Centre d'Estudis Avançats de Blanes (CEAB-CSIC), Accés a la cala Sant Francesc 14, 17300, Blanes, Spain.
Centre d'Estudis Avançats de Blanes (CEAB-CSIC), Accés a la cala Sant Francesc 14, 17300, Blanes, Spain; Nature Conservation Foundation, Amritha 1311, 12th Cross, Vijayanagara 1st Stage, Mysore, 570017, India.
Mar Environ Res. 2021 Mar;165:105237. doi: 10.1016/j.marenvres.2020.105237. Epub 2020 Dec 15.
Apart from directly influencing individual life histories of species, climate change is altering key biotic interactions as well, causing community processes to unravel. With rising temperatures, disruptions to producer-consumer relationships can have major knock-on effects, particularly when the producer is a habitat-forming species. We studied how sea surface temperature (SST) modifies multiple pathways influencing the interaction between the foundational seagrass species, Posidonia oceanica, and its main consumer, the fish Sarpa salpa in the Mediterranean Sea. We used a combination of a field-based temperature gradient approaches and experimental manipulations to assess the effect of temperature on seagrass performance (growth) and fish early life history (larval development) as well as on the interaction itself (seagrass palatability and fish foraging activity). Within the range of temperatures assessed, S. salpa larvae grew slightly faster at warmer conditions but maintained their settlement size, resulting in a relatively small reduction in pelagic larval duration (PLD) and potentially reducing dispersion. Under warmer conditions (>24 °C), P. oceanica reduced its growth rate considerably and seemed to display fewer deterring mechanisms as indicated by a disproportionate consumption in choice experiments. However, our field-based observations along the temperature gradient showed no change in fish foraging time, or in other aspects of feeding behaviour. As oceans warm, our results indicate that, while S. salpa may show little change in early life history, its preference towards P. oceanica might increase, which, together with reduced seagrass growth, could considerably intensify the strength of herbivory. It is unclear if P. oceanica meadows can sustain such an intensification, but it will clearly add to the raft of pressures this threatened ecosystem already faces from global and local environmental change.
除了直接影响物种的个体生活史外，气候变化还在改变关键的生物相互作用，导致群落过程解体。随着温度的升高，生产者-消费者关系的中断可能会产生重大的连锁反应，尤其是当生产者是形成栖息地的物种时。我们研究了海水温度（SST）如何改变影响基础海草物种波西多尼亚海草（Posidonia oceanica）与其主要消费者地中海梭鱼（Sarpa salpa）之间相互作用的多个途径。我们使用了基于实地的温度梯度方法和实验操作的组合，来评估温度对海草性能（生长）和鱼类早期生活史（幼虫发育）以及对相互作用本身（海草适口性和鱼类觅食活动）的影响。在所评估的温度范围内，S. salpa 幼虫在温暖条件下生长略快，但保持其定居大小，从而导致浮游幼体持续时间（PLD）相对较小的减少，并且可能减少分散。在较温暖的条件下（>24°C），P. oceanica 的生长速度大幅下降，并且在选择实验中表现出较少的抑制机制，表明其吸引力下降。然而，我们在温度梯度上的实地观测并没有显示出鱼类觅食时间的变化，或者在其他方面的进食行为发生变化。随着海洋变暖，我们的研究结果表明，虽然 S. salpa 在早期生活史中可能变化不大，但它对 P. oceanica 的偏好可能会增加，这与海草生长减少一起，可能会大大加剧食草作用的强度。目前尚不清楚波西多尼亚海草草甸是否能够承受这种加剧的情况，但它显然会增加这个受到威胁的生态系统已经面临的来自全球和局部环境变化的一系列压力。
