增温对鼎湖山混交林中4种优势树种生物量分配和养分积累的影响

Effects of Warming on Biomass Allocation Patterns and Nutrient Accumulations of Four Dominant Tree Species in Mixed Forest of Dinghushan, China

摘要:

为了解未来全球变暖对南亚热带森林生态系统物种组成的影响，在广东鼎湖山采用沿海拔梯度垂直移位的方法，研究了模拟增温对木荷（Schima superba）、红枝蒲桃（Syzygium rehderianum）、红锥（Castanopsis hystrix）和马尾松（Pinus massoniana）等4种优势树种的生物量分配模式和养分（氮和磷）积累的影响。结果表明，增温使大气平均温度增加（1.28±0.60）℃，土壤平均温度增加（1.04±0.30）℃；6 a长期增温使木荷和马尾松的树高增长率分别显著提高83.0%和52.1%，基径增长率分别显著提高37.1%和76.9%，二者的茎质比都显著增加，根质比、叶质比和根冠比都显著降低，养分积累量分别显著增加100.3%和185.7%；但增温对红枝蒲桃和红锥的树高、基径、生物量分配模式和养分积累无显著影响。因此，6 a增温对4种优势树种生物量分配模式和养分积累的影响具有一定的种间差异，木荷和马尾松由于生物量和养分积累量较高，所以在长期增温条件下可能具有较强的适应性，这种差异可能会对我国南亚热带混交林中的群落结构和功能带来潜在影响。

Abstract:

In order to understand the effects of future global warming on species composition of forest ecosystems in the south subtropical region, the biomass allocation patterns and nutrient accumulations of four dominant tree species, such as Schima superba, Syzygium rehderianum, Castanopsis hystrix and Pinus massoniana, were studied under simulated warming by translocating model forest from high altitude to low altitude in Dinghushan, Guangdong. The results showed that warming increases the average atmospheric temperature by (1.28±0.60)℃, and the average soil temperature by (1.04±0.30)℃. For Schima superba and P. massoniana under warming for 6 years, the height significantly increased by 83.0% and 52.1%, and basal diameter by 37.1% and 76.9%, respectively, and the stem mass ratio significantly increased, but the ratios of root mass, leaf biomass and root to shoot significantly decreased, as well as nutrient accumulations increased significantly by 100.3% and 185.7%, respectively. However, warming had no significant effect on the height, basal diameter, biomass allocation patterns, and nutrient accumulations of Syzygium rehderianum and C. hystrix. Therefore, the effects of 6-year warming on biomass allocation pattern and nutrient accumulation were different among four dominant tree species. Schima superba and P. massoniana might have strong adaptability under long-term warming due to their high biomass and nutrient accumulation. These differences might have a potential impact on community structure and function in subtropical mixed forests in China.