Ground-based and remotely sensed nutrient availability across a tropical landscape.
Ground-based and remotely sensed nutrient availability across a tropical landscape.
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DOI：
10.1073/pnas.0504929102
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发表时间：
2005-08
影响因子：
11.1
通讯作者：
S. Porder;G. Asner;P. Vitousek
中科院分区：
文献类型：
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作者：
S. Porder;G. Asner;P. Vitousek
热带土壤通常被认为是高度风化的，因此养分耗尽，但这一预测主要适用于地貌稳定的表面。地形使养分耗竭的假设复杂化，因为侵蚀可以增加热带生态系统的养分供应。因此，了解养分供应景观需要一个明确的空间评估的相对强度的消耗和增强。我们记录了在夏威夷考艾岛一个20公里（2），4- 5百万年的侵蚀景观中叶面营养物质和地形位置之间的关系，并使用这种关系来建立一个自下而上的地图，预测整个景观中的营养物质的可用性。只有大约17%的景观是营养贫乏的，主要是在稳定的高地上;斜坡和谷底的养分供应要高得多，在某些情况下类似于夏威夷群岛最肥沃的山地森林。这种模式得到了证实，自上而下的遥感面积综合冠层磷浓度。
Tropical soils often are assumed to be highly weathered and thus nutrient-depleted, but this prediction applies primarily to geomorphically stable surfaces. Topography complicates the assumption of nutrient depletion, because erosion can enhance the supply of nutrients to tropical ecosystems. Consequently, understanding nutrient availability across landscapes requires a spatially explicit assessment of the relative strength of depletion and enhancement. We document the relationship between foliar nutrients and topographic position across a 20-km(2), 4- to 5-million-year-old eroded landscape in Kaua'i, Hawai'i, and use this relationship to build a bottom-up map of predicted nutrient availability across this landscape. Only approximately 17% of the landscape is nutrient-poor, mostly on stable uplands; nutrient availability on slopes and valley bottoms is much higher, in some cases similar to the most fertile montane forests in the Hawaiian Islands. This pattern was corroborated by top-down remote sensing of area-integrated canopy phosphorus concentrations.