Department of Forest Resources Management, College of Forestry, Nanjing Forestry University, Nanjing 210037, Jiangsu, China; Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, Jiangsu, China.
Department of Forest Resources Management, College of Forestry, Nanjing Forestry University, Nanjing 210037, Jiangsu, China; Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, Jiangsu, China.
Sci Total Environ. 2021 Mar 20;761:143238. doi: 10.1016/j.scitotenv.2020.143238. Epub 2020 Oct 26.
The relationships between plant functional traits and aboveground biomass (AGB) stock have been explored across forest biomes. Yet, meta-analyses synthesizing our understanding regarding the influences of climate and soil on the functional traits - AGB relationships at a community-level in global forests are still unavailable. Here, we evaluated the latitudinal gradient in the functional traits -AGB relationships in forests, including functional trait diversity (FTD) - AGB (FTD-AGB), community-weighted mean (CWM) of conservative traits (CWMCT-AGB), CWM of acquisitive traits (CWMAT-AGB), and CWM of plant maximum height or diameter (FunDom-AGB), and then answer the question whether climate and soil conditions modulate the functional traits - AGB relationships in global forests. To do so, we selected those studies which reported the relationships of FTD and CWM with AGB stock (i.e. in Mg ha) rather with AGB productivity or growth (i.e. Mg ha yr) at a community-level (i.e. forest plot). By using piecewise structural equation meta-modeling, we found that: (1) functional traits - AGB relationships at a community-level were driven by mean annual temperature (MAT), aridity and soil fertility. (2) Higher MAT and low aridity promoted FTD-AGB relationships but the opposite trend was true for CWMCT-AGB, whereas higher MAT promoted CWMAT-AGB and FunDom-AGB at high aridity levels. (3) The FunDom-AGB relationship increased with increasing the number of forest plots but other relationships declined. (4) The negligible or negative FTD-AGB relationships but the positive AGB-FunDom relationships were conspicuous across global forests, indicating the mass ratio effect in terms of functional dominance. Our meta-analysis suggests that functional dominance and conservative species' strategy in relation to favorable abiotic conditions should be promoted to increase AGB stock under global environmental changes.
植物功能性状与地上生物量（AGB）之间的关系已在森林生物群落中得到广泛研究。然而，目前仍缺乏关于气候和土壤对全球森林群落水平功能性状-AGB 关系影响的综合分析。在这里，我们评估了森林中功能性状-AGB 关系的纬度梯度，包括功能性状多样性（FTD）-AGB（FTD-AGB）、保守性状的群落加权平均值（CWMCT-AGB）、获取性状的群落加权平均值（CWMAT-AGB）和植物最大高度或直径的群落加权平均值（FunDom-AGB），并回答了气候和土壤条件是否调节全球森林中功能性状-AGB 关系的问题。为此，我们选择了那些在群落水平（即森林样地）上报告 FTD 和 CWM 与 AGB 储量（即 Mg ha）而不是与 AGB 生产力或生长（即 Mg ha yr）关系的研究。通过使用分段结构方程元模型，我们发现：（1）群落水平的功能性状-AGB 关系受年平均温度（MAT）、干旱和土壤肥力的驱动。（2）较高的 MAT 和较低的干旱度促进了 FTD-AGB 关系，但对于 CWMCT-AGB 则相反，而在较高的干旱度水平下，较高的 MAT 促进了 CWMAT-AGB 和 FunDom-AGB。（3）FunDom-AGB 关系随着森林样地数量的增加而增加，但其他关系则减少。（4）在全球森林中，功能性状多样性-AGB 关系的不显著或负相关以及 AGB-FunDom 关系的正相关现象十分明显，这表明了功能优势方面的质量比效应。我们的元分析表明，在全球环境变化下，为了增加 AGB 储量，应促进与有利非生物条件有关的功能优势和保守物种策略。
