Data from: Tracking global change using lichen diversity: towards a global-scale ecological indicator

Lichens have been used to efficiently track major drivers of global change from the local to regional scale since the beginning of the industrial revolution (sulphur dioxide) to the present (nitrogen deposition and climate change). Currently, the challenge is to universalize monitoring methodologies to compare global change drivers’ simultaneous and independent effects on ecosystems and to assess the efficacy of mitigation measures.
Because two protocols are now used at a continental scale North America (US) and Europe (EU), it is timely to investigate the compatibility of the interpretation of their outcomes. For the first time, we present an analytical framework to compare the interpretation of data sets coming from these methods utilizing broadly accepted biodiversity metrics, featuring a paired data set from the US Pacific Northwest.
The methodologies yielded highly similar interpretation trends between response metrics: taxonomic diversity, functional diversity and community composition shifts in response to two major drivers of global change (nitrogen deposition and climate). A framework was designed to incorporate surrogates of species richness (the most commonly used empirical trend in taxonomic diversity), shifts in species composition (compositional turnover) and metrics of functional diversity (link between community shifts to effects and ecosystem structure and functioning). These metrics are essential to more thoroughly comprehend biodiversity response to global change. Its inclusion in this framework enables future cross-continental analysis of lichen biodiversity change from North America and Europe in response to global change. Future works should focus on developing independent metrics for response to global change drivers, namely climate and pollution, taking us one step closer to a lichen-based global ecological indicator.

地衣（Lichens）自工业革命伊始便被用于高效追踪从局地到区域尺度的全球变化主要驱动因子，其研究时段覆盖工业革命初期的二氧化硫（sulphur dioxide）污染，直至当下的氮沉降（nitrogen deposition）与气候变化（climate change）。当前面临的核心挑战在于统一监测方法体系，以对比全球变化驱动因子对生态系统的同步独立影响，并评估减缓措施的实施成效。
目前北美（US）与欧洲（EU）均已采用两套大陆尺度的监测规程，此时开展其结果解释兼容性的研究恰逢其时。本研究首次提出一套分析框架，借助广泛认可的生物多样性度量（biodiversity metrics），对比两套方法所得数据集的解释结果，该框架依托来自美国太平洋西北地区的配对数据集（paired data set）构建。
两套方法在响应指标层面展现出高度一致的解释趋势，这些响应指标包括针对全球变化两大驱动因子（氮沉降与气候变化）的分类多样性（taxonomic diversity）、功能多样性（functional diversity）与群落组成偏移（community composition shifts）。本框架纳入了物种丰富度替代指标（surrogates of species richness，即分类多样性中最常用的经验趋势）、物种组成偏移（即组成周转（compositional turnover））以及功能多样性度量（关联群落变化与生态系统结构及功能的纽带）。
上述指标对于全面理解生物多样性对全球变化的响应至关重要。将其纳入本框架后，未来可开展跨大陆尺度的分析，对比北美与欧洲地衣生物多样性在全球变化驱动下的变化情况。
后续研究应聚焦于开发针对全球变化驱动因子（即气候与污染）的独立响应指标，这将推动我们向构建基于地衣的全球生态指示体系迈出关键一步。