气候变化下板栗适宜性分析及分布预测

Suitability Analysis and Distribution Prediction of Castanea mollissima under Climate Change

【目的】探究影响板栗分布的主导环境因子,模拟不同气候条件下板栗潜在分布区,为板栗种质资源保护和引种提供理论依据。【方法】基于472个板栗现有种群分布地理信息与21个环境变量,采用物种分布组合模型模拟板栗潜在适宜分布区,通过AUC与TSS值评价模型准确性。利用组合模型推测末次冰盛期、全新世中期、当前、2030年和2050年板栗适宜区分布及其变化趋势。【结果】1)10种模型中,RF、GBM、MARES和GAM预测精度最好且稳定,最终组合模型AUC和TSS值分别为0.974和0.816,精度较高。2)影响板栗地理分布的主要环境因子为最冷月极端低温、海拔、最湿季降水量、年温变化范围和最湿月降水量,累计贡献率达89.79%。3)当前气候条件下中国潜在板栗适宜区分布广泛,自末次冰盛期以来,板栗适宜区不断向高纬度地区扩张,气候越暖扩张越快。但板栗整体适宜性不断下降,南方较为突出,北方则降幅较小,高适宜区总面积逐步减少。【结论】气候和地形因子共同影响板栗的地理分布,其中气候因子中温度因子贡献最大,地形因子中海拔因子贡献最大。当前气候条件下板栗在中国适宜区分布广泛,建议在高适宜区进行引种栽植及种质资源保护,当未来气候不利于板栗生长时向高纬度适宜区进行迁移引种,减少气候变化带来的损失。

【Objective】This study aims to explore the dominant environmental factors affecting the distribution of C.mollissima and simulate the potential distribution areas of C.mollissima under different climatic conditions,which would provide a theoretical basis for the conservation and introduction of C.mollissima germplasm resources.【Method】Based on geographical information on 472 distribution points of existing C.mollissima populations and 21 environmental variables,an ensemble species distribution model was used to simulate the potential suitable distribution areas of C.mollissima,and the accuracy of the model was evaluated by the value of AUC and TSS.The ensemble model was used to speculate the distribution of suitable areas for C.mollissima and their change trends in the Last Glacial Maximum,Mid-Holocene,Current,2030 and 2050.【Result】1)Among the 10 models,RF,GBM,MARES and GAM displayed the best and stable performance in prediction accuracy,and AUC and TSS values of the ensemble model were 0.974 and 0.816,respectively,indicating a high accuracy.2)The main environmental factors affecting the geographical distribution of C.mollissima were the minimum temperature of the coldest month,altitude,precipitation of the wettest quarter,temperature annual range and precipitation of wettest month,and their cumulative contribution was 89.79%.3)Under the current climate conditions,the potential growing areas of C.mollissima in China were widely distributed,and since the Last Glacial Maximum,the growing areas of C.mollissima have been expanding to higher latitudes,and the warmer the climate,the faster the expansion.The overall suitability of C.mollissima has been decreasing,more prominently in the south and less in the north,and the total area of high suitability zones has been gradually decreasing.【Conclusion】The geographical distribution of C.mollissima is influenced by both climatic and topographic factors,among which the temperature makes the greatest contribution and altitude also plays a crucial role.Under the current climate,C.mollissima have a wide range of suitable areas in China,and it is recommended that planting and germplasm conservation should be carried out in highly suitable areas,and migration to higher latitudes should be appropriate when climate conditions are unfavorable for C.mollissima growth in the future,so as to reduce the losses caused by climate change.