Am Nat. 2021 Mar;197(3):281-295. doi: 10.1086/712813. Epub 2021 Jan 28.
AbstractPredicting 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, suggesting that both are needed for regime transitions. A cluster analysis of long-term data from Lake Baikal, Siberia, supports the model results, revealing a change from regularly occurring winter blooms of endemic diatoms to less frequent winter bloom years with decreasing ice cover. Together, the results show that even gradual environmental change, such as declining ice cover duration, may cause discontinuous or abrupt transitions between dynamic regimes in food webs.
摘要 由于生物因素和非生物因素之间的复杂相互作用，预测食物网对全球环境变化的反应是困难的。在季节性环境中对物种相互作用进行的机制模型可以帮助了解不同生态系统中全球变化的影响。季节性冰封的湖泊比许多其他生态系统升温更快，并且正在经历明显的食物网变化，因此尤其需要预测这些变化。我们使用具有一般性浮游动物食草动物和竞争的寒冷适应冬季和温暖适应夏季浮游植物的季节性驱动的食物网模型，表明随着冰层覆盖的减少，食物网会通过不同的动态状态，从年度周期转变为两年周期，冬季浮游植物的爆发减少，然后消失，最大生物量转移到夏季。有趣的是，当不包括捕食者-猎物相互作用时，冰层覆盖的减少并不会导致动态状态的转变，这表明两者都需要发生状态转变。对西伯利亚贝加尔湖长期数据的聚类分析支持了模型结果，表明与冬季藻类大量繁殖的规律年份相比，随着冰层覆盖的减少，冬季藻类大量繁殖的年份越来越少。总之，研究结果表明，即使是环境的逐渐变化，例如冰层覆盖持续时间的减少，也可能导致食物网中动态状态之间发生不连续或突然的转变。
