In accordance with the classification of wetlands by Lamsar Convention, Hani’s terrace paddyfield of Yunnan Province in China, is one type of the constructed wetlands. Hani’s terrace paddyfield distributs from 144 m to 2000 m above sea level (ASL) in the southern slopes of Ailao Mountains. The degree of the slopes ranged from 15° to 75°. In this case study, we investigated the ecosystem of terrace paddyfield of Mengpin and Quanfuzhuang administrative villages, located in the center of the cultural heritage conservation district of Hani’s terrace paddyfield. The ecosystem of Hani’s terrace paddyfield is composed of “forest-village-terrace paddyfield-river" with decrease of altitude. Soil and water samples were taken in forests, villages and terrace paddyfield to study the vertical characteristics of Hani’s terrace paddyfield. PO₄-P and NH₃-N in water were measured. Seven nutrient factors of soil were determined, including organic matter, C/N, pH, total N, total P, available P, and available K. We also evaluated the soil quality using the soil nutrient factors.
Vertical changes of landscape, wetland types, wetland plants, hydrographic characteristic and soil nutrients were characterized. The results showed that: (1) Hani’s terrace paddyfield could been divided into five types of wetlands: North tropical valley terrace paddyfiled, South subtropical mountain terrace paddyfield, Middle subtropical mountain terrace paddyfield, North subtropical mountain terrace paddyfield, and South Temperate zone mountain terrace paddyfiled. In different types of terrace paddyfield, about 108 species of rice and some different cultivated modes were used to adapt to climate and environment. The rice varieties and cultivate ways were different in each type of wetland. (2) Hani’s terrace paddyfield had great water conservation capacity and had strong ability of purifying the contaminations. The impoundage of Hani’s terrace paddyfieldies was about 5050m³/hm². The contaminants in the terrace paddyfield soils decreased exponentially with the decrease of altitude. (3) Comparison of soil quality in five different land use types indicated decreasing order of soil quality: forest>terrace land>terrace paddyfield>water source. Except soil of headwaters, unit-factors such as OM, TN and TP, and the comprehensive qualities of soil all increased with the increase of altitude in individual sampling zone. Soil general quality of Quanfuzhuang sampling zone was better than Mengpin sampling zone.
The characteristics of structures, functions and values were compared among Hani’s terrace paddyfield, paddyfield in plain, and natural wetlands to emphasize the vertical characteristic. It was concluded that Hani’s terrace paddyfield have stronger functions and higher values than the paddyfiekd in plain, but lower than natural wetlands.