Community structure and ecosystem function may be driven by the size or the energy within a given habitat, but these metrics (space and energy) are difficult to separate, especially in systems where the habitat itself is also food, such as detritus. Only a handful of studies have attempted to isolate potential mechanisms experimentally, which has left a notable knowledge gap in understanding the drivers of community structure and function. Here, we tested whether fine woody debris (FWD) affects leaf litter communities primarily as a source of space or energy. We used a crossed factor design to isolate the effects of FWD as space and energy, with four treatments: (1) no FWD, (2) only energy‐providing FWD (sawdust), (3) only space‐providing synthetic wood debris, and (4) a combination of both space and energy. We hypothesized that the highest levels of diversity, carnivore:detritivore ratio, and decomposition rate would occur on plots supplied with sawdust (representing energy), synthetic woody debris (representing space), or a combination of both, depending on the relative significance of FWD as a source of either energy or space. After 7 months, FWD as a source of energy but not space led to decreased decomposer abundance and richness. Conversely, increased proportion of carnivores and labile substrate decomposition was primarily driven by FWD as a source of space. However, the fastest decomposition of more recalcitrant substrates required both space and energy (additive), and the synergy of space and energy supported the greatest proportion of carnivores. These results suggest that the presence of FWD in forest ecosystems supports increased diversity and decomposition through a synergistic interaction of space and energy and the maintenance of deadwood like FWD in forest ecosystems can thus significantly contribute to forest ecosystem function.

中文翻译：

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公寓还是美食？细小木质碎片在驱动分解、食碎屑动物及其捕食者中的功能


群落结构和生态系统功能可能由给定栖息地内的大小或能量驱动，但这些指标（空间和能量）很难区分，尤其是在栖息地本身也是食物（如碎屑）的系统中。只有少数研究试图通过实验分离潜在的机制，这在理解群落结构和功能的驱动因素方面留下了明显的知识空白。在这里，我们测试了细木屑碎片 （FWD） 是否主要作为空间或能量来源影响落叶群落。我们使用交叉因子设计来分离 FWD 对空间和能量的影响，采用四种处理方式：（1） 无 FWD，（2） 仅提供能量的 FWD（锯末），（3） 仅提供空间的合成木材碎片，以及 （4） 空间和能量的组合。我们假设最高水平的多样性、食肉动物：食腐动物比率和分解速率将出现在由锯末（代表能源）、合成木质碎片（代表太空）或两者的组合提供的地块上，这取决于 FWD 作为能源或空间来源的相对重要性。7 个月后，FWD 作为能量来源而不是空间来源导致分解器丰度和丰富度降低。相反，食肉动物比例的增加和不稳定的底物分解主要是由 FWD 作为空间来源驱动的。然而，更顽固的基材的最快分解需要空间和能源（加法），而空间和能源的协同作用支持了最大比例的食肉动物。 这些结果表明，森林生态系统中 FWD 的存在通过空间和能源的协同相互作用支持增加多样性和分解，因此，在森林生态系统中维护像 FWD 这样的枯木可以显着促进森林生态系统的功能。