摘要:掌握气候变化对珍稀濒危物种的分布和适应性变化趋势的影响，是开展保护生物学研究的基础。闽楠（Phoebe bournei）是我国东部亚热带森林的优势树种，也是金丝楠木的主要来源树种。它具有重要的经济、园林与生态价值，目前已被列为国家II级保护植物。预测不同气候背景下该物种的地理分布格局可为这一珍贵树种的资源保护、合理利用与开发提供指导依据，同时也为闽楠的起源与地理分化研究奠定基础。本研究基于闽楠的123个分布点信息与19个气候因子，采用最大熵模型（MaxEnt）与ArcGIS空间分析，构建闽楠于末次冰期（距今22000年）、当前（1950-2000年）以及未来（2050年与2070年）相应地潜在分布区格局，并确定未来受威胁的适生区、面积与影响分布的气候因子。结果表明：闽楠的适生区覆盖浙江、福建、江西、广东、广西、湖南、湖北、贵州及重庆，制约闽楠地理分布的气候因子主要是温度季节性变化标准差（Bio4）、最暖月最高温（Bio5）与最干季降水量（Bio17）；在末次盛冰期闽楠退缩到我国东部的许多山区，诸如武夷山、浙闽丘陵、武陵山、雪峰山、湘黔桂毗邻的山区；随着全球气候变暖，到2050年与2070年闽楠的适生区有着破碎化甚至丧失的风险。



Abstract:Understanding the effect of climate changes on potential distribution of rare and/or endangered species is a primer of biology conservation. Phoebe bournei (Hesml.) Yang, a dominant tree in subtropical forest in eastern China, is one of the main sources for the "Golden-thread wood". P. bournei incorporates the value of the economy, landscape, and ecology. Now, it has been listed as Category II protected plants in the Chinese List of Wild Plants and as vulnerable according to the IUCN Red List of Threatened Species. A prediction of the impact of climate changes on the distribution of P. bournei will facilitate the utilization of germplasm resources as well as its evolutionary history. The 123 occurrences data covering the whole distribution range of P. bournei in China were obtained and the eight main bioclimatic variables were selected in this study. We used the maximum-entropy (Maxent) model for predicting potentially suitable habitat for P. bournei under paleoclimate, current and future climate background. The maxent model was highly accurate with a statistically significant AUC of 0.8. The results showed that the suitable region for P. bournei was Zhejiang, Fujian, Jiangxi, Guangdong, Guangxi, Hunan, Hubei, and Chongqing. From the area of current distribution, with a total area of 1047314 km², 233142 km² (22.26%), 360626 km² (34.43%), and 453545 km² (43.31%) were highly suitable area, moderately suitable habitat area, and poorly suitable habitat area for P. bournei in China, respectively. The variation coefficient of temperature (Bio4), the warmest month of temperature (Bio5) and precipitation of the driest quarter (Bio17) were the major climatic factors determining its suitable region. In addition, P. bournei retreated to many mountains in eastern China, such as Wuyi Mountain, Zhejiang-Fujian hills, Wuling Mountain, Xuefeng Mountain, and the mountains near Hunan-Guizhou-Guangxi borders during the Last Glacial Maximum (LGM) period. Under global warming, the suitable habitat for P. bournei will be at risk of fragmentation or even loss by 2050 and 2070. The predicted suitable areas of P. bournei located in Jiangxi and Fujian will be more seriously fragmented, and ones located in the Hunan-Guizhou border might be disappeared. To protect this valuable timber tree, we suggested should use in-situ and ex-situ conservation strategies. Especially, the wild populations should be taken in-situ conservation strategies, such as Guanshan population located in Jiangxi, Shaxian population located in Fujian and Chebaling population located in Guangdong province. This study would provide theoretical suggestions for the protection, cultivation management, and sustainable utilization of P. bournei resources to face the challenge of global climate changes.





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