Leaf litter dominates particulate organic carbon inputs to forest streams. Using data‐informed simulations, we explored how litter type (slow‐ vs. fast‐decomposing species), pulsed autumn litter inputs, groundwater‐mediated temperature regimes, and climate warming affect litter breakdown in a 3rd‐order stream network. We found that the time‐dependent interactions of these variables govern network‐scale litter breakdown phenology, with greater thermal sensitivity of slow‐decomposing litter for both current and future scenarios. Groundwater thermal inputs modified litter breakdown phenology by reducing spring and summer and elevating winter litter breakdown fluxes. Under future warming scenarios, the source depth of contributing groundwater influenced summer detrital resources; shallow groundwater‐fed streams had reduced summer resources compared to deep groundwater‐fed streams. Our results demonstrate that predicting in‐stream carbon cycling requires explicit consideration of the phenology of resource inputs and the seasonal timing of environmental factors, notably stream thermal regimes.

中文翻译：

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源头河流网络中的叶凋落物分解物候学受地下水热状况和凋落物类型的调节


落叶物在森林溪流中的颗粒有机碳输入中占主导地位。通过基于数据的模拟，我们探索了凋落物类型（缓慢分解物种与快速分解物种）、脉冲式秋季凋落物输入、地下水介导的温度状况和气候变暖如何影响三阶河流网络中的凋落物分解。我们发现这些变量的时间依赖性相互作用控制着网络规模的垃圾分解物候学，对于当前和未来的情况，缓慢分解的垃圾具有更大的热敏感性。地下水热输入通过减少春季和夏季以及提高冬季凋落物分解通量来改变凋落物分解物候。未来变暖情景下，地下水来源深度影响夏季碎屑资源；与深层地下水供给的河流相比，浅层地下水供给的河流减少了夏季资源。我们的结果表明，预测河流内碳循环需要明确考虑资源输入的物候和环境因素的季节时间，特别是河流的热力状况。