Centre of Excellence PLECO (Plants and Ecosystems), Department of Biology, University of Antwerp, Wilrijk, Belgium.
Research Institute for Nature and Forest (INBO), Geraardsbergen, Belgium.
Glob Chang Biol. 2020 Feb;26(2):392-409. doi: 10.1111/gcb.14802. Epub 2019 Sep 19.
Nutrient availability influences virtually every aspect of an ecosystem, and is a critical modifier of ecosystem responses to global change. Although this crucial role of nutrient availability in regulating ecosystem structure and functioning has been widely acknowledged, nutrients are still often neglected in observational and experimental synthesis studies due to difficulties in comparing the nutrient status across sites. In the current study, we explain different nutrient-related concepts and discuss the potential of soil-, plant- and remote sensing-based metrics to compare the nutrient status across space. Based on our review and additional analyses on a dataset of European, managed temperate and boreal forests (ICP [International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests] Forests dataset), we conclude that the use of plant- and remote sensing-based metrics that rely on tissue stoichiometry is limited due to their strong dependence on species identity. The potential use of other plant-based metrics such as Ellenberg indicator values and plant-functional traits is also discussed. We conclude from our analyses and review that soil-based metrics have the highest potential for successful intersite comparison of the nutrient status. As an example, we used and adjusted a soil-based metric, previously developed for conifer forests across Sweden, against the same ICP Forests data. We suggest that this adjusted and further adaptable metric, which included the organic carbon concentration in the upper 20 cm of the soil (including the organic fermentation-humus [FH] layer), the C:N ratio and of the FH layer, can be used as a complementary tool along with other indicators of nutrient availability, to compare the background nutrient status across temperate and boreal forests dominated by spruce, pine or beech. Future collection and provision of harmonized soil data from observational and experimental sites is crucial for further testing and adjusting the metric.
养分供应几乎影响生态系统的各个方面，是生态系统对全球变化响应的关键调节因子。尽管养分供应在调节生态系统结构和功能方面的关键作用已得到广泛认可，但由于难以跨站点比较养分状况，养分在观测和实验综合研究中仍然经常被忽视。在当前的研究中，我们解释了不同的与养分相关的概念，并讨论了基于土壤、植物和遥感的指标来比较空间养分状况的潜力。基于我们对欧洲、管理温带和北方森林（国际合作计划评估和监测空气污染对森林影响数据集）的数据集的综述和额外分析，我们得出结论，基于组织化学计量学的植物和遥感指标的使用受到限制，因为它们强烈依赖于物种身份。还讨论了其他基于植物的指标（如 Ellenberg 指示值和植物功能性状）的潜在用途。我们从分析和综述中得出结论，基于土壤的指标最有可能成功地进行跨站点养分状况比较。作为一个例子，我们使用并调整了一个以前为瑞典各地的针叶林开发的基于土壤的指标，以适应相同的 ICP 森林数据。我们建议，该调整后的指标具有可进一步适应的特点，包括土壤上层 20cm 内的有机碳浓度（包括有机发酵腐殖质[FH]层）、FH 层的 C:N 比和。可以作为一种补充工具，与其他养分可用性指标一起，用于比较以云杉、松树或山毛榉为主的温带和北方森林的背景养分状况。未来从观测和实验站点收集和提供协调一致的土壤数据对于进一步测试和调整该指标至关重要。
