Quantitative analysis of resource and environment carrying capacity for Water Conservation Area in Qin-Ba Mountains

Under nationwide construction of ecological civilization, research on the sustainable development of ecological regions has become increasingly important. As resources and environment carrying capacity of important ecological areas are part of regional economic development, there is practical significance for its objective and accurate evaluation. Water Conservation Area in Qin-Ba Mountains is critical for water conservation and biodiversity protection of area between Qinling Mountain and Daba Mountain, a region with a total area of 183 697.03 km². In this study, the carrying capacity of resources and environment of the Water Conservation Area in Qin-Ba Mountains were evaluated based on data from regional survey and theoretical framework of ESI model and state-space method. The evaluation system of the carrying capacity of resources and environment was established according to the local development characteristics. This included two target layers (ecological carrying capacity and social and economic pressure) and 18 indexes. The regional ecological carrying capacity, resources exploitation and pollution discharge conditions of the Water Conservation Area in Qin-Ba Mountains were assessed. The regional environmental conditions affected by human activities were quantitatively analyzed. Also using 2010 regional statistical data, the distribution of resources and environment carrying capacity of the study area was analyzed, and the relationship between ecological carrying capacity and social economic pressure explored. The results showed that the ecological environment of the Water Conservation Area in Qin-Ba Mountains was fragile, with the smallest ecological carrying capacity index of 0.135. There were significant differences in the spatial distribution of the ecological carrying capacity, with higher ecological carrying capacity index in the central and southern parts of the study area, and with the highest value of 0.795. Water retention capacity, carbon sequestration and oxygen release ability were the main driving factors of the ecological carrying capacity of the area. Social and economic pressure index of the study area was higher, with the highest value of 0.517. This suggested that there was a great pressure on the ecological environment, driven by social and economic development. The correlation between resource consumption and environmental pollution indicated that the development of the area somewhat depended on resource consumption. The main driving factors of social and economic pressure index were industrial “three-waste” emissions per unit area, population density, energy consumption index and domestic sewage discharge per unit area. The resources and environment carrying capacity of the central and southern parts of the study area were higher than those of the periphery areas. In few “overload” areas, the highest index reached 6.790. The driving factors of the resources and environment carrying capacity were average annual temperature, vegetation cover and domestic sewage discharge per unit area. Decoupling index showed that the separate effects of ecological or social factors on the resources and environment carrying capacity of the area were small, belonging to “relative decoupling”. In general, the effects of vegetation cover and sewage discharge were obvious. Overall, the development of the area was still at the steady stage. It was necessary to make different development strategies for different regions in the study area.