气候变化下基于GIS的农田恶性杂草旱雀麦在中国的分布与发展趋势

Distribution and development trends of farmland malignant weed Bromus tectorum L.in China under climate change

为确定旱雀麦在我国的空间分布及其对气候变化的响应,以期进一步开展生态防控,本研究利用旱雀麦在中国的地理分布数据,结合当前气候数据和未来气候变化情景(RCP8.5情景下2050_(s),2070_(s)),建立最大熵模型(MaxEnt模型),确定影响旱雀麦分布的主导环境因子。应用地理信息系统(GIS)对中国地区旱雀麦的适生区进行划分,以ROC曲线作为模拟的准确性评价指标。结果表明,MaxEnt模型模拟效果极好(AUC=0.965);当前气候条件下,旱雀麦适生面积为2.5534×106 km2,主要集中分布于青海省东北部、甘肃省与青海省接壤的地区、四川省的西北部,以及新疆的西北部;其中影响旱雀麦分布的主要环境因子为海拔、bio12(年降水量)、bio9(最干季度平均温度)和bio15(降水量季变异系数),其贡献率分别为45.0%、17.5%、9.7%、9.7%,累计贡献率达81.9%;在RCP8.5情景下,未来2个时期,旱雀麦潜在高适生区分布面积与当前相比增加了12.2%~23.3%,但RCP8.5情景下2070s较RCP8.5情景下2050s旱雀麦的潜在高度适生区分布面积减少了8.9%。综上所述,气候变化情景下旱雀麦的潜在分布面积呈现出扩大趋势,且RCP8.5情景下2070_(s)较RCP8.5情景下2050s的适生区分布面积有缩减趋势。

The purpose of this study was to determine the spatial distribution of Bromus tectorum L.in China and its response to climate change so as to develop ecological prevention and control measures.The study used the geographical distribution datas of Bromus tectorum L.in China with current climate datas and future climate change scenarios(2050_(s) and 2070_(s) under RCP8.5 scenarios)to establish a maximum entropy model(MaxEnt model)and decide the dominant influence on the distribution of Bromus tectorum L.environmental factors.The geographic information system(GIS)was used to divide the suitable areas of Bromus tectorum L.in China,and the ROC curve was used as the accuracy evaluation index of the simulation.The results showed that the MaxEnt model had an excellent simulation effect(AUC=0.965).Under current climatic conditions,the suitable area for Bromus tectorum L.was 2.5534×106 km2,which was mainly distributed in the northeastern part of Qinghai Province and the area bordering Qinghai Province and Gansu Province,the northwest of Sichuan Province and the northwest of Xinjiang.Among them,the main environmental factors affecting the distribution of Bromus tectorum L.were altitude,bio12(annual precipitation),bio9(average temperature of the driest quarter)and bio15(coefficient of seasonal variation of precipitation).Their contribution rates were 45.0%,17.5%,9.7%and 9.7%respectively,and the cumulative contribution rate was 81.9%;Under the RCP8.5 scenario,during the next two periods(2050_(s) and 2070_(s)),the distribution area of the potential high-fitness area of Bromus tectorum L.would be increased by 12.2%~23.3%compared with the current situation.The distribution area of potential highly suitable areas would be reduced by 8.9%in the 2070s,compared with that of the 2050s.In summary,the potential distribution area of Bromus tectorum L.under the climate change scenario showed a trend of future expansion compared with current times,and the distribution area of suitable area in the 2070s under RCP8.5 scenario showed a decreasing trend compared with that of the 2050_(s) under RCP8.5 scenario.