Climate change-driven regime shifts in a planktonic food web

Predicting how food webs will respond to global environmental change is difficult because of the complex interplay between the abiotic forcing and biotic interactions. Mechanistic models of species interactions in seasonal environments can help understand the effects of global change in different ecosystems. Seasonally ice-covered lakes are warming faster than many other ecosystems and undergoing pronounced food web changes, making the need to forecast those changes especially urgent. Using a seasonally forced food web model with a generalist zooplankton grazer and competing cold-adapted winter and warm-adapted summer phytoplankton, we show that with declining ice cover, the food web moves through different dynamic regimes, from annual to biennial cycles, with decreasing and then disappearing winter phytoplankton blooms and a shift of maximum biomass to summer season. Interestingly, when predator-prey interactions were not included, a declining ice cover did not cause regime shifts, sug...

预测食物网（food web）对全球环境变化的响应极具挑战，这是由于非生物胁迫（abiotic forcing）与生物相互作用（biotic interactions）之间存在复杂的交互效应。针对季节性环境中的物种种间相互作用构建的机理模型（mechanistic models），可助力解析全球变化对各类生态系统的影响。季节性冰封湖泊的升温速率远超多数其他生态系统，且正经历显著的食物网变化，因此对这类变化进行预测的需求尤为迫切。本研究采用包含广食性浮游动物植食者（zooplankton grazer），以及存在竞争关系的适冷冬季浮游植物（phytoplankton）与适温夏季浮游植物的季节性驱动食物网模型，结果表明：随着冰盖面积缩减，食物网会经历不同的动态模式转换——从年度周期循环转向双年度周期循环，伴随冬季浮游植物水华（phytoplankton blooms）逐渐消退直至消失，且生物量峰值向夏季时段转移。有趣的是，当未纳入捕食者-猎物相互作用（predator-prey interactions）时，冰盖缩减并不会引发状态转换（regime shifts），……