Finstad Anders G, Nilsen Erlend B, Hendrichsen Ditte K, Schmidt Niels Martin
Centre for Biodiversity Dynamics, Department of Natural History, NTNU University Museum, Norwegian University of Science and Technology, Trondheim, Norway.
Norwegian Institute for Nature Research, Trondheim, Norway.
PLoS One. 2017 Apr 17;12(4):e0174904. doi: 10.1371/journal.pone.0174904. eCollection 2017.
Climatic factors influence the interactions among trophic levels in an ecosystem in multiple ways. However, whereas most studies focus on single factors in isolation, mainly due to interrelation and correlation among drivers complicating interpretation and analyses, there are still only few studies on how multiple ecosystems respond to climate related factors at the same time. Here, we use a hierarchical Bayesian model with a bioenergetic predator-prey framework to study how different climatic factors affect trophic interactions and production in small Arctic lakes. Natural variation in temperature and catchment land-cover was used as a natural experiment to exemplify how interactions between and production of primary producers (phytoplankton) and grazers (zooplankton) are driven by direct (temperature) and indirect (catchment vegetation) factors, as well as the presence or absence of apex predators (fish). The results show that increased vegetation cover increased phytoplankton growth rate by mediating lake nutrient concentration. At the same time, increased temperature also increased grazing rates by zooplankton. Presence of fish increased zooplankton mortality rates, thus reducing grazing. The Arctic is currently experiencing an increase in both temperature and shrub vegetation cover due to climate change, a trend, which is likely to continue. Our results point towards a possible future general weakening of zooplankton grazing on phytoplankton and greening of arctic lakes with increasing temperatures. At the same time, the impact of the presence of an apex predator indicate considerable local variation in the response. This makes direction and strength of global change impacts difficult to forecast.
气候因素以多种方式影响生态系统中营养级之间的相互作用。然而，尽管大多数研究孤立地关注单一因素，主要是因为驱动因素之间的相互关系和相关性使解释和分析变得复杂，但关于多个生态系统如何同时应对与气候相关因素的研究仍然很少。在这里，我们使用具有生物能量捕食者 - 猎物框架的分层贝叶斯模型来研究不同气候因素如何影响北极小湖泊中的营养相互作用和生产力。利用温度和集水区土地覆盖的自然变化作为自然实验，以例证初级生产者（浮游植物）和食草动物（浮游动物）之间的相互作用以及它们的生产力是如何由直接（温度）和间接（集水区植被）因素以及顶级捕食者（鱼类）的存在与否驱动的。结果表明，植被覆盖增加通过调节湖泊营养浓度提高了浮游植物的生长速率。同时，温度升高也提高了浮游动物的摄食率。鱼类的存在增加了浮游动物的死亡率，从而减少了摄食。由于气候变化，北极目前正经历温度和灌木植被覆盖的增加，这种趋势可能会持续。我们的结果表明，未来随着温度升高，浮游动物对浮游植物的摄食可能普遍减弱，北极湖泊可能会绿化。同时，顶级捕食者存在的影响表明各地的响应存在相当大的差异。这使得全球变化影响的方向和强度难以预测。
