Fine root dynamics across pantropical rainforest ecosystems
Fine root dynamics across pantropical rainforest ecosystems
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DOI：
10.1111/gcb.15677
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发表时间：
2021-05-31
影响因子：
11.6
通讯作者：
Malhi, Yadvinder
中科院分区：
文献类型：
--
作者：
Huaraca Huasco, Walter;Riutta, Terhi;Malhi, Yadvinder
细根是森林生态系统净第一性生产力的重要组成部分，但其研究远少于地上部分。不同地点和区域之间的比较也受到方法不一致的阻碍，特别是在热带地区。在这里，我们提出了一个新的数据集细根生物量，生产力，停留时间，并在全球热带古老的雨林网站的分配，使用一致的方法测量，并检查这些变量是如何与一致确定的土壤和气候特征。我们的泛热带数据集涵盖了南美洲，非洲和东南亚（n = 47）的低地（潮湿，半落叶和落叶）和山地热带森林的密集监测地块。在山地和低地森林类型中观察到细根动态的大的空间变化。在低地森林中，细根生产力与土壤含砂量之间存在较强的线性正相关关系，当我们考虑总NPP在细根中的分配比例时，这种关系更强，这表明理解分配增加了理解细根生产力和总NPP的解释力。细根停留时间是一个功能的多个因素：土壤砂含量，土壤pH值，最大水分亏缺，最长的停留时间在酸性，桑迪，水分胁迫土壤。另一方面，在热带山地森林中，则有一套不同的关系，突出了山地和低地森林生物群落的性质非常不同。根系生产力与年平均温度呈强线性正相关，根系停留时间与土壤氮含量呈强线性正相关，降低土壤磷含量有利于生产力向细根的分配。与低地相比，环境条件是一个更好的预测细根生产力比总NPP的分数分配到细根，这表明根生产力是一个特别强大的驱动力的NPP分配在热带山区。
Fine roots constitute a significant component of the net primary productivity (NPP) of forest ecosystems but are much less studied than aboveground NPP. Comparisons across sites and regions are also hampered by inconsistent methodologies, especially in tropical areas. Here, we present a novel dataset of fine root biomass, productivity, residence time, and allocation in tropical old-growth rainforest sites worldwide, measured using consistent methods, and examine how these variables are related to consistently determined soil and climatic characteristics. Our pantropical dataset spans intensive monitoring plots in lowland (wet, semi-deciduous, and deciduous) and montane tropical forests in South America, Africa, and Southeast Asia (n = 47). Large spatial variation in fine root dynamics was observed across montane and lowland forest types. In lowland forests, we found a strong positive linear relationship between fine root productivity and sand content, this relationship was even stronger when we considered the fractional allocation of total NPP to fine roots, demonstrating that understanding allocation adds explanatory power to understanding fine root productivity and total NPP. Fine root residence time was a function of multiple factors: soil sand content, soil pH, and maximum water deficit, with longest residence times in acidic, sandy, and water-stressed soils. In tropical montane forests, on the other hand, a different set of relationships prevailed, highlighting the very different nature of montane and lowland forest biomes. Root productivity was a strong positive linear function of mean annual temperature, root residence time was a strong positive function of soil nitrogen content in montane forests, and lastly decreasing soil P content increased allocation of productivity to fine roots. In contrast to the lowlands, environmental conditions were a better predictor for fine root productivity than for fractional allocation of total NPP to fine roots, suggesting that root productivity is a particularly strong driver of NPP allocation in tropical mountain regions.