[Influence of landscape pattern on elevation effect of δ 18 O in surface water in Hani Terrace].

With the Quanfuzhuang River basin located at Hani Rice Terrace core region as study area, we analyzed the isotopic composition and the effects of 12 surface water sampling sites for the forest landscape type and terrace landscape type from May 2015 to April 2016. The results showed that: 1) For the variation of isotope composition, both the average value and the variation range of δ ¹⁸ O in surface water under forest patches were smaller than that under terrace patches. 2) The overall elevation effect of the hydrogen and oxygen stable isotopes in surface water was obvious, except that in August and March, which could be expressed as the linear regression equation δ ¹⁸ O=-0.012 H +13.84 ( r =-0.83, n =12). 3) The altitude gradient of δ ¹⁸ O in surface water was -1.2‰·(100 m) ^-1 , which was not the true altitude gradient affected by precipitation but by landscape gradient of δ ¹⁸ O in surface water between forest patches and terrace patches. 4) Under the "Forest-Terrace" landscape pattern, the δ ¹⁸ O differences in surface water between forest patches and terrace patches enhanced the elevation effect. Therefore, when landscape heterogeneity was strong, isotopic effect was strengthened, even with opposite isotope effect.