Tvärminne Zoological Station, University of Helsinki, J.A. Palméns väg 260, FI-10900 Hanko, Finland.
Department of Bioscience, Aarhus University, Frederiksborgvej 399, DK-4000, Roskilde, Denmark.
Ecology. 2013 Oct;94(10):2275-87. doi: 10.1890/12-1716.1.
Ecosystem functioning is threatened by an increasing number of anthropogenic stressors, creating a legacy of disturbance that undermines ecosystem resilience. However, few empirical studies have assessed to what extent an ecosystem can tolerate repeated disturbances and sustain its multiple functions. By inducing increasingly recurring hypoxic disturbances to a sedimentary ecosystem, we show that the majority of individual ecosystem functions experience gradual degradation patterns in response to repetitive pulse disturbances. The degradation in overall ecosystem functioning was, however, evident at an earlier stage than for single ecosystem functions and was induced after a short pulse of hypoxia (i.e., three days), which likely reduced ecosystem resistance to further hypoxic perturbations. The increasing number of repeated pulse disturbances gradually moved the system closer to a press response. In addition to the disturbance regime, the changes in benthic trait composition as well as habitat heterogeneity were important for explaining the variability in overall ecosystem functioning. Our results suggest that disturbance-induced responses across multiple ecosystem functions can serve as a warning signal for losses of the adaptive capacity of an ecosystem, and might at an early stage provide information to managers and policy makers when remediation efforts should be initiated.
生态系统功能受到越来越多人为压力的威胁,造成了干扰的遗留问题,破坏了生态系统的恢复力。然而,很少有实证研究评估一个生态系统可以在多大程度上耐受重复的干扰并维持其多种功能。通过对沉积生态系统进行越来越频繁的缺氧干扰,我们表明,大多数单个生态系统功能在对重复脉冲干扰的响应中逐渐出现退化模式。然而,整体生态系统功能的退化比单个生态系统功能更早出现,并且是在短暂的缺氧脉冲(即三天)之后发生的,这可能降低了生态系统对进一步缺氧扰动的抵抗力。随着重复脉冲干扰次数的增加,系统逐渐接近压力反应。除了干扰模式外,底栖特征组成的变化以及栖息地异质性对解释整体生态系统功能的变异性也很重要。我们的研究结果表明,多个生态系统功能的干扰诱导响应可以作为生态系统适应能力丧失的预警信号,并且在早期阶段可能为管理者和政策制定者提供有关何时应开始补救措施的信息。