Department of Biology, University of Pisa, CoNISMa, Via Derna 1, Pisa, Italy.
Glob Chang Biol. 2017 Aug;23(8):3259-3268. doi: 10.1111/gcb.13656. Epub 2017 Mar 6.
Understanding how historical processes modulate the response of ecosystems to perturbations is becoming increasingly important. In contrast to the growing interest in projecting biodiversity and ecosystem functioning under future climate scenarios, how legacy effects originating from historical conditions drive change in ecosystems remains largely unexplored. Using experiments in combination with stochastic antecedent modelling, we evaluated how extreme warming, sediment deposition and grazing events modulated the ecological memory of rocky intertidal epilithic microphytobenthos (EMPB). We found memory effects in the non-clustered scenario of disturbance (60 days apart), where EMPB biomass fluctuated in time, but not under clustered disturbances (15 days apart), where EMPB biomass was consistently low. A massive grazing event impacted on EMPB biomass in a second run of the experiment, also muting ecological memory. Our results provide empirical support to the theoretical expectation that stochastic fluctuations promote ecological memory, but also show that contingencies may lead to memory loss.
了解历史进程如何调节生态系统对干扰的响应正变得越来越重要。与越来越多的关注在预测生物多样性和生态系统功能在未来气候情景下相比，起源于历史条件的遗留效应如何驱动生态系统的变化在很大程度上仍未得到探索。本研究采用实验与随机前序模型相结合的方法，评估了极端升温、沉积物沉积和放牧事件如何调节岩石潮间带附生微藻（EMPB）的生态记忆。我们发现，在干扰的非聚类情景（间隔 60 天）中存在记忆效应，EMPB 生物量随时间波动，但在聚类干扰（间隔 15 天）下不存在，其中 EMPB 生物量持续较低。在实验的第二次运行中，一次大规模的放牧事件对 EMPB 生物量产生了影响，也使生态记忆消失。我们的研究结果为理论预期提供了经验支持，即随机波动促进了生态记忆，但也表明偶然事件可能导致记忆丧失。
