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As the second batch of international wetland cities, Wuhan and Nanchang, both provincial capital cities in China, have abundant wetland resources. An important sign of achievement of protecting the urban wetland areas is the international wetland city designation. Understanding the growth and changes of wetlands in international wetland cities is necessary for wetland protection and management. Thus, it is crucial to conduct proper wetland mapping in these international wetland cities. By studying wetland cities, sustainable planning can be provided to promote the coordinated development of wetlands and cities. In this research, Google Earth Engine and random forest machine learning were used. According to the “Data-Information-Knowledge-Wisdom” research framework, we carried out mapping of diverse wetlands in Wuhan and Nanchang with a resolution of 10 m in 2015 and 2020. Then, using the findings of wetland mapping, we examined changes in the wetland landscapes of the two cities. Finally, this study examined changes in international wetland city indicators over this time frame. The research results are as follows. 1) Our wetland mapping results in 2015 and 2020 achieved good accuracy, with an overall accuracy of over 0.90 and a kappa coefficient of over 0.85. 2) The total wetland area in both cities increased. Nanchang grew by 91.11 km2, whereas Wuhan grew by 290.68 km2. Most restored wetland areas were far from urban construction areas. In the two cities, the fragmentation of wetlands decreased, the diversity of wetlands increased, and the growth rate of wetlands was high. 3) Wetland rates rose from 17.79% to 19.07% in Nanchang and from 19.74% to 23.12% in Wuhan, according to mapping results between 2015 and 2020. The wetland protection rate in Nanchang remained unchanged, but the wetland protection rate in Wuhan decreased. Wuhan needs to strengthen the protection of increased wetlands. In addition, the study found that most of the increased areas of wetlands were previously cultivated land. The international wetland mapping framework of this study can be easily implemented in other regions of the world.

A reversed-phase HPLC method for simultaneous determination of gatrorrhizine, columbamine, epiberberine, coptisine, palmatine and berberine in Coptis chinensis was developed. Analysis was carried out on an Xtimate C18 column (4.6 mm x 250 mm, 5 microm) eluted with acetonitrile-30 mmol x L(-1) ammonium bicarbonate solution (including 0.7% ammonia and 0.1% triethylamine) by gradient elution. The detective wavelength was 270 nm, the column temperature was 30 degrees C, and the flow rate was 1.0 mL x min(-1). By the above method, the linear ranges of gatrorrhizine, columbamine, epiberberine, coptisine, palmatine and berberine were 0.85-16.96 (r = 0.9997), 1.25-24.96 (r = 0.999 5), 2.05-40.96 (r = 0.999 9), 3.65-72.96 (r = 0.999 9), 2.88-57.60 (r = 0. 999 8),13.25-264.96 mg x L(-1) (r = 0.999 6), respectively. The average recoveries (n = 6) of the six alkaloids were 101.6% (RSD 1.3%),102.5% (RSD 1.5%), 100.8% (RSD 1.9%),102. 6% (RSD 1.2%), 97.80% (RSD 1.3%), 99.01% (RSD 1.5%), respectively. The determined results demonstrate that there is a significant difference in the contents of six alkaloids and total alkaloids among the tested samples. The method is accurate, reliable and repeatable for simultaneous determination of gatrorrhizine, columbamine, epiberberine, coptisine, palmatine and berberine in C. chinensis.