Ecosystem structure and productivity of tropical rain forests along altitudinal gradients with contrasting soil phosphorus pools on Mount Kinabalu, Borneo
Ecosystem structure and productivity of tropical rain forests along altitudinal gradients with contrasting soil phosphorus pools on Mount Kinabalu, Borneo
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DOI：
10.1046/j.0022-0477.2001.00634.x
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发表时间：
2002-02-01
影响因子：
5.5
通讯作者：
Aiba, SI
中科院分区：
文献类型：
--
作者：
Kitayama, K;Aiba, SI
1我们测量了婆罗洲基纳巴卢山4个海拔高度(700、1700、2700和3100m)的8个雨林林分的地上净初级生产力(ANPP)和生态系统结构和过程。2所有超基性林地的土壤全磷(P)和活性无机磷(P)库都比相同海拔的沉积林地小。我们预测，在超基性基底上，ANPP的高度变化幅度将小于在沉积基质上，这反映了在较强的P限制下，ANPP对温度的依赖性较低。3尽管两种基质上的ANPP都随着海拔的升高而下降，但两条回归线的斜率相似。4林分水平N、P养分利用效率(凋落物质量与养分归还量之比)仅受海拔高度的影响，在超基性基质上，N、P养分利用率呈指数增长。两种基质的单位叶面积平均叶N、P含量均随海拔的升高而增加，但相同海拔的基质间差异较大，仅P(超碱性下)。5叶面积指数(LAI)在两种基质上呈下降趋势。我们假设一半的初级生产力被分配到地下，以评估林分水平的净同化率(NAR)。这在沉积基质上几乎是恒定的，但在超基性基质上随着海拔的升高而线性下降，这可能需要加上LAI来解释ANPP模式。6我们认为，在沉积基质上，树木可能能够通过增加单位叶面积的叶N和P来维持较冷环境下的NAR，但磷缺乏阻碍了它们在超基性基质上的调节。
1 We measured above-ground net primary productivity (ANPP) and ecosystem structure and processes in eight rain forest stands at four elevations (700, 1700, 2700 and 3100 m) and on two geological substrates (sedimentary vs. ultrabasic rock) on Mount Kinabalu, Borneo.2 All ultrabasic sites had smaller pools of total soil phosphorus (P) and of labile inorganic P than did the sedimentary sites at the same altitudes. We predicted that the magnitude of altitudinal changes in ANPP would be less on ultrabasic than on sedimentary substrates, reflecting lower temperature dependency of ANPP under stronger P limitation.3 Although ANPP declined with increasing altitude on both substrates, the slopes of the two regression lines were similar. The intercept was, however, marginally greater on sedimentary than on ultrabasic substrate.4 Stand-level nutrient-use efficiencies (the ratio of litterfall mass to nutrient return) for N and P were only affected by altitude on ultrabasic substrate where they increased exponentially. Mean foliar N and P contents per unit leaf area of the canopy species increased with altitude on both substrates, but differed between substrates at the same altitude only for P (lower on ultrabasic).5 Leaf area index (LAI) decreased upslope on both substrates. We assumed that half of primary production was allocated below-ground in order to evaluate stand level net assimilation rate (NAR). This was nearly constant on sedimentary substrate, but declined linearly with increasing altitude on ultrabasic substrate, where it may have to be added to LAI to explain ANPP patterns.6 We suggest that on sedimentary substrate trees may be able to maintain NAR under colder environments by increasing foliar N and P per unit leaf area, but P deficiency prevents them from adjusting on ultrabasic substrate.