School of Science, University of Waikato, Tauranga, New Zealand.
Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia.
Glob Chang Biol. 2019 Dec;25(12):4131-4146. doi: 10.1111/gcb.14819. Epub 2019 Oct 9.
Global climate change has profound implications on species distributions and ecosystem functioning. In the coastal zone, ecological responses may be driven by various biogeochemical and physical environmental factors. Synergistic interactions can occur when the combined effects of stressors exceed their individual effects. The Red Sea, characterized by strong gradients in temperature, salinity, and nutrients along the latitudinal axis provides a unique opportunity to study ecological responses over a range of these environmental variables. Using multiple linear regression models integrating in situ, satellite and oceanographic data, we investigated the response of coral reef taxa to local stressors and recent climate variability. Taxa and functional groups responded to a combination of climate (temperature, salinity, air-sea heat fluxes, irradiance, wind speed), fishing pressure and biogeochemical (chlorophyll a and nutrients - phosphate, nitrate, nitrite) factors. The regression model for each species showed interactive effects of climate, fishing pressure and nutrient variables. The nature of the effects (antagonistic or synergistic) was dependent on the species and stressor pair. Variables consistently associated with the highest number of synergistic interactions included heat flux terms, temperature, and wind speed followed by fishing pressure. Hard corals and coralline algae abundance were sensitive to changing environmental conditions where synergistic interactions decreased their percentage cover. These synergistic interactions suggest that the negative effects of fishing pressure and eutrophication may exacerbate the impact of climate change on corals. A high number of interactions were also recorded for algae, however for this group, synergistic interactions increased algal abundance. This study is unique in applying regression analysis to multiple environmental variables simultaneously to understand stressor interactions in the field. The observed responses have important implications for understanding climate change impacts on marine ecosystems and whether managing local stressors, such as nutrient enrichment and fishing activities, may help mitigate global drivers of change.
全球气候变化对物种分布和生态系统功能有着深远的影响。在沿海地区，生态响应可能受到各种生物地球化学和物理环境因素的驱动。当压力源的综合效应超过其个体效应时，就会发生协同作用。红海的特点是沿着纬度轴存在强烈的温度、盐度和营养物质梯度，为研究这些环境变量范围内的生态响应提供了独特的机会。本研究使用整合了原位、卫星和海洋学数据的多元线性回归模型，调查了珊瑚礁分类群对局部压力源和最近气候变化的响应。分类群和功能组对气候（温度、盐度、海气热通量、辐照度、风速）、捕捞压力和生物地球化学（叶绿素 a 和营养物质 - 磷酸盐、硝酸盐、亚硝酸盐）因素的组合做出了响应。每个物种的回归模型都显示了气候、捕捞压力和营养变量之间的相互作用效应。效应的性质（拮抗或协同）取决于物种和压力源对。与最高数量的协同相互作用一致的变量包括热通量项、温度和风速，其次是捕捞压力。硬珊瑚和珊瑚藻丰度对环境条件的变化很敏感，协同相互作用降低了它们的覆盖率。这些协同相互作用表明，捕捞压力和富营养化的负面影响可能会加剧气候变化对珊瑚的影响。藻类也记录了大量的相互作用，但对于这一组，协同相互作用增加了藻类的丰度。本研究的独特之处在于同时应用回归分析来研究多个环境变量，以了解现场的压力源相互作用。所观察到的响应对理解气候变化对海洋生态系统的影响以及管理局部压力源（如营养盐富化和捕捞活动）是否有助于减轻全球变化驱动因素具有重要意义。
