Strategies of a Bornean tropical rainforest water use as a function of rainfall regime: isohydric or anisohydric?
Strategies of a Bornean tropical rainforest water use as a function of rainfall regime: isohydric or anisohydric?
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DOI：
10.1111/j.1365-3040.2011.02428.x
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发表时间：
2012-01-01
影响因子：
7.3
通讯作者：
Porporato, Amilcare
中科院分区：
文献类型：
--
作者：
Kumagai, Tomo'omi;Porporato, Amilcare
尽管婆罗洲的热带雨林是世界上最潮湿的生物群之一，但它们偶尔会经历一段时间的水分压力。观察表明，尽管出现了相对严重的干旱，但这些生态系统往往对水的使用几乎没有监管。这种用水行为通常被称为各向异性行为，而不是调节气孔运动以防止水力失灵的等水植物。虽然人们普遍认为各向异性植物的行为是对更容易干旱的生境的适应，但我们表明，在非常潮湿的环境中，各向异性植物也可能比同质植物更受欢迎，因为在那里水力故障的风险很小。为了探讨这一问题，我们使用由野外观测参数化的土壤水分和碳同化动力学的随机模型，检验了等氢物种和各向异性物种作为水文气候环境的函数的优势。结果表明，在非常潮湿的条件下，各向异性植物往往比等水分植物具有更高的生产力，尽管这两种植物表现出几乎相同的干旱引起的死亡。随着降雨量的减少，各向异性植物的死亡率急剧增加，而各向异性植物的死亡率保持相对恒定和较低的水平；在这些条件下，各向异性植物的生产力超过各向异性植物。
Although Bornean tropical rainforests are among the moistest biomes in the world, they sporadically experience periods of water stress. The observations indicate that these ecosystems tend to have little regulation of water use, despite episodes of relatively severe drought. This water-use behaviour is often referred to as anisohydric behaviour, as opposed to isohydric plants that regulate stomatal movement to prevent hydraulic failure. Although it is generally thought that anisohydric behaviour is an adaptation to more drought-prone habitats, we show that anisohydric plants may also be more favoured than isohydric plants under very moist environments where there is little risk of hydraulic failure. To explore this subject, we examined the advantages of isohydric and anisohydric species as a function of the hydroclimatic environment using a stochastic model of soil moisture and carbon assimilation dynamics parameterized by field observations. The results showed that under very moist conditions, anisohydric species tend to have higher productivity than isohydric plants, despite the fact that the two plant types show almost the same drought-induced mortality. As precipitation decreases, the mortality of anisohydric plants drastically increases whereas that of isohydric plants remains relatively constant and low; in these conditions, isohydric plants surpass anisohydric plants in their productivity.