Afforestation with Pinus halepensis reduces native shrub performance in a Mediterranean semiarid area
Afforestation with Pinus halepensis reduces native shrub performance in a Mediterranean semiarid area
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DOI：
10.1016/j.actao.2003.10.001
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发表时间：
2004-03-01
影响因子：
1.8
通讯作者：
de Urbina, JO
中科院分区：
文献类型：
--
作者：
Bellot, J;Maestre, FT;de Urbina, JO
经常有人建议，引进黑松造林可以促进长期殖民化和后期演替物种在地中海干旱和半干旱地区的发展，但这种肯定很少在现场进行实验测试。在这项研究中，我们分析了种植的R halepensis密度（0，1500和3470树公顷（-1））对土壤水分在两个深度（0-10和10-30厘米）的影响，并在三个灌木物种（栎coccifera，埃里卡multiflora和Rhamnus lycioides）在西班牙东南部的半干旱地区的生理状态。与R halepensis的影响有负面影响，土壤水分，效果与树木密度增加。这种影响在0-10 cm深度比在10-30 cm深度更明显，并且在春季和夏末气候变化之后尤其明显。春、夏两季，在无黄背飞虱的地区，平均黎明前水势分别为-1.5、-2.4和-2.2MPa。coccifera、球孢E. multiflora和R. lycioides。在同一地区和同一时期，Q的平均净光合值分别为1.2、1.0和L5 μ mol CO_2·m ~（-2）·s ~（-1）。coccifera、球孢E. multiflora和R. lycioides。Q的平均气孔导度分别为15.1、16.4和21.7 mmol H2O m（-2）s（-1）。coccifera、球孢E. multiflora和R. lycioides。值大幅降低（高达56%）与增加P. halepensis密度，表明存在一个强大的竞争水。我们的研究结果提供的证据表明，引进R halepensis造林对现有的后期演替灌木有负面影响，并建议，这种引进不会刺激地中海半干旱地区的演替过程。(C)2003年，Elsevier SAS。All rights reserved.
It has been often suggested that the introduction of Pinus halepensis with afforestation could facilitate long-term colonisation and development of late-successional species in Mediterranean dry and semiarid areas, but this affirmation has rarely been experimentally tested in the field. In this study, we analyse the effects of planted R halepensis density (0, 1500 and 3470 trees-ha(-1)) on soil moisture at two depths (0-10 and 10-30 cm), and on the physiological status of three shrub species (Quercus coccifera, Erica multiflora and Rhamnus lycioides) in a semiarid area of SE Spain. Afforestation with R halepensis had a negative effect on soil moisture, an effect that increased with tree density. This effect was more pronounced at 0-10 cm depth than at 10-30 cm depth, and was especially evident after the spring and late summer rainfalls. During spring and summer, mean predawn water potentials in the area without P. halepensis were -1.5, -2.4 and -2.2 MPa for Q. coccifera, E. multiflora, and R. lycioides, respectively. Mean net photosynthesis values in the same area and period were 1.2, 1.0 and L5 mumol CO2 m(-2) s(-1) for Q. coccifera, E. multiflora, and R. lycioides, respectively. Similarly, mean stomatal conductance was 15.1, 16.4 and 21.7 mmol H2O m(-2) s(-1) for Q. coccifera, E. multiflora, and R. lycioides, respectively. Values were substantially reduced (up to 56%) with increasing P. halepensis density, suggesting the presence of a strong competition for water. Our results provide evidence that the introduction of R halepensis with afforestation has a negative effect on existing late-successional shrubs, and suggest that this introduction does not stimulate successional processes in Mediterranean semiarid areas. (C) 2003 Elsevier SAS. All rights reserved.