未来气候变化对粤港澳地区杜鹃花适生区的影响

位于我国南方丘陵的粤港澳地区拥有丰富杜鹃花资源,长期以来受杜鹃花不适宜在高温低海拔地区进行开发利用等思想的影响,该区域野生杜鹃花的开发、保护与利用研究寥寥无几,但低海拔野生杜鹃花在气候变化下正面临较高灭绝风险。基于粤港澳地区杜鹃花属(Rhododendron)14个筛选后的野生物种229个标本点位数据,利用最大熵模型(Maxent)模拟粤港澳地区野生杜鹃花在2070年低、中、高3种温室气体排放模式(RCP2.6、RCP4.5、RCP8.5)下的适生区范围大小与方向的变化及其主导环境变量。研究发现未来粤港澳地区野生杜鹃花的适生区范围整体呈缩小趋势,且随着温室气体排放浓度的增加,即从RCP2.6到RCP8.5,越来越多杜鹃花物种适生区呈现向高纬度、高海拔方向迁移的趋势;对杜鹃花分布影响最大的变量为最冷月的最低温、温度季节性和最干月降水量。本研究通过探究气候变化对野生杜鹃花适生区范围的影响,以期为粤港澳地区野生杜鹃花的保护与开发利用提供科学指导。

Effect of future climate change on suitable areas of Rhododendrons in Guangdong-Hong Kong-Macao region

Biodiversity loss and variation in species responses to climate change have been found across broad taxonomic groups. Exploring the spatial distribution of varying species and their relationship with the environment provides important scientific basis for understanding and protecting biodiversity. Guangdong-Hong Kong-Macao region, located in the hilly areas of southern China, is rich in Rhododendron resources. However, previous studies only focus on the growth characteristics, seedling introduction, garden application, and community characteristics of Rhododendron in this region, very few studies have focused on the distribution and conservation of Rhododendron, due to the bias that high temperature and low altitudes are not suitable as habitats for Rhododendron growing. Nevertheless it worth noting that Rhododendron species growing at the low-altitude region are highly vulnerable to climate change and are at an elevated risk of extinction. By using 229 species records, 6 bioclimate variables, and the maximum entropy model (Maxent), we analyzed the change of suitable areas and dominant climatic factors for distribution of 14 Rhododendron species under three (low, medium and high) Representative Concentration Pathway (RCP) scenarios (RCP2.6, RCP4.5, RCP8.5) at the Guangdong-Hong Kong-Macao region in 2070s. And we employed SDMtoolbox to simulate the shift direction and trajectory of the suitable areas under different climate change scenarios compared to the current pattern. By adding a "distance" field to the attribute table and using the field calculator geometry tool to calculate the distance that the centroid of the suitable areas migrate. The results showed that most of the Rhododendron suitable areas are centrally distributed in the northern part of Guangdong Province under the current climate scenario. Rhododendron would shift to the higher latitude and altitude areas in the future. As the emission concentration increases, more species would migrate to north, whereas there are still very few species would migrate south. The dominate climatic factors for Rhododendron distribution were the minimum temperature of coldest month, temperature seasonality, and the precipitation of driest month. The results indicate that protecting Rhododendron should be strengthened, especially in winter, and more attention should be paid to the construction of protected areas for Rhododendron in northern Guangdong-Hong Kong-Macao region. This study also provides some inspiration for the protection and management of other shade-loving and humidity-loving species in Guangdong-Hong Kong-Macao region. This study deepens the understanding of the impact of climate change on the distribution pattern of species and provides a scientific guidance for the conservation of Rhododendron and biodiversity in Guangdong-Hong Kong-Macao region.