Study On Ecological Safety Assessment In Hulunbeier Steppe

As the main part of Eurasia steppe, Hulunbeier steppe plays a key role in environmental protection with important ecosystem services (e.g. wind prevention and sand fixation, water conservation, biodiversity protection, etc.) and providing significant material basis for economic development in pastoral area. At the same time, many minorities (e.g. Monglian, Ewenki, Daurians, Buryats, etc.) live in this region. Whether grassland ecological safety situation is good or not will directly affect the sustainable development of the whole pastoral areas, and even affect the social stability in border area and daily life of180million people living in downstream region.This study takes Hulunbeier steppe as the research object and identifies main ecological safety issues in study area. From the perspective of grassland degradation, landscape ecological safety and ecosystem services, ecological safety assessment based on single factor were carried out. Then, combined with Pressure-State-Response concept model, ecological safety assessment indices were selected. Based on strong spatial analysis and visual representation of GIS, evaluation unit was a grid (250m×250m) instead of obeying to administrative boundary, and then every index was displayed spatially. With weighted superposition of each index layer, spatial pattern of ecological safety in Hulunbeier steppe was calculated and the influence factors were analyzed. The main conclusions are drawn as follow:(1) By comparing with grassland degradation in different years (2000,2005and2010), ecological quality status is getting better. The moderate and heavy degradation grassland presented a decreasing trend. In2010, non-degradation and light degradation accounted for over70%of the total area. Heavy degradation grassland was mainly distributed along Kelulun River because of lack of precipitation and over-grazing.(2) The overall landscape tended to become fragmentized and complex with the total number of patches increasing by4549in study area from1995to2010, which will do harm to biodiversity in study area. The ecological safety index of landscape types can be classified into four grades, grassland (0.4-0.6)> unused land, wood land (0.1-0.2)> water area, crop land (0.06-0.08)> construction land (0.008-0.04). Grassland is the safest and construction land is the most unsafe. However, the area of construction land had a continuous increase with a higher growth rate (7.41%per year during2005-2010), which will be unfavorable to regional ecological safety as the biggest potential risk.(3) Ecological values increased by5.69×108RMB during1995-2000. But it has showed an opposite trend since2000(14.66×108RMB,2000-2005;6.04×108RMB,2005-2010) due to industrialization and urbanization. However, the growth rate of the patch number and area of extremely unsafe region had a decrease trend which was closely related to grassland protection policies.(4) As can be seen from the comprehensive assessment results,50.72%of the total area remains relatively safe level; ecological safety area comes next and the ecological status of Ewenke was best among six counties in study area. The percentage of unsafe region was less than16.10%, mainly distributed both sides of Kelulun River, Hailar River and Wuerxun River, which suggest that the overall ecological status is getting better.