基于MaxEnt与ArcGIS对白水江国家级自然保护区缺苞箭竹适生区分析

缺苞箭竹是甘肃白水江国家级自然保护区大熊猫的主要食用竹种之一,是该区天然分布最广的一种箭竹,掌握其地理分布对于野生大熊猫的保护具有重要意义。通过野外实地调查和数据整理,获取缺苞箭竹有效分布记录共73条,同时对保护区气候、土壤、地形和蒸散4类45个环境变量进行多重共线性分析,筛选出7个气候变量、3个土壤变量、2个地形变量和2个蒸散变量作为模型输入;进而采用最大熵模型MaxEnt与地理信息系统ArcGIS模拟缺苞箭竹的地理分布,分析环境变量对缺苞箭竹分布的影响,并划分适生区等级,分析适生区环境特征。结果表明,基于最大熵模型的缺苞箭竹受试者工作特征曲线AUC值为0.932,模型结果很好,可信度高。刀切法检验结果表明,最冷月份的最低温度、海拔、温度季节性变化的标准差、最潮湿月份的降雨量、年温度范围对缺苞箭竹分布影响较大。适生区分析显示,缺苞箭竹集中分布在保护区西部,适生面积为584.76 km²,占保护区总面积的31.13%,其中最适生区面积103.15 km²,其特征是最冷月份的最低温度-15～-9℃,海拔2148～3468 m。研究认为,最大熵模...

Analysis of suitable distribution areas of Fargesia denudata in Baishuijiang National Nature Reserve using MaxEnt model and ArcGIS

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 km^2,accounting for 31.13%of the total area of the reserve.The most suitable area was 103.15 km^2,with minimum temperature of coldest month from-15℃to-9℃and altitude range of 2148-3468 m.The Max Ent 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.