基于优化MaxEnt模型的中国紫堇属植物生境适宜性研究

Habitat suitability of Corydalis based on the optimized MaxEnt model in China

气候变化正深刻地影响着植物的地理分布格局,预测紫堇属植物的潜在适生区有利于认识气候变化对紫堇属植物分布的影响,对制定紫堇属植物的保护策略具有重要意义。以紫堇属植物作为研究对象,基于优化的MaxEnt模型,对1910个紫堇属植物分布点和22个环境因子进行潜在适生区预测,探讨影响紫堇属植物分布的主要环境因子,并预测其在末次盛冰期(last glacial maximum,LGM)、当代(Current)、未来2021—2040年(2040s)、2041—2060年(2060s)、2061—2080年(2080s)和2081—2100年(2100s)2种温室气体排放浓度场景(SSP126和SSP585)下的潜在适生区的空间分布格局及其质心迁移趋势,最后对其保护现状进行了分析。结果表明:(1)最优化模型参数组合为RM=1.4,FC=LQPT,此时MaxEnt模型的复杂度和过拟合都最低,模型预测精度较高,AUC=0.793;(2)由刀切法贡献率、置换贡献率和单因子响应曲线可知影响紫堇属植物地理分布的主要环境因子为气温年较差(bio7)、气温季节性变动系数(bio4)、年降水量(bio12)、平均气温日较差(bio2),其中温度是影响紫堇属植物分布的最重要环境因子;(3)当前气候条件下紫堇属植物分布的范围几乎涵盖整个中国,在气候分区上看,从北亚热带、南亚热带、中温带、南温带及高原气候区均有分布。然而,各个时期间紫堇属植物的潜在适生区变化较大,其潜在适生区总体呈现向高原气候区及中温带地区扩张的趋势,且面积不断扩大;随着温室气体浓度的增加,适生区的破碎化逐渐严重。质心迁移结果也表明紫堇属植物在未来的潜在适生区总体呈现向西北移动的趋势;(4)我国东喜马拉雅地区及横断山区为紫堇属植物保护的关键地区,然而该地区自然保护区面积较小且破碎化严重,亟待对该地区的紫堇属植物进行保护,同时也应继续加强西北地区自然保护区的建设。

Climate change significantly impacts plant distribution,predicting the potential suitable areas of Corydalis is useful for understanding the effects of climate change,and it is vital for the development of conservation strategy of Corydalis.Using the optimized MaxEnt model,we projected potential suitable areas for 1910 Corydalis distribution sites along with 22 environmental factors.We examined key environmental factors influencing Corydalis distribution and forecasted their effects during the last glacial maximum(LGM),the present,and future scenarios.Additionally,we forecasted the spatial distribution pattern and center⁃of⁃mass migration trends of Corydalis under two greenhouse gas(GHG)emission scenarios(SSP126 and SSP585)during the LGM,current,future,and future periods(2021—2100).Furthermore,we assessed the current conservation status of Corydalis and conducted a conservation analysis.The results indicated the following:(1)The optimized model parameters included RM=1.4 and FC=LQPT,resulting in the lowest complexity and overfitting in the MaxEnt model and high predictive accuracy with AUC=0.793.(2)The primary environmental factors affecting the distribution of Corydalis were temperature annual range(bio7),Seasonal variation coefficient of temperature(bio4),annual precipitation(bio12)and mean diurnal range(bio2).Among these,temperature was the most influential environmental factor on Corydalis distribution.(3)Corydalis currently inhabit abroad region across China,spanning the climatic zones of northern subtropics,southern subtropics,mesothermal,southern temperate,and high plateau areas.In contrast,the potential suitable area of Corydalis has fluctuated significantly,generally expanding towards plateau areas and mid⁃temperate regions,and the size is growing.However,with rising GHG concentrations,habitat fragmentation is becoming more severe.Center⁃of⁃mass migration results also suggest that the potential suitable area of Corydalis will shift northwestward in the future.(4)The East Himalayan region and the Hengduan Mountains region in China is crucial for Corydalis conservation.However,the nature reserve area in this region is limited and fragmented,thus conservation efforts is needed in this area,and nature reserves in northwest China should also should strengthen.