Data_Sheet_1_Cascading impacts of a climate-driven ecosystem transition intensifies population vulnerabilities and fishery collapse.zip

The recent large-scale intensification of marine heatwaves, and other climate-related stressors, has dramatically impacted biogenic habitats around the globe, including marine ecosystems such as coral reefs, seagrasses, and kelp forests. While the impacts to foundation species may be of particular concern, these ecological catastrophes underscore the need to examine how whole systems respond to a suite of stressors. The recent climate-driven collapse of the bull kelp forest and recreational red abalone fishery in northern California provides an example of unanticipated ripple and lagged effects in the system, intensifying vulnerabilities and accelerating population and fishery collapse. For this case study, we examined 15 years (2003–2018) of biological survey data on the bull kelp forest ecosystem—before, during, and after an extreme climate event. We document the interactions and complexity of impacts over time, as well as the resulting increased vulnerability of red abalone to additional anthropogenic, biological, and environmental stressors. We observed progressively stronger population-level responses of the red abalone to the marine heatwave and the regional loss of kelp, driving the movement of adults and juveniles in search of food. As food remained scarce, we documented the loss of productivity with diminished gonad and body condition, the absence of larval or newly-settled abalone, mass mortalities, and shoreward shifts in depth distributions. With 40% of the population dead or dying, juvenile and trophy-sized abalone abandoning cryptic habitats, the shift in the distribution to shallower depths increased the vulnerability of red abalone to the fishery. Other anthropogenic, biological, and climate-related stressors that disproportionately impact shallow habitats are now a growing concern for the survivors. For red abalone, previously unanticipated cascading risks include increased wave energy, warming air temperatures, freshwater flooding, landslides, as well as possible oil spills and harmful algal blooms. Climate-driven changes in vulnerability to fishing and environmental stressors present significant challenges for sustainable natural resource management in dynamic stressed systems, and underscore the need for continued system-focused monitoring. We present a conceptual framework supporting similar ecosystem investigations of recent and future climate impacts to inform adaptive ecosystem-based management strategies.

近年来，海洋热浪（marine heatwaves）及其他气候相关胁迫因子的大规模加剧，已对全球范围内的生物成因生境（biogenic habitats）造成了显著冲击，涵盖珊瑚礁、海草床、海带林等各类海洋生态系统。尽管建群种（foundation species）所受影响或最受关注，但此类生态灾难凸显了研究完整生态系统如何应对一系列胁迫因子的迫切需求。近期加利福尼亚北部的海带林（bull kelp forest）与休闲式红色鲍（red abalone）渔业因气候驱动发生崩溃，便是该系统中出现未预期级联效应与滞后效应的典型案例，进一步加剧了系统脆弱性，加速了种群与渔业的崩塌。在本案例研究中，我们分析了2003年至2018年间共15年的海带林生态系统生物调查数据，覆盖极端气候事件发生前、发生期间与发生后三个阶段。我们记录了随时间推移的影响交互关系与复杂性，以及红色鲍因此进一步面临的人为、生物与环境胁迫的加剧脆弱性。我们观察到红色鲍种群对海洋热浪与区域海带消失的响应逐渐增强，推动成体与幼体为觅食而发生移动。随着食物持续匮乏，我们记录到生产力下降、性腺与身体状况变差、未出现幼体或新附着的鲍、大规模死亡事件，以及种群深度分布向近岸浅水区转移的现象。在40%的种群死亡或濒死、幼体与超大型鲍个体放弃隐蔽生境的情况下，种群分布向浅水区的转移进一步增加了红色鲍面临渔业捕捞的脆弱性。如今，其他不成比例地影响浅水生境的人为、生物与气候相关胁迫因子，正对残存种群构成日益严峻的威胁。对于红色鲍而言，此前未被预见的级联风险包括海浪能量增强、气温升高、淡水洪水、山体滑坡，以及可能发生的石油泄漏与有害藻华（harmful algal blooms）。气候驱动的捕捞与环境胁迫脆弱性变化，给动态胁迫系统下的可持续自然资源管理带来了严峻挑战，同时凸显了持续开展系统导向型监测的必要性。我们提出了一套概念框架，可用于支撑针对近期及未来气候影响的同类生态系统研究，从而为基于生态系统的适应性管理策略提供决策参考。