Institute of Marine Science, University of Auckland, Auckland, 1010, New Zealand.
Sci Rep. 2017 Aug 31;7(1):10218. doi: 10.1038/s41598-017-11058-7.
In coastal ecosystems, climate change affects multiple environmental factors, yet most predictive models are based on simple cause-and-effect relationships. Multiple stressor scenarios are difficult to predict because they can create a ripple effect through networked ecosystem functions. Estuarine ecosystem function relies on an interconnected network of physical and biological processes. Estuarine habitats play critical roles in service provision and represent global hotspots for organic matter processing, nutrient cycling and primary production. Within these systems, we predicted functional changes in the impacts of land-based stressors, mediated by changing light climate and sediment permeability. Our in-situ field experiment manipulated sea level, nutrient supply, and mud content. We used these stressors to determine how interacting environmental stressors influence ecosystem function and compared results with data collected along elevation gradients to substitute space for time. We show non-linear, multi-stressor effects deconstruct networks governing ecosystem function. Sea level rise altered nutrient processing and impacted broader estuarine services ameliorating nutrient and sediment pollution. Our experiment demonstrates how the relationships between nutrient processing and biological/physical controls degrade with environmental stress. Our results emphasise the importance of moving beyond simple physically-forced relationships to assess consequences of climate change in the context of ecosystem interactions and multiple stressors.
在沿海生态系统中，气候变化会影响多种环境因素，但大多数预测模型都是基于简单的因果关系。由于多胁迫情景会通过网络生态系统功能产生连锁反应，因此很难预测。河口生态系统的功能依赖于物理和生物过程的相互关联的网络。河口生境在提供服务方面起着至关重要的作用，并且是全球有机质处理、养分循环和初级生产的热点地区。在这些系统中，我们预测了由光照变化和沉积物渗透性介导的陆源胁迫影响的功能变化。我们在现场进行了实验，操纵海平面、养分供应和淤泥含量。我们使用这些胁迫来确定相互作用的环境胁迫如何影响生态系统功能，并将结果与沿海拔梯度收集的数据进行比较，以时间代替空间。我们展示了非线性的多胁迫效应，这些效应解构了控制生态系统功能的网络。海平面上升改变了养分处理，并影响了更广泛的河口服务，从而减轻了养分和沉积物污染。我们的实验表明，养分处理与生物/物理控制之间的关系如何随着环境胁迫而恶化。我们的研究结果强调了超越简单的物理强制关系的重要性，以在生态系统相互作用和多种胁迫的背景下评估气候变化的后果。
