Heat waves and their significance for a temperate benthic community: A near-natural experimental approach
Heat waves and their significance for a temperate benthic community: A near-natural experimental approach
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DOI：
10.1111/gcb.14282
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发表时间：
2018-09-01
影响因子：
11.6
通讯作者：
Wahl, Martin
中科院分区：
文献类型：
--
作者：
Pansch, Christian;Scotti, Marco;Wahl, Martin
气候变化不仅会改变环境手段，还会增加极端事件的强度，给生态系统带来额外的压力。虽然关于热浪生态后果的实地观察不断涌现，但实验证据很少，而且缺乏社区层面的证据。这项研究使用一种新颖的近自然的室外中生态系统方法，测试了海洋夏季热浪是否对温带沿海群落的大型动物产生不利影响，以及连续的热浪是否会引起对热应力敏感性的增加或减少。通过对实验地点 15 年温度记录的统计分析，应用、定义和表征了三种处理方式：(1) 无热浪；(2) 六月和七月两次热浪，随后在八月出现夏季热浪；(3) 仅夏季热浪。总体而言，50% 的物种在丰度和/或生物量方面表现出积极、消极或积极/消极反应。我们强调了单个物种对随后的三场热浪或一场夏季热浪的四种可能的反应方式：（1）缺乏反应（耐受性，50％的物种），（2）随后的三场热浪（双壳类双壳类动物）的负面累积影响，（3）由于适应和/或物候变化（螺类多毛类）而通过持续的热浪进行缓冲，以及（4）后续热浪的累积积极影响（片脚类）。物种层面对单次或连续热浪的不同反应导致了群落层面的变化。单次热浪和三次热浪之间的社区水平差异比有热浪和无热浪的地区之间的差异更为明显。单次热浪减少了碎屑，而在三重热浪情况下悬浮喂食不太常见。如今，严重的极端事件已经发生，并且在气候变化的情况下将会更加频繁地发生，从而对沿海海洋系统造成有害影响。
Climate change will not only shift environmental means but will also increase the intensity of extreme events, exerting additional stress on ecosystems. While field observations on the ecological consequences of heat waves are emerging, experimental evidence is rare, and lacking at the community level. Using a novel near-natural outdoor mesocosms approach, this study tested whether marine summer heat waves have detrimental consequences for macrofauna of a temperate coastal community, and whether sequential heat waves provoke an increase or decrease of sensitivity to thermal stress. Three treatments were applied, defined and characterized through a statistical analysis of 15 years of temperature records from the experimental site: (1) no heat wave, (2) two heat waves in June and July followed by a summer heat wave in August and (3) the summer heat wave only. Overall, 50% of the species showed positive, negative or positive/negative responses in either abundance and/or biomass. We highlight four possible ways in which single species responded to either three subsequent heat waves or one summer heat wave: (1) absence of a response (tolerance, 50% of species), (2) negative accumulative effects by three subsequent heat waves (tellinid bivalve), (3) buffering by proceeding heat waves due to acclimation and/or shifts in phenology (spionid polychaete) and (4) an accumulative positive effect by subsequent heat waves (amphipod). The differential responses to single or sequential heat waves at the species level entailed shifts at the community level. Community-level differences between single and triple heat waves were more pronounced than those between regimes with vs. without heat waves. Detritivory was reduced by the single heat wave while suspension feeding was less common in the triple heat wave regime. Critical extreme events occur already today and will occur more frequently in a changing climate, thus, leading to detrimental impacts on coastal marine systems.