Spalding Christopher, Hull Pincelli M
Department of Astronomy, Yale University, New Haven, CT 06511, USA.
Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA.
Proc Biol Sci. 2021 Apr 28;288(1949):20202332. doi: 10.1098/rspb.2020.2332.
To make sense of our present biodiversity crises, the modern rate of species extinctions is commonly compared to a benchmark, or 'background,' rate derived from the fossil record. These estimates are critical for bounding the scale of modern diversity loss, but are yet to fully account for the fundamental structure of extinction rates through time. Namely, a substantial fraction of extinctions within the fossil record occurs within relatively short-lived extinction pulses, and not during intervals characterized by background rates of extinction. Accordingly, it is more appropriate to compare the modern event to these pulses than to the long-term average rate. Unfortunately, neither the duration of extinction pulses in the geological record nor the ultimate magnitude of the extinction pulse today is resolved, making assessments of their relative sizes difficult. In addition, the common metric used to compare current and past extinction rates does not correct for large differences in observation duration. Here, we propose a new predictive metric that may be used to ascertain the ultimate extent of the ongoing extinction threat, building on the observation that extinction magnitude in the marine fossil record is correlated to the magnitude of sedimentary turnover. Thus, we propose that the ultimate number of species destined for extinction today can be predicted by way of a quantitative appraisal of humanity's modification of ecosystems as recorded in sediments-that is, by comparing our future rock record with that of the past. The ubiquity of habitat disruption worldwide suggests that a profound mass extinction debt exists today, but one that might yet be averted by preserving and restoring ecosystems and their geological traces.
为了理解我们当前的生物多样性危机，现代物种灭绝速率通常与从化石记录得出的基准或“背景”速率相比较。这些估计对于界定现代多样性丧失的规模至关重要，但尚未充分考虑灭绝速率随时间的基本结构。也就是说，化石记录中的很大一部分灭绝发生在相对短暂的灭绝脉冲期间，而不是在以背景灭绝速率为特征的时间段内。因此，将现代事件与这些脉冲进行比较比与长期平均速率进行比较更为合适。不幸的是，地质记录中灭绝脉冲的持续时间以及当今灭绝脉冲的最终规模都尚未确定，这使得评估它们的相对大小变得困难。此外，用于比较当前和过去灭绝速率的常用指标并未对观测持续时间的巨大差异进行校正。在此，我们提出一种新的预测指标，该指标可用于确定当前灭绝威胁的最终程度，其依据是海洋化石记录中的灭绝规模与沉积周转规模相关这一观察结果。因此，我们提出，通过对沉积物中记录的人类对生态系统的改变进行定量评估，即通过将我们未来的岩石记录与过去的记录进行比较，可以预测当今注定灭绝的物种的最终数量。全球范围内栖息地破坏的普遍性表明，如今存在着巨大的灭绝债务，但通过保护和恢复生态系统及其地质痕迹，这一债务仍有可能避免。
