Nutrient dynamics on a precipitation gradient in Hawai'i
Nutrient dynamics on a precipitation gradient in Hawai'i
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DOI：
10.1007/s004420050405
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发表时间：
1998-02-01
期刊：
影响因子：
2.7
通讯作者：
Vitousek, PM
中科院分区：
文献类型：
--
作者：
Austin, AT;Vitousek, PM
我们对夏威夷5个原生森林的土壤和叶面养分进行了评估，这些森林的年降雨量在500毫米到5500毫米之间。所有样点海拔相同，基材年龄相同；均为原生优势林，含多形金缕莲。土壤可提取NO3-N和PO4-P以及主要阳离子（Ca、Mg和K）浓度随着年降水量的增加而降低，土壤和植被中的δ (15)N值都变得更加枯竭。随着降水的增加，多叶松叶片的叶面积质量（LMA）和木质素浓度显著增加，δ (13)C值逐渐减少。随着降水的增加，多形草叶片磷和主要阳离子（Ca、Mg和K）浓度均显著降低。在其他原生森林物种中，LMA、δ (13)C和δ (15)N的分布模式与多叶茅的分布模式基本一致。土壤中有效岩石营养物质浓度的下降表明，降雨增加对淋滤的影响大于降水增加对风化的影响。单位叶面积叶面养分浓度下降和木质素增加的模式表明，随着年降水量的增加，生产者从相对较高的养分有效性向相对较高的碳增益转变。在氮循环方面，干旱地区无机土壤氮浓度较高的模式，以及土壤和植被中逐渐耗尽的三角洲（15）氮特征表明，氮循环在干旱地区更为开放，随着年降水量的增加，相对于周转的损失较小。
We evaluated soil and foliar nutrients in five native forests in Hawai'i with annual rainfall ranging from 500 mm to 5500 mm. All of the sites were at the same elevation and of the same substrate age; all were native-dominated forests containing Metrosideros polymorpha Gaud. Soil concentrations of extractable NO3-N and PO4-P, as well as major cations (Ca, Mg, and K), decreased with increasing annual precipitation, and delta(15)N values became more depleted in both soils and vegetation. For M. polymorpha leaves, leaf mass per area (LMA) and lignin concentrations increased significantly, while delta(13)C values became more depleted with increasing precipitation. Foliar phosphorus, and major cation (Ca, Mg, and K) concentrations for M. polymorpha all decreased significantly with increasing precipitation. For other native forest species, patterns of LMA, delta(13)C, and delta(15)N generally mirrored the pattern observed for M. polymorpha. Decreasing concentrations of available rock-derived nutrients in soil suggest that the effect of increased rainfall on leaching outweighs the effect of increasing precipitation on weathering. The pattern of decreased foliar nutrient concentrations per unit leaf area and of increased lignin indicates a shift from relatively high nutrient availability to relatively high carbon gain by producers as annual precipitation increases. For nitrogen cycling, the pattern of higher inorganic soil nitrogen concentrations in the drier sites, together with the progressively depleted delta(15)N signature in both soils and vegetation, suggests that nitrogen cycling is more open at the drier sites, with smaller losses relative to turnover as annual precipitation increases.