关键词: 养分状况, 水分利用效率, 年龄序列, 杉木

Abstract: Fargesia denudata is one of the primary edible bamboo species for giant panda and the most widely distributed species of genus Fargesia in Baishuijiang National Nature Reserve, Gansu Province. Understanding the geographical distribution of F. denudata will facilitate the conservation of wild giant panda. Through field investigation and data sorting, 73 effective distribution recordsofF. denudata were obtained. A total of 45 environmental variables with respect to climate, soil, topography, and evapotranspiration were analyzed by multicollinearity. After eliminating environmental factors with low contribution rates, seven climate variables, three soil variables, two topography variables, and two evapotranspiration variables were chosen as model inputs. MaxEnt was used to simulate geographical distribution of F. denudata and the contributions of different variables. Finally, ArcGIS was used to classify the grades of suitable distribution and extract environmental characteristics. The AUC value of ROC curve was 0.932, suggesting high reliability and accuracy of the simulation. Results of Jackknife test showed that minimum temperature of coldest month, altitude, standard deviation of seasonal variation of temperature, precipitation of wettest month, and temperature annual range affected the distribution of F. denudata. Distribution of suitable area of F. denudata was concentrated in the western part of the reserve. The suitable area was 584.76 km², accounting for 31.13% of the total area of the reserve. The most suitable area was 103.15 km², with minimum temperature of coldest month from -15 ℃ to -9 ℃ and altitude range of 2148-3468 m. The MaxEnt can well simulate the geographical distribution of F. denudata and evaluate the importance of environmental variables. Our results could provide reference for F. denudataprotection of wild giant panda’s main food resources in the reserve.

Key words: Cunninghamia lanceolata, chronosequence, nutrient status., water use efficiency