气候变化对落叶松人工林在中国适生区分布的影响

落叶松(Larix)是我国的主要造林树种,其适生区的分布在很大程度上受气象要素等环境因子的影响。研究落叶松人工林适生区分布在气候变化下的变迁,可为应对气候变化的林业管理策略提供技术指导和科学依据。选取华北落叶松、日本落叶松、长白落叶松和兴安落叶松为研究对象,搜集整理了它们在中国地区的308条有效分布记录和22个环境因子变量,运用最大熵(MaxEnt)模型探测了制约落叶松人工林分布的主要环境因子及其适生区范围,模拟并分析了1931-2020年落叶松人工林适生区受气候变化影响的空间分布变化。结果表明:(1)研究选取的MaxEnt模型对落叶松适生区的模拟效果都达到了"极准确"的程度,受试者工作特征曲线面积(AUC值)在0.92-0.977之间。影响落叶松人工林分布的主要环境变量为最湿月降水量、海拔、最湿季度平均温度和温度季节变化方差,累计贡献率达到了73.8%。(2)当前(1991-2020年)气候条件下落叶松人工林适生区面积为182.34×10⁴km²。其中,高适生区面积为53.57×10⁴km²,占总适生面积的29.38%。高适生区集中分布在长白山脉、大兴安岭、燕山、小陇山、太行山脉以及秦岭-大巴山等地区。(3)1931-1960年期间落叶松的高适生区面积为28.33×10⁴km²,1961-1990年期间为33.10×10⁴km²,当前气候条件下进一步增至53.57×10⁴km²。落叶松适生区的范围在过去90年间整体呈现向北移动的趋势。其中,华北落叶松分布在整体上向北大约移动了3°,且分布面积显著增加。日本落叶松位于辽宁东部的高适生区向北移动,位于秦岭-大巴山地区的高适生区则没有明显的偏移,但是分布范围却向高海拔地区集中。长白落叶松的适生区范围向北移动了5°,且分布面积先减少后增加,增加的主要区域是长白山北部。兴安落叶松的适生区范围同样是向北移动,有部分适生区移出了我国北界, 这是其适生区面积在近些年减小的主要原因。

Influence of climate change on distribution of suitable areas of Larix plantation in China

Larix is one of the most important conifer species for afforestation in China. The distribution of its suitable areas is largely affected by meteorological and other environmental factors. Studying on changes of the distribution of suitable areas of Larix plantation under the background of climate change can provide technical guideline and scientific basis for the forestry management strategy on coping with climate change. In this study, Larix principis-rupprechtii, Larix kaempferi, Larix gmelinii, and Larix olgensis were selected. Based on 308 distribution records of Larix plantation and 22 environmental factors, the maximum entropy (MaxEnt) model was used to detect the main environmental factors restricting the distribution of Larix plantation, and to simulate and analyze the distribution of suitable areas of Larix plantation affected by climate change since 1931. The results showed that: (1) the accuracy of MaxEnt model appeared to perform in the level of "excellent", and the area under curve (AUC) values ranged from 0.92 to 0.977. The main environmental factors affecting the distribution of Larix plantation were the precipitation of wettest month, altitude, the mean temperature of wettest quarter, and the temperature seasonality. The cumulative contribution the main environmental factors was 73.8%. (2) Under the current climate conditions (1991-2020), the total suitable area of Larix plantation was 182.34×10⁴km², with an optimal area of 53.57×10⁴km², which accounts for 29.38% of the total suitable area. The optimal area distributed in Changbai Mountains, the Greater Khingan Mountains of northeast China, Yanshan Mountain, Xiaolong Mountains, Taihang Mountains, and "Qinling-Daba Mountain". (3) The areas of optimal area of Larix plantation were 28.33×10⁴km² during 1931-1960, 33.10×10⁴km² during 1961-1990, and optimal area increased to 53.57×10⁴km² under the current climatic conditions. The suitable area of Larix plantation showed a tendency to move northward in the past 90 years. The distribution of Larix principis-rupprechtii generally moved about 3° to the north and the suitable area has significantly increased. The suitable area of Larix kaempferi in eastern Liaoning moved northward, while the suitable area of Larix kaempferi in "Qinling-Daba Mountain" region did not shift significantly, but concentrated in the high-altitude area. The range of Larix olgensis suitable area moved 5° to the north, the suitable area firstly decreased and then increased, with the main area increasing in the northern part of Changbai Mountain. The potential distribution area of Larix gmelinii moved northward in general, and some suitable areas moved out of the northern boundary of China, this explains why the suitable area of Larix gmelinii in China decreased in recent years.