Laboratoire Microorganismes, Génome Et Environnement, CNRS, Université Clermont Auvergne, Clermont-Ferrand, France.
Departamento de Ecología, Instituto de Biologia, Universidade Federal Do Rio de Janeiro (UFRJ), Ilha Do Fundão, Rio de Janeiro, Brazil.
Sci Rep. 2022 May 19;12(1):8392. doi: 10.1038/s41598-022-12537-2.
The predicted increase in the intensity and frequency of drought events associated with global climate change will impose severe hydrological stress to freshwater ecosystems, potentially altering their structure and function. Unlike freshwater communities' direct response to drought, their post-drought recovery capacities remain understudied despite being an essential component driving ecosystem resilience. Here we used tank bromeliad as model ecosystem to emulate droughts of different duration and then assess the recovery capacities of ecosystem structure and function. We followed macroinvertebrate predator and prey biomass to characterize the recovery dynamics of trophic structure (i.e. predator-prey biomass ratio) during the post-drought rewetting phase. We showed that drought significantly affects the trophic structure of macroinvertebrates by reducing the predator-prey biomass ratio. The asynchronous recovery of predator and prey biomass appeared as a critical driver of the post-drought recovery trajectory of trophic structure. Litter decomposition rate, which is an essential ecosystem function, remained stable after drought events, indicating the presence of compensatory effects between detritivores biomass and detritivores feeding activity. We conclude that, in a context of global change, the asynchrony in post-drought recovery of different trophic levels may impact the overall drought resilience of small freshwater ecosystems in a more complex way than expected.
与全球气候变化相关的干旱事件强度和频率的预计增加,将给淡水生态系统带来严重的水文压力,可能改变它们的结构和功能。与淡水群落对干旱的直接响应不同,尽管它们是驱动生态系统恢复力的重要组成部分,但它们的干旱后恢复能力仍未得到充分研究。在这里,我们使用水箱凤梨科植物作为模型生态系统来模拟不同持续时间的干旱,然后评估生态系统结构和功能的恢复能力。我们跟踪大型无脊椎动物捕食者和猎物的生物量,以描述在干旱后重新湿润阶段,营养结构(即捕食者-猎物生物量比)的恢复动态。我们表明,干旱通过降低捕食者-猎物生物量比显著影响了大型无脊椎动物的营养结构。捕食者和猎物生物量的不同步恢复似乎是营养结构干旱后恢复轨迹的关键驱动因素。作为一个重要的生态系统功能,凋落物分解率在干旱事件后保持稳定,这表明在碎屑食者生物量和碎屑食者摄食活动之间存在补偿效应。我们的结论是,在全球变化的背景下,不同营养层次在干旱后的恢复不同步,可能会以比预期更复杂的方式影响小型淡水生态系统的整体干旱恢复能力。