Zhou Xiongdong, Wang Congcong, Kattel Giri, Zhang Jiahao, Xu Mengzhen
Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.
State Key Laboratory of Hydroscience and Engineering, Department of Hydraulic Engineering, Tsinghua University, Beijing, 100084, China.
Environ Sci Ecotechnol. 2024 Aug 22;22:100478. doi: 10.1016/j.ese.2024.100478. eCollection 2024 Nov.
Urbanization is modifying aquatic ecosystems, with hydrodynamic and trophic variations altering biotic assemblages in rapidly expanding cities worldwide. Despite the fundamental bioenergetic role of food webs within these assemblages, their responding mechanism to the hydrodynamic and trophic variations remains largely unknown. Here we show that hydrodynamic and trophic loss, coupled with the weakening of cascade controls by key trophic guilds, leads to a significant decline in the structure, function and stability of macroinvertebrate food webs. Utilizing the allometric diet breadth model and biomass balance model, we established representative food webs for macroinvertebrate groups under varying hydrodynamic and trophic stresses. We found that such losses have reduced ∼75% trophic guild richness, ∼85% biomass flux, and ∼80% biomass storage. These reductions promote trophic guild specialization, further destabilizing food web, eroding interactive strength asymmetry, and diminishing the control of trophic guilds. Furthermore, macroinvertebrate food webs show divergent stability responses under similar stress levels, mainly driven by differences in the cascade controls exerted by key trophic guilds. Our results underscore the critical role of hydrodynamic and trophic variations in shaping urban aquatic ecosystems and highlight the significance of both external environmental revitalization and internal food web dynamics enhancement in restoring the ecological stability in urban settings.
城市化正在改变水生生态系统，水动力和营养变化正在改变全球快速扩张城市中的生物群落。尽管食物网在这些群落中具有基本的生物能量作用，但其对水动力和营养变化的响应机制仍 largely 未知。在这里，我们表明水动力和营养损失，加上关键营养类群的级联控制减弱，导致大型无脊椎动物食物网的结构、功能和稳定性显著下降。利用异速生长饮食广度模型和生物量平衡模型，我们建立了在不同水动力和营养压力下大型无脊椎动物群体的代表性食物网。我们发现，这些损失使营养类群丰富度降低了约 75%，生物量通量降低了约 85%，生物量存储降低了约 80%。这些减少促进了营养类群的专业化，进一步破坏了食物网的稳定性，削弱了相互作用强度的不对称性，并减少了营养类群的控制。此外，大型无脊椎动物食物网在相似的压力水平下表现出不同的稳定性响应，主要由关键营养类群施加的级联控制差异驱动。我们的结果强调了水动力和营养变化在塑造城市水生生态系统中的关键作用，并突出了外部环境振兴和内部食物网动态增强在恢复城市环境生态稳定性方面的重要性。
