Qilian Mountain Nature Reserve Ecological Carrying Capacity

Qilian Mountain Nature Reserve, situated in the upper reaches of three big inland rivers: Heihe River, Shiyang River and Shule River, not only plays a decisive role in the stabilization of the ecosystem of Hexi Region, but is the pivotal site for the study of global changes. This eco-region's unique ecologically functional positioning and its natural, social and economical natures as a sparsely populated region render the traditional land carrying capacity and resources carrying capacity evaluation inadequate to reflect the main ecological problems of the region.The current project aims, by means of ecological resilience evaluation, to analyze the features of the ecosystem, the interference of the ecosystem by human activities and the system's interference of human activities, and reveal the main ecological problems of Qilian Mountain Nature Reserve, so as to formulate proposals for decision-makers with respect to the conservation and sustainable development of the Nature Reserve.This paper, on the basis of the analysis and summarization of the previous research results in this field, first discusses the basic concept and evaluation method of ecological resilience, and then points out that ecological resilience is an ecosystem's resilience from interferences, especially human interferences, and thus, the evaluation of ecological resilience should involve both the estimation of ecological resilience and evaluation of ecological load. With the aid of such basic mathematical tools as analytic hierarchy process and fuzzy pattern recognition, a comprehensive evaluation model is thus established, focusing on the analyses of the ecological resilience and ecological load of forest, grassland and farmland, the three elements subject to the strongest human interferences within the ecosystem, on the basis of which the overall ecological resilience and ecological load of the whole Nature Reserve are then analyzed.Our research shows that the ecosystem of Qilian Mountain ecoregion has been subject to strong human interferences and is ecologically overloaded. But within the ecosystem, discrepancies do exist among subsystems and in the spatial distribution of ecological load". The subsystem Of forest and that of grassland are severely overloaded while that of farmland is medium overloaded; in the spatial distribution of ecological load, the northwest region is more severely overloaded than the southeast; as for the overloading of subsystems, the subsystem of forest and that of grassland are less severely overloaded in the southeast than in the northwest, but as for the overloading of the farmland subsystem, it is more severe in the southeast than in the northwest.Our research indicates, 1st, the main ecological problems of Qilian MountainNature Reserve can not simply be attributed to overpopulation that surpasses the land resources bearer capacity, nor to the water shortage in the normal sense; instead, it is due to the diminishing of the region's water holding and anti-erosion capability resulted from deforestation and over-grazing; 2nd, there is a time lag of the ecosystem's response to human activities - strict protection of forests in the Qilian Mountain Range has been implemented since 1980s when the Nature Reserve was established, but so far we have witnessed no dramatic improvement of the forest ecosystem severely damaged in the past, so it is a long and hard task to bring the ecosystem of the Nature Reserve back to normal state and allow it to function duly; 3rd, the most severely affected regions of the damage done to Qilian Mountain ecosystem are not the Nature Reserve itself, but such regions as Hexi Corridor and Ejina Qi in the lower reaches of Heihe River.