Testing metabolic theory with models of tree growth that include light competition
Testing metabolic theory with models of tree growth that include light competition
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DOI：
10.1111/j.1365-2435.2012.01981.x
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发表时间：
2012-06-01
影响因子：
5.2
通讯作者：
Condit, Richard
中科院分区：
文献类型：
--
作者：
Rueger, Nadja;Condit, Richard
1.代谢标度理论预测，树种直径生长速率与树径之间存在普适的标度关系。这种模式受到批评，因为它忽略了对资源的竞争的影响，例如光对人口比例与规模的缩放。2.在这里，我们测试丰富的热带树种的标度指数是否符合代谢标度理论的预测，并评估是否缩放生长与大小取决于光的可用性。光到达每棵树估计每年垂直普查的郁闭度，和分层贝叶斯方法允许量化的置信区间的标度指数和会计的不同来源的错误。3.我们发现没有普遍的标度关系，和50 - 70%的物种的标度指数，显着不同于预测值的1/3。正如所预期的，如果对光的竞争是重要的，当所有树木组合时，大多数物种的标度指数>1/3。然而，当仅考虑在强光条件下生长的个体时，群体平均标度指数与预测值1/3没有显著差异。4.这些结果支持了这一假设，即代谢生态学的树木生长与大小的缩放预测是唯一有效的竞争时，光是不重要的。
1. Metabolic scaling theory predicts that diameter growth rates of tree species are related to tree diameter by a universal scaling law. This model has been criticised because it ignores the influence of competition for resources such as light on the scaling of demographic rates with size. 2. We here test whether scaling exponents of abundant tropical tree species comply with the prediction of metabolic scaling theory and evaluate whether the scaling of growth with size depends on light availability. Light reaching each individual tree was estimated from yearly vertical censuses of canopy density, and a hierarchical Bayesian approach allowed quantifying confidence intervals for scaling exponents and accounting for different sources of error. 3. We found no universal scaling relationship, and 5070% of the species had scaling exponents that significantly differed from the predicted value of 1/3. As would be expected if competition for light were important, scaling exponents were >1/3 for the majority of species when all trees were combined. However, the community average of scaling exponents was not significantly different from the predicted value of 1/3 when only considering individuals that grew under high-light conditions. 4. These results support the hypothesis that the prediction of metabolic ecology for the scaling of tree growth with size is only valid when competition for light is unimportant.