Centre for Biological Diversity, School of Biology, University of St Andrews, St Andrews, UK.
Scottish Oceans Institute, School of Biology, University of St Andrews, St Andrews, UK.
Ecol Lett. 2023 Jul;26(7):1071-1083. doi: 10.1111/ele.14214. Epub 2023 May 14.
The composition of ecological assemblages has changed rapidly over the past century. Compositional reorganization rates are high relative to rates of alpha diversity change, creating an urgent need to understand how this compositional reorganization is progressing. We developed a quantitative framework for comparing temporal trajectories of compositional reorganization and applied it to two long-term bird and marine fish datasets. We then evaluated how the number and magnitude of short-term changes relate to overall rates of change. We found varied trajectories of turnover across birds and fish, with linear directional change predominating in birds and non-directional change more common in fish. The number of changes away from the baseline was a more consistent correlate of the overall rate of change than the magnitude of such changes, but large unreversed changes were found in both fish and birds, as were time series with accelerating compositional change. Compositional reorganization is progressing through a complex mix of temporal trajectories, including both threshold-like behaviour and the accumulation of repeated, linear change.
在过去的一个世纪里，生态组合的构成迅速发生了变化。相对于α多样性变化的速度，组成性重组的速度很高，这就迫切需要了解这种组成性重组是如何进行的。我们开发了一种定量框架来比较组成性重组的时间轨迹，并将其应用于两个长期的鸟类和海洋鱼类数据集。然后，我们评估了短期变化的数量和幅度与整体变化率的关系。我们发现鸟类和鱼类的周转率存在不同的轨迹，鸟类以线性定向变化为主，鱼类以非定向变化为主。偏离基线的变化数量比这些变化的幅度更能一致地反映整体变化率，但无论是在鱼类还是鸟类中，都发现了较大的不可逆转的变化，以及具有加速组成变化的时间序列。组成性重组正在通过一系列复杂的时间轨迹进行，包括类似阈值的行为和重复的线性变化的积累。
