The Study Of Sustainable Development On Grazing Ecosystem Of Natural Grassland

In recent years, severe degradation of natural grassland and consequent issues in ecological, environmental and social aspects has received more and more attention worldwide. Inner Mongolia steppe, locating at the north part of china, plays important roles not only in developing livestock husbandry, but in maintaining ecological security of the country since this widely distributed grassland also serves as a green belt. Nowadays, building socialist harmonious society prevails nationwide. Thus, understanding pathways of sustainable development in this region is necessary and desirable.According to up-to-date achievements of sustainability science, the research of sustainable development on Nature-Economy-Social Complex Ecosystem (NESCE) of Inner Mongolia steppe was carried out from household perspectives by analyzing huge volume of data observed and collected in 7th pasture, Baiyinxile of Xilingol League. The main results showed that:(1) Both human activities and natural ecosystems have being altered greatly during past two decades. The number of the household increased, and spatial pattern changed, clearly. And both of the two features standing for human disturbance were likely to change a little at present. The structure and function of grassland ecosystems have being changed simultaneously. Land covers became relatively stable after experiencing dramatic transformations. In general, grassland resources degraded gradually. Analyzing the grazed intensity from the perspective of biomass, taking 1998 as the turning point, the area of lightly grazed grassland showed decrease before that point and increase after 1998. Thus, structure and function of grassland ecosystems demonstrated non-synchronous changing when strong grazing pressure disturbed continuously.(2) Based on the demand-supply-structure model of grazed natural grassland ecosystems, the index system for evaluating sustainable use of grassland resources was established, and evaluation according to this system was achieved. The result showed that both early (1989～1995) and later (since 1998) stage expressed greater sustainability, characterized by remaining much more sustainable grassland accounting for 84.46% and 85.82% of the total respectively, than did middle stage (1995-1998) while sustainable grassland was only 57.39%. Nevertheless, despite of great deal sustainable grassland appeared, NESCEs in early and later stage have different features. Ecosystems in early period maintain more complicated structure, and produce higher biomass as well. There is no obvious degradation, and the social need is low. In latter stage, on the contrary, due to large amount of social need met mainly from grassland grazing, ecosystems are degraded widely. Acceptance left is just that biomass remains in a relatively high level. What's more, grazing (demand) is one of main drive forces altering natural grassland ecosystems, and changes of both standing live aboveground biomass (supply) and types of plant community (structure) indicate responses of ecosystem to disturbances. When demand increases and exceeds limitation, moreover, there is no enough external energy input, grassland productivity drops inevitably, and then, changes of ecosystem structure take place. When demand remains more or less stable, the ecosystem will be in a new sub-stable status characterized by slowly changing of above mentioned two main ecosystem attributes.(3) At the atmosphere of both "double rights one system" land regime and market economy, households become free, independent entities. Ways of producing and managing among households showed diversity and differentiation, resulted in appearing different levels of sustainable development, and in unbalanced development affected by many factors. Scale and behavior of management played significant roles in determining household sustainability. Households at low level of sustainable development were weak in acquiring energy, information, material supply, and were lack of ability to respond environmental hazards efficiently. Meanwhile, households at higher level of sustainability had more power to use resources and to adapt changing environment, efficiently. But, these abilities are still need to improve, comparing with the overall power of those households.(4) From the potential point of view, theoretically, expenditures in aspects of grassland area, livestock number, and management activities suggested decrease by 49.86%, 47.29% and 60.79%, respectively, with optimized scenarios. Furthermore, it was also likely to increase living consumption per capita and saving per capita by 33.50% and 7.06%, respectively, without significant degradation in grassland resources. Nevertheless, it is necessary to integrate theories and achievements derived from trans-disciplinary fields for in-depth study on sustainable development. Consequently, aspects as "humanity" and "land regime" relevant to social science, should be paid more and the same attention as did in natural science in the future.