Data from: Evaluating the accuracy of biodiversity changes through geological times: from simulation to solution

Estimating biodiversity and its variations through geological time is a notoriously difficult task, due to several taphonomical and methodological reasons making the reconstructed signal potentially distinct from the unknown, original one. Through a simulation approach, we examine the effect of a major, while surprisingly still understudied source of potential disturbance: the effect of time discretization through biochronological construction, generating spurious coexistences of taxa within discrete time intervals, and thus potentially making continuous- and discrete-time biodiversity curves very different. Focusing on the taxonomic richness dimension of biodiversity, our approach relies on the random generation of continuous-time richness curves, then time-discretized to estimate the actual noise generated by this manipulation. A broad spectrum of dataset parameters are evaluated through sensitivity analysis, showing that the worsening effect of time discretization on the richness signal highly depends on such parameters, most particularly on average biozone duration and taxonomic longevity because of their direct relationship with the number of false coexistence generated by time discretization. With several worst-case but realistic parameter combinations, the original and time-discretized richness curves can ultimately show a very weak to null correlation, making these two time series independent. Based on these simulation results, we propose a simple algorithm allowing the back-transformation of a discrete-time taxonomic richness dataset as customarily constructed by palaeontologists into a continuous-time dataset. We show that the reconstructed richness curve obtained this way fits the original signal much more closely, even when the original dataset parameter combination is particularly hostile to an effective time-discretized reconstruction.

通过地质时间尺度估算生物多样性及其变化始终是一项公认的艰巨任务，诸多埋藏学 (taphonomy) 与方法学层面的因素会导致重建得到的生物多样性信号与未知的原始信号存在显著差异。本研究采用模拟方法，探究了一个影响重大却长期未被充分关注的潜在干扰源：生物年代学 (biochronology) 构建过程中的时间离散化 (time discretization) 效应——该效应会在离散时间区间内引发分类群 (taxa) 的虚假共存现象，进而可能使连续时间与离散时间的生物多样性曲线出现显著偏离。本研究聚焦生物多样性的分类丰富度维度，通过随机生成连续时间丰富度曲线，再对其进行时间离散化处理，以此量化该操作所产生的实际噪声。我们通过敏感性分析 (sensitivity analysis) 对广泛的数据集参数组合进行了评估，结果显示，时间离散化对丰富度信号的负面影响程度高度依赖于这些参数，其中尤以平均生物带时长与分类群存续期最为关键，这是因为二者与时间离散化所产生的虚假共存数量直接相关。在若干极端但符合实际的参数组合下，原始丰富度曲线与经时间离散化处理的丰富度曲线最终可能呈现极弱甚至无相关性，使得这两个时间序列相互独立。基于上述模拟结果，我们提出了一种简单算法，可将古生物学家 (palaeontologists) 常规构建的离散时间分类丰富度数据集反向转换 (back-transformation) 为连续时间数据集。研究表明，通过该方法得到的重建丰富度曲线能够更精准地拟合原始信号，即便原始数据集的参数组合对有效的离散时间重建极为不利。