Magnitude and direction of stream–forest community interactions change with timescale
Magnitude and direction of stream–forest community interactions change with timescale
复制标题
溪流与森林群落互动的幅度和方向随时间尺度的变化而变化
DOI：
10.1002/ecy.3064
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发表时间：
2020
期刊：
影响因子：
4.8
通讯作者：
Nakano, Shigeru
中科院分区：
文献类型：
--
作者：
Marcarelli, Amy M.;Baxter, Colden V.;Benjamin, Joseph R.;Miyake, Yo;Murakami, Masashi;Fausch, Kurt D.;Nakano, Shigeru
直接和间接的生物相互作用网络支撑着生态系统的复杂动力学和稳定性，然而，关于这些相互作用的方向(积极或消极)或大小，实验和理论研究往往得出相互矛盾的证据。我们重新审视了在落叶森林覆盖的霍罗奈溪收集的开创性数据集，并进行了生态系统层面的合成，以证明直接和间接相互作用的方向可以根据观测的时间尺度而改变。先前的实验研究表明，从邻近森林进入溪流的陆地猎物在夏季通过转移鱼类的消费对水生无脊椎动物产生了积极的间接影响。对食物网路径上的次生生产力和有机质流动的季节性和年度估计表明，这种陆生无脊椎动物猎物的季节性输入增加了某些鱼种的产量，将对水生无脊椎动物的间接影响从季节性时间尺度上的正值扭转为年度时间尺度上的负值。尽管陆生无脊椎动物猎物贡献了鱼类每年有机质通量的54%，主要是在夏季，但鱼类仍然消耗了水生无脊椎动物年生产量的98%，这导致了短期实验中没有揭示的自上而下的控制，并表明水生猎物可能是鱼类的有限资源。相互作用的方向或大小的变化可能是在复杂系统中产生非线性或稳定反馈的关键因素，这些动力学可以通过合并不同尺度上的实验和比较方法来揭示。
Networks of direct and indirect biotic interactions underpin the complex dynamics and stability of ecological systems, yet experimental and theoretical studies often yield conflicting evidence regarding the direction (positive or negative) or magnitude of these interactions. We revisited pioneering data sets collected at the deciduous forested Horonai Stream and conducted ecosystem‐level syntheses to demonstrate that the direction of direct and indirect interactions can change depending on the timescale of observation. Prior experimental studies showed that terrestrial prey that enter the stream from the adjacent forest caused positive indirect effects on aquatic invertebrates during summer by diverting fish consumption. Seasonal and annual estimates of secondary production and organic matter flows along food web pathways demonstrate that this seasonal input of terrestrial invertebrate prey increases production of certain fish species, reversing the indirect effect on aquatic invertebrates from positive at the seasonal timescale to negative at the annual timescale. Even though terrestrial invertebrate prey contributed 54% of the annual organic matter flux to fishes, primarily during summer, fish still consumed 98% of the aquatic invertebrate annual production, leading to top‐down control that is not revealed in short‐term experiments and demonstrating that aquatic prey may be a limiting resource for fishes. Changes in the direction or magnitude of interactions may be a key factor creating nonlinear or stabilizing feedbacks in complex systems, and these dynamics can be revealed by merging experimental and comparative approaches at different scales.