Wood vs. Canopy Allocation of Aboveground Net Primary Productivity in a Mediterranean Forest during 21 Years of Experimental Rainfall Exclusion
Wood vs. Canopy Allocation of Aboveground Net Primary Productivity in a Mediterranean Forest during 21 Years of Experimental Rainfall Exclusion
复制标题
地中海森林 21 年降雨排除实验期间地上净初级生产力的木材与树冠分配
作者：
R. Ogaya;J. Peñuelas
在连续21年的时间里，对地中海霍尔姆橡树林进行了实验性的部分降雨排除，以研究未来几十年地中海植被可用水预期减少的影响。林木结构分配和地上总分配与年降雨量相关，而林冠分配和林冠分配比与降雨量无关。果实生产力也与年降雨量相关，但仅在栓皮栎中相关。研究区有两种林分结构：高冠层明显以栓皮栎为主，低层林分中高大灌木树种宽叶连翘丰度较高。在高大冠层林分中，对木本结构的分配在排雨试验中有所减少，但对冠层的分配没有减少。在低郁闭度林分中，无论是对照地还是禁雨区，栓皮栎的木材分配量都很小，但宽叶栎林分的木材分配量甚至高于高大冠层林分，尤其是在接受雨阻试验区的样地。这些结果突出表明，由于可用水减少，未来可能会改变这一生态系统的结构和功能。这片地中海森林减缓气候变化的能力可能会严重下降，宽叶栎属利用有限的能力应对在栓皮栎中检测到的干旱条件的能力，可能使物种优势即将发生变化，特别是在树冠较低的林分中。
A Mediterranean holm oak forest was subjected to experimental partial rainfall exclusion during 21 consecutive years to study the effects of the expected decrease in water availability for Mediterranean vegetation in the coming decades. Allocation in woody structures and total aboveground allocation were correlated with annual rainfall, whereas canopy allocation and the ratio of wood/canopy allocation were not dependent on rainfall. Fruit productivity was also correlated with annual rainfall, but only in Quercus ilex. In the studied site, there were two types of forest structure: high canopy stand clearly dominated by Quercus ilex, and low canopy stand with more abundance of a tall shrub species, Phillyrea latifolia. In the tall canopy stand, the allocation to woody structures decreased in the experimental rainfall exclusion, but not the allocation to canopy. In the low canopy stand, wood allocation in Quercus ilex was very small in both control and plots with rainfall exclusion, but wood allocation in Phillyrea latifolia was even higher than that obtained in tall canopy plots, especially in the plots receiving the experimental rainfall exclusion. These results highlight likely future changes in the structure and functioning of this ecosystem induced by the decrease in water availability. A serious drop in the capacity to mitigate climate change for this Mediterranean forest can be expected, and the ability of Phillyrea latifolia to take advantage of the limited capacity to cope with drought conditions detected in Quercus ilex makes likely a forthcoming change in species dominance, especially in the low canopy stands.
DOI：
10.1073/pnas.0505734102
发表时间：
2005-10-18
影响因子：
11.1
作者：
Breshears, DD;Cobb, NS;Meyer, CW
通讯作者：
Meyer, CW
影响因子：
5.2
作者：
Doughty, Christopher E.;Metcalfe, D. B.;Malhi, Y.
通讯作者：
Malhi, Y.