关键词: 消落带, 富营养化, 分解, 氮磷释放

Abstract: Davidia involucrataBaill is a rare and precious tree species in China. The prediction of its suitable habitats can provide important reference for its protection and research. Based on 387 sample distribution and 27 environmental factors in China, the MaxEnt model and geographic information system (GIS) were used to predict the potential suitable habitats. The accuracy of the model was verified by receiver operating characteristic curve (ROC). The results showed that the mean value of the area under ROC curve was 0.951, and the accuracy of the model was high, which was suitable for predicting potential suitable habitats of D. involucrata. The potential suitable habitats for D. involucrata were mainly located in Sichuan, Yunnan, Guizhou, Hunan, Hubei, Chongqing, Shanxi, and Tibet. The highly potential suitable habitats distributed in an irregular circular shape, with the Hengduan Mountains to the west, the Qinling WudangJinshan Mountains to the north, the ZhangjiajieXuefeng Mountains to the east and the south to Guiyang. In addition, they are also distributed in the Yarlung Zangbo River Valley in the southeast of Tibet and the Dabie Mountains in western Anhui. The major factors determining the potential suitable distribution were annual temperature range, annual precipitation, minimum temperature of coldest month, diurnal temperature difference, and annual precipitation variation coefficient. Other environmental factors, such as topography, soil, hydrology, had limited influence on the distribution of D. involucrata.

Key words: reservoir riparian region, eutrophication, decomposition, release of nitrogen and phosphorus.