Durant Joël M, Ono Kotaro, Stenseth Nils Chr, Langangen Øystein
Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway.
Institute for Marine Research (IMR), Bergen, Norway.
Glob Chang Biol. 2020 Oct;26(10):5554-5563. doi: 10.1111/gcb.15264. Epub 2020 Aug 20.
Climate change has profound ecological effects, yet our understanding of how trophic interactions among species are affected by climate change is still patchy. The sympatric Atlantic haddock and cod are co-occurring across the North Atlantic. They compete for food at younger stages and thereafter the former is preyed by the latter. Climate change might affect the interaction and coexistence of these two species. Particularly, the increase in sea temperature (ST) has been shown to affect distribution, population growth and trophic interactions in marine systems. We used 33-year long time series of haddock and cod abundances estimates from two data sources (acoustic and trawl survey) to analyse the dynamic effect of climate on the coexistence of these two sympatric species in the Arcto-Boreal Barents Sea. Using a Bayesian state-space threshold model, we demonstrated that long-term climate variation, as expressed by changes of ST, affected species demography through different influences on density-independent processes. The interaction between cod and haddock has shifted in the last two decades due to an increase in ST, altering the equilibrium abundances and the dynamics of the system. During warm years (ST over ca. 4°C), the increase in the cod abundance negatively affected haddock abundance while it did not during cold years. This change in interactions therefore changed the equilibrium population size with a higher population size during warm years. Our analyses show that long-term climate change in the Arcto-Boreal system can generate differences in the equilibrium conditions of species assemblages.
气候变化具有深远的生态影响，然而我们对于物种间营养相互作用如何受到气候变化影响的理解仍不完整。同域分布的大西洋黑线鳕和鳕鱼在北大西洋共同出现。它们在幼鱼阶段争夺食物，之后黑线鳕成为鳕鱼的猎物。气候变化可能会影响这两个物种的相互作用和共存。特别是，海水温度（ST）的升高已被证明会影响海洋系统中的分布、种群增长和营养相互作用。我们使用了来自两个数据源（声学和拖网调查）的长达33年的黑线鳕和鳕鱼丰度估计时间序列，来分析气候对北极-北方巴伦支海这两个同域物种共存的动态影响。使用贝叶斯状态空间阈值模型，我们证明了以海水温度变化表示的长期气候变化，通过对密度独立过程的不同影响来影响物种动态。由于海水温度升高，鳕鱼和黑线鳕之间的相互作用在过去二十年中发生了变化，改变了系统的平衡丰度和动态。在温暖年份（海水温度超过约4°C），鳕鱼丰度的增加对黑线鳕丰度产生负面影响，而在寒冷年份则没有。因此，这种相互作用的变化改变了平衡种群规模，温暖年份的种群规模更大。我们的分析表明，北极-北方系统中的长期气候变化会导致物种组合平衡条件的差异。
