中国东北地区12个建群树种对气候变化响应的MaxEnt模型分析

气候变化是当前全球生物多样性面临的最大威胁之一，对物种地理分布格局具有较大影响。东北森林物种丰富度较高，目前尚缺乏基于主要树种、未来不同气候模式的综合研究。基于12种建群树种的分布数据及23个环境变量（19个生物气候因子、土地利用类型、海拔、坡度、坡向）数据，应用MaxEnt模型首次对东北地区乔木树种在3种气候变化情景下（SSP126可持续路径、SSP245中间路径、SSP585化石燃料为主发展路径）的潜在丰富度分布格局、主导环境变量以及树种损失、获得和周转情况进行了预测。结果表明：不同未来气候情景下东北地区各树种的潜在分布变化存在差异，适生区面积减小的树种有：兴安落叶松、山杨、春榆、白桦、水曲柳、胡桃楸、蒙古栎、辽东桤木，减小幅度达到10%-30%；适生区面积变化不大的树种有：红皮云杉、樟子松、黄檗，多数情况下低、中和高适生区面积变化发生了抵消，导致总适生区面积变化不大；适生区增加的树种有：红松，增加幅度达20%左右。环境因素将影响东北地区乔木树种潜在适宜性分布，其中，降水因素对东北地区树种分布格局起关键作用，尤其是降水量季节性变化，是影响东北地区50%左右树种分布格局的主导环境因子。东北地区乔木树种在无迁移和SSP585气候情景下受威胁程度相对较高，而在SSP126气候情景下大多处于低风险状态；物种迁移假设的对物种受威胁程度的影响先于气候变化情景的影响，树种发生适度迁移能够缓解树种受威胁的状况。网格单元中物种损失和周转的预测表明，东北地区树种高周转率主要由树种高损失率造成，损失率较高的地区往往树种周转率也相对较高。预测气候变化对东北地区树木分布格局的影响，有助于制定更有效的气候变化适应策略，以促进东北地区树木的可持续发展。

Future climatic adaption of 12 dominant tree species in Northeast China under 3 climatic scenarios by using MaxEnt modeling

Climate change is one of the biggest threats to global biodiversity, and it has a great impact on the geographic distribution of species. Forest species richness in the Northeast China is relatively high, and there is still a lack of comprehensive research based on major tree species and future climate patterns. Based on the distribution data of 12 constructive tree species and 23 environmental variables(19 bioclimatic factors, land use type, altitude, slope, slope aspect) data, this study applied the MaxEnt model to analyze the three climatic changes of arbor species in the Northeast China. The potential abundance distribution patterns, dominant environmental variables, and tree species loss, gain, and turnover under the scenarios (SSP126 sustainable pathway, SSP245 intermediate pathway, and SSP585 fossil fuel-based development pathway) were predicted. The results show that there are differences in the potential distribution changes of various tree species in Northeast China under different future climate scenarios. The tree species with reduced area of suitable habitats are Larix gmelinii, Populus davidiana, Ulmus davidiana var. japonica, Betula platyphylla, Fraxinus mandshurica, Juglans mandshurica, Quercus mongolica, Alnus sibirica, with a decrease rate of 10%-30%; the tree species with little change in the suitable areas are:Picea koraiensis, Pinus sylvestris var. mongolica, and Phellodendron amurense. In most cases, the changes in the areas of low, medium and high suitable areas are offset, resulting in little change in the total of suitable areas; the tree species with increased suitable area are:Pinus koraiensis, with an increase of about 20%. Environmental factors will affect the potential suitability distribution of arbor species in Northeast China. Among them, precipitation plays a key role in the distribution pattern of tree species in Northeast China, especially the seasonal variation of precipitation, which is the dominant environmental factor affecting about 50% of the tree species distribution pattern in Northeast China. Tree species in Northeast China are relatively threatened under no migration and SSP585 climate scenarios, but are mostly at low risk under SSP126 climate scenarios. The moderate migration of tree species can alleviate the threatened situation of tree species. The prediction of species loss and turnover in grid cells shows that the high tree species turnover rate in Northeast China is mainly caused by the high tree species loss rate. Predicting the impact of climate change on tree distribution patterns in Northeast China will help us formulate more effective climate change adaptation strategies to promote sustainable tree development in Northeast China.