Global engineering effects of soil invertebrates on ecosystem functions

We compiled a global dataset and synthesized published data from 1,047 studies (Fig. 1 and Fig. S1; see the dataset for details) of the engineering effects of termites, ants, and earthworms on 47 ecosystem properties (with the number of observations varying from 2 to 598). We extracted 14 properties for soil nutrients, 11 for soil physical and chemical properties, 8 for nutrient cycling, and 14 for the state (e.g. biomass and diversity) of associated biota including plants, microbes, and animals. Among these ecosystem properties, soil C, N, and P content, soil respiration, and plant biomass were more frequently investigated than the others, and thus stressed in this meta-analysis. We calculated the effect of soil engineering (i.e. biogenic structure vs. reference soil; or presence vs. absence of invertebrate engineers) on the ecosystem properties as the log response ratio (LnRR). The density (or weight) of biogenic structures ranged between 0.63~~1,500/ha (0.2~~151.3 ton/ha) for termite mounds, 0.3~~58,622/ha (0.2~~652 ton/ha) for ant hills, and 200~~935,000/ha (0.1~~192.2 ton/ha) for earthworm casts according to the studies included. To include data with incomplete statistics (i.e. averages without standard deviations or sample sizes), we modelled the log-response ratio of ecosystem properties with and without sampling variance as parameter weight simultaneously. To include data with incomplete statistics (i.e. averages without standard deviations), we modelled the log-response ratio of ecosystem properties with the sample size or sampling variance as parameter weight respectively. We therefore defined the “significant” effects only if they were significant (p < 0.05) in both models, or significant in one model and marginally significant (p < 0.1) in another model. Our synthesis addressed three major questions: (1) What are the similarities and differences among the three dominant invertebrate taxa in soil engineering effects on each ecosystem property? (2) Can resource availability (e.g. as represented by NPP and soil depth) or climate (e.g. MAT and water availability) explain the latitudinal patterns of soil engineering effects? (3) Does the impact of these taxa on soil nutrients and physical properties co-determine C dynamics, by increasing soil respiration and plant biomass, respectively?

We found that all three taxa increased soil macronutrients, soil respiration, microbial and plant biomass in bioturbated soil compared with surrounding soil. Temperature and aridity were the dominant drivers for termite and earthworm effects that exhibited linear latitudinal patterns, while net primary productivity (NPP) was responsible for the hump-shaped latitudinal patterns of ant effects. Notably, termite effects on plant growth and soil respiration increased with temperature, while termite and earthworm effects on plant growth and survival, respectively, strengthened with aridity. Besides, termites and ants boosted plant growth by resolving plant P and N limitation, respectively, in the tropics and temperate regions.

Description of the data and file structure
This study provided seven datasets for analyses and visualization. The first three datasets ("Data source compilation_taxa.xlsx") contain the original records and reference source of ecosystem properties in treatment and control soil for termites, ants and earthworms. The log-response ratio and sampling variance were calculated according to the formula in Lajeunesse 2011 (Ecology), while the replication weighting was calculated according to the formula in Adams et al. 1997 (Ecology). We also grouped similar ecosystem functions into another dataset ("Data source compilation_multifunctionality.xlsx") to test if the three taxa can simultaneously enhance multiple ecosystem functions. We further extracted environmental predictors (wetness, MAT, NPP, soil depth and the ratio of N limitation and P limitation index) based on the spatial coordinates of field studies, which could be found in the fourth dataset ("coordinates with predictors.csv"). Moreover, we summarized the pairwise observations of soil properties (nutrients, moisture content and clay content) and C dynamics (soil respiration and plant biomass) from the same study ("Pairwise correlation between soil engineering effects.xlsx"). Finally, we also provided the summary tables ("Tables.S1-S3.xlsx") for the overall soil engineering effects on individual function and on grouped functions to plot Figure 2, considering that it may take ~10 hr to generate summary tables. Please put all files (except the "Tables.S1-S3.xlsx") under the same working directory to reproduce the results and figures.

