Lei Jiesi, Feng Jiajie, Ding Junjun, Yang Yunfeng
State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China.
School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China.
PNAS Nexus. 2025 Apr 5;4(4):pgaf114. doi: 10.1093/pnasnexus/pgaf114. eCollection 2025 Apr.
The question of how biodiversity influences ecosystem functioning and stability has been a central focus in ecological research. Yet, this question remains unresolved, primarily because of the widely divergent definitions of functioning, stability, and diversity. Consequently, forecasts of ecosystem services will remain speculative until we can establish more precise and comprehensive definitions for these concepts than previously. Here, we investigated how the maximum specific growth rate, productivity, mortality rate, and species interaction in microbial communities vary with a diversity gradient ranging from 1 to 16 species under control conditions, starvation, or saline stress. We found that diversity played a critical role in maintaining community growth and stability under control conditions, with higher diversity associated with increased maximum specific growth rate and decreased mortality rate. However, higher diversity was associated with an increased mortality rate under starvation, while diversity did not affect the mortality rate under saline stress. Diversity stabilized microbial productivity only under control conditions, defying the "diversity begets stability" hypothesis under stress. Beneficial interactions among species were prevalent in most samples, but species interaction increased mortality rates under starvation. Our findings suggest that while biodiversity is crucial for preserving ecosystem functioning and stability, the presence of multiple definitions and contextual dependence on environmental conditions argues against any general relationship between diversity and ecosystem functioning/stability. Furthermore, we provide new insights into the longstanding debate surrounding the "diversity begets stability" hypothesis and the "diversity destabilizes ecosystem" hypothesis in that diversity begets stability under control conditions but destabilizes ecosystems under severe stress.
生物多样性如何影响生态系统功能和稳定性的问题一直是生态学研究的核心焦点。然而，这个问题仍未得到解决，主要是因为功能、稳定性和多样性的定义差异很大。因此，在我们能够为这些概念建立比以前更精确和全面的定义之前，对生态系统服务的预测仍将是推测性的。在这里，我们研究了在对照条件、饥饿或盐胁迫下，微生物群落中的最大比生长速率、生产力、死亡率和物种相互作用如何随1至16个物种的多样性梯度而变化。我们发现，在对照条件下，多样性在维持群落生长和稳定性方面发挥了关键作用，更高的多样性与最大比生长速率的增加和死亡率的降低相关。然而，在饥饿条件下，更高的多样性与死亡率的增加相关，而在盐胁迫下，多样性对死亡率没有影响。多样性仅在对照条件下稳定微生物生产力，这与胁迫下的“多样性带来稳定性”假说相悖。物种间的有益相互作用在大多数样本中普遍存在，但在饥饿条件下，物种相互作用会增加死亡率。我们的研究结果表明，虽然生物多样性对于维持生态系统功能和稳定性至关重要，但多种定义的存在以及对环境条件的背景依赖性表明，多样性与生态系统功能/稳定性之间不存在任何普遍关系。此外，我们为围绕“多样性带来稳定性”假说和“多样性破坏生态系统”假说的长期争论提供了新的见解，即多样性在对照条件下带来稳定性，但在严重胁迫下会破坏生态系统。
