Diverse functional responses to drought in a Mediterranean-type shrubland in South Africa.
Diverse functional responses to drought in a Mediterranean-type shrubland in South Africa.
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DOI：
10.1111/j.1469-8137.2012.04170.x
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发表时间：
2012-07
期刊：
影响因子：
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通讯作者：
A. West;A. West;Todd E. Dawson;E. February;G. Midgley;William J. Bond;T. Aston
中科院分区：
文献类型：
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作者：
A. West;A. West;Todd E. Dawson;E. February;G. Midgley;William J. Bond;T. Aston
·地中海型生态系统包含地球上所有维管植物多样性的20%，已被确定为受到未来干旱加剧的特别威胁。特别令人担忧的是南非的开普弗洛拉尔地区，这是一个全球生物多样性热点，但验证对植物区系的预测影响的实验数据有限。在田间降雨试验中，我们测试了根的深度和等湿或非等湿的程度是否有助于对不同生长形式的干旱反应进行功能分类。·我们在一片山间凤尾草灌木丛中实施了为期六个月的夏季干旱，持续了两年。我们监测了七个物种的一系列参数，从生理特征到形态结果，包括三种主要的生长形式(深根蛋白类灌木、浅根埃里克样灌木和禾本科类类固醇)。·在生长形式之间和内部的干旱反应都有相当大的差异。浅根、异山梨状灌木的生长和开花都有相当大的减慢，死亡率也增加了。相比之下，浅根、等水类固醇和深根、等水类蛋白质灌木基本上没有受到干旱的影响。·根的深度和等/各向异性的程度允许对该植物区系中的干旱反应途径进行一级功能分类。对其他特征的考虑将进一步完善这一方法。
• Mediterranean-type ecosystems contain 20% of all vascular plant diversity on Earth and have been identified as being particularly threatened by future increases in drought. Of particular concern is the Cape Floral Region of South Africa, a global biodiversity hotspot, yet there are limited experimental data to validate predicted impacts on the flora. In a field rainout experiment, we tested whether rooting depth and degree of isohydry or anisohydry could aid in the functional classification of drought responses across diverse growth forms. • We imposed a 6-month summer drought, for 2 yr, in a mountain fynbos shrubland. We monitored a suite of parameters, from physiological traits to morphological outcomes, in seven species comprising the three dominant growth forms (deep-rooted proteoid shrubs, shallow-rooted ericoid shrubs and graminoid restioids). • There was considerable variation in drought response both between and within the growth forms. The shallow-rooted, anisohydric ericoid shrubs all suffered considerable reductions in growth and flowering and increased mortality. By contrast, the shallow-rooted, isohydric restioids and deep-rooted, isohydric proteoid shrubs were largely unaffected by the drought. • Rooting depth and degree of iso/anisohydry allow a first-order functional classification of drought response pathways in this flora. Consideration of additional traits would further refine this approach.