Global-scale patterns of nutrient density and partitioning in forests in relation to climate
Global-scale patterns of nutrient density and partitioning in forests in relation to climate
复制标题
全球范围内与气候相关的森林养分密度和分配模式
DOI：
10.1111/gcb.13860
复制
发表时间：
2018
影响因子：
11.6
通讯作者：
Quanfa Zhang
中科院分区：
文献类型：
--
作者：
Kerong Zhang;Conghe Song;Yulong Zhang;Haishan Dang;Xiaoli Cheng;Quanfa Zhang
森林养分储存和分配的知识是生态系统模型和生态理论的必要条件。森林生物量中储存的营养物质（N、P、K、Ca和Mg）及其分配模式是否在气候梯度上系统地变化仍不清楚。在这里，我们使用新编译的数据集（包括372个林分）探索了全球范围内的营养密度和分区模式。我们发现，温度和降水量是驱动全球范围内森林活生物量中养分储存的关键因素。在越来越温暖的气候中，生物量中储存的N，K和Mg往往更大。热带、亚热带、温带和寒带森林的平均生物量N密度分别为577.0、530.4、513.2和336.7 kg/ha。约76%的生物量N密度的变化可以通过结合生物量密度、生育力（即，被子植物，裸子植物），以及年平均温度和降水量的相互作用。气候、林龄和生物量密度显著影响森林群落养分分配。养分分配到根系的分数随温度的升高而显著降低，表明寒冷气候下的森林将更多的养分分配到根系。裸子植物林比被子植物林更倾向于将养分分配到叶中，而被子植物林则更多地分配到茎中。基于养分的根冠比（R：S），R：SN平均为0.30，R：SP平均为0.36，R：SK平均为0.32，R：SCa平均为0.27，R：SMg平均为0.35。描述根养分作为地上部养分的函数的关系的标度指数大于1.0，这表明，随着养分分配到地上部的增加，养分分配到根的增加速度比线性增加养分在地上部。土壤类型对森林生物量中N、P、K、Ca、Mg的总量有显著影响，其中以红壤类最低。
Knowledge of nutrient storage and partitioning in forests is imperative for ecosystem models and ecological theory. Whether the nutrients (N, P, K, Ca, and Mg) stored in forest biomass and their partitioning patterns vary systematically across climatic gradients remains unknown. Here, we explored the global‐scale patterns of nutrient density and partitioning using a newly compiled dataset including 372 forest stands. We found that temperature and precipitation were key factors driving the nutrients stored in living biomass of forests at global scale. The N, K, and Mg stored in living biomass tended to be greater in increasingly warm climates. The mean biomass N density was 577.0, 530.4, 513.2, and 336.7 kg/ha for tropical, subtropical, temperate, and boreal forests, respectively. Around 76% of the variation in biomass N density could be accounted by the empirical model combining biomass density, phylogeny (i.e., angiosperm, gymnosperm), and the interaction of mean annual temperature and precipitation. Climate, stand age, and biomass density significantly affected nutrients partitioning at forest community level. The fractional distribution of nutrients to roots decreased significantly with temperature, suggesting that forests in cold climates allocate greater nutrients to roots. Gymnosperm forests tended to allocate more nutrients to leaves as compared with angiosperm forests, whereas the angiosperm forests distributed more nutrients in stems. The nutrient‐based Root:Shoot ratios (R:S), averaged 0.30 for R:SN, 0.36 for R:SP, 0.32 for R:SK, 0.27 for R:SCa, and 0.35 for R:SMg, respectively. The scaling exponents of the relationships describing root nutrients as a function of shoot nutrients were more than 1.0, suggesting that as nutrient allocated to shoot increases, nutrient allocated to roots increases faster than linearly with nutrient in shoot. Soil type significantly affected the total N, P, K, Ca, and Mg stored in living biomass of forests, and the Acrisols group displayed the lowest P, K, Ca, and Mg.