In this approach, grassland is classified into 3 management sectors. The first is conservation grassland, which is mainly devoted to ecological and social values; the second is the moderately productive grassland, dedicated to multiple benefits by rational use; and the third is intensively productive grassland, focusing on maximum economic effect. For the arid Aletai region, no intensively productive grassland was available. Conservation grassland occupied 2.5 million ha, accounted for 25.4% of grassland area, and included alpine meadow, mountain meadow, mountain meadow steppe, mountain steppe and flat meadow. In these grasslands, grazing should be eliminated to allow restoration of degenerated areas, protect grasslands with important ecological values from destruction, and to further improve the environment. Moderately productive grassland covered 7.3 million ha, and the grassland types were alpine steppe, mountain desert steppe, plain desert steppe, steppe desert, and plain desert. Agricultural measures, such as fertiliser and irrigation application, should be used to enhance the productivity of these grasslands.

Buffered clock tree synthesis (CTS) is increasingly critical as VLSI technology continually scales down. Many researches have been done on this topic due to its key role in CTS, but current approaches either lack the obstacle-avoiding functionality or lead to large clock latency and/or skew. This paper presents a new obstacle-avoiding CTS approach with separate clock tree construction and buffer insertion stages based on an integral view to explore the global optimization space. Aiming at skew optimization under constraints of slew and obstacles, our CTS approach features the clock tree construction stage with the obstacle-aware topology generation algorithm called OBB, balanced insertion of candidate buffer positions, and a fast heuristic buffer insertion algorithm. Experimental results show the effectiveness of our CTS approach with significantly improved skew and latency than [6] by 46% and 63% on average, and 15.3% reduction in skew than [5]. Our OBB heuristic obtains 36% improvement in skew than the classic balanced bipartition algorithm (BB) in [9].

During 2002–2004, a broad-scale survey on the plant diversity of grassland communities along a natural elevation gradient in the permafrost regions of the Qinghai–Tibet plateau, China, was conducted to investigate the effect of highway construction nearly 30 years ago. Richness index was not significantly different among undisturbed communities (Kobresia pygmaea meadow, K. humilis meadow, Stipa purpurea steppe, Carex moorcroftii steppe), but significant differences (P < 0.05) were observed for evenness and diversity indices among four undisturbed communities. Three indices significantly decreased from communities 100 m (lightly disturbed communities), 200 m (undisturbed communities), and 50 m (severely disturbed communities) from the Qinghai–Xicang Highway, and three indices of severely disturbed communities were similar to that of 30 m communities (extremely-severely disturbed communities). Diversity and richness indices peaked at intermediate elevations of 4720 m in undisturbed communities and lightly disturbed communities, but were uniform in the severely disturbed communities and extremely-severely disturbed communities along with the increase of elevation. β-Diversity decreased in communities at 30, 50, and 100–200 m distance from the highway. This indicated that β-diversity of communities was enhanced with the increase of disturbance for each grassland type in the study region. Both undisturbed and disturbed communities showed the same changeable bell-shaped trend with elevation increase, increasing from 4320–4620 m, decreasing from 4720 to 4920 m, and peaking at 4620 to ~4720 m, indicating that elevation from 4620–4720 m was a transition zone in permafrost region.

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