Fitness evaluation of Dike-pond utilization based on Niche model

Dike-pond was a special land use type and played an important role in the land use pattern of Pearl River Delta. This paper took Dike-pond as the research object, Nanhai District of Foshan City as the research area, introduced the Niche-fitness model into the quality evaluation of Dike-pond, and constructed the Niche-fitness evaluation index system of Dike-pond utilization from three dimensions: Natural quality, social and economic, spatial form. Then it used the means of Hibbert space, weighted average, limiting factor and weighted summation models to calculate the Niche-fitness in different dimensions, divide the fitness level, and analyze Dike-pond utilization quality and its distribution characteristics. The results showed: 1) From the natural quality dimension, Dike-pond was dominated by relatively high and middling fitness, and the distribution was high in the south and low in the north. The areas of high and relatively high fitness were 3 266.04 and 7 130.09 hm2, respectively, which were concentrated in Jiujiang, Xiqiao and Danzao of the southwestern part. The area of middling fitness was 5 622.52 hm2, mainly distributed in Xiqiao, Danzao and Shishan. And the low fitness of Dike-pond was the most in Jiujiang, Shishan and Danzao. 2) From the social and economic dimension, Dike-pond was dominated by middling and relatively high fitness, and the overall level was relatively low. The areas of middling and relatively high fitness were 6 373.32 and 5 596.50 hm2, which were concentrated in the southwestern part; The high fitness was the most in Jiujiang and Shishan, the low fitness was the most in Danzao and Xiqiao. 3) From the spatial form dimension, the Niche fitness was generally higher, and the distribution was high in the south and low in the north. The area of high fitness was 9 494.36 hm2, mostly distributed in the southwestern part; The area of relatively high fitness was 2 942.02 hm2, which was evenly distributed in the southwest and the north; The middling fitness was the most in Shishan, the low fitness was the most in Shishan and Lishui. 4) The Niche fitness level of Dike-pond in Nanhai District was generally high, and high fitness was the main type, the distribution was high in the south and low in the north. The area of high fitness was 9 494.36 hm2, accounting for 53.96% of the total Dike-pond area, concentrating in Xiqiao, Jiujiang and Danzao, and also the cradle of traditional Dike-pond in Pearl River Delta. The area of relatively high fitness was 3 301.35 hm2, distributed in the southwest and the north; The area of middling fitness was 3 274.72 hm2, with the largest number of Shishan; The low fitness was 1 406.43 hm2, the northern part was the most. It was an effective way to improve the Niche fitness level of Dike-pond by protective development measure, using the segmentation, increasing the intensity of remediation, improving the ecological environment.