Evaluation on the adaptability of Yunnan karst ecosystems based on “rock-soil-water-vegetation”

Abstract

Because of its fragile nature, the karst ecosystem is prone to instability and gradual degradation of the key elements with “rock-soil-water-vegetation” under the continuous interference of human unreasonable activity, resulting in the final formation of the rocky desertification landscape. Based on the research of the structure of karst critical zone, it was proposed to establish the concept of karst ecosystem adaptability with the evaluation system of “rock-soil-water-vegetation”. At the same time, the analysis of the stress and coupling relationship was conducted in combination with the analysis of human activity intensity in Yunnan karst rocky desertification areas. The results showed that: (1) On the county scale, the karst ecosystem adaptability mainly fell into Level 2–3 (0.10 < Ake ≤ 0.30). The contribution degree of indicators followed the order of annual precipitation > proportion of waterbody area, biological abundance index > rock outcrop rate > wetness index, vegetation cover > soil erosion index. (2) The synergistic relationship between karst ecosystem adaptability and human activity intensity was mainly characterized by ecological priority type (S ≥ 1.20), which was mainly found in West, Northwest and Southwest Yunnan. The development priority type (0 < S ≤ 0.80) was mainly centered around Kunming City, extending eastward to Qilin District of Qujing City, southward to Hongta District of Yuxi City, and further to Gejiu-Mengzi-Kaiyuan of Honghe Prefecture and Wenshan City of Wenshan Prefecture. (3) The coupling relationship between the karst ecosystem adaptability and human activity intensity was mainly in the running-in coupling state (0.50 < C ≤ 0.80). The coupling centers were mainly in Kunming City, Yuxi City, Qujing City and Honghe Prefecture (a high-level coupling, 0.80 < C < 1.00). (4) The coordination relationship between the karst ecosystem adaptability and human activity intensity mainly fell into the imbalanced development category, mostly moderately and mildly imbalanced development (0.20 ≤ D < 0.40). The coordinated development center was mainly centered in Kunming City of Central Yunnan (a coordinated development, D ≥ 0.5), which widely extended southward to Hongta-Jiangchuan-Chengjiang -Tonghai in Yuxi City and slightly spread eastward to Qilin District in Qujing City. The research results can provide effective ways and evaluation basis for enhancing the resilience and stability of the karst ecosystem and repairing damaged links, and also provide theoretical support for further studies on sustainable development of karst rocky desertification areas.