亚热带植物春季和秋季物候格局及其对气候变化的响应

Spring and autumn phenology patterns of subtropical plants and their responses to climate change

关键词:  展叶, 开花, 叶变色, 落叶, 功能群, 全球变暖

Key words:  leaf-out, flowering, leaf-coloration, defoliation, functional groups, global warming

摘要:

全球变暖导致的物候变化已经对生物多样性和生态系统产生了重要影响,与温带和寒带相比,亚热带物候学的研究相对较少,秋季物候的研究也十分缺乏,不同功能群植物的物候对气候变化的响应是否存在差别,都有待进一步研究。为了研究亚热带植物春季和秋季物候对气候变化的响应以及不同功能群间的差异性,该研究利用湖南省长沙植物园25种木本植物20 a的物候观测数据,根据AIC信息标准,先筛选各物种最佳温度和降水模型,并利用Wilcoxon秩和检验分析不同功能群的物种对温度的响应是否一致。结果表明:(1)大多数物种的春季物候和秋季物候都对温度变化响应显著,展叶与开花的提前速率分别是3.76 d·℃^-1和6.53 d·℃^-1,叶变色与落叶的推迟速率分别是16.66 d·℃^-1和3.50 d·℃^-1。(2)部分物种的春季(展叶物候:60%,开花物候:35%)和秋季(叶变色物候:25%,落叶物候:13%)对降水显著响应。(3)除不同落叶性物种(常绿和落叶之间)的展叶物候表现出对气候的响应有显著差异外,其他不同功能群的物种对气候的响应均无显著差异。该研究认为,亚热带地区植物春季物候显著提前,秋季物候显著推迟,且亚热带地区不同功能群的物种对温度的响应大部分无显著差异,表明气候变化对亚热带地区不同功能群的影响程度大部分趋同。

Abstract:

Phenological changes caused by global warming have already impacted global biodiversity and ecosystems. Compared to temperate and boreal zones, subtropical phenology has been studied relatively less. It remains largely unknown that how autumn phenology response to climate change and how the responses vary among different functional groups. In order to investigate the spring and autumn phenological responses of subtropical plants to climate change and whether the responses vary in different functional groups, an 20-year observational phenological datasets for 25 woody species in Changsha Botanical Garden of Hunan Province were used, and based on the AIC information standard, the best temperature and precipitation models of each species were selected. Wilcoxon test was applied to analyze the consistency of species' responses to temperature for different functional groups. The results were as follows:(1)Spring phenology and autumn phendogy were significantly responded to temperature for most species by advancing their leaf-out time and flowering time on average 3.76 d·℃^-1 and 6.53 d·℃^-1, respectively. Leaf-coloration time and defoliation time were significantly responded to temperature for parts of the species by delaying on average, 16.66 d·℃^-1 and 3.50 d·℃^-1, respectively.(2)Only part of the species showed significant response to precipitation in spring(leaf-out phenology: 60%; flowering phenology: 35%)and autumn(leaf-coloration phenology: 25%; defoliation phenology: 13%).(3)There were no significant differences in response to temperature change among different functional groups, except species of different deciduousness showed significant differences in response to temperature change. We conclude that the spring phenology of plants in the subtropical area is significantly advanced and the autumn phenology is significantly delayed, and there are no significant differences in response to temperature among different functional groups in the subtropical area. The results show that different functional groups converge on their response to climate change in the subtropical area.