Integrating landscape planning and stream quality management in mountainous watersheds: A targeted ecological planning approach for the characteristic landscapes

摘要

Landscapes in the watersheds can comprehensively reflect and actively drive the dynamic changes of water quality along a river. Therefore, scientific landscape-ecological planning is critical to stream quality manage-ment. However, due to the complicated socioeconomic attributes of landscapes, it is very difficult to fully realize the optimal configuration of each type of landscape. Therefore, it remains a challenge in how to incorporate the trade-offs of different landscapes and the priority in landscape optimization into watershed landscape planning approaches to promote effective planning practices, especially in mountainous watersheds. To better solve this problem, we proposed an improved and targeted ecological planning method based on landscape ecology, which emphasized the significant roles of the characteristic source-sink landscapes (CSSL) and their structure that contribute the most to stream quality changes in sustainable management for mountainous stream quality. We conducted this study in Yinglong watershed, a mountainous watershed in Chongqing, China, and carried out the landscape ecological planning through "CSSL extraction -constraint functions construction -CSSL optimization". The research showed that (1) agricultural and forest landscapes were the CSSL that could represent the impact of the overall landscapes on stream quality in mountainous watershed; (2) besides the landscape area, stream quality also highly cohered with the quantitative structure of the CSSL; (3) the sustainable management for stream quality in mountainous watersheds could be promoted by conducting ecological planning for the CSSL and controlling their quantity structure within a reasonable range. Our research showed that it was feasible to optimize the main conflict landscapes tightly associated with stream quality changes through landscape ecology methods to help manage stream quality more effectively. This more targeted and easy-measured ecological planning method can promote the conversion of theoretical planning outcomes to planning practices, and can also encourage landscape planners, not just scientific researchers, to participate in specific ecological planning practices.