本研究构建了全球尺度数据集，整合了1047项已发表研究（图1、补充材料图S1；详见数据集文档）中关于白蚁、蚂蚁和蚯蚓的土壤生态系统工程效应的相关数据，共涵盖47项生态系统属性（观测样本量范围为2至598）。本研究提取了14项土壤养分相关属性、11项土壤理化属性、8项养分循环相关属性，以及14项包括植物、微生物与动物在内的关联生物群落状态（如生物量、多样性）相关属性。在上述生态系统属性中，土壤碳（C）、氮（N）、磷（P）含量、土壤呼吸速率与植物生物量的研究频次高于其他属性，因此为本元分析（meta-analysis）的重点关注对象。
本研究以对数响应比（log response ratio, LnRR）量化土壤工程效应（即生物成因结构与对照土壤的差异，或无脊椎动物工程生物（invertebrate engineers）存在与缺失的差异）对生态系统属性的影响。纳入本研究的观测数据显示，白蚁丘的生物成因结构密度（或生物量）范围为0.63~1500个/公顷（0.2~151.3吨/公顷），蚁丘为0.3~58622个/公顷（0.2~652吨/公顷），蚯蚓粪则为200~935000个/公顷（0.1~192.2吨/公顷）。
为纳入统计信息不全的数据（即仅提供均值但无标准差或样本量），本研究同时以包含与不包含抽样方差的对数响应比作为参数权重构建模型；为纳入仅提供均值但无标准差的数据，本研究分别以样本量或抽样方差作为参数权重构建对数响应比模型。因此，本研究仅将同时满足两种模型均显著（p<0.05），或一种模型显著且另一种模型边际显著（p<0.1）的效应定义为“显著效应”。
本整合分析聚焦三大核心科学问题：（1）三类优势无脊椎动物类群对各项生态系统属性的土壤工程效应存在哪些异同？（2）资源可获得性（如以净初级生产力（Net Primary Productivity, NPP）和土壤深度表征）或气候因子（如年平均气温（Mean Annual Temperature, MAT）和水分可获得性）能否解释土壤工程效应的纬度格局？（3）这三类类群对土壤养分与理化属性的影响，是否分别通过提升土壤呼吸速率与植物生物量，共同调控陆地碳动态？

研究结果显示，与周边对照土壤相比，三类无脊椎动物类群均能提升生物扰动土壤（bioturbated soil）中的大量元素养分含量、土壤呼吸速率、微生物生物量与植物生物量。白蚁和蚯蚓的土壤工程效应呈现线性纬度格局，其主导驱动因子为气温与干旱度；而蚂蚁的土壤工程效应呈驼峰状纬度格局，其主导驱动因子为净初级生产力（NPP）。值得注意的是，白蚁对植物生长与土壤呼吸的效应随气温升高而增强，而白蚁与蚯蚓分别对植物生长与存活的效应随干旱度升高而强化。此外，在热带与温带区域，白蚁与蚂蚁分别通过缓解植物磷限制与氮限制，促进植物生长。

数据与文件结构说明
本研究共提供7套数据集用于分析与可视化。前3套数据集（"Data source compilation_taxa.xlsx"）包含白蚁、蚂蚁与蚯蚓的处理组与对照组土壤生态系统属性的原始记录及参考文献来源。对数响应比与抽样方差的计算参照Lajeunesse于2011年发表于《Ecology》的公式，重复加权则参照Adams等人1997年发表于《Ecology》的公式。本研究还将相似的生态系统功能整合为第4套数据集（"Data source compilation_multifunctionality.xlsx"），用于检验三类类群是否可同时提升多项生态系统功能。基于野外研究的空间坐标，本研究提取了环境预测因子（湿度、年平均气温MAT、净初级生产力NPP、土壤深度以及氮限制与磷限制指数的比值），相关数据见第4套数据集（"coordinates with predictors.csv"）。此外，本研究从同一研究中汇总了土壤属性（养分、含水量与黏粒含量）与碳动态（土壤呼吸速率与植物生物量）的成对观测数据，对应文件为"Pairwise correlation between soil engineering effects.xlsx"。最后，考虑到生成汇总表需耗时约10小时，本研究还提供了用于绘制图2的总体土壤工程效应（针对单功能与分组功能）汇总表（"Tables.S1-S3.xlsx"）。请将除"Tables.S1-S3.xlsx"外的所有文件置于同一工作目录下，即可复现研究结果与图表。

搜集汇总

背景与挑战

背景概述

该数据集整合了全球范围内土壤无脊椎动物（白蚁、蚂蚁和蚯蚓）对47种生态系统属性的工程效应数据，重点关注土壤养分、呼吸及植物生物量等关键指标，并分析了气候和资源可用性对这些效应的影响。数据集包含多个文件，用于支持相关分析和可视化工作。