Shrub species richness decreases negative impacts of drought in a Mediterranean ecosystem
Shrub species richness decreases negative impacts of drought in a Mediterranean ecosystem
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DOI：
10.1111/jvs.12558
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发表时间：
2017-09
影响因子：
2.8
通讯作者：
Natalia Rodriguez‐Ramirez;M. Santonja;V. Baldy;C. Ballini;N. Montes
中科院分区：
文献类型：
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作者：
Natalia Rodriguez‐Ramirez;M. Santonja;V. Baldy;C. Ballini;N. Montes
全球变化预测预测了未来几十年地中海盆地生物多样性的变化和干旱强度的增加。这可能会影响植物性能、植物群落组成和生态系统功能。灌丛在地中海地区分布广泛，但灌丛对干旱加剧和植物多样性变化的综合影响的反应尚不清楚。地理位置天然地中海灌木，马赛，法国南部（北纬43°22 ‘；东经5°25 ’）。方法在法国南部地中海灌丛地进行降雨调控试验，研究四种优势灌丛对干旱的响应。研究组合跨越4个灌木丰富度等级（单种、双种、三种和四种植物混合）和15种不同的灌木组合梯度。在2012-2014年2年的非破坏性实验中，我们测量了4种优势植物：山楂、球果栎、迷迭香和细花榆的凋落物、林分坏死块和植物盖度。结果随着灌木丰富度的增加，4种植物凋落物产量均增加，栎和榆干枝数量减少。拒雨处理对灌丛物种的响应有影响，但主要取决于灌丛丰富度。在单种样地，干旱条件加重导致凋落物减少，迷迭香和百合花凋落物增加。总的来说，随着植物群落中灌木种类的增加，这些负面干旱效应逐渐消失。禁雨处理下，单特异区迷迭香盖度降低，双特异区栎盖度增加，四特异区迷迭香盖度增加。我们观察到两种抗旱模式，栎和迷迭香的抗旱能力较强，桉树和山竹的抗旱能力较弱。结论干旱对灌丛生产性能的影响程度具有物种特异性和物种组合依赖性。高灌木丰富度可以调节干旱加剧的负面影响。我们的研究结果表明，在水资源短缺的情况下，种间关系可能会发生变化。由于干旱影响在低多样性群落中不受调节，物种对干旱条件的特定响应可能导致植物群落组成的变化，有利于最抗旱的物种，如栎和迷迭香。维持较高的多样性水平对于调解抗旱性较低的物种（本研究中的山竹属植物和山竹属植物）的干旱效应至关重要。这篇文章受版权保护。版权所有。
Questions Global change projections predict biodiversity changes and increased drought intensity in the Mediterranean Basin in the decades to come. This will presumably affect plant performances, plant community composition, and ecosystem functioning. Shrublands are widespread in the Mediterranean area, yet we have no clear understanding of shrubland responses to the combined effects of increased drought and changes in plant diversity. Location Natural Mediterranean shrubland, Marseille, South of France (43°22′ N; 5°25′ E). Methods A rainfall manipulation experiment was conducted in a Mediterranean shrubland in southern France to examine the performances of four dominant shrub species in response to increased drought. The study assemblages spanned a gradient of 4 shrub richness levels (mono-, bi-, tri-, and tetraspecific plant mixtures) and 15 different shrub combinations. Throughout the two years of non-destructive experiment (2012-2014), we measured plant litterfall, stand necromass and plant cover of the 4 dominant plant species: Cistus albidus, Quercus coccifera, Rosmarinus officinalis and Ulex parviflorus. Results Increasing shrub richness levels in the plant community led to higher litter production by all 4 species and a decrease of dry shoots for Quercus and Ulex. Shrub species responses were affected by the rain exclusion treatment, but the effects were mainly dependent on shrub richness level. In monospecific plots, aggravated drought conditions led to a decrease of litterfall of Cistus, Rosmarinus and Ulex and an increase of necromass of all 4 species. In general, these negative drought effects disappeared as number of shrub species in the plant community increased. Under rain exclusion treatment, Rosmarinus cover decreased in monospecific plots whereas Quercus cover increased in bispecific plots and Rosmarinus cover increased in tetraspecific plots. We observed two drought tolerance patterns, with Quercus and Rosmarinus being more tolerant species and Ulex and Cistus less tolerant. Conclusions The magnitude of drought effects on shrub performance is species-specific, and plant species combination-dependent. High shrub richness levels could modulate the negative impacts of aggravated drought conditions. Our results pointed to a probable shift of interspecific relationships in response to water resource shortage. As drought impacts are not mediated in low-diversity communities, species-specific responses to drier conditions could lead to shifts in plant community composition favoring the most drought-resistant species, i.e. Quercus and Rosmarinus here. Maintaining a high diversity level appears critical to mediate drought effect for less resistant species (Cistus and Ulex in our study). This article is protected by copyright. All rights reserved.