Damalas Dimitrios, Sgardeli Vasiliki, Vasilakopoulos Paraskevas, Tserpes Georgios, Maravelias Christos
Hellenic Centre for Marine Research Institute of Marine Biological Resources and Inland Waters Heraklion Greece.
Joint Research Centre European Commission Ispra Italy.
Ecol Evol. 2021 Nov 13;11(23):16951-16971. doi: 10.1002/ece3.8330. eCollection 2021 Dec.
Climate change (CC) can alter the configuration of marine ecosystems; however, ecosystem response and resilience to change are usually case-specific. The effect of CC on the demersal resources of the Aegean Sea (east Mediterranean Sea) was investigated during the past six decades applying a combination of multivariate analysis, non-additive modeling and the Integrated Resilience Assessment (IRA) framework. We focused on the study of: (i) the biological "system" complex, using proxies of biomass (landings per unit of capacity) for 12 demersal taxa, and (ii) the environmental "stressor" complex, described by 12 abiotic variables. Pronounced changes have occurred in both the environmental and biological system over the studied period. The majority of the environmental stressors exhibited strikingly increasing trends (temperature, salinity, primary production indices) with values started exceeding the global historical means during late 1980s-early 1990s. It is suggested that the biological system exhibited a discontinuous response to CC, with two apparently climate-induced regime shifts occurring in the past 25 years. There is evidence for two-fold bifurcations and four tipping points in the system, forming a folded stability landscape with three basins of attraction. The shape of the stability landscape for the Aegean Sea's biological system suggests that while the initial state (1966-1991) was rather resilient to CC, absorbing two environmental step-changes, this was not the case for the two subsequent ones (intermediate: 1992-2002; recent: 2003-2016). Given the current trajectory of environmental change, it is highly unlikely that the biological system will ever return to its pre-1990s state, as it is entering areas of unprecedented climatic conditions and there is some evidence that the system may be even shifting toward a new state. Our approach and findings may be relevant to other marine areas of the Mediterranean and beyond, undergoing climate-driven regime shifts, and can assist to their adaptive management.
气候变化（CC）会改变海洋生态系统的结构；然而，生态系统对变化的响应和恢复力通常因具体情况而异。在过去六十年中，通过多元分析、非加性建模和综合恢复力评估（IRA）框架相结合的方法，研究了气候变化对爱琴海（地中海东部）底栖资源的影响。我们重点研究了：（i）生物“系统”复合体，使用12种底栖生物类群的生物量指标（单位捕捞能力的渔获量），以及（ii）环境“压力源”复合体，由12个非生物变量描述。在研究期间，环境和生物系统都发生了显著变化。大多数环境压力源呈现出明显的上升趋势（温度、盐度、初级生产指数），其值在20世纪80年代末至90年代初开始超过全球历史均值。研究表明，生物系统对气候变化表现出不连续的响应，在过去25年中发生了两次明显由气候引起的状态转变。有证据表明该系统存在双重分岔和四个临界点，形成了一个具有三个吸引域的折叠稳定性景观。爱琴海生物系统稳定性景观的形状表明，虽然初始状态（1966 - 1991年）对气候变化具有较强的恢复力，能够吸收两次环境阶跃变化，但随后的两个阶段（中期：1992 - 2002年；近期：2003 - 2016年）并非如此。鉴于当前环境变化的轨迹，生物系统极不可能恢复到20世纪90年代以前的状态，因为它正进入前所未有的气候条件区域，并且有证据表明该系统甚至可能正在向一个新状态转变。我们的方法和研究结果可能与地中海及其他地区正在经历气候驱动状态转变的其他海洋区域相关，并有助于它们的适应性管理。
