To analyze the distribution pattern of thorny shrubs and its impact factors, 460 sample sites were collected in mountains of the Beijing-Tianjin-Hebei region. Results showed that about 60% of sample sites had thorny shrubs, which were mainly the shrub community dominated by Vitex negundo var. heterophylla. In a small number of sample sites, thorny shrubs even became the dominant species. Twenty-four thorny shrub species were mainly from the families Rhamnaceae, Rosaceae and Leguminosae. The most common three species (Ziziphus jujuba, Rhamnus parvifolia and Caragana rosea) are mainly distributed on the gentle sunny and half-sunny slopes in the hilly area with elevation lower than 600 m a.s.l.. Quantitative analysis also showed that light condition and drought were limiting factors for growth of thorny shrubs (especially Ziziphus jujuba). Affected by climate, topography, and community factors together, thorny shrubs can be distributed under different habitats in mountains of the Beijing-Tianjin-Hebei region.
Based on status assessment of ecological environment and ecological system, this paper mainly analyzed significance and sensibility of ecological functions in Lushan earthquake-hit regions. An optimization program of land spatial pattern for the reconstructions of Lushan earthquake-hit regions was proposed to restore ecosystem function and optimize land spatial pattern. It could be divided into three sub-regions, ecological reserve, eco-agriculture development area, and eco-town development area. Main results are as follows. 1) The ecological protection area is extensive in Lushan earthquake-hit regions, accounting for 80.6% of the total area. In ecological protection area, the protection goal is to maintain ecological security by protect important ecological functions and carry out ecological restoration. 2) The eco-agriculture development area accounts for 13.4% of the total area. As an important agricultural production function zone, the dominant ecological function of this area is to provide safeguard for supply of agricultural products. It also needs providing guarantee of soil conservation function. 3) The eco-town development area only accounts for 6.0% of the total area. This area is the core region of regional urbanization and industrial development. On the premise of protecting ecological, the reconstructions direction is to construct the ecological city through optimization industrial structure and distribution.
By using spatial dataset of ecosystem types, ecosystem transfer matrix and dynamic degree methods, the changes of ecosystem structure and spatial distribution in Qinghai-Tibet Plateau ecological barrier area were analyzed during recent ten years. The results show that: 1) The ecosystem structure of Qinghai-Tibet Plateau ecological barrier area is relatively stable, 69% of the total land area is grassland ecosystem. 2) There are increase or decrease both in ecological and un-ecological land use, the wetland increases 2660.9 km2, the grassland cuts 1377.5 km2, the urban expands 224.6 km2, the farmland reduces 163.4 km2, and the desert reduces 1388.5 km2. 3) The change rates of urban and farmland, which are significantly influenced by human activities, are distinctly higher than the wetland. For example, the urban area increases rapidly with an average annual growth rate of 2.88% and the farmland decreases 0.64% per year on average from 2000 to 2010, however the average annual growth rate of wetland is only 0.44%. 4) The overall transfer of ecosystem is small and only for 0.5% of entire study area. The areas of grassland shift to wetland and the desert shift to wetland are larger and contribute 69% to entire ecosystem transfer. 5) Both natural and human factors are the driving forces of ecosystem change, among which climate change is the main factor causing the increase of wetland area; the rapidly growth of population and GDP causes the urban expanding, but the development of industry and mining industry is the deep reason for the expansion; the increase of grazing capacity is the main cause of the grassland degradation , but the ecological protection projects play a rather positive role in grassland ecosystem recovery.